From db7d21ca01c67889c304647cd32c03d0b312ed94 Mon Sep 17 00:00:00 2001 From: V3n3RiX Date: Sun, 7 Jul 2019 11:55:16 +0100 Subject: sys-kernel/linux-{image,sources}-redcore : fix UKSM build --- .../files/5.1-0001-uksm-apply-52d1e606ee733.patch | 75 + ...01-uksm-initial-submission-linux-hardened.patch | 6922 ++++++++++++++++++++ .../files/5.1-uksm-linux-hardened.patch | 6901 ------------------- .../linux-image-redcore-5.1.15.ebuild | 3 +- .../files/5.1-0001-uksm-apply-52d1e606ee733.patch | 75 + ...01-uksm-initial-submission-linux-hardened.patch | 6922 ++++++++++++++++++++ .../files/5.1-uksm-linux-hardened.patch | 6901 ------------------- .../linux-sources-redcore-5.1.15.ebuild | 3 +- 8 files changed, 13998 insertions(+), 13804 deletions(-) create mode 100644 sys-kernel/linux-image-redcore/files/5.1-0001-uksm-apply-52d1e606ee733.patch create mode 100644 sys-kernel/linux-image-redcore/files/5.1-0001-uksm-initial-submission-linux-hardened.patch delete mode 100644 sys-kernel/linux-image-redcore/files/5.1-uksm-linux-hardened.patch create mode 100644 sys-kernel/linux-sources-redcore/files/5.1-0001-uksm-apply-52d1e606ee733.patch create mode 100644 sys-kernel/linux-sources-redcore/files/5.1-0001-uksm-initial-submission-linux-hardened.patch delete mode 100644 sys-kernel/linux-sources-redcore/files/5.1-uksm-linux-hardened.patch diff --git a/sys-kernel/linux-image-redcore/files/5.1-0001-uksm-apply-52d1e606ee733.patch b/sys-kernel/linux-image-redcore/files/5.1-0001-uksm-apply-52d1e606ee733.patch new file mode 100644 index 00000000..dbc5357c --- /dev/null +++ b/sys-kernel/linux-image-redcore/files/5.1-0001-uksm-apply-52d1e606ee733.patch @@ -0,0 +1,75 @@ +From ea0c9d768bade0bc87046841a3e667f477d90668 Mon Sep 17 00:00:00 2001 +From: Oleksandr Natalenko +Date: Mon, 6 May 2019 22:02:49 +0200 +Subject: [PATCH] uksm-5.1: apply 52d1e606ee733 + +Signed-off-by: Oleksandr Natalenko +--- + mm/uksm.c | 36 +++++++++++++++++++++++++++++++----- + 1 file changed, 31 insertions(+), 5 deletions(-) + +diff --git a/mm/uksm.c b/mm/uksm.c +index 174e1921eade..2531599038b8 100644 +--- a/mm/uksm.c ++++ b/mm/uksm.c +@@ -875,8 +875,8 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node, + * to keep the page_count protocol described with page_cache_get_speculative. + * + * Note: it is possible that get_uksm_page() will return NULL one moment, +- * then page the next, if the page is in between page_freeze_refs() and +- * page_unfreeze_refs(): this shouldn't be a problem anywhere, the page ++ * then page the next, if the page is in between page_ref_freeze() and ++ * page_ref_unfreeze(): this shouldn't be a problem anywhere, the page + * is on its way to being freed; but it is an anomaly to bear in mind. + * + * @unlink_rb: if the removal of this node will firstly unlink from +@@ -914,10 +914,11 @@ static struct page *get_uksm_page(struct stable_node *stable_node, + * We cannot do anything with the page while its refcount is 0. + * Usually 0 means free, or tail of a higher-order page: in which + * case this node is no longer referenced, and should be freed; +- * however, it might mean that the page is under page_freeze_refs(). ++ * however, it might mean that the page is under page_ref_freeze(). + * The __remove_mapping() case is easy, again the node is now stale; +- * but if page is swapcache in migrate_page_move_mapping(), it might +- * still be our page, in which case it's essential to keep the node. ++ * the same is in reuse_ksm_page() case; but if page is swapcache ++ * in migrate_page_move_mapping(), it might still be our page, ++ * in which case it's essential to keep the node. + */ + while (!get_page_unless_zero(page)) { + /* +@@ -4749,6 +4750,31 @@ void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) + goto again; + } + ++bool reuse_ksm_page(struct page *page, ++ struct vm_area_struct *vma, ++ unsigned long address) ++{ ++#ifdef CONFIG_DEBUG_VM ++ if (WARN_ON(is_zero_pfn(page_to_pfn(page))) || ++ WARN_ON(!page_mapped(page)) || ++ WARN_ON(!PageLocked(page))) { ++ dump_page(page, "reuse_ksm_page"); ++ return false; ++ } ++#endif ++ ++ if (PageSwapCache(page) || !page_stable_node(page)) ++ return false; ++ /* Prohibit parallel get_ksm_page() */ ++ if (!page_ref_freeze(page, 1)) ++ return false; ++ ++ page_move_anon_rmap(page, vma); ++ page->index = linear_page_index(vma, address); ++ page_ref_unfreeze(page, 1); ++ ++ return true; ++} + #ifdef CONFIG_MIGRATION + /* Common ksm interface but may be specific to uksm */ + void ksm_migrate_page(struct page *newpage, struct page *oldpage) +-- +2.21.0.777.g83232e3864 + diff --git a/sys-kernel/linux-image-redcore/files/5.1-0001-uksm-initial-submission-linux-hardened.patch b/sys-kernel/linux-image-redcore/files/5.1-0001-uksm-initial-submission-linux-hardened.patch new file mode 100644 index 00000000..d2f3a41f --- /dev/null +++ b/sys-kernel/linux-image-redcore/files/5.1-0001-uksm-initial-submission-linux-hardened.patch @@ -0,0 +1,6922 @@ +diff -Nur a/Documentation/vm/uksm.txt b/Documentation/vm/uksm.txt +--- a/Documentation/vm/uksm.txt 1970-01-01 01:00:00.000000000 +0100 ++++ b/Documentation/vm/uksm.txt 2019-07-07 11:43:00.138836975 +0100 +@@ -0,0 +1,61 @@ ++The Ultra Kernel Samepage Merging feature ++---------------------------------------------- ++/* ++ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia ++ * ++ * This is an improvement upon KSM. Some basic data structures and routines ++ * are borrowed from ksm.c . ++ * ++ * Its new features: ++ * 1. Full system scan: ++ * It automatically scans all user processes' anonymous VMAs. Kernel-user ++ * interaction to submit a memory area to KSM is no longer needed. ++ * ++ * 2. Rich area detection: ++ * It automatically detects rich areas containing abundant duplicated ++ * pages based. Rich areas are given a full scan speed. Poor areas are ++ * sampled at a reasonable speed with very low CPU consumption. ++ * ++ * 3. Ultra Per-page scan speed improvement: ++ * A new hash algorithm is proposed. As a result, on a machine with ++ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it ++ * can scan memory areas that does not contain duplicated pages at speed of ++ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of ++ * 477MB/sec ~ 923MB/sec. ++ * ++ * 4. Thrashing area avoidance: ++ * Thrashing area(an VMA that has frequent Ksm page break-out) can be ++ * filtered out. My benchmark shows it's more efficient than KSM's per-page ++ * hash value based volatile page detection. ++ * ++ * ++ * 5. Misc changes upon KSM: ++ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page ++ * comparison. It's much faster than default C version on x86. ++ * * rmap_item now has an struct *page member to loosely cache a ++ * address-->page mapping, which reduces too much time-costly ++ * follow_page(). ++ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. ++ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ ++ * ksm is needed for this case. ++ * ++ * 6. Full Zero Page consideration(contributed by Figo Zhang) ++ * Now uksmd consider full zero pages as special pages and merge them to an ++ * special unswappable uksm zero page. ++ */ ++ ++ChangeLog: ++ ++2012-05-05 The creation of this Doc ++2012-05-08 UKSM 0.1.1.1 libc crash bug fix, api clean up, doc clean up. ++2012-05-28 UKSM 0.1.1.2 bug fix release ++2012-06-26 UKSM 0.1.2-beta1 first beta release for 0.1.2 ++2012-07-2 UKSM 0.1.2-beta2 ++2012-07-10 UKSM 0.1.2-beta3 ++2012-07-26 UKSM 0.1.2 Fine grained speed control, more scan optimization. ++2012-10-13 UKSM 0.1.2.1 Bug fixes. ++2012-12-31 UKSM 0.1.2.2 Minor bug fixes. ++2014-07-02 UKSM 0.1.2.3 Fix a " __this_cpu_read() in preemptible bug". ++2015-04-22 UKSM 0.1.2.4 Fix a race condition that can sometimes trigger anonying warnings. ++2016-09-10 UKSM 0.1.2.5 Fix a bug in dedup ratio calculation. ++2017-02-26 UKSM 0.1.2.6 Fix a bug in hugetlbpage handling and a race bug with page migration. +diff -Nur a/fs/exec.c b/fs/exec.c +--- a/fs/exec.c 2019-07-07 11:39:06.860827790 +0100 ++++ b/fs/exec.c 2019-07-07 11:44:01.830966115 +0100 +@@ -63,6 +63,8 @@ + #include + #include + #include ++#include ++#include + + #include + #include +@@ -1385,6 +1387,7 @@ + /* An exec changes our domain. We are no longer part of the thread + group */ + current->self_exec_id++; ++ + flush_signal_handlers(current, 0); + } + EXPORT_SYMBOL(setup_new_exec); +diff -Nur a/fs/proc/meminfo.c b/fs/proc/meminfo.c +--- a/fs/proc/meminfo.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/fs/proc/meminfo.c 2019-07-07 11:43:00.138836975 +0100 +@@ -106,6 +106,10 @@ + global_zone_page_state(NR_KERNEL_STACK_KB)); + show_val_kb(m, "PageTables: ", + global_zone_page_state(NR_PAGETABLE)); ++#ifdef CONFIG_UKSM ++ show_val_kb(m, "KsmZeroPages: ", ++ global_zone_page_state(NR_UKSM_ZERO_PAGES)); ++#endif + #ifdef CONFIG_QUICKLIST + show_val_kb(m, "Quicklists: ", quicklist_total_size()); + #endif +diff -Nur a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h +--- a/include/asm-generic/pgtable.h 2019-06-25 04:34:56.000000000 +0100 ++++ b/include/asm-generic/pgtable.h 2019-07-07 11:43:00.138836975 +0100 +@@ -855,12 +855,25 @@ + extern void untrack_pfn_moved(struct vm_area_struct *vma); + #endif + ++#ifdef CONFIG_UKSM ++static inline int is_uksm_zero_pfn(unsigned long pfn) ++{ ++ extern unsigned long uksm_zero_pfn; ++ return pfn == uksm_zero_pfn; ++} ++#else ++static inline int is_uksm_zero_pfn(unsigned long pfn) ++{ ++ return 0; ++} ++#endif ++ + #ifdef __HAVE_COLOR_ZERO_PAGE + static inline int is_zero_pfn(unsigned long pfn) + { + extern unsigned long zero_pfn; + unsigned long offset_from_zero_pfn = pfn - zero_pfn; +- return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT); ++ return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT) || is_uksm_zero_pfn(pfn); + } + + #define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) +@@ -869,7 +882,7 @@ + static inline int is_zero_pfn(unsigned long pfn) + { + extern unsigned long zero_pfn; +- return pfn == zero_pfn; ++ return (pfn == zero_pfn) || (is_uksm_zero_pfn(pfn)); + } + + static inline unsigned long my_zero_pfn(unsigned long addr) +diff -Nur a/include/linux/ksm.h b/include/linux/ksm.h +--- a/include/linux/ksm.h 2019-06-25 04:34:56.000000000 +0100 ++++ b/include/linux/ksm.h 2019-07-07 11:43:00.138836975 +0100 +@@ -21,20 +21,16 @@ + #ifdef CONFIG_KSM + int ksm_madvise(struct vm_area_struct *vma, unsigned long start, + unsigned long end, int advice, unsigned long *vm_flags); +-int __ksm_enter(struct mm_struct *mm); +-void __ksm_exit(struct mm_struct *mm); + +-static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) ++static inline struct stable_node *page_stable_node(struct page *page) + { +- if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) +- return __ksm_enter(mm); +- return 0; ++ return PageKsm(page) ? page_rmapping(page) : NULL; + } + +-static inline void ksm_exit(struct mm_struct *mm) ++static inline void set_page_stable_node(struct page *page, ++ struct stable_node *stable_node) + { +- if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) +- __ksm_exit(mm); ++ page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); + } + + /* +@@ -56,6 +52,33 @@ + bool reuse_ksm_page(struct page *page, + struct vm_area_struct *vma, unsigned long address); + ++#ifdef CONFIG_KSM_LEGACY ++int __ksm_enter(struct mm_struct *mm); ++void __ksm_exit(struct mm_struct *mm); ++static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) ++{ ++ if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) ++ return __ksm_enter(mm); ++ return 0; ++} ++ ++static inline void ksm_exit(struct mm_struct *mm) ++{ ++ if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) ++ __ksm_exit(mm); ++} ++ ++#elif defined(CONFIG_UKSM) ++static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) ++{ ++ return 0; ++} ++ ++static inline void ksm_exit(struct mm_struct *mm) ++{ ++} ++#endif /* !CONFIG_UKSM */ ++ + #else /* !CONFIG_KSM */ + + static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) +@@ -96,4 +119,6 @@ + #endif /* CONFIG_MMU */ + #endif /* !CONFIG_KSM */ + ++#include ++ + #endif /* __LINUX_KSM_H */ +diff -Nur a/include/linux/mm_types.h b/include/linux/mm_types.h +--- a/include/linux/mm_types.h 2019-06-25 04:34:56.000000000 +0100 ++++ b/include/linux/mm_types.h 2019-07-07 11:43:00.138836975 +0100 +@@ -334,6 +334,9 @@ + struct mempolicy *vm_policy; /* NUMA policy for the VMA */ + #endif + struct vm_userfaultfd_ctx vm_userfaultfd_ctx; ++#ifdef CONFIG_UKSM ++ struct vma_slot *uksm_vma_slot; ++#endif + } __randomize_layout; + + struct core_thread { +diff -Nur a/include/linux/mmzone.h b/include/linux/mmzone.h +--- a/include/linux/mmzone.h 2019-06-25 04:34:56.000000000 +0100 ++++ b/include/linux/mmzone.h 2019-07-07 11:43:00.138836975 +0100 +@@ -148,6 +148,9 @@ + NR_ZSPAGES, /* allocated in zsmalloc */ + #endif + NR_FREE_CMA_PAGES, ++#ifdef CONFIG_UKSM ++ NR_UKSM_ZERO_PAGES, ++#endif + NR_VM_ZONE_STAT_ITEMS }; + + enum node_stat_item { +diff -Nur a/include/linux/sradix-tree.h b/include/linux/sradix-tree.h +--- a/include/linux/sradix-tree.h 1970-01-01 01:00:00.000000000 +0100 ++++ b/include/linux/sradix-tree.h 2019-07-07 11:43:00.148837320 +0100 +@@ -0,0 +1,77 @@ ++#ifndef _LINUX_SRADIX_TREE_H ++#define _LINUX_SRADIX_TREE_H ++ ++ ++#define INIT_SRADIX_TREE(root, mask) \ ++do { \ ++ (root)->height = 0; \ ++ (root)->gfp_mask = (mask); \ ++ (root)->rnode = NULL; \ ++} while (0) ++ ++#define ULONG_BITS (sizeof(unsigned long) * 8) ++#define SRADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) ++//#define SRADIX_TREE_MAP_SHIFT 6 ++//#define SRADIX_TREE_MAP_SIZE (1UL << SRADIX_TREE_MAP_SHIFT) ++//#define SRADIX_TREE_MAP_MASK (SRADIX_TREE_MAP_SIZE-1) ++ ++struct sradix_tree_node { ++ unsigned int height; /* Height from the bottom */ ++ unsigned int count; ++ unsigned int fulls; /* Number of full sublevel trees */ ++ struct sradix_tree_node *parent; ++ void *stores[0]; ++}; ++ ++/* A simple radix tree implementation */ ++struct sradix_tree_root { ++ unsigned int height; ++ struct sradix_tree_node *rnode; ++ ++ /* Where found to have available empty stores in its sublevels */ ++ struct sradix_tree_node *enter_node; ++ unsigned int shift; ++ unsigned int stores_size; ++ unsigned int mask; ++ unsigned long min; /* The first hole index */ ++ unsigned long num; ++ //unsigned long *height_to_maxindex; ++ ++ /* How the node is allocated and freed. */ ++ struct sradix_tree_node *(*alloc)(void); ++ void (*free)(struct sradix_tree_node *node); ++ ++ /* When a new node is added and removed */ ++ void (*extend)(struct sradix_tree_node *parent, struct sradix_tree_node *child); ++ void (*assign)(struct sradix_tree_node *node, unsigned int index, void *item); ++ void (*rm)(struct sradix_tree_node *node, unsigned int offset); ++}; ++ ++struct sradix_tree_path { ++ struct sradix_tree_node *node; ++ int offset; ++}; ++ ++static inline ++void init_sradix_tree_root(struct sradix_tree_root *root, unsigned long shift) ++{ ++ root->height = 0; ++ root->rnode = NULL; ++ root->shift = shift; ++ root->stores_size = 1UL << shift; ++ root->mask = root->stores_size - 1; ++} ++ ++ ++extern void *sradix_tree_next(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index, ++ int (*iter)(void *, unsigned long)); ++ ++extern int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num); ++ ++extern void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index); ++ ++extern void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index); ++ ++#endif /* _LINUX_SRADIX_TREE_H */ +diff -Nur a/include/linux/uksm.h b/include/linux/uksm.h +--- a/include/linux/uksm.h 1970-01-01 01:00:00.000000000 +0100 ++++ b/include/linux/uksm.h 2019-07-07 11:43:00.148837320 +0100 +@@ -0,0 +1,149 @@ ++#ifndef __LINUX_UKSM_H ++#define __LINUX_UKSM_H ++/* ++ * Memory merging support. ++ * ++ * This code enables dynamic sharing of identical pages found in different ++ * memory areas, even if they are not shared by fork(). ++ */ ++ ++/* if !CONFIG_UKSM this file should not be compiled at all. */ ++#ifdef CONFIG_UKSM ++ ++#include ++#include ++#include ++#include ++#include ++ ++extern unsigned long zero_pfn __read_mostly; ++extern unsigned long uksm_zero_pfn __read_mostly; ++extern struct page *empty_uksm_zero_page; ++ ++/* must be done before linked to mm */ ++extern void uksm_vma_add_new(struct vm_area_struct *vma); ++extern void uksm_remove_vma(struct vm_area_struct *vma); ++ ++#define UKSM_SLOT_NEED_SORT (1 << 0) ++#define UKSM_SLOT_NEED_RERAND (1 << 1) ++#define UKSM_SLOT_SCANNED (1 << 2) /* It's scanned in this round */ ++#define UKSM_SLOT_FUL_SCANNED (1 << 3) ++#define UKSM_SLOT_IN_UKSM (1 << 4) ++ ++struct vma_slot { ++ struct sradix_tree_node *snode; ++ unsigned long sindex; ++ ++ struct list_head slot_list; ++ unsigned long fully_scanned_round; ++ unsigned long dedup_num; ++ unsigned long pages_scanned; ++ unsigned long this_sampled; ++ unsigned long last_scanned; ++ unsigned long pages_to_scan; ++ struct scan_rung *rung; ++ struct page **rmap_list_pool; ++ unsigned int *pool_counts; ++ unsigned long pool_size; ++ struct vm_area_struct *vma; ++ struct mm_struct *mm; ++ unsigned long ctime_j; ++ unsigned long pages; ++ unsigned long flags; ++ unsigned long pages_cowed; /* pages cowed this round */ ++ unsigned long pages_merged; /* pages merged this round */ ++ unsigned long pages_bemerged; ++ ++ /* when it has page merged in this eval round */ ++ struct list_head dedup_list; ++}; ++ ++static inline void uksm_unmap_zero_page(pte_t pte) ++{ ++ if (pte_pfn(pte) == uksm_zero_pfn) ++ __dec_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); ++} ++ ++static inline void uksm_map_zero_page(pte_t pte) ++{ ++ if (pte_pfn(pte) == uksm_zero_pfn) ++ __inc_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); ++} ++ ++static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) ++{ ++ if (vma->uksm_vma_slot && PageKsm(page)) ++ vma->uksm_vma_slot->pages_cowed++; ++} ++ ++static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) ++{ ++ if (vma->uksm_vma_slot && pte_pfn(pte) == uksm_zero_pfn) ++ vma->uksm_vma_slot->pages_cowed++; ++} ++ ++static inline int uksm_flags_can_scan(unsigned long vm_flags) ++{ ++#ifdef VM_SAO ++ if (vm_flags & VM_SAO) ++ return 0; ++#endif ++ ++ return !(vm_flags & (VM_PFNMAP | VM_IO | VM_DONTEXPAND | ++ VM_HUGETLB | VM_MIXEDMAP | VM_SHARED ++ | VM_MAYSHARE | VM_GROWSUP | VM_GROWSDOWN)); ++} ++ ++static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) ++{ ++ if (uksm_flags_can_scan(*vm_flags_p)) ++ *vm_flags_p |= VM_MERGEABLE; ++} ++ ++/* ++ * Just a wrapper for BUG_ON for where ksm_zeropage must not be. TODO: it will ++ * be removed when uksm zero page patch is stable enough. ++ */ ++static inline void uksm_bugon_zeropage(pte_t pte) ++{ ++ BUG_ON(pte_pfn(pte) == uksm_zero_pfn); ++} ++#else ++static inline void uksm_vma_add_new(struct vm_area_struct *vma) ++{ ++} ++ ++static inline void uksm_remove_vma(struct vm_area_struct *vma) ++{ ++} ++ ++static inline void uksm_unmap_zero_page(pte_t pte) ++{ ++} ++ ++static inline void uksm_map_zero_page(pte_t pte) ++{ ++} ++ ++static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) ++{ ++} ++ ++static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) ++{ ++} ++ ++static inline int uksm_flags_can_scan(unsigned long vm_flags) ++{ ++ return 0; ++} ++ ++static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) ++{ ++} ++ ++static inline void uksm_bugon_zeropage(pte_t pte) ++{ ++} ++#endif /* !CONFIG_UKSM */ ++#endif /* __LINUX_UKSM_H */ +diff -Nur a/kernel/fork.c b/kernel/fork.c +--- a/kernel/fork.c 2019-07-07 11:39:06.870828132 +0100 ++++ b/kernel/fork.c 2019-07-07 11:43:00.148837320 +0100 +@@ -584,7 +584,7 @@ + __vma_link_rb(mm, tmp, rb_link, rb_parent); + rb_link = &tmp->vm_rb.rb_right; + rb_parent = &tmp->vm_rb; +- ++ uksm_vma_add_new(tmp); + mm->map_count++; + if (!(tmp->vm_flags & VM_WIPEONFORK)) + retval = copy_page_range(mm, oldmm, mpnt); +diff -Nur a/lib/Makefile b/lib/Makefile +--- a/lib/Makefile 2019-06-25 04:34:56.000000000 +0100 ++++ b/lib/Makefile 2019-07-07 11:43:00.148837320 +0100 +@@ -29,7 +29,7 @@ + endif + + lib-y := ctype.o string.o vsprintf.o cmdline.o \ +- rbtree.o radix-tree.o timerqueue.o xarray.o \ ++ rbtree.o radix-tree.o sradix-tree.o timerqueue.o xarray.o \ + idr.o int_sqrt.o extable.o \ + sha1.o chacha.o irq_regs.o argv_split.o \ + flex_proportions.o ratelimit.o show_mem.o \ +diff -Nur a/lib/sradix-tree.c b/lib/sradix-tree.c +--- a/lib/sradix-tree.c 1970-01-01 01:00:00.000000000 +0100 ++++ b/lib/sradix-tree.c 2019-07-07 11:43:00.148837320 +0100 +@@ -0,0 +1,476 @@ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++ ++static inline int sradix_node_full(struct sradix_tree_root *root, struct sradix_tree_node *node) ++{ ++ return node->fulls == root->stores_size || ++ (node->height == 1 && node->count == root->stores_size); ++} ++ ++/* ++ * Extend a sradix tree so it can store key @index. ++ */ ++static int sradix_tree_extend(struct sradix_tree_root *root, unsigned long index) ++{ ++ struct sradix_tree_node *node; ++ unsigned int height; ++ ++ if (unlikely(root->rnode == NULL)) { ++ if (!(node = root->alloc())) ++ return -ENOMEM; ++ ++ node->height = 1; ++ root->rnode = node; ++ root->height = 1; ++ } ++ ++ /* Figure out what the height should be. */ ++ height = root->height; ++ index >>= root->shift * height; ++ ++ while (index) { ++ index >>= root->shift; ++ height++; ++ } ++ ++ while (height > root->height) { ++ unsigned int newheight; ++ ++ if (!(node = root->alloc())) ++ return -ENOMEM; ++ ++ /* Increase the height. */ ++ node->stores[0] = root->rnode; ++ root->rnode->parent = node; ++ if (root->extend) ++ root->extend(node, root->rnode); ++ ++ newheight = root->height + 1; ++ node->height = newheight; ++ node->count = 1; ++ if (sradix_node_full(root, root->rnode)) ++ node->fulls = 1; ++ ++ root->rnode = node; ++ root->height = newheight; ++ } ++ ++ return 0; ++} ++ ++/* ++ * Search the next item from the current node, that is not NULL ++ * and can satify root->iter(). ++ */ ++void *sradix_tree_next(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index, ++ int (*iter)(void *item, unsigned long height)) ++{ ++ unsigned long offset; ++ void *item; ++ ++ if (unlikely(node == NULL)) { ++ node = root->rnode; ++ for (offset = 0; offset < root->stores_size; offset++) { ++ item = node->stores[offset]; ++ if (item && (!iter || iter(item, node->height))) ++ break; ++ } ++ ++ if (unlikely(offset >= root->stores_size)) ++ return NULL; ++ ++ if (node->height == 1) ++ return item; ++ else ++ goto go_down; ++ } ++ ++ while (node) { ++ offset = (index & root->mask) + 1; ++ for (; offset < root->stores_size; offset++) { ++ item = node->stores[offset]; ++ if (item && (!iter || iter(item, node->height))) ++ break; ++ } ++ ++ if (offset < root->stores_size) ++ break; ++ ++ node = node->parent; ++ index >>= root->shift; ++ } ++ ++ if (!node) ++ return NULL; ++ ++ while (node->height > 1) { ++go_down: ++ node = item; ++ for (offset = 0; offset < root->stores_size; offset++) { ++ item = node->stores[offset]; ++ if (item && (!iter || iter(item, node->height))) ++ break; ++ } ++ ++ if (unlikely(offset >= root->stores_size)) ++ return NULL; ++ } ++ ++ BUG_ON(offset > root->stores_size); ++ ++ return item; ++} ++ ++/* ++ * Blindly insert the item to the tree. Typically, we reuse the ++ * first empty store item. ++ */ ++int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num) ++{ ++ unsigned long index; ++ unsigned int height; ++ struct sradix_tree_node *node, *tmp = NULL; ++ int offset, offset_saved; ++ void **store = NULL; ++ int error, i, j, shift; ++ ++go_on: ++ index = root->min; ++ ++ if (root->enter_node && !sradix_node_full(root, root->enter_node)) { ++ node = root->enter_node; ++ BUG_ON((index >> (root->shift * root->height))); ++ } else { ++ node = root->rnode; ++ if (node == NULL || (index >> (root->shift * root->height)) ++ || sradix_node_full(root, node)) { ++ error = sradix_tree_extend(root, index); ++ if (error) ++ return error; ++ ++ node = root->rnode; ++ } ++ } ++ ++ ++ height = node->height; ++ shift = (height - 1) * root->shift; ++ offset = (index >> shift) & root->mask; ++ while (shift > 0) { ++ offset_saved = offset; ++ for (; offset < root->stores_size; offset++) { ++ store = &node->stores[offset]; ++ tmp = *store; ++ ++ if (!tmp || !sradix_node_full(root, tmp)) ++ break; ++ } ++ BUG_ON(offset >= root->stores_size); ++ ++ if (offset != offset_saved) { ++ index += (offset - offset_saved) << shift; ++ index &= ~((1UL << shift) - 1); ++ } ++ ++ if (!tmp) { ++ if (!(tmp = root->alloc())) ++ return -ENOMEM; ++ ++ tmp->height = shift / root->shift; ++ *store = tmp; ++ tmp->parent = node; ++ node->count++; ++// if (root->extend) ++// root->extend(node, tmp); ++ } ++ ++ node = tmp; ++ shift -= root->shift; ++ offset = (index >> shift) & root->mask; ++ } ++ ++ BUG_ON(node->height != 1); ++ ++ ++ store = &node->stores[offset]; ++ for (i = 0, j = 0; ++ j < root->stores_size - node->count && ++ i < root->stores_size - offset && j < num; i++) { ++ if (!store[i]) { ++ store[i] = item[j]; ++ if (root->assign) ++ root->assign(node, index + i, item[j]); ++ j++; ++ } ++ } ++ ++ node->count += j; ++ root->num += j; ++ num -= j; ++ ++ while (sradix_node_full(root, node)) { ++ node = node->parent; ++ if (!node) ++ break; ++ ++ node->fulls++; ++ } ++ ++ if (unlikely(!node)) { ++ /* All nodes are full */ ++ root->min = 1 << (root->height * root->shift); ++ root->enter_node = NULL; ++ } else { ++ root->min = index + i - 1; ++ root->min |= (1UL << (node->height - 1)) - 1; ++ root->min++; ++ root->enter_node = node; ++ } ++ ++ if (num) { ++ item += j; ++ goto go_on; ++ } ++ ++ return 0; ++} ++ ++ ++/** ++ * sradix_tree_shrink - shrink height of a sradix tree to minimal ++ * @root sradix tree root ++ * ++ */ ++static inline void sradix_tree_shrink(struct sradix_tree_root *root) ++{ ++ /* try to shrink tree height */ ++ while (root->height > 1) { ++ struct sradix_tree_node *to_free = root->rnode; ++ ++ /* ++ * The candidate node has more than one child, or its child ++ * is not at the leftmost store, we cannot shrink. ++ */ ++ if (to_free->count != 1 || !to_free->stores[0]) ++ break; ++ ++ root->rnode = to_free->stores[0]; ++ root->rnode->parent = NULL; ++ root->height--; ++ if (unlikely(root->enter_node == to_free)) ++ root->enter_node = NULL; ++ root->free(to_free); ++ } ++} ++ ++/* ++ * Del the item on the known leaf node and index ++ */ ++void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index) ++{ ++ unsigned int offset; ++ struct sradix_tree_node *start, *end; ++ ++ BUG_ON(node->height != 1); ++ ++ start = node; ++ while (node && !(--node->count)) ++ node = node->parent; ++ ++ end = node; ++ if (!node) { ++ root->rnode = NULL; ++ root->height = 0; ++ root->min = 0; ++ root->num = 0; ++ root->enter_node = NULL; ++ } else { ++ offset = (index >> (root->shift * (node->height - 1))) & root->mask; ++ if (root->rm) ++ root->rm(node, offset); ++ node->stores[offset] = NULL; ++ root->num--; ++ if (root->min > index) { ++ root->min = index; ++ root->enter_node = node; ++ } ++ } ++ ++ if (start != end) { ++ do { ++ node = start; ++ start = start->parent; ++ if (unlikely(root->enter_node == node)) ++ root->enter_node = end; ++ root->free(node); ++ } while (start != end); ++ ++ /* ++ * Note that shrink may free "end", so enter_node still need to ++ * be checked inside. ++ */ ++ sradix_tree_shrink(root); ++ } else if (node->count == root->stores_size - 1) { ++ /* It WAS a full leaf node. Update the ancestors */ ++ node = node->parent; ++ while (node) { ++ node->fulls--; ++ if (node->fulls != root->stores_size - 1) ++ break; ++ ++ node = node->parent; ++ } ++ } ++} ++ ++void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index) ++{ ++ unsigned int height, offset; ++ struct sradix_tree_node *node; ++ int shift; ++ ++ node = root->rnode; ++ if (node == NULL || (index >> (root->shift * root->height))) ++ return NULL; ++ ++ height = root->height; ++ shift = (height - 1) * root->shift; ++ ++ do { ++ offset = (index >> shift) & root->mask; ++ node = node->stores[offset]; ++ if (!node) ++ return NULL; ++ ++ shift -= root->shift; ++ } while (shift >= 0); ++ ++ return node; ++} ++ ++/* ++ * Return the item if it exists, otherwise create it in place ++ * and return the created item. ++ */ ++void *sradix_tree_lookup_create(struct sradix_tree_root *root, ++ unsigned long index, void *(*item_alloc)(void)) ++{ ++ unsigned int height, offset; ++ struct sradix_tree_node *node, *tmp; ++ void *item; ++ int shift, error; ++ ++ if (root->rnode == NULL || (index >> (root->shift * root->height))) { ++ if (item_alloc) { ++ error = sradix_tree_extend(root, index); ++ if (error) ++ return NULL; ++ } else { ++ return NULL; ++ } ++ } ++ ++ node = root->rnode; ++ height = root->height; ++ shift = (height - 1) * root->shift; ++ ++ do { ++ offset = (index >> shift) & root->mask; ++ if (!node->stores[offset]) { ++ if (!(tmp = root->alloc())) ++ return NULL; ++ ++ tmp->height = shift / root->shift; ++ node->stores[offset] = tmp; ++ tmp->parent = node; ++ node->count++; ++ node = tmp; ++ } else { ++ node = node->stores[offset]; ++ } ++ ++ shift -= root->shift; ++ } while (shift > 0); ++ ++ BUG_ON(node->height != 1); ++ offset = index & root->mask; ++ if (node->stores[offset]) { ++ return node->stores[offset]; ++ } else if (item_alloc) { ++ if (!(item = item_alloc())) ++ return NULL; ++ ++ node->stores[offset] = item; ++ ++ /* ++ * NOTE: we do NOT call root->assign here, since this item is ++ * newly created by us having no meaning. Caller can call this ++ * if it's necessary to do so. ++ */ ++ ++ node->count++; ++ root->num++; ++ ++ while (sradix_node_full(root, node)) { ++ node = node->parent; ++ if (!node) ++ break; ++ ++ node->fulls++; ++ } ++ ++ if (unlikely(!node)) { ++ /* All nodes are full */ ++ root->min = 1 << (root->height * root->shift); ++ } else { ++ if (root->min == index) { ++ root->min |= (1UL << (node->height - 1)) - 1; ++ root->min++; ++ root->enter_node = node; ++ } ++ } ++ ++ return item; ++ } else { ++ return NULL; ++ } ++ ++} ++ ++int sradix_tree_delete(struct sradix_tree_root *root, unsigned long index) ++{ ++ unsigned int height, offset; ++ struct sradix_tree_node *node; ++ int shift; ++ ++ node = root->rnode; ++ if (node == NULL || (index >> (root->shift * root->height))) ++ return -ENOENT; ++ ++ height = root->height; ++ shift = (height - 1) * root->shift; ++ ++ do { ++ offset = (index >> shift) & root->mask; ++ node = node->stores[offset]; ++ if (!node) ++ return -ENOENT; ++ ++ shift -= root->shift; ++ } while (shift > 0); ++ ++ offset = index & root->mask; ++ if (!node->stores[offset]) ++ return -ENOENT; ++ ++ sradix_tree_delete_from_leaf(root, node, index); ++ ++ return 0; ++} +diff -Nur a/mm/Kconfig b/mm/Kconfig +--- a/mm/Kconfig 2019-07-07 11:39:06.880828472 +0100 ++++ b/mm/Kconfig 2019-07-07 11:43:00.148837320 +0100 +@@ -302,6 +302,32 @@ + See Documentation/vm/ksm.rst for more information: KSM is inactive + until a program has madvised that an area is MADV_MERGEABLE, and + root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set). ++choice ++ prompt "Choose UKSM/KSM strategy" ++ default UKSM ++ depends on KSM ++ help ++ This option allows to select a UKSM/KSM stragety. ++ ++config UKSM ++ bool "Ultra-KSM for page merging" ++ depends on KSM ++ help ++ UKSM is inspired by the Linux kernel project \u2014 KSM(Kernel Same ++ page Merging), but with a fundamentally rewritten core algorithm. With ++ an advanced algorithm, UKSM now can transparently scans all anonymously ++ mapped user space applications with an significantly improved scan speed ++ and CPU efficiency. Since KVM is friendly to KSM, KVM can also benefit from ++ UKSM. Now UKSM has its first stable release and first real world enterprise user. ++ For more information, please goto its project page. ++ (www.kerneldedup.org) ++ ++config KSM_LEGACY ++ bool "Legacy KSM implementation" ++ depends on KSM ++ help ++ The legacy KSM implementation from Red Hat. ++endchoice + + config DEFAULT_MMAP_MIN_ADDR + int "Low address space to protect from user allocation" +diff -Nur a/mm/ksm.c b/mm/ksm.c +--- a/mm/ksm.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/ksm.c 2019-07-07 11:43:00.148837320 +0100 +@@ -858,17 +858,6 @@ + return err; + } + +-static inline struct stable_node *page_stable_node(struct page *page) +-{ +- return PageKsm(page) ? page_rmapping(page) : NULL; +-} +- +-static inline void set_page_stable_node(struct page *page, +- struct stable_node *stable_node) +-{ +- page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); +-} +- + #ifdef CONFIG_SYSFS + /* + * Only called through the sysfs control interface: +diff -Nur a/mm/Makefile b/mm/Makefile +--- a/mm/Makefile 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/Makefile 2019-07-07 11:43:00.148837320 +0100 +@@ -58,7 +58,8 @@ + obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o + obj-$(CONFIG_SLOB) += slob.o + obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o +-obj-$(CONFIG_KSM) += ksm.o ++obj-$(CONFIG_KSM_LEGACY) += ksm.o ++obj-$(CONFIG_UKSM) += uksm.o + obj-$(CONFIG_PAGE_POISONING) += page_poison.o + obj-$(CONFIG_SLAB) += slab.o + obj-$(CONFIG_SLUB) += slub.o +diff -Nur a/mm/memory.c b/mm/memory.c +--- a/mm/memory.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/memory.c 2019-07-07 11:43:00.148837320 +0100 +@@ -129,6 +129,25 @@ + + unsigned long highest_memmap_pfn __read_mostly; + ++#ifdef CONFIG_UKSM ++unsigned long uksm_zero_pfn __read_mostly; ++EXPORT_SYMBOL_GPL(uksm_zero_pfn); ++struct page *empty_uksm_zero_page; ++ ++static int __init setup_uksm_zero_page(void) ++{ ++ empty_uksm_zero_page = alloc_pages(__GFP_ZERO & ~__GFP_MOVABLE, 0); ++ if (!empty_uksm_zero_page) ++ panic("Oh boy, that early out of memory?"); ++ ++ SetPageReserved(empty_uksm_zero_page); ++ uksm_zero_pfn = page_to_pfn(empty_uksm_zero_page); ++ ++ return 0; ++} ++core_initcall(setup_uksm_zero_page); ++#endif ++ + /* + * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() + */ +@@ -140,6 +159,7 @@ + core_initcall(init_zero_pfn); + + ++ + #if defined(SPLIT_RSS_COUNTING) + + void sync_mm_rss(struct mm_struct *mm) +@@ -794,6 +814,9 @@ + get_page(page); + page_dup_rmap(page, false); + rss[mm_counter(page)]++; ++ ++ /* Should return NULL in vm_normal_page() */ ++ uksm_bugon_zeropage(pte); + } else if (pte_devmap(pte)) { + page = pte_page(pte); + +@@ -807,6 +830,8 @@ + page_dup_rmap(page, false); + rss[mm_counter(page)]++; + } ++ } else { ++ uksm_map_zero_page(pte); + } + + out_set_pte: +@@ -1075,8 +1100,10 @@ + ptent = ptep_get_and_clear_full(mm, addr, pte, + tlb->fullmm); + tlb_remove_tlb_entry(tlb, pte, addr); +- if (unlikely(!page)) ++ if (unlikely(!page)) { ++ uksm_unmap_zero_page(ptent); + continue; ++ } + + if (!PageAnon(page)) { + if (pte_dirty(ptent)) { +@@ -2117,8 +2144,10 @@ + clear_page(kaddr); + kunmap_atomic(kaddr); + flush_dcache_page(dst); +- } else ++ } else { + copy_user_highpage(dst, src, va, vma); ++ uksm_cow_page(vma, src); ++ } + } + + static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) +@@ -2266,6 +2295,7 @@ + vmf->address); + if (!new_page) + goto oom; ++ uksm_cow_pte(vma, vmf->orig_pte); + } else { + new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, + vmf->address); +@@ -2294,7 +2324,9 @@ + mm_counter_file(old_page)); + inc_mm_counter_fast(mm, MM_ANONPAGES); + } ++ uksm_bugon_zeropage(vmf->orig_pte); + } else { ++ uksm_unmap_zero_page(vmf->orig_pte); + inc_mm_counter_fast(mm, MM_ANONPAGES); + } + flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); +diff -Nur a/mm/mmap.c b/mm/mmap.c +--- a/mm/mmap.c 2019-07-07 11:39:06.880828472 +0100 ++++ b/mm/mmap.c 2019-07-07 11:43:00.148837320 +0100 +@@ -46,6 +46,7 @@ + #include + #include + #include ++#include + + #include + #include +@@ -183,6 +184,7 @@ + if (vma->vm_file) + fput(vma->vm_file); + mpol_put(vma_policy(vma)); ++ uksm_remove_vma(vma); + vm_area_free(vma); + return next; + } +@@ -733,9 +735,16 @@ + long adjust_next = 0; + int remove_next = 0; + ++/* ++ * to avoid deadlock, ksm_remove_vma must be done before any spin_lock is ++ * acquired ++ */ ++ uksm_remove_vma(vma); ++ + if (next && !insert) { + struct vm_area_struct *exporter = NULL, *importer = NULL; + ++ uksm_remove_vma(next); + if (end >= next->vm_end) { + /* + * vma expands, overlapping all the next, and +@@ -868,6 +877,7 @@ + end_changed = true; + } + vma->vm_pgoff = pgoff; ++ + if (adjust_next) { + next->vm_start += adjust_next << PAGE_SHIFT; + next->vm_pgoff += adjust_next; +@@ -973,6 +983,7 @@ + if (remove_next == 2) { + remove_next = 1; + end = next->vm_end; ++ uksm_remove_vma(next); + goto again; + } + else if (next) +@@ -999,10 +1010,14 @@ + */ + VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma)); + } ++ } else { ++ if (next && !insert) ++ uksm_vma_add_new(next); + } + if (insert && file) + uprobe_mmap(insert); + ++ uksm_vma_add_new(vma); + validate_mm(mm); + + return 0; +@@ -1459,6 +1474,9 @@ + vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | + mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; + ++ /* If uksm is enabled, we add VM_MERGEABLE to new VMAs. */ ++ uksm_vm_flags_mod(&vm_flags); ++ + if (flags & MAP_LOCKED) + if (!can_do_mlock()) + return -EPERM; +@@ -1823,6 +1841,7 @@ + allow_write_access(file); + } + file = vma->vm_file; ++ uksm_vma_add_new(vma); + out: + perf_event_mmap(vma); + +@@ -1865,6 +1884,7 @@ + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); + free_vma: ++ uksm_remove_vma(vma); + vm_area_free(vma); + unacct_error: + if (charged) +@@ -2697,6 +2717,8 @@ + else + err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); + ++ uksm_vma_add_new(new); ++ + /* Success. */ + if (!err) + return 0; +@@ -3001,6 +3023,7 @@ + if ((flags & (~VM_EXEC)) != 0) + return -EINVAL; + flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; ++ uksm_vm_flags_mod(&flags); + + error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); + if (offset_in_page(error)) +@@ -3051,6 +3074,7 @@ + vma->vm_flags = flags; + vma->vm_page_prot = vm_get_page_prot(flags); + vma_link(mm, vma, prev, rb_link, rb_parent); ++ uksm_vma_add_new(vma); + out: + perf_event_mmap(vma); + mm->total_vm += len >> PAGE_SHIFT; +@@ -3128,6 +3152,12 @@ + up_write(&mm->mmap_sem); + } + ++ /* ++ * Taking write lock on mmap_sem does not harm others, ++ * but it's crucial for uksm to avoid races. ++ */ ++ down_write(&mm->mmap_sem); ++ + if (mm->locked_vm) { + vma = mm->mmap; + while (vma) { +@@ -3140,8 +3170,12 @@ + arch_exit_mmap(mm); + + vma = mm->mmap; +- if (!vma) /* Can happen if dup_mmap() received an OOM */ ++ /* Can happen if dup_mmap() received an OOM */ ++ if (!vma) { ++ /* Release write lock previously taken for UKSM */ ++ up_write(&mm->mmap_sem); + return; ++ } + + lru_add_drain(); + flush_cache_mm(mm); +@@ -3162,6 +3196,11 @@ + vma = remove_vma(vma); + } + vm_unacct_memory(nr_accounted); ++ ++ mm->mmap = NULL; ++ mm->mm_rb = RB_ROOT; ++ vmacache_invalidate(mm); ++ up_write(&mm->mmap_sem); + } + + /* Insert vm structure into process list sorted by address +@@ -3269,6 +3308,7 @@ + new_vma->vm_ops->open(new_vma); + vma_link(mm, new_vma, prev, rb_link, rb_parent); + *need_rmap_locks = false; ++ uksm_vma_add_new(new_vma); + } + return new_vma; + +@@ -3419,6 +3459,7 @@ + vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); + + perf_event_mmap(vma); ++ uksm_vma_add_new(vma); + + return vma; + +diff -Nur a/mm/rmap.c b/mm/rmap.c +--- a/mm/rmap.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/rmap.c 2019-07-07 11:43:00.148837320 +0100 +@@ -1021,7 +1021,7 @@ + * __page_set_anon_rmap - set up new anonymous rmap + * @page: Page or Hugepage to add to rmap + * @vma: VM area to add page to. +- * @address: User virtual address of the mapping ++ * @address: User virtual address of the mapping + * @exclusive: the page is exclusively owned by the current process + */ + static void __page_set_anon_rmap(struct page *page, +diff -Nur a/mm/uksm.c b/mm/uksm.c +--- a/mm/uksm.c 1970-01-01 01:00:00.000000000 +0100 ++++ b/mm/uksm.c 2019-07-07 11:43:00.148837320 +0100 +@@ -0,0 +1,5580 @@ ++/* ++ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia ++ * ++ * This is an improvement upon KSM. Some basic data structures and routines ++ * are borrowed from ksm.c . ++ * ++ * Its new features: ++ * 1. Full system scan: ++ * It automatically scans all user processes' anonymous VMAs. Kernel-user ++ * interaction to submit a memory area to KSM is no longer needed. ++ * ++ * 2. Rich area detection: ++ * It automatically detects rich areas containing abundant duplicated ++ * pages based. Rich areas are given a full scan speed. Poor areas are ++ * sampled at a reasonable speed with very low CPU consumption. ++ * ++ * 3. Ultra Per-page scan speed improvement: ++ * A new hash algorithm is proposed. As a result, on a machine with ++ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it ++ * can scan memory areas that does not contain duplicated pages at speed of ++ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of ++ * 477MB/sec ~ 923MB/sec. ++ * ++ * 4. Thrashing area avoidance: ++ * Thrashing area(an VMA that has frequent Ksm page break-out) can be ++ * filtered out. My benchmark shows it's more efficient than KSM's per-page ++ * hash value based volatile page detection. ++ * ++ * ++ * 5. Misc changes upon KSM: ++ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page ++ * comparison. It's much faster than default C version on x86. ++ * * rmap_item now has an struct *page member to loosely cache a ++ * address-->page mapping, which reduces too much time-costly ++ * follow_page(). ++ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. ++ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ ++ * ksm is needed for this case. ++ * ++ * 6. Full Zero Page consideration(contributed by Figo Zhang) ++ * Now uksmd consider full zero pages as special pages and merge them to an ++ * special unswappable uksm zero page. ++ */ ++ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++ ++#include ++#include "internal.h" ++ ++#ifdef CONFIG_X86 ++#undef memcmp ++ ++#ifdef CONFIG_X86_32 ++#define memcmp memcmpx86_32 ++/* ++ * Compare 4-byte-aligned address s1 and s2, with length n ++ */ ++int memcmpx86_32(void *s1, void *s2, size_t n) ++{ ++ size_t num = n / 4; ++ register int res; ++ ++ __asm__ __volatile__ ++ ( ++ "testl %3,%3\n\t" ++ "repe; cmpsd\n\t" ++ "je 1f\n\t" ++ "sbbl %0,%0\n\t" ++ "orl $1,%0\n" ++ "1:" ++ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) ++ : "0" (0) ++ : "cc"); ++ ++ return res; ++} ++ ++/* ++ * Check the page is all zero ? ++ */ ++static int is_full_zero(const void *s1, size_t len) ++{ ++ unsigned char same; ++ ++ len /= 4; ++ ++ __asm__ __volatile__ ++ ("repe; scasl;" ++ "sete %0" ++ : "=qm" (same), "+D" (s1), "+c" (len) ++ : "a" (0) ++ : "cc"); ++ ++ return same; ++} ++ ++ ++#elif defined(CONFIG_X86_64) ++#define memcmp memcmpx86_64 ++/* ++ * Compare 8-byte-aligned address s1 and s2, with length n ++ */ ++int memcmpx86_64(void *s1, void *s2, size_t n) ++{ ++ size_t num = n / 8; ++ register int res; ++ ++ __asm__ __volatile__ ++ ( ++ "testq %q3,%q3\n\t" ++ "repe; cmpsq\n\t" ++ "je 1f\n\t" ++ "sbbq %q0,%q0\n\t" ++ "orq $1,%q0\n" ++ "1:" ++ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) ++ : "0" (0) ++ : "cc"); ++ ++ return res; ++} ++ ++static int is_full_zero(const void *s1, size_t len) ++{ ++ unsigned char same; ++ ++ len /= 8; ++ ++ __asm__ __volatile__ ++ ("repe; scasq;" ++ "sete %0" ++ : "=qm" (same), "+D" (s1), "+c" (len) ++ : "a" (0) ++ : "cc"); ++ ++ return same; ++} ++ ++#endif ++#else ++static int is_full_zero(const void *s1, size_t len) ++{ ++ unsigned long *src = s1; ++ int i; ++ ++ len /= sizeof(*src); ++ ++ for (i = 0; i < len; i++) { ++ if (src[i]) ++ return 0; ++ } ++ ++ return 1; ++} ++#endif ++ ++#define UKSM_RUNG_ROUND_FINISHED (1 << 0) ++#define TIME_RATIO_SCALE 10000 ++ ++#define SLOT_TREE_NODE_SHIFT 8 ++#define SLOT_TREE_NODE_STORE_SIZE (1UL << SLOT_TREE_NODE_SHIFT) ++struct slot_tree_node { ++ unsigned long size; ++ struct sradix_tree_node snode; ++ void *stores[SLOT_TREE_NODE_STORE_SIZE]; ++}; ++ ++static struct kmem_cache *slot_tree_node_cachep; ++ ++static struct sradix_tree_node *slot_tree_node_alloc(void) ++{ ++ struct slot_tree_node *p; ++ ++ p = kmem_cache_zalloc(slot_tree_node_cachep, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (!p) ++ return NULL; ++ ++ return &p->snode; ++} ++ ++static void slot_tree_node_free(struct sradix_tree_node *node) ++{ ++ struct slot_tree_node *p; ++ ++ p = container_of(node, struct slot_tree_node, snode); ++ kmem_cache_free(slot_tree_node_cachep, p); ++} ++ ++static void slot_tree_node_extend(struct sradix_tree_node *parent, ++ struct sradix_tree_node *child) ++{ ++ struct slot_tree_node *p, *c; ++ ++ p = container_of(parent, struct slot_tree_node, snode); ++ c = container_of(child, struct slot_tree_node, snode); ++ ++ p->size += c->size; ++} ++ ++void slot_tree_node_assign(struct sradix_tree_node *node, ++ unsigned int index, void *item) ++{ ++ struct vma_slot *slot = item; ++ struct slot_tree_node *cur; ++ ++ slot->snode = node; ++ slot->sindex = index; ++ ++ while (node) { ++ cur = container_of(node, struct slot_tree_node, snode); ++ cur->size += slot->pages; ++ node = node->parent; ++ } ++} ++ ++void slot_tree_node_rm(struct sradix_tree_node *node, unsigned int offset) ++{ ++ struct vma_slot *slot; ++ struct slot_tree_node *cur; ++ unsigned long pages; ++ ++ if (node->height == 1) { ++ slot = node->stores[offset]; ++ pages = slot->pages; ++ } else { ++ cur = container_of(node->stores[offset], ++ struct slot_tree_node, snode); ++ pages = cur->size; ++ } ++ ++ while (node) { ++ cur = container_of(node, struct slot_tree_node, snode); ++ cur->size -= pages; ++ node = node->parent; ++ } ++} ++ ++unsigned long slot_iter_index; ++int slot_iter(void *item, unsigned long height) ++{ ++ struct slot_tree_node *node; ++ struct vma_slot *slot; ++ ++ if (height == 1) { ++ slot = item; ++ if (slot_iter_index < slot->pages) { ++ /*in this one*/ ++ return 1; ++ } else { ++ slot_iter_index -= slot->pages; ++ return 0; ++ } ++ ++ } else { ++ node = container_of(item, struct slot_tree_node, snode); ++ if (slot_iter_index < node->size) { ++ /*in this one*/ ++ return 1; ++ } else { ++ slot_iter_index -= node->size; ++ return 0; ++ } ++ } ++} ++ ++ ++static inline void slot_tree_init_root(struct sradix_tree_root *root) ++{ ++ init_sradix_tree_root(root, SLOT_TREE_NODE_SHIFT); ++ root->alloc = slot_tree_node_alloc; ++ root->free = slot_tree_node_free; ++ root->extend = slot_tree_node_extend; ++ root->assign = slot_tree_node_assign; ++ root->rm = slot_tree_node_rm; ++} ++ ++void slot_tree_init(void) ++{ ++ slot_tree_node_cachep = kmem_cache_create("slot_tree_node", ++ sizeof(struct slot_tree_node), 0, ++ SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, ++ NULL); ++} ++ ++ ++/* Each rung of this ladder is a list of VMAs having a same scan ratio */ ++struct scan_rung { ++ //struct list_head scanned_list; ++ struct sradix_tree_root vma_root; ++ struct sradix_tree_root vma_root2; ++ ++ struct vma_slot *current_scan; ++ unsigned long current_offset; ++ ++ /* ++ * The initial value for current_offset, it should loop over ++ * [0~ step - 1] to let all slot have its chance to be scanned. ++ */ ++ unsigned long offset_init; ++ unsigned long step; /* dynamic step for current_offset */ ++ unsigned int flags; ++ unsigned long pages_to_scan; ++ //unsigned long fully_scanned_slots; ++ /* ++ * a little bit tricky - if cpu_time_ratio > 0, then the value is the ++ * the cpu time ratio it can spend in rung_i for every scan ++ * period. if < 0, then it is the cpu time ratio relative to the ++ * max cpu percentage user specified. Both in unit of ++ * 1/TIME_RATIO_SCALE ++ */ ++ int cpu_ratio; ++ ++ /* ++ * How long it will take for all slots in this rung to be fully ++ * scanned? If it's zero, we don't care about the cover time: ++ * it's fully scanned. ++ */ ++ unsigned int cover_msecs; ++ //unsigned long vma_num; ++ //unsigned long pages; /* Sum of all slot's pages in rung */ ++}; ++ ++/** ++ * node of either the stable or unstale rbtree ++ * ++ */ ++struct tree_node { ++ struct rb_node node; /* link in the main (un)stable rbtree */ ++ struct rb_root sub_root; /* rb_root for sublevel collision rbtree */ ++ u32 hash; ++ unsigned long count; /* TODO: merged with sub_root */ ++ struct list_head all_list; /* all tree nodes in stable/unstable tree */ ++}; ++ ++/** ++ * struct stable_node - node of the stable rbtree ++ * @node: rb node of this ksm page in the stable tree ++ * @hlist: hlist head of rmap_items using this ksm page ++ * @kpfn: page frame number of this ksm page ++ */ ++struct stable_node { ++ struct rb_node node; /* link in sub-rbtree */ ++ struct tree_node *tree_node; /* it's tree node root in stable tree, NULL if it's in hell list */ ++ struct hlist_head hlist; ++ unsigned long kpfn; ++ u32 hash_max; /* if ==0 then it's not been calculated yet */ ++ struct list_head all_list; /* in a list for all stable nodes */ ++}; ++ ++/** ++ * struct node_vma - group rmap_items linked in a same stable ++ * node together. ++ */ ++struct node_vma { ++ union { ++ struct vma_slot *slot; ++ unsigned long key; /* slot is used as key sorted on hlist */ ++ }; ++ struct hlist_node hlist; ++ struct hlist_head rmap_hlist; ++ struct stable_node *head; ++}; ++ ++/** ++ * struct rmap_item - reverse mapping item for virtual addresses ++ * @rmap_list: next rmap_item in mm_slot's singly-linked rmap_list ++ * @anon_vma: pointer to anon_vma for this mm,address, when in stable tree ++ * @mm: the memory structure this rmap_item is pointing into ++ * @address: the virtual address this rmap_item tracks (+ flags in low bits) ++ * @node: rb node of this rmap_item in the unstable tree ++ * @head: pointer to stable_node heading this list in the stable tree ++ * @hlist: link into hlist of rmap_items hanging off that stable_node ++ */ ++struct rmap_item { ++ struct vma_slot *slot; ++ struct page *page; ++ unsigned long address; /* + low bits used for flags below */ ++ unsigned long hash_round; ++ unsigned long entry_index; ++ union { ++ struct {/* when in unstable tree */ ++ struct rb_node node; ++ struct tree_node *tree_node; ++ u32 hash_max; ++ }; ++ struct { /* when in stable tree */ ++ struct node_vma *head; ++ struct hlist_node hlist; ++ struct anon_vma *anon_vma; ++ }; ++ }; ++} __aligned(4); ++ ++struct rmap_list_entry { ++ union { ++ struct rmap_item *item; ++ unsigned long addr; ++ }; ++ /* lowest bit is used for is_addr tag */ ++} __aligned(4); /* 4 aligned to fit in to pages*/ ++ ++ ++/* Basic data structure definition ends */ ++ ++ ++/* ++ * Flags for rmap_item to judge if it's listed in the stable/unstable tree. ++ * The flags use the low bits of rmap_item.address ++ */ ++#define UNSTABLE_FLAG 0x1 ++#define STABLE_FLAG 0x2 ++#define get_rmap_addr(x) ((x)->address & PAGE_MASK) ++ ++/* ++ * rmap_list_entry helpers ++ */ ++#define IS_ADDR_FLAG 1 ++#define is_addr(ptr) ((unsigned long)(ptr) & IS_ADDR_FLAG) ++#define set_is_addr(ptr) ((ptr) |= IS_ADDR_FLAG) ++#define get_clean_addr(ptr) (((ptr) & ~(__typeof__(ptr))IS_ADDR_FLAG)) ++ ++ ++/* ++ * High speed caches for frequently allocated and freed structs ++ */ ++static struct kmem_cache *rmap_item_cache; ++static struct kmem_cache *stable_node_cache; ++static struct kmem_cache *node_vma_cache; ++static struct kmem_cache *vma_slot_cache; ++static struct kmem_cache *tree_node_cache; ++#define UKSM_KMEM_CACHE(__struct, __flags) kmem_cache_create("uksm_"#__struct,\ ++ sizeof(struct __struct), __alignof__(struct __struct),\ ++ (__flags), NULL) ++ ++/* Array of all scan_rung, uksm_scan_ladder[0] having the minimum scan ratio */ ++#define SCAN_LADDER_SIZE 4 ++static struct scan_rung uksm_scan_ladder[SCAN_LADDER_SIZE]; ++ ++/* The evaluation rounds uksmd has finished */ ++static unsigned long long uksm_eval_round = 1; ++ ++/* ++ * we add 1 to this var when we consider we should rebuild the whole ++ * unstable tree. ++ */ ++static unsigned long uksm_hash_round = 1; ++ ++/* ++ * How many times the whole memory is scanned. ++ */ ++static unsigned long long fully_scanned_round = 1; ++ ++/* The total number of virtual pages of all vma slots */ ++static u64 uksm_pages_total; ++ ++/* The number of pages has been scanned since the start up */ ++static u64 uksm_pages_scanned; ++ ++static u64 scanned_virtual_pages; ++ ++/* The number of pages has been scanned since last encode_benefit call */ ++static u64 uksm_pages_scanned_last; ++ ++/* If the scanned number is tooo large, we encode it here */ ++static u64 pages_scanned_stored; ++ ++static unsigned long pages_scanned_base; ++ ++/* The number of nodes in the stable tree */ ++static unsigned long uksm_pages_shared; ++ ++/* The number of page slots additionally sharing those nodes */ ++static unsigned long uksm_pages_sharing; ++ ++/* The number of nodes in the unstable tree */ ++static unsigned long uksm_pages_unshared; ++ ++/* ++ * Milliseconds ksmd should sleep between scans, ++ * >= 100ms to be consistent with ++ * scan_time_to_sleep_msec() ++ */ ++static unsigned int uksm_sleep_jiffies; ++ ++/* The real value for the uksmd next sleep */ ++static unsigned int uksm_sleep_real; ++ ++/* Saved value for user input uksm_sleep_jiffies when it's enlarged */ ++static unsigned int uksm_sleep_saved; ++ ++/* Max percentage of cpu utilization ksmd can take to scan in one batch */ ++static unsigned int uksm_max_cpu_percentage; ++ ++static int uksm_cpu_governor; ++ ++static char *uksm_cpu_governor_str[4] = { "full", "medium", "low", "quiet" }; ++ ++struct uksm_cpu_preset_s { ++ int cpu_ratio[SCAN_LADDER_SIZE]; ++ unsigned int cover_msecs[SCAN_LADDER_SIZE]; ++ unsigned int max_cpu; /* percentage */ ++}; ++ ++struct uksm_cpu_preset_s uksm_cpu_preset[4] = { ++ { {20, 40, -2500, -10000}, {1000, 500, 200, 50}, 95}, ++ { {20, 30, -2500, -10000}, {1000, 500, 400, 100}, 50}, ++ { {10, 20, -5000, -10000}, {1500, 1000, 1000, 250}, 20}, ++ { {10, 20, 40, 75}, {2000, 1000, 1000, 1000}, 1}, ++}; ++ ++/* The default value for uksm_ema_page_time if it's not initialized */ ++#define UKSM_PAGE_TIME_DEFAULT 500 ++ ++/*cost to scan one page by expotional moving average in nsecs */ ++static unsigned long uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; ++ ++/* The expotional moving average alpha weight, in percentage. */ ++#define EMA_ALPHA 20 ++ ++/* ++ * The threshold used to filter out thrashing areas, ++ * If it == 0, filtering is disabled, otherwise it's the percentage up-bound ++ * of the thrashing ratio of all areas. Any area with a bigger thrashing ratio ++ * will be considered as having a zero duplication ratio. ++ */ ++static unsigned int uksm_thrash_threshold = 50; ++ ++/* How much dedup ratio is considered to be abundant*/ ++static unsigned int uksm_abundant_threshold = 10; ++ ++/* All slots having merged pages in this eval round. */ ++struct list_head vma_slot_dedup = LIST_HEAD_INIT(vma_slot_dedup); ++ ++/* How many times the ksmd has slept since startup */ ++static unsigned long long uksm_sleep_times; ++ ++#define UKSM_RUN_STOP 0 ++#define UKSM_RUN_MERGE 1 ++static unsigned int uksm_run = 1; ++ ++static DECLARE_WAIT_QUEUE_HEAD(uksm_thread_wait); ++static DEFINE_MUTEX(uksm_thread_mutex); ++ ++/* ++ * List vma_slot_new is for newly created vma_slot waiting to be added by ++ * ksmd. If one cannot be added(e.g. due to it's too small), it's moved to ++ * vma_slot_noadd. vma_slot_del is the list for vma_slot whose corresponding ++ * VMA has been removed/freed. ++ */ ++struct list_head vma_slot_new = LIST_HEAD_INIT(vma_slot_new); ++struct list_head vma_slot_noadd = LIST_HEAD_INIT(vma_slot_noadd); ++struct list_head vma_slot_del = LIST_HEAD_INIT(vma_slot_del); ++static DEFINE_SPINLOCK(vma_slot_list_lock); ++ ++/* The unstable tree heads */ ++static struct rb_root root_unstable_tree = RB_ROOT; ++ ++/* ++ * All tree_nodes are in a list to be freed at once when unstable tree is ++ * freed after each scan round. ++ */ ++static struct list_head unstable_tree_node_list = ++ LIST_HEAD_INIT(unstable_tree_node_list); ++ ++/* List contains all stable nodes */ ++static struct list_head stable_node_list = LIST_HEAD_INIT(stable_node_list); ++ ++/* ++ * When the hash strength is changed, the stable tree must be delta_hashed and ++ * re-structured. We use two set of below structs to speed up the ++ * re-structuring of stable tree. ++ */ ++static struct list_head ++stable_tree_node_list[2] = {LIST_HEAD_INIT(stable_tree_node_list[0]), ++ LIST_HEAD_INIT(stable_tree_node_list[1])}; ++ ++static struct list_head *stable_tree_node_listp = &stable_tree_node_list[0]; ++static struct rb_root root_stable_tree[2] = {RB_ROOT, RB_ROOT}; ++static struct rb_root *root_stable_treep = &root_stable_tree[0]; ++static unsigned long stable_tree_index; ++ ++/* The hash strength needed to hash a full page */ ++#define HASH_STRENGTH_FULL (PAGE_SIZE / sizeof(u32)) ++ ++/* The hash strength needed for loop-back hashing */ ++#define HASH_STRENGTH_MAX (HASH_STRENGTH_FULL + 10) ++ ++/* The random offsets in a page */ ++static u32 *random_nums; ++ ++/* The hash strength */ ++static unsigned long hash_strength = HASH_STRENGTH_FULL >> 4; ++ ++/* The delta value each time the hash strength increases or decreases */ ++static unsigned long hash_strength_delta; ++#define HASH_STRENGTH_DELTA_MAX 5 ++ ++/* The time we have saved due to random_sample_hash */ ++static u64 rshash_pos; ++ ++/* The time we have wasted due to hash collision */ ++static u64 rshash_neg; ++ ++struct uksm_benefit { ++ u64 pos; ++ u64 neg; ++ u64 scanned; ++ unsigned long base; ++} benefit; ++ ++/* ++ * The relative cost of memcmp, compared to 1 time unit of random sample ++ * hash, this value is tested when ksm module is initialized ++ */ ++static unsigned long memcmp_cost; ++ ++static unsigned long rshash_neg_cont_zero; ++static unsigned long rshash_cont_obscure; ++ ++/* The possible states of hash strength adjustment heuristic */ ++enum rshash_states { ++ RSHASH_STILL, ++ RSHASH_TRYUP, ++ RSHASH_TRYDOWN, ++ RSHASH_NEW, ++ RSHASH_PRE_STILL, ++}; ++ ++/* The possible direction we are about to adjust hash strength */ ++enum rshash_direct { ++ GO_UP, ++ GO_DOWN, ++ OBSCURE, ++ STILL, ++}; ++ ++/* random sampling hash state machine */ ++static struct { ++ enum rshash_states state; ++ enum rshash_direct pre_direct; ++ u8 below_count; ++ /* Keep a lookup window of size 5, iff above_count/below_count > 3 ++ * in this window we stop trying. ++ */ ++ u8 lookup_window_index; ++ u64 stable_benefit; ++ unsigned long turn_point_down; ++ unsigned long turn_benefit_down; ++ unsigned long turn_point_up; ++ unsigned long turn_benefit_up; ++ unsigned long stable_point; ++} rshash_state; ++ ++/*zero page hash table, hash_strength [0 ~ HASH_STRENGTH_MAX]*/ ++static u32 *zero_hash_table; ++ ++static inline struct node_vma *alloc_node_vma(void) ++{ ++ struct node_vma *node_vma; ++ ++ node_vma = kmem_cache_zalloc(node_vma_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (node_vma) { ++ INIT_HLIST_HEAD(&node_vma->rmap_hlist); ++ INIT_HLIST_NODE(&node_vma->hlist); ++ } ++ return node_vma; ++} ++ ++static inline void free_node_vma(struct node_vma *node_vma) ++{ ++ kmem_cache_free(node_vma_cache, node_vma); ++} ++ ++ ++static inline struct vma_slot *alloc_vma_slot(void) ++{ ++ struct vma_slot *slot; ++ ++ /* ++ * In case ksm is not initialized by now. ++ * Oops, we need to consider the call site of uksm_init() in the future. ++ */ ++ if (!vma_slot_cache) ++ return NULL; ++ ++ slot = kmem_cache_zalloc(vma_slot_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (slot) { ++ INIT_LIST_HEAD(&slot->slot_list); ++ INIT_LIST_HEAD(&slot->dedup_list); ++ slot->flags |= UKSM_SLOT_NEED_RERAND; ++ } ++ return slot; ++} ++ ++static inline void free_vma_slot(struct vma_slot *vma_slot) ++{ ++ kmem_cache_free(vma_slot_cache, vma_slot); ++} ++ ++ ++ ++static inline struct rmap_item *alloc_rmap_item(void) ++{ ++ struct rmap_item *rmap_item; ++ ++ rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (rmap_item) { ++ /* bug on lowest bit is not clear for flag use */ ++ BUG_ON(is_addr(rmap_item)); ++ } ++ return rmap_item; ++} ++ ++static inline void free_rmap_item(struct rmap_item *rmap_item) ++{ ++ rmap_item->slot = NULL; /* debug safety */ ++ kmem_cache_free(rmap_item_cache, rmap_item); ++} ++ ++static inline struct stable_node *alloc_stable_node(void) ++{ ++ struct stable_node *node; ++ ++ node = kmem_cache_alloc(stable_node_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (!node) ++ return NULL; ++ ++ INIT_HLIST_HEAD(&node->hlist); ++ list_add(&node->all_list, &stable_node_list); ++ return node; ++} ++ ++static inline void free_stable_node(struct stable_node *stable_node) ++{ ++ list_del(&stable_node->all_list); ++ kmem_cache_free(stable_node_cache, stable_node); ++} ++ ++static inline struct tree_node *alloc_tree_node(struct list_head *list) ++{ ++ struct tree_node *node; ++ ++ node = kmem_cache_zalloc(tree_node_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (!node) ++ return NULL; ++ ++ list_add(&node->all_list, list); ++ return node; ++} ++ ++static inline void free_tree_node(struct tree_node *node) ++{ ++ list_del(&node->all_list); ++ kmem_cache_free(tree_node_cache, node); ++} ++ ++static void uksm_drop_anon_vma(struct rmap_item *rmap_item) ++{ ++ struct anon_vma *anon_vma = rmap_item->anon_vma; ++ ++ put_anon_vma(anon_vma); ++} ++ ++ ++/** ++ * Remove a stable node from stable_tree, may unlink from its tree_node and ++ * may remove its parent tree_node if no other stable node is pending. ++ * ++ * @stable_node The node need to be removed ++ * @unlink_rb Will this node be unlinked from the rbtree? ++ * @remove_tree_ node Will its tree_node be removed if empty? ++ */ ++static void remove_node_from_stable_tree(struct stable_node *stable_node, ++ int unlink_rb, int remove_tree_node) ++{ ++ struct node_vma *node_vma; ++ struct rmap_item *rmap_item; ++ struct hlist_node *n; ++ ++ if (!hlist_empty(&stable_node->hlist)) { ++ hlist_for_each_entry_safe(node_vma, n, ++ &stable_node->hlist, hlist) { ++ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { ++ uksm_pages_sharing--; ++ ++ uksm_drop_anon_vma(rmap_item); ++ rmap_item->address &= PAGE_MASK; ++ } ++ free_node_vma(node_vma); ++ cond_resched(); ++ } ++ ++ /* the last one is counted as shared */ ++ uksm_pages_shared--; ++ uksm_pages_sharing++; ++ } ++ ++ if (stable_node->tree_node && unlink_rb) { ++ rb_erase(&stable_node->node, ++ &stable_node->tree_node->sub_root); ++ ++ if (RB_EMPTY_ROOT(&stable_node->tree_node->sub_root) && ++ remove_tree_node) { ++ rb_erase(&stable_node->tree_node->node, ++ root_stable_treep); ++ free_tree_node(stable_node->tree_node); ++ } else { ++ stable_node->tree_node->count--; ++ } ++ } ++ ++ free_stable_node(stable_node); ++} ++ ++ ++/* ++ * get_uksm_page: checks if the page indicated by the stable node ++ * is still its ksm page, despite having held no reference to it. ++ * In which case we can trust the content of the page, and it ++ * returns the gotten page; but if the page has now been zapped, ++ * remove the stale node from the stable tree and return NULL. ++ * ++ * You would expect the stable_node to hold a reference to the ksm page. ++ * But if it increments the page's count, swapping out has to wait for ++ * ksmd to come around again before it can free the page, which may take ++ * seconds or even minutes: much too unresponsive. So instead we use a ++ * "keyhole reference": access to the ksm page from the stable node peeps ++ * out through its keyhole to see if that page still holds the right key, ++ * pointing back to this stable node. This relies on freeing a PageAnon ++ * page to reset its page->mapping to NULL, and relies on no other use of ++ * a page to put something that might look like our key in page->mapping. ++ * ++ * include/linux/pagemap.h page_cache_get_speculative() is a good reference, ++ * but this is different - made simpler by uksm_thread_mutex being held, but ++ * interesting for assuming that no other use of the struct page could ever ++ * put our expected_mapping into page->mapping (or a field of the union which ++ * coincides with page->mapping). The RCU calls are not for KSM at all, but ++ * to keep the page_count protocol described with page_cache_get_speculative. ++ * ++ * Note: it is possible that get_uksm_page() will return NULL one moment, ++ * then page the next, if the page is in between page_freeze_refs() and ++ * page_unfreeze_refs(): this shouldn't be a problem anywhere, the page ++ * is on its way to being freed; but it is an anomaly to bear in mind. ++ * ++ * @unlink_rb: if the removal of this node will firstly unlink from ++ * its rbtree. stable_node_reinsert will prevent this when restructuring the ++ * node from its old tree. ++ * ++ * @remove_tree_node: if this is the last one of its tree_node, will the ++ * tree_node be freed ? If we are inserting stable node, this tree_node may ++ * be reused, so don't free it. ++ */ ++static struct page *get_uksm_page(struct stable_node *stable_node, ++ int unlink_rb, int remove_tree_node) ++{ ++ struct page *page; ++ void *expected_mapping; ++ unsigned long kpfn; ++ ++ expected_mapping = (void *)((unsigned long)stable_node | ++ PAGE_MAPPING_KSM); ++again: ++ kpfn = READ_ONCE(stable_node->kpfn); ++ page = pfn_to_page(kpfn); ++ ++ /* ++ * page is computed from kpfn, so on most architectures reading ++ * page->mapping is naturally ordered after reading node->kpfn, ++ * but on Alpha we need to be more careful. ++ */ ++ smp_read_barrier_depends(); ++ ++ if (READ_ONCE(page->mapping) != expected_mapping) ++ goto stale; ++ ++ /* ++ * We cannot do anything with the page while its refcount is 0. ++ * Usually 0 means free, or tail of a higher-order page: in which ++ * case this node is no longer referenced, and should be freed; ++ * however, it might mean that the page is under page_freeze_refs(). ++ * The __remove_mapping() case is easy, again the node is now stale; ++ * but if page is swapcache in migrate_page_move_mapping(), it might ++ * still be our page, in which case it's essential to keep the node. ++ */ ++ while (!get_page_unless_zero(page)) { ++ /* ++ * Another check for page->mapping != expected_mapping would ++ * work here too. We have chosen the !PageSwapCache test to ++ * optimize the common case, when the page is or is about to ++ * be freed: PageSwapCache is cleared (under spin_lock_irq) ++ * in the freeze_refs section of __remove_mapping(); but Anon ++ * page->mapping reset to NULL later, in free_pages_prepare(). ++ */ ++ if (!PageSwapCache(page)) ++ goto stale; ++ cpu_relax(); ++ } ++ ++ if (READ_ONCE(page->mapping) != expected_mapping) { ++ put_page(page); ++ goto stale; ++ } ++ ++ lock_page(page); ++ if (READ_ONCE(page->mapping) != expected_mapping) { ++ unlock_page(page); ++ put_page(page); ++ goto stale; ++ } ++ unlock_page(page); ++ return page; ++stale: ++ /* ++ * We come here from above when page->mapping or !PageSwapCache ++ * suggests that the node is stale; but it might be under migration. ++ * We need smp_rmb(), matching the smp_wmb() in ksm_migrate_page(), ++ * before checking whether node->kpfn has been changed. ++ */ ++ smp_rmb(); ++ if (stable_node->kpfn != kpfn) ++ goto again; ++ ++ remove_node_from_stable_tree(stable_node, unlink_rb, remove_tree_node); ++ ++ return NULL; ++} ++ ++/* ++ * Removing rmap_item from stable or unstable tree. ++ * This function will clean the information from the stable/unstable tree. ++ */ ++static inline void remove_rmap_item_from_tree(struct rmap_item *rmap_item) ++{ ++ if (rmap_item->address & STABLE_FLAG) { ++ struct stable_node *stable_node; ++ struct node_vma *node_vma; ++ struct page *page; ++ ++ node_vma = rmap_item->head; ++ stable_node = node_vma->head; ++ page = get_uksm_page(stable_node, 1, 1); ++ if (!page) ++ goto out; ++ ++ /* ++ * page lock is needed because it's racing with ++ * try_to_unmap_ksm(), etc. ++ */ ++ lock_page(page); ++ hlist_del(&rmap_item->hlist); ++ ++ if (hlist_empty(&node_vma->rmap_hlist)) { ++ hlist_del(&node_vma->hlist); ++ free_node_vma(node_vma); ++ } ++ unlock_page(page); ++ ++ put_page(page); ++ if (hlist_empty(&stable_node->hlist)) { ++ /* do NOT call remove_node_from_stable_tree() here, ++ * it's possible for a forked rmap_item not in ++ * stable tree while the in-tree rmap_items were ++ * deleted. ++ */ ++ uksm_pages_shared--; ++ } else ++ uksm_pages_sharing--; ++ ++ ++ uksm_drop_anon_vma(rmap_item); ++ } else if (rmap_item->address & UNSTABLE_FLAG) { ++ if (rmap_item->hash_round == uksm_hash_round) { ++ ++ rb_erase(&rmap_item->node, ++ &rmap_item->tree_node->sub_root); ++ if (RB_EMPTY_ROOT(&rmap_item->tree_node->sub_root)) { ++ rb_erase(&rmap_item->tree_node->node, ++ &root_unstable_tree); ++ ++ free_tree_node(rmap_item->tree_node); ++ } else ++ rmap_item->tree_node->count--; ++ } ++ uksm_pages_unshared--; ++ } ++ ++ rmap_item->address &= PAGE_MASK; ++ rmap_item->hash_max = 0; ++ ++out: ++ cond_resched(); /* we're called from many long loops */ ++} ++ ++static inline int slot_in_uksm(struct vma_slot *slot) ++{ ++ return list_empty(&slot->slot_list); ++} ++ ++/* ++ * Test if the mm is exiting ++ */ ++static inline bool uksm_test_exit(struct mm_struct *mm) ++{ ++ return atomic_read(&mm->mm_users) == 0; ++} ++ ++static inline unsigned long vma_pool_size(struct vma_slot *slot) ++{ ++ return round_up(sizeof(struct rmap_list_entry) * slot->pages, ++ PAGE_SIZE) >> PAGE_SHIFT; ++} ++ ++#define CAN_OVERFLOW_U64(x, delta) (U64_MAX - (x) < (delta)) ++ ++/* must be done with sem locked */ ++static int slot_pool_alloc(struct vma_slot *slot) ++{ ++ unsigned long pool_size; ++ ++ if (slot->rmap_list_pool) ++ return 0; ++ ++ pool_size = vma_pool_size(slot); ++ slot->rmap_list_pool = kcalloc(pool_size, sizeof(struct page *), ++ GFP_KERNEL); ++ if (!slot->rmap_list_pool) ++ return -ENOMEM; ++ ++ slot->pool_counts = kcalloc(pool_size, sizeof(unsigned int), ++ GFP_KERNEL); ++ if (!slot->pool_counts) { ++ kfree(slot->rmap_list_pool); ++ return -ENOMEM; ++ } ++ ++ slot->pool_size = pool_size; ++ BUG_ON(CAN_OVERFLOW_U64(uksm_pages_total, slot->pages)); ++ slot->flags |= UKSM_SLOT_IN_UKSM; ++ uksm_pages_total += slot->pages; ++ ++ return 0; ++} ++ ++/* ++ * Called after vma is unlinked from its mm ++ */ ++void uksm_remove_vma(struct vm_area_struct *vma) ++{ ++ struct vma_slot *slot; ++ ++ if (!vma->uksm_vma_slot) ++ return; ++ ++ spin_lock(&vma_slot_list_lock); ++ slot = vma->uksm_vma_slot; ++ if (!slot) ++ goto out; ++ ++ if (slot_in_uksm(slot)) { ++ /** ++ * This slot has been added by ksmd, so move to the del list ++ * waiting ksmd to free it. ++ */ ++ list_add_tail(&slot->slot_list, &vma_slot_del); ++ } else { ++ /** ++ * It's still on new list. It's ok to free slot directly. ++ */ ++ list_del(&slot->slot_list); ++ free_vma_slot(slot); ++ } ++out: ++ vma->uksm_vma_slot = NULL; ++ spin_unlock(&vma_slot_list_lock); ++} ++ ++/** ++ * Need to do two things: ++ * 1. check if slot was moved to del list ++ * 2. make sure the mmap_sem is manipulated under valid vma. ++ * ++ * My concern here is that in some cases, this may make ++ * vma_slot_list_lock() waiters to serialized further by some ++ * sem->wait_lock, can this really be expensive? ++ * ++ * ++ * @return ++ * 0: if successfully locked mmap_sem ++ * -ENOENT: this slot was moved to del list ++ * -EBUSY: vma lock failed ++ */ ++static int try_down_read_slot_mmap_sem(struct vma_slot *slot) ++{ ++ struct vm_area_struct *vma; ++ struct mm_struct *mm; ++ struct rw_semaphore *sem; ++ ++ spin_lock(&vma_slot_list_lock); ++ ++ /* the slot_list was removed and inited from new list, when it enters ++ * uksm_list. If now it's not empty, then it must be moved to del list ++ */ ++ if (!slot_in_uksm(slot)) { ++ spin_unlock(&vma_slot_list_lock); ++ return -ENOENT; ++ } ++ ++ BUG_ON(slot->pages != vma_pages(slot->vma)); ++ /* Ok, vma still valid */ ++ vma = slot->vma; ++ mm = vma->vm_mm; ++ sem = &mm->mmap_sem; ++ ++ if (uksm_test_exit(mm)) { ++ spin_unlock(&vma_slot_list_lock); ++ return -ENOENT; ++ } ++ ++ if (down_read_trylock(sem)) { ++ spin_unlock(&vma_slot_list_lock); ++ if (slot_pool_alloc(slot)) { ++ uksm_remove_vma(vma); ++ up_read(sem); ++ return -ENOENT; ++ } ++ return 0; ++ } ++ ++ spin_unlock(&vma_slot_list_lock); ++ return -EBUSY; ++} ++ ++static inline unsigned long ++vma_page_address(struct page *page, struct vm_area_struct *vma) ++{ ++ pgoff_t pgoff = page->index; ++ unsigned long address; ++ ++ address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); ++ if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { ++ /* page should be within @vma mapping range */ ++ return -EFAULT; ++ } ++ return address; ++} ++ ++ ++/* return 0 on success with the item's mmap_sem locked */ ++static inline int get_mergeable_page_lock_mmap(struct rmap_item *item) ++{ ++ struct mm_struct *mm; ++ struct vma_slot *slot = item->slot; ++ int err = -EINVAL; ++ ++ struct page *page; ++ ++ /* ++ * try_down_read_slot_mmap_sem() returns non-zero if the slot ++ * has been removed by uksm_remove_vma(). ++ */ ++ if (try_down_read_slot_mmap_sem(slot)) ++ return -EBUSY; ++ ++ mm = slot->vma->vm_mm; ++ ++ if (uksm_test_exit(mm)) ++ goto failout_up; ++ ++ page = item->page; ++ rcu_read_lock(); ++ if (!get_page_unless_zero(page)) { ++ rcu_read_unlock(); ++ goto failout_up; ++ } ++ ++ /* No need to consider huge page here. */ ++ if (item->slot->vma->anon_vma != page_anon_vma(page) || ++ vma_page_address(page, item->slot->vma) != get_rmap_addr(item)) { ++ /* ++ * TODO: ++ * should we release this item becase of its stale page ++ * mapping? ++ */ ++ put_page(page); ++ rcu_read_unlock(); ++ goto failout_up; ++ } ++ rcu_read_unlock(); ++ return 0; ++ ++failout_up: ++ up_read(&mm->mmap_sem); ++ return err; ++} ++ ++/* ++ * What kind of VMA is considered ? ++ */ ++static inline int vma_can_enter(struct vm_area_struct *vma) ++{ ++ return uksm_flags_can_scan(vma->vm_flags); ++} ++ ++/* ++ * Called whenever a fresh new vma is created A new vma_slot. ++ * is created and inserted into a global list Must be called. ++ * after vma is inserted to its mm. ++ */ ++void uksm_vma_add_new(struct vm_area_struct *vma) ++{ ++ struct vma_slot *slot; ++ ++ if (!vma_can_enter(vma)) { ++ vma->uksm_vma_slot = NULL; ++ return; ++ } ++ ++ slot = alloc_vma_slot(); ++ if (!slot) { ++ vma->uksm_vma_slot = NULL; ++ return; ++ } ++ ++ vma->uksm_vma_slot = slot; ++ vma->vm_flags |= VM_MERGEABLE; ++ slot->vma = vma; ++ slot->mm = vma->vm_mm; ++ slot->ctime_j = jiffies; ++ slot->pages = vma_pages(vma); ++ spin_lock(&vma_slot_list_lock); ++ list_add_tail(&slot->slot_list, &vma_slot_new); ++ spin_unlock(&vma_slot_list_lock); ++} ++ ++/* 32/3 < they < 32/2 */ ++#define shiftl 8 ++#define shiftr 12 ++ ++#define HASH_FROM_TO(from, to) \ ++for (index = from; index < to; index++) { \ ++ pos = random_nums[index]; \ ++ hash += key[pos]; \ ++ hash += (hash << shiftl); \ ++ hash ^= (hash >> shiftr); \ ++} ++ ++ ++#define HASH_FROM_DOWN_TO(from, to) \ ++for (index = from - 1; index >= to; index--) { \ ++ hash ^= (hash >> shiftr); \ ++ hash ^= (hash >> (shiftr*2)); \ ++ hash -= (hash << shiftl); \ ++ hash += (hash << (shiftl*2)); \ ++ pos = random_nums[index]; \ ++ hash -= key[pos]; \ ++} ++ ++/* ++ * The main random sample hash function. ++ */ ++static u32 random_sample_hash(void *addr, u32 hash_strength) ++{ ++ u32 hash = 0xdeadbeef; ++ int index, pos, loop = hash_strength; ++ u32 *key = (u32 *)addr; ++ ++ if (loop > HASH_STRENGTH_FULL) ++ loop = HASH_STRENGTH_FULL; ++ ++ HASH_FROM_TO(0, loop); ++ ++ if (hash_strength > HASH_STRENGTH_FULL) { ++ loop = hash_strength - HASH_STRENGTH_FULL; ++ HASH_FROM_TO(0, loop); ++ } ++ ++ return hash; ++} ++ ++ ++/** ++ * It's used when hash strength is adjusted ++ * ++ * @addr The page's virtual address ++ * @from The original hash strength ++ * @to The hash strength changed to ++ * @hash The hash value generated with "from" hash value ++ * ++ * return the hash value ++ */ ++static u32 delta_hash(void *addr, int from, int to, u32 hash) ++{ ++ u32 *key = (u32 *)addr; ++ int index, pos; /* make sure they are int type */ ++ ++ if (to > from) { ++ if (from >= HASH_STRENGTH_FULL) { ++ from -= HASH_STRENGTH_FULL; ++ to -= HASH_STRENGTH_FULL; ++ HASH_FROM_TO(from, to); ++ } else if (to <= HASH_STRENGTH_FULL) { ++ HASH_FROM_TO(from, to); ++ } else { ++ HASH_FROM_TO(from, HASH_STRENGTH_FULL); ++ HASH_FROM_TO(0, to - HASH_STRENGTH_FULL); ++ } ++ } else { ++ if (from <= HASH_STRENGTH_FULL) { ++ HASH_FROM_DOWN_TO(from, to); ++ } else if (to >= HASH_STRENGTH_FULL) { ++ from -= HASH_STRENGTH_FULL; ++ to -= HASH_STRENGTH_FULL; ++ HASH_FROM_DOWN_TO(from, to); ++ } else { ++ HASH_FROM_DOWN_TO(from - HASH_STRENGTH_FULL, 0); ++ HASH_FROM_DOWN_TO(HASH_STRENGTH_FULL, to); ++ } ++ } ++ ++ return hash; ++} ++ ++/** ++ * ++ * Called when: rshash_pos or rshash_neg is about to overflow or a scan round ++ * has finished. ++ * ++ * return 0 if no page has been scanned since last call, 1 otherwise. ++ */ ++static inline int encode_benefit(void) ++{ ++ u64 scanned_delta, pos_delta, neg_delta; ++ unsigned long base = benefit.base; ++ ++ scanned_delta = uksm_pages_scanned - uksm_pages_scanned_last; ++ ++ if (!scanned_delta) ++ return 0; ++ ++ scanned_delta >>= base; ++ pos_delta = rshash_pos >> base; ++ neg_delta = rshash_neg >> base; ++ ++ if (CAN_OVERFLOW_U64(benefit.pos, pos_delta) || ++ CAN_OVERFLOW_U64(benefit.neg, neg_delta) || ++ CAN_OVERFLOW_U64(benefit.scanned, scanned_delta)) { ++ benefit.scanned >>= 1; ++ benefit.neg >>= 1; ++ benefit.pos >>= 1; ++ benefit.base++; ++ scanned_delta >>= 1; ++ pos_delta >>= 1; ++ neg_delta >>= 1; ++ } ++ ++ benefit.pos += pos_delta; ++ benefit.neg += neg_delta; ++ benefit.scanned += scanned_delta; ++ ++ BUG_ON(!benefit.scanned); ++ ++ rshash_pos = rshash_neg = 0; ++ uksm_pages_scanned_last = uksm_pages_scanned; ++ ++ return 1; ++} ++ ++static inline void reset_benefit(void) ++{ ++ benefit.pos = 0; ++ benefit.neg = 0; ++ benefit.base = 0; ++ benefit.scanned = 0; ++} ++ ++static inline void inc_rshash_pos(unsigned long delta) ++{ ++ if (CAN_OVERFLOW_U64(rshash_pos, delta)) ++ encode_benefit(); ++ ++ rshash_pos += delta; ++} ++ ++static inline void inc_rshash_neg(unsigned long delta) ++{ ++ if (CAN_OVERFLOW_U64(rshash_neg, delta)) ++ encode_benefit(); ++ ++ rshash_neg += delta; ++} ++ ++ ++static inline u32 page_hash(struct page *page, unsigned long hash_strength, ++ int cost_accounting) ++{ ++ u32 val; ++ unsigned long delta; ++ ++ void *addr = kmap_atomic(page); ++ ++ val = random_sample_hash(addr, hash_strength); ++ kunmap_atomic(addr); ++ ++ if (cost_accounting) { ++ if (hash_strength < HASH_STRENGTH_FULL) ++ delta = HASH_STRENGTH_FULL - hash_strength; ++ else ++ delta = 0; ++ ++ inc_rshash_pos(delta); ++ } ++ ++ return val; ++} ++ ++static int memcmp_pages(struct page *page1, struct page *page2, ++ int cost_accounting) ++{ ++ char *addr1, *addr2; ++ int ret; ++ ++ addr1 = kmap_atomic(page1); ++ addr2 = kmap_atomic(page2); ++ ret = memcmp(addr1, addr2, PAGE_SIZE); ++ kunmap_atomic(addr2); ++ kunmap_atomic(addr1); ++ ++ if (cost_accounting) ++ inc_rshash_neg(memcmp_cost); ++ ++ return ret; ++} ++ ++static inline int pages_identical(struct page *page1, struct page *page2) ++{ ++ return !memcmp_pages(page1, page2, 0); ++} ++ ++static inline int is_page_full_zero(struct page *page) ++{ ++ char *addr; ++ int ret; ++ ++ addr = kmap_atomic(page); ++ ret = is_full_zero(addr, PAGE_SIZE); ++ kunmap_atomic(addr); ++ ++ return ret; ++} ++ ++static int write_protect_page(struct vm_area_struct *vma, struct page *page, ++ pte_t *orig_pte, pte_t *old_pte) ++{ ++ struct mm_struct *mm = vma->vm_mm; ++ struct page_vma_mapped_walk pvmw = { ++ .page = page, ++ .vma = vma, ++ }; ++ int swapped; ++ int err = -EFAULT; ++ struct mmu_notifier_range range; ++ ++ pvmw.address = page_address_in_vma(page, vma); ++ if (pvmw.address == -EFAULT) ++ goto out; ++ ++ BUG_ON(PageTransCompound(page)); ++ ++ mmu_notifier_range_init(&range, mm, pvmw.address, pvmw.address + PAGE_SIZE); ++ mmu_notifier_invalidate_range_start(&range); ++ ++ if (!page_vma_mapped_walk(&pvmw)) ++ goto out_mn; ++ if (WARN_ONCE(!pvmw.pte, "Unexpected PMD mapping?")) ++ goto out_unlock; ++ ++ if (old_pte) ++ *old_pte = *pvmw.pte; ++ ++ if (pte_write(*pvmw.pte) || pte_dirty(*pvmw.pte) || ++ (pte_protnone(*pvmw.pte) && pte_savedwrite(*pvmw.pte)) || mm_tlb_flush_pending(mm)) { ++ pte_t entry; ++ ++ swapped = PageSwapCache(page); ++ flush_cache_page(vma, pvmw.address, page_to_pfn(page)); ++ /* ++ * Ok this is tricky, when get_user_pages_fast() run it doesn't ++ * take any lock, therefore the check that we are going to make ++ * with the pagecount against the mapcount is racey and ++ * O_DIRECT can happen right after the check. ++ * So we clear the pte and flush the tlb before the check ++ * this assure us that no O_DIRECT can happen after the check ++ * or in the middle of the check. ++ */ ++ entry = ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte); ++ /* ++ * Check that no O_DIRECT or similar I/O is in progress on the ++ * page ++ */ ++ if (page_mapcount(page) + 1 + swapped != page_count(page)) { ++ set_pte_at(mm, pvmw.address, pvmw.pte, entry); ++ goto out_unlock; ++ } ++ if (pte_dirty(entry)) ++ set_page_dirty(page); ++ ++ if (pte_protnone(entry)) ++ entry = pte_mkclean(pte_clear_savedwrite(entry)); ++ else ++ entry = pte_mkclean(pte_wrprotect(entry)); ++ ++ set_pte_at_notify(mm, pvmw.address, pvmw.pte, entry); ++ } ++ *orig_pte = *pvmw.pte; ++ err = 0; ++ ++out_unlock: ++ page_vma_mapped_walk_done(&pvmw); ++out_mn: ++ mmu_notifier_invalidate_range_end(&range); ++out: ++ return err; ++} ++ ++#define MERGE_ERR_PGERR 1 /* the page is invalid cannot continue */ ++#define MERGE_ERR_COLLI 2 /* there is a collision */ ++#define MERGE_ERR_COLLI_MAX 3 /* collision at the max hash strength */ ++#define MERGE_ERR_CHANGED 4 /* the page has changed since last hash */ ++ ++ ++/** ++ * replace_page - replace page in vma by new ksm page ++ * @vma: vma that holds the pte pointing to page ++ * @page: the page we are replacing by kpage ++ * @kpage: the ksm page we replace page by ++ * @orig_pte: the original value of the pte ++ * ++ * Returns 0 on success, MERGE_ERR_PGERR on failure. ++ */ ++static int replace_page(struct vm_area_struct *vma, struct page *page, ++ struct page *kpage, pte_t orig_pte) ++{ ++ struct mm_struct *mm = vma->vm_mm; ++ pgd_t *pgd; ++ p4d_t *p4d; ++ pud_t *pud; ++ pmd_t *pmd; ++ pte_t *ptep; ++ spinlock_t *ptl; ++ pte_t entry; ++ ++ unsigned long addr; ++ int err = MERGE_ERR_PGERR; ++ struct mmu_notifier_range range; ++ ++ addr = page_address_in_vma(page, vma); ++ if (addr == -EFAULT) ++ goto out; ++ ++ pgd = pgd_offset(mm, addr); ++ if (!pgd_present(*pgd)) ++ goto out; ++ ++ p4d = p4d_offset(pgd, addr); ++ pud = pud_offset(p4d, addr); ++ if (!pud_present(*pud)) ++ goto out; ++ ++ pmd = pmd_offset(pud, addr); ++ BUG_ON(pmd_trans_huge(*pmd)); ++ if (!pmd_present(*pmd)) ++ goto out; ++ ++ mmu_notifier_range_init(&range, mm, addr, addr + PAGE_SIZE); ++ mmu_notifier_invalidate_range_start(&range); ++ ++ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); ++ if (!pte_same(*ptep, orig_pte)) { ++ pte_unmap_unlock(ptep, ptl); ++ goto out_mn; ++ } ++ ++ flush_cache_page(vma, addr, pte_pfn(*ptep)); ++ ptep_clear_flush_notify(vma, addr, ptep); ++ entry = mk_pte(kpage, vma->vm_page_prot); ++ ++ /* special treatment is needed for zero_page */ ++ if ((page_to_pfn(kpage) == uksm_zero_pfn) || ++ (page_to_pfn(kpage) == zero_pfn)) { ++ entry = pte_mkspecial(entry); ++ dec_mm_counter(mm, MM_ANONPAGES); ++ inc_zone_page_state(page, NR_UKSM_ZERO_PAGES); ++ } else { ++ get_page(kpage); ++ page_add_anon_rmap(kpage, vma, addr, false); ++ } ++ ++ set_pte_at_notify(mm, addr, ptep, entry); ++ ++ page_remove_rmap(page, false); ++ if (!page_mapped(page)) ++ try_to_free_swap(page); ++ put_page(page); ++ ++ pte_unmap_unlock(ptep, ptl); ++ err = 0; ++out_mn: ++ mmu_notifier_invalidate_range_end(&range); ++out: ++ return err; ++} ++ ++ ++/** ++ * Fully hash a page with HASH_STRENGTH_MAX return a non-zero hash value. The ++ * zero hash value at HASH_STRENGTH_MAX is used to indicated that its ++ * hash_max member has not been calculated. ++ * ++ * @page The page needs to be hashed ++ * @hash_old The hash value calculated with current hash strength ++ * ++ * return the new hash value calculated at HASH_STRENGTH_MAX ++ */ ++static inline u32 page_hash_max(struct page *page, u32 hash_old) ++{ ++ u32 hash_max = 0; ++ void *addr; ++ ++ addr = kmap_atomic(page); ++ hash_max = delta_hash(addr, hash_strength, ++ HASH_STRENGTH_MAX, hash_old); ++ ++ kunmap_atomic(addr); ++ ++ if (!hash_max) ++ hash_max = 1; ++ ++ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); ++ return hash_max; ++} ++ ++/* ++ * We compare the hash again, to ensure that it is really a hash collision ++ * instead of being caused by page write. ++ */ ++static inline int check_collision(struct rmap_item *rmap_item, ++ u32 hash) ++{ ++ int err; ++ struct page *page = rmap_item->page; ++ ++ /* if this rmap_item has already been hash_maxed, then the collision ++ * must appears in the second-level rbtree search. In this case we check ++ * if its hash_max value has been changed. Otherwise, the collision ++ * happens in the first-level rbtree search, so we check against it's ++ * current hash value. ++ */ ++ if (rmap_item->hash_max) { ++ inc_rshash_neg(memcmp_cost); ++ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); ++ ++ if (rmap_item->hash_max == page_hash_max(page, hash)) ++ err = MERGE_ERR_COLLI; ++ else ++ err = MERGE_ERR_CHANGED; ++ } else { ++ inc_rshash_neg(memcmp_cost + hash_strength); ++ ++ if (page_hash(page, hash_strength, 0) == hash) ++ err = MERGE_ERR_COLLI; ++ else ++ err = MERGE_ERR_CHANGED; ++ } ++ ++ return err; ++} ++ ++/** ++ * Try to merge a rmap_item.page with a kpage in stable node. kpage must ++ * already be a ksm page. ++ * ++ * @return 0 if the pages were merged, -EFAULT otherwise. ++ */ ++static int try_to_merge_with_uksm_page(struct rmap_item *rmap_item, ++ struct page *kpage, u32 hash) ++{ ++ struct vm_area_struct *vma = rmap_item->slot->vma; ++ struct mm_struct *mm = vma->vm_mm; ++ pte_t orig_pte = __pte(0); ++ int err = MERGE_ERR_PGERR; ++ struct page *page; ++ ++ if (uksm_test_exit(mm)) ++ goto out; ++ ++ page = rmap_item->page; ++ ++ if (page == kpage) { /* ksm page forked */ ++ err = 0; ++ goto out; ++ } ++ ++ /* ++ * We need the page lock to read a stable PageSwapCache in ++ * write_protect_page(). We use trylock_page() instead of ++ * lock_page() because we don't want to wait here - we ++ * prefer to continue scanning and merging different pages, ++ * then come back to this page when it is unlocked. ++ */ ++ if (!trylock_page(page)) ++ goto out; ++ ++ if (!PageAnon(page) || !PageKsm(kpage)) ++ goto out_unlock; ++ ++ if (PageTransCompound(page)) { ++ err = split_huge_page(page); ++ if (err) ++ goto out_unlock; ++ } ++ ++ /* ++ * If this anonymous page is mapped only here, its pte may need ++ * to be write-protected. If it's mapped elsewhere, all of its ++ * ptes are necessarily already write-protected. But in either ++ * case, we need to lock and check page_count is not raised. ++ */ ++ if (write_protect_page(vma, page, &orig_pte, NULL) == 0) { ++ if (pages_identical(page, kpage)) ++ err = replace_page(vma, page, kpage, orig_pte); ++ else ++ err = check_collision(rmap_item, hash); ++ } ++ ++ if ((vma->vm_flags & VM_LOCKED) && kpage && !err) { ++ munlock_vma_page(page); ++ if (!PageMlocked(kpage)) { ++ unlock_page(page); ++ lock_page(kpage); ++ mlock_vma_page(kpage); ++ page = kpage; /* for final unlock */ ++ } ++ } ++ ++out_unlock: ++ unlock_page(page); ++out: ++ return err; ++} ++ ++ ++ ++/** ++ * If two pages fail to merge in try_to_merge_two_pages, then we have a chance ++ * to restore a page mapping that has been changed in try_to_merge_two_pages. ++ * ++ * @return 0 on success. ++ */ ++static int restore_uksm_page_pte(struct vm_area_struct *vma, unsigned long addr, ++ pte_t orig_pte, pte_t wprt_pte) ++{ ++ struct mm_struct *mm = vma->vm_mm; ++ pgd_t *pgd; ++ p4d_t *p4d; ++ pud_t *pud; ++ pmd_t *pmd; ++ pte_t *ptep; ++ spinlock_t *ptl; ++ ++ int err = -EFAULT; ++ ++ pgd = pgd_offset(mm, addr); ++ if (!pgd_present(*pgd)) ++ goto out; ++ ++ p4d = p4d_offset(pgd, addr); ++ pud = pud_offset(p4d, addr); ++ if (!pud_present(*pud)) ++ goto out; ++ ++ pmd = pmd_offset(pud, addr); ++ if (!pmd_present(*pmd)) ++ goto out; ++ ++ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); ++ if (!pte_same(*ptep, wprt_pte)) { ++ /* already copied, let it be */ ++ pte_unmap_unlock(ptep, ptl); ++ goto out; ++ } ++ ++ /* ++ * Good boy, still here. When we still get the ksm page, it does not ++ * return to the free page pool, there is no way that a pte was changed ++ * to other page and gets back to this page. And remind that ksm page ++ * do not reuse in do_wp_page(). So it's safe to restore the original ++ * pte. ++ */ ++ flush_cache_page(vma, addr, pte_pfn(*ptep)); ++ ptep_clear_flush_notify(vma, addr, ptep); ++ set_pte_at_notify(mm, addr, ptep, orig_pte); ++ ++ pte_unmap_unlock(ptep, ptl); ++ err = 0; ++out: ++ return err; ++} ++ ++/** ++ * try_to_merge_two_pages() - take two identical pages and prepare ++ * them to be merged into one page(rmap_item->page) ++ * ++ * @return 0 if we successfully merged two identical pages into ++ * one ksm page. MERGE_ERR_COLLI if it's only a hash collision ++ * search in rbtree. MERGE_ERR_CHANGED if rmap_item has been ++ * changed since it's hashed. MERGE_ERR_PGERR otherwise. ++ * ++ */ ++static int try_to_merge_two_pages(struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ u32 hash) ++{ ++ pte_t orig_pte1 = __pte(0), orig_pte2 = __pte(0); ++ pte_t wprt_pte1 = __pte(0), wprt_pte2 = __pte(0); ++ struct vm_area_struct *vma1 = rmap_item->slot->vma; ++ struct vm_area_struct *vma2 = tree_rmap_item->slot->vma; ++ struct page *page = rmap_item->page; ++ struct page *tree_page = tree_rmap_item->page; ++ int err = MERGE_ERR_PGERR; ++ struct address_space *saved_mapping; ++ ++ ++ if (rmap_item->page == tree_rmap_item->page) ++ goto out; ++ ++ if (!trylock_page(page)) ++ goto out; ++ ++ if (!PageAnon(page)) ++ goto out_unlock; ++ ++ if (PageTransCompound(page)) { ++ err = split_huge_page(page); ++ if (err) ++ goto out_unlock; ++ } ++ ++ if (write_protect_page(vma1, page, &wprt_pte1, &orig_pte1) != 0) { ++ unlock_page(page); ++ goto out; ++ } ++ ++ /* ++ * While we hold page lock, upgrade page from ++ * PageAnon+anon_vma to PageKsm+NULL stable_node: ++ * stable_tree_insert() will update stable_node. ++ */ ++ saved_mapping = page->mapping; ++ set_page_stable_node(page, NULL); ++ mark_page_accessed(page); ++ if (!PageDirty(page)) ++ SetPageDirty(page); ++ ++ unlock_page(page); ++ ++ if (!trylock_page(tree_page)) ++ goto restore_out; ++ ++ if (!PageAnon(tree_page)) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ ++ if (PageTransCompound(tree_page)) { ++ err = split_huge_page(tree_page); ++ if (err) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ } ++ ++ if (write_protect_page(vma2, tree_page, &wprt_pte2, &orig_pte2) != 0) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ ++ if (pages_identical(page, tree_page)) { ++ err = replace_page(vma2, tree_page, page, wprt_pte2); ++ if (err) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ ++ if ((vma2->vm_flags & VM_LOCKED)) { ++ munlock_vma_page(tree_page); ++ if (!PageMlocked(page)) { ++ unlock_page(tree_page); ++ lock_page(page); ++ mlock_vma_page(page); ++ tree_page = page; /* for final unlock */ ++ } ++ } ++ ++ unlock_page(tree_page); ++ ++ goto out; /* success */ ++ ++ } else { ++ if (tree_rmap_item->hash_max && ++ tree_rmap_item->hash_max == rmap_item->hash_max) { ++ err = MERGE_ERR_COLLI_MAX; ++ } else if (page_hash(page, hash_strength, 0) == ++ page_hash(tree_page, hash_strength, 0)) { ++ inc_rshash_neg(memcmp_cost + hash_strength * 2); ++ err = MERGE_ERR_COLLI; ++ } else { ++ err = MERGE_ERR_CHANGED; ++ } ++ ++ unlock_page(tree_page); ++ } ++ ++restore_out: ++ lock_page(page); ++ if (!restore_uksm_page_pte(vma1, get_rmap_addr(rmap_item), ++ orig_pte1, wprt_pte1)) ++ page->mapping = saved_mapping; ++ ++out_unlock: ++ unlock_page(page); ++out: ++ return err; ++} ++ ++static inline int hash_cmp(u32 new_val, u32 node_val) ++{ ++ if (new_val > node_val) ++ return 1; ++ else if (new_val < node_val) ++ return -1; ++ else ++ return 0; ++} ++ ++static inline u32 rmap_item_hash_max(struct rmap_item *item, u32 hash) ++{ ++ u32 hash_max = item->hash_max; ++ ++ if (!hash_max) { ++ hash_max = page_hash_max(item->page, hash); ++ ++ item->hash_max = hash_max; ++ } ++ ++ return hash_max; ++} ++ ++ ++ ++/** ++ * stable_tree_search() - search the stable tree for a page ++ * ++ * @item: the rmap_item we are comparing with ++ * @hash: the hash value of this item->page already calculated ++ * ++ * @return the page we have found, NULL otherwise. The page returned has ++ * been gotten. ++ */ ++static struct page *stable_tree_search(struct rmap_item *item, u32 hash) ++{ ++ struct rb_node *node = root_stable_treep->rb_node; ++ struct tree_node *tree_node; ++ unsigned long hash_max; ++ struct page *page = item->page; ++ struct stable_node *stable_node; ++ ++ stable_node = page_stable_node(page); ++ if (stable_node) { ++ /* ksm page forked, that is ++ * if (PageKsm(page) && !in_stable_tree(rmap_item)) ++ * it's actually gotten once outside. ++ */ ++ get_page(page); ++ return page; ++ } ++ ++ while (node) { ++ int cmp; ++ ++ tree_node = rb_entry(node, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) ++ node = node->rb_left; ++ else if (cmp > 0) ++ node = node->rb_right; ++ else ++ break; ++ } ++ ++ if (!node) ++ return NULL; ++ ++ if (tree_node->count == 1) { ++ stable_node = rb_entry(tree_node->sub_root.rb_node, ++ struct stable_node, node); ++ BUG_ON(!stable_node); ++ ++ goto get_page_out; ++ } ++ ++ /* ++ * ok, we have to search the second ++ * level subtree, hash the page to a ++ * full strength. ++ */ ++ node = tree_node->sub_root.rb_node; ++ BUG_ON(!node); ++ hash_max = rmap_item_hash_max(item, hash); ++ ++ while (node) { ++ int cmp; ++ ++ stable_node = rb_entry(node, struct stable_node, node); ++ ++ cmp = hash_cmp(hash_max, stable_node->hash_max); ++ ++ if (cmp < 0) ++ node = node->rb_left; ++ else if (cmp > 0) ++ node = node->rb_right; ++ else ++ goto get_page_out; ++ } ++ ++ return NULL; ++ ++get_page_out: ++ page = get_uksm_page(stable_node, 1, 1); ++ return page; ++} ++ ++static int try_merge_rmap_item(struct rmap_item *item, ++ struct page *kpage, ++ struct page *tree_page) ++{ ++ struct vm_area_struct *vma = item->slot->vma; ++ struct page_vma_mapped_walk pvmw = { ++ .page = kpage, ++ .vma = vma, ++ }; ++ ++ pvmw.address = get_rmap_addr(item); ++ if (!page_vma_mapped_walk(&pvmw)) ++ return 0; ++ ++ if (pte_write(*pvmw.pte)) { ++ /* has changed, abort! */ ++ page_vma_mapped_walk_done(&pvmw); ++ return 0; ++ } ++ ++ get_page(tree_page); ++ page_add_anon_rmap(tree_page, vma, pvmw.address, false); ++ ++ flush_cache_page(vma, pvmw.address, page_to_pfn(kpage)); ++ ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte); ++ set_pte_at_notify(vma->vm_mm, pvmw.address, pvmw.pte, ++ mk_pte(tree_page, vma->vm_page_prot)); ++ ++ page_remove_rmap(kpage, false); ++ put_page(kpage); ++ ++ page_vma_mapped_walk_done(&pvmw); ++ ++ return 1; ++} ++ ++/** ++ * try_to_merge_with_stable_page() - when two rmap_items need to be inserted ++ * into stable tree, the page was found to be identical to a stable ksm page, ++ * this is the last chance we can merge them into one. ++ * ++ * @item1: the rmap_item holding the page which we wanted to insert ++ * into stable tree. ++ * @item2: the other rmap_item we found when unstable tree search ++ * @oldpage: the page currently mapped by the two rmap_items ++ * @tree_page: the page we found identical in stable tree node ++ * @success1: return if item1 is successfully merged ++ * @success2: return if item2 is successfully merged ++ */ ++static void try_merge_with_stable(struct rmap_item *item1, ++ struct rmap_item *item2, ++ struct page **kpage, ++ struct page *tree_page, ++ int *success1, int *success2) ++{ ++ struct vm_area_struct *vma1 = item1->slot->vma; ++ struct vm_area_struct *vma2 = item2->slot->vma; ++ *success1 = 0; ++ *success2 = 0; ++ ++ if (unlikely(*kpage == tree_page)) { ++ /* I don't think this can really happen */ ++ pr_warn("UKSM: unexpected condition detected in " ++ "%s -- *kpage == tree_page !\n", __func__); ++ *success1 = 1; ++ *success2 = 1; ++ return; ++ } ++ ++ if (!PageAnon(*kpage) || !PageKsm(*kpage)) ++ goto failed; ++ ++ if (!trylock_page(tree_page)) ++ goto failed; ++ ++ /* If the oldpage is still ksm and still pointed ++ * to in the right place, and still write protected, ++ * we are confident it's not changed, no need to ++ * memcmp anymore. ++ * be ware, we cannot take nested pte locks, ++ * deadlock risk. ++ */ ++ if (!try_merge_rmap_item(item1, *kpage, tree_page)) ++ goto unlock_failed; ++ ++ /* ok, then vma2, remind that pte1 already set */ ++ if (!try_merge_rmap_item(item2, *kpage, tree_page)) ++ goto success_1; ++ ++ *success2 = 1; ++success_1: ++ *success1 = 1; ++ ++ ++ if ((*success1 && vma1->vm_flags & VM_LOCKED) || ++ (*success2 && vma2->vm_flags & VM_LOCKED)) { ++ munlock_vma_page(*kpage); ++ if (!PageMlocked(tree_page)) ++ mlock_vma_page(tree_page); ++ } ++ ++ /* ++ * We do not need oldpage any more in the caller, so can break the lock ++ * now. ++ */ ++ unlock_page(*kpage); ++ *kpage = tree_page; /* Get unlocked outside. */ ++ return; ++ ++unlock_failed: ++ unlock_page(tree_page); ++failed: ++ return; ++} ++ ++static inline void stable_node_hash_max(struct stable_node *node, ++ struct page *page, u32 hash) ++{ ++ u32 hash_max = node->hash_max; ++ ++ if (!hash_max) { ++ hash_max = page_hash_max(page, hash); ++ node->hash_max = hash_max; ++ } ++} ++ ++static inline ++struct stable_node *new_stable_node(struct tree_node *tree_node, ++ struct page *kpage, u32 hash_max) ++{ ++ struct stable_node *new_stable_node; ++ ++ new_stable_node = alloc_stable_node(); ++ if (!new_stable_node) ++ return NULL; ++ ++ new_stable_node->kpfn = page_to_pfn(kpage); ++ new_stable_node->hash_max = hash_max; ++ new_stable_node->tree_node = tree_node; ++ set_page_stable_node(kpage, new_stable_node); ++ ++ return new_stable_node; ++} ++ ++static inline ++struct stable_node *first_level_insert(struct tree_node *tree_node, ++ struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ struct page **kpage, u32 hash, ++ int *success1, int *success2) ++{ ++ int cmp; ++ struct page *tree_page; ++ u32 hash_max = 0; ++ struct stable_node *stable_node, *new_snode; ++ struct rb_node *parent = NULL, **new; ++ ++ /* this tree node contains no sub-tree yet */ ++ stable_node = rb_entry(tree_node->sub_root.rb_node, ++ struct stable_node, node); ++ ++ tree_page = get_uksm_page(stable_node, 1, 0); ++ if (tree_page) { ++ cmp = memcmp_pages(*kpage, tree_page, 1); ++ if (!cmp) { ++ try_merge_with_stable(rmap_item, tree_rmap_item, kpage, ++ tree_page, success1, success2); ++ put_page(tree_page); ++ if (!*success1 && !*success2) ++ goto failed; ++ ++ return stable_node; ++ ++ } else { ++ /* ++ * collision in first level try to create a subtree. ++ * A new node need to be created. ++ */ ++ put_page(tree_page); ++ ++ stable_node_hash_max(stable_node, tree_page, ++ tree_node->hash); ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ cmp = hash_cmp(hash_max, stable_node->hash_max); ++ ++ parent = &stable_node->node; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto failed; ++ } ++ ++ } else { ++ /* the only stable_node deleted, we reuse its tree_node. ++ */ ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ ++ new_snode = new_stable_node(tree_node, *kpage, hash_max); ++ if (!new_snode) ++ goto failed; ++ ++ rb_link_node(&new_snode->node, parent, new); ++ rb_insert_color(&new_snode->node, &tree_node->sub_root); ++ tree_node->count++; ++ *success1 = *success2 = 1; ++ ++ return new_snode; ++ ++failed: ++ return NULL; ++} ++ ++static inline ++struct stable_node *stable_subtree_insert(struct tree_node *tree_node, ++ struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ struct page **kpage, u32 hash, ++ int *success1, int *success2) ++{ ++ struct page *tree_page; ++ u32 hash_max; ++ struct stable_node *stable_node, *new_snode; ++ struct rb_node *parent, **new; ++ ++research: ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ BUG_ON(!*new); ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ while (*new) { ++ int cmp; ++ ++ stable_node = rb_entry(*new, struct stable_node, node); ++ ++ cmp = hash_cmp(hash_max, stable_node->hash_max); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else { ++ tree_page = get_uksm_page(stable_node, 1, 0); ++ if (tree_page) { ++ cmp = memcmp_pages(*kpage, tree_page, 1); ++ if (!cmp) { ++ try_merge_with_stable(rmap_item, ++ tree_rmap_item, kpage, ++ tree_page, success1, success2); ++ ++ put_page(tree_page); ++ if (!*success1 && !*success2) ++ goto failed; ++ /* ++ * successfully merged with a stable ++ * node ++ */ ++ return stable_node; ++ } else { ++ put_page(tree_page); ++ goto failed; ++ } ++ } else { ++ /* ++ * stable node may be deleted, ++ * and subtree maybe ++ * restructed, cannot ++ * continue, research it. ++ */ ++ if (tree_node->count) { ++ goto research; ++ } else { ++ /* reuse the tree node*/ ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ } ++ } ++ } ++ ++ new_snode = new_stable_node(tree_node, *kpage, hash_max); ++ if (!new_snode) ++ goto failed; ++ ++ rb_link_node(&new_snode->node, parent, new); ++ rb_insert_color(&new_snode->node, &tree_node->sub_root); ++ tree_node->count++; ++ *success1 = *success2 = 1; ++ ++ return new_snode; ++ ++failed: ++ return NULL; ++} ++ ++ ++/** ++ * stable_tree_insert() - try to insert a merged page in unstable tree to ++ * the stable tree ++ * ++ * @kpage: the page need to be inserted ++ * @hash: the current hash of this page ++ * @rmap_item: the rmap_item being scanned ++ * @tree_rmap_item: the rmap_item found on unstable tree ++ * @success1: return if rmap_item is merged ++ * @success2: return if tree_rmap_item is merged ++ * ++ * @return the stable_node on stable tree if at least one ++ * rmap_item is inserted into stable tree, NULL ++ * otherwise. ++ */ ++static struct stable_node * ++stable_tree_insert(struct page **kpage, u32 hash, ++ struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ int *success1, int *success2) ++{ ++ struct rb_node **new = &root_stable_treep->rb_node; ++ struct rb_node *parent = NULL; ++ struct stable_node *stable_node; ++ struct tree_node *tree_node; ++ u32 hash_max = 0; ++ ++ *success1 = *success2 = 0; ++ ++ while (*new) { ++ int cmp; ++ ++ tree_node = rb_entry(*new, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else ++ break; ++ } ++ ++ if (*new) { ++ if (tree_node->count == 1) { ++ stable_node = first_level_insert(tree_node, rmap_item, ++ tree_rmap_item, kpage, ++ hash, success1, success2); ++ } else { ++ stable_node = stable_subtree_insert(tree_node, ++ rmap_item, tree_rmap_item, kpage, ++ hash, success1, success2); ++ } ++ } else { ++ ++ /* no tree node found */ ++ tree_node = alloc_tree_node(stable_tree_node_listp); ++ if (!tree_node) { ++ stable_node = NULL; ++ goto out; ++ } ++ ++ stable_node = new_stable_node(tree_node, *kpage, hash_max); ++ if (!stable_node) { ++ free_tree_node(tree_node); ++ goto out; ++ } ++ ++ tree_node->hash = hash; ++ rb_link_node(&tree_node->node, parent, new); ++ rb_insert_color(&tree_node->node, root_stable_treep); ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ ++ rb_link_node(&stable_node->node, parent, new); ++ rb_insert_color(&stable_node->node, &tree_node->sub_root); ++ tree_node->count++; ++ *success1 = *success2 = 1; ++ } ++ ++out: ++ return stable_node; ++} ++ ++ ++/** ++ * get_tree_rmap_item_page() - try to get the page and lock the mmap_sem ++ * ++ * @return 0 on success, -EBUSY if unable to lock the mmap_sem, ++ * -EINVAL if the page mapping has been changed. ++ */ ++static inline int get_tree_rmap_item_page(struct rmap_item *tree_rmap_item) ++{ ++ int err; ++ ++ err = get_mergeable_page_lock_mmap(tree_rmap_item); ++ ++ if (err == -EINVAL) { ++ /* its page map has been changed, remove it */ ++ remove_rmap_item_from_tree(tree_rmap_item); ++ } ++ ++ /* The page is gotten and mmap_sem is locked now. */ ++ return err; ++} ++ ++ ++/** ++ * unstable_tree_search_insert() - search an unstable tree rmap_item with the ++ * same hash value. Get its page and trylock the mmap_sem ++ */ ++static inline ++struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, ++ u32 hash) ++ ++{ ++ struct rb_node **new = &root_unstable_tree.rb_node; ++ struct rb_node *parent = NULL; ++ struct tree_node *tree_node; ++ u32 hash_max; ++ struct rmap_item *tree_rmap_item; ++ ++ while (*new) { ++ int cmp; ++ ++ tree_node = rb_entry(*new, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else ++ break; ++ } ++ ++ if (*new) { ++ /* got the tree_node */ ++ if (tree_node->count == 1) { ++ tree_rmap_item = rb_entry(tree_node->sub_root.rb_node, ++ struct rmap_item, node); ++ BUG_ON(!tree_rmap_item); ++ ++ goto get_page_out; ++ } ++ ++ /* well, search the collision subtree */ ++ new = &tree_node->sub_root.rb_node; ++ BUG_ON(!*new); ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ ++ while (*new) { ++ int cmp; ++ ++ tree_rmap_item = rb_entry(*new, struct rmap_item, ++ node); ++ ++ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); ++ parent = *new; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto get_page_out; ++ } ++ } else { ++ /* alloc a new tree_node */ ++ tree_node = alloc_tree_node(&unstable_tree_node_list); ++ if (!tree_node) ++ return NULL; ++ ++ tree_node->hash = hash; ++ rb_link_node(&tree_node->node, parent, new); ++ rb_insert_color(&tree_node->node, &root_unstable_tree); ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ ++ /* did not found even in sub-tree */ ++ rmap_item->tree_node = tree_node; ++ rmap_item->address |= UNSTABLE_FLAG; ++ rmap_item->hash_round = uksm_hash_round; ++ rb_link_node(&rmap_item->node, parent, new); ++ rb_insert_color(&rmap_item->node, &tree_node->sub_root); ++ ++ uksm_pages_unshared++; ++ return NULL; ++ ++get_page_out: ++ if (tree_rmap_item->page == rmap_item->page) ++ return NULL; ++ ++ if (get_tree_rmap_item_page(tree_rmap_item)) ++ return NULL; ++ ++ return tree_rmap_item; ++} ++ ++static void hold_anon_vma(struct rmap_item *rmap_item, ++ struct anon_vma *anon_vma) ++{ ++ rmap_item->anon_vma = anon_vma; ++ get_anon_vma(anon_vma); ++} ++ ++ ++/** ++ * stable_tree_append() - append a rmap_item to a stable node. Deduplication ++ * ratio statistics is done in this function. ++ * ++ */ ++static void stable_tree_append(struct rmap_item *rmap_item, ++ struct stable_node *stable_node, int logdedup) ++{ ++ struct node_vma *node_vma = NULL, *new_node_vma, *node_vma_cont = NULL; ++ unsigned long key = (unsigned long)rmap_item->slot; ++ unsigned long factor = rmap_item->slot->rung->step; ++ ++ BUG_ON(!stable_node); ++ rmap_item->address |= STABLE_FLAG; ++ ++ if (hlist_empty(&stable_node->hlist)) { ++ uksm_pages_shared++; ++ goto node_vma_new; ++ } else { ++ uksm_pages_sharing++; ++ } ++ ++ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { ++ if (node_vma->key >= key) ++ break; ++ ++ if (logdedup) { ++ node_vma->slot->pages_bemerged += factor; ++ if (list_empty(&node_vma->slot->dedup_list)) ++ list_add(&node_vma->slot->dedup_list, ++ &vma_slot_dedup); ++ } ++ } ++ ++ if (node_vma) { ++ if (node_vma->key == key) { ++ node_vma_cont = hlist_entry_safe(node_vma->hlist.next, struct node_vma, hlist); ++ goto node_vma_ok; ++ } else if (node_vma->key > key) { ++ node_vma_cont = node_vma; ++ } ++ } ++ ++node_vma_new: ++ /* no same vma already in node, alloc a new node_vma */ ++ new_node_vma = alloc_node_vma(); ++ BUG_ON(!new_node_vma); ++ new_node_vma->head = stable_node; ++ new_node_vma->slot = rmap_item->slot; ++ ++ if (!node_vma) { ++ hlist_add_head(&new_node_vma->hlist, &stable_node->hlist); ++ } else if (node_vma->key != key) { ++ if (node_vma->key < key) ++ hlist_add_behind(&new_node_vma->hlist, &node_vma->hlist); ++ else { ++ hlist_add_before(&new_node_vma->hlist, ++ &node_vma->hlist); ++ } ++ ++ } ++ node_vma = new_node_vma; ++ ++node_vma_ok: /* ok, ready to add to the list */ ++ rmap_item->head = node_vma; ++ hlist_add_head(&rmap_item->hlist, &node_vma->rmap_hlist); ++ hold_anon_vma(rmap_item, rmap_item->slot->vma->anon_vma); ++ if (logdedup) { ++ rmap_item->slot->pages_merged++; ++ if (node_vma_cont) { ++ node_vma = node_vma_cont; ++ hlist_for_each_entry_continue(node_vma, hlist) { ++ node_vma->slot->pages_bemerged += factor; ++ if (list_empty(&node_vma->slot->dedup_list)) ++ list_add(&node_vma->slot->dedup_list, ++ &vma_slot_dedup); ++ } ++ } ++ } ++} ++ ++/* ++ * We use break_ksm to break COW on a ksm page: it's a stripped down ++ * ++ * if (get_user_pages(addr, 1, 1, 1, &page, NULL) == 1) ++ * put_page(page); ++ * ++ * but taking great care only to touch a ksm page, in a VM_MERGEABLE vma, ++ * in case the application has unmapped and remapped mm,addr meanwhile. ++ * Could a ksm page appear anywhere else? Actually yes, in a VM_PFNMAP ++ * mmap of /dev/mem or /dev/kmem, where we would not want to touch it. ++ */ ++static int break_ksm(struct vm_area_struct *vma, unsigned long addr) ++{ ++ struct page *page; ++ int ret = 0; ++ ++ do { ++ cond_resched(); ++ page = follow_page(vma, addr, FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); ++ if (IS_ERR_OR_NULL(page)) ++ break; ++ if (PageKsm(page)) { ++ ret = handle_mm_fault(vma, addr, ++ FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE); ++ } else ++ ret = VM_FAULT_WRITE; ++ put_page(page); ++ } while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | VM_FAULT_OOM))); ++ /* ++ * We must loop because handle_mm_fault() may back out if there's ++ * any difficulty e.g. if pte accessed bit gets updated concurrently. ++ * ++ * VM_FAULT_WRITE is what we have been hoping for: it indicates that ++ * COW has been broken, even if the vma does not permit VM_WRITE; ++ * but note that a concurrent fault might break PageKsm for us. ++ * ++ * VM_FAULT_SIGBUS could occur if we race with truncation of the ++ * backing file, which also invalidates anonymous pages: that's ++ * okay, that truncation will have unmapped the PageKsm for us. ++ * ++ * VM_FAULT_OOM: at the time of writing (late July 2009), setting ++ * aside mem_cgroup limits, VM_FAULT_OOM would only be set if the ++ * current task has TIF_MEMDIE set, and will be OOM killed on return ++ * to user; and ksmd, having no mm, would never be chosen for that. ++ * ++ * But if the mm is in a limited mem_cgroup, then the fault may fail ++ * with VM_FAULT_OOM even if the current task is not TIF_MEMDIE; and ++ * even ksmd can fail in this way - though it's usually breaking ksm ++ * just to undo a merge it made a moment before, so unlikely to oom. ++ * ++ * That's a pity: we might therefore have more kernel pages allocated ++ * than we're counting as nodes in the stable tree; but uksm_do_scan ++ * will retry to break_cow on each pass, so should recover the page ++ * in due course. The important thing is to not let VM_MERGEABLE ++ * be cleared while any such pages might remain in the area. ++ */ ++ return (ret & VM_FAULT_OOM) ? -ENOMEM : 0; ++} ++ ++static void break_cow(struct rmap_item *rmap_item) ++{ ++ struct vm_area_struct *vma = rmap_item->slot->vma; ++ struct mm_struct *mm = vma->vm_mm; ++ unsigned long addr = get_rmap_addr(rmap_item); ++ ++ if (uksm_test_exit(mm)) ++ goto out; ++ ++ break_ksm(vma, addr); ++out: ++ return; ++} ++ ++/* ++ * Though it's very tempting to unmerge in_stable_tree(rmap_item)s rather ++ * than check every pte of a given vma, the locking doesn't quite work for ++ * that - an rmap_item is assigned to the stable tree after inserting ksm ++ * page and upping mmap_sem. Nor does it fit with the way we skip dup'ing ++ * rmap_items from parent to child at fork time (so as not to waste time ++ * if exit comes before the next scan reaches it). ++ * ++ * Similarly, although we'd like to remove rmap_items (so updating counts ++ * and freeing memory) when unmerging an area, it's easier to leave that ++ * to the next pass of ksmd - consider, for example, how ksmd might be ++ * in cmp_and_merge_page on one of the rmap_items we would be removing. ++ */ ++inline int unmerge_uksm_pages(struct vm_area_struct *vma, ++ unsigned long start, unsigned long end) ++{ ++ unsigned long addr; ++ int err = 0; ++ ++ for (addr = start; addr < end && !err; addr += PAGE_SIZE) { ++ if (uksm_test_exit(vma->vm_mm)) ++ break; ++ if (signal_pending(current)) ++ err = -ERESTARTSYS; ++ else ++ err = break_ksm(vma, addr); ++ } ++ return err; ++} ++ ++static inline void inc_uksm_pages_scanned(void) ++{ ++ u64 delta; ++ ++ ++ if (uksm_pages_scanned == U64_MAX) { ++ encode_benefit(); ++ ++ delta = uksm_pages_scanned >> pages_scanned_base; ++ ++ if (CAN_OVERFLOW_U64(pages_scanned_stored, delta)) { ++ pages_scanned_stored >>= 1; ++ delta >>= 1; ++ pages_scanned_base++; ++ } ++ ++ pages_scanned_stored += delta; ++ ++ uksm_pages_scanned = uksm_pages_scanned_last = 0; ++ } ++ ++ uksm_pages_scanned++; ++} ++ ++static inline int find_zero_page_hash(int strength, u32 hash) ++{ ++ return (zero_hash_table[strength] == hash); ++} ++ ++static ++int cmp_and_merge_zero_page(struct vm_area_struct *vma, struct page *page) ++{ ++ struct page *zero_page = empty_uksm_zero_page; ++ struct mm_struct *mm = vma->vm_mm; ++ pte_t orig_pte = __pte(0); ++ int err = -EFAULT; ++ ++ if (uksm_test_exit(mm)) ++ goto out; ++ ++ if (!trylock_page(page)) ++ goto out; ++ ++ if (!PageAnon(page)) ++ goto out_unlock; ++ ++ if (PageTransCompound(page)) { ++ err = split_huge_page(page); ++ if (err) ++ goto out_unlock; ++ } ++ ++ if (write_protect_page(vma, page, &orig_pte, 0) == 0) { ++ if (is_page_full_zero(page)) ++ err = replace_page(vma, page, zero_page, orig_pte); ++ } ++ ++out_unlock: ++ unlock_page(page); ++out: ++ return err; ++} ++ ++/* ++ * cmp_and_merge_page() - first see if page can be merged into the stable ++ * tree; if not, compare hash to previous and if it's the same, see if page ++ * can be inserted into the unstable tree, or merged with a page already there ++ * and both transferred to the stable tree. ++ * ++ * @page: the page that we are searching identical page to. ++ * @rmap_item: the reverse mapping into the virtual address of this page ++ */ ++static void cmp_and_merge_page(struct rmap_item *rmap_item, u32 hash) ++{ ++ struct rmap_item *tree_rmap_item; ++ struct page *page; ++ struct page *kpage = NULL; ++ u32 hash_max; ++ int err; ++ unsigned int success1, success2; ++ struct stable_node *snode; ++ int cmp; ++ struct rb_node *parent = NULL, **new; ++ ++ remove_rmap_item_from_tree(rmap_item); ++ page = rmap_item->page; ++ ++ /* We first start with searching the page inside the stable tree */ ++ kpage = stable_tree_search(rmap_item, hash); ++ if (kpage) { ++ err = try_to_merge_with_uksm_page(rmap_item, kpage, ++ hash); ++ if (!err) { ++ /* ++ * The page was successfully merged, add ++ * its rmap_item to the stable tree. ++ * page lock is needed because it's ++ * racing with try_to_unmap_ksm(), etc. ++ */ ++ lock_page(kpage); ++ snode = page_stable_node(kpage); ++ stable_tree_append(rmap_item, snode, 1); ++ unlock_page(kpage); ++ put_page(kpage); ++ return; /* success */ ++ } ++ put_page(kpage); ++ ++ /* ++ * if it's a collision and it has been search in sub-rbtree ++ * (hash_max != 0), we want to abort, because if it is ++ * successfully merged in unstable tree, the collision trends to ++ * happen again. ++ */ ++ if (err == MERGE_ERR_COLLI && rmap_item->hash_max) ++ return; ++ } ++ ++ tree_rmap_item = ++ unstable_tree_search_insert(rmap_item, hash); ++ if (tree_rmap_item) { ++ err = try_to_merge_two_pages(rmap_item, tree_rmap_item, hash); ++ /* ++ * As soon as we merge this page, we want to remove the ++ * rmap_item of the page we have merged with from the unstable ++ * tree, and insert it instead as new node in the stable tree. ++ */ ++ if (!err) { ++ kpage = page; ++ remove_rmap_item_from_tree(tree_rmap_item); ++ lock_page(kpage); ++ snode = stable_tree_insert(&kpage, hash, ++ rmap_item, tree_rmap_item, ++ &success1, &success2); ++ ++ /* ++ * Do not log dedup for tree item, it's not counted as ++ * scanned in this round. ++ */ ++ if (success2) ++ stable_tree_append(tree_rmap_item, snode, 0); ++ ++ /* ++ * The order of these two stable append is important: ++ * we are scanning rmap_item. ++ */ ++ if (success1) ++ stable_tree_append(rmap_item, snode, 1); ++ ++ /* ++ * The original kpage may be unlocked inside ++ * stable_tree_insert() already. This page ++ * should be unlocked before doing ++ * break_cow(). ++ */ ++ unlock_page(kpage); ++ ++ if (!success1) ++ break_cow(rmap_item); ++ ++ if (!success2) ++ break_cow(tree_rmap_item); ++ ++ } else if (err == MERGE_ERR_COLLI) { ++ BUG_ON(tree_rmap_item->tree_node->count > 1); ++ ++ rmap_item_hash_max(tree_rmap_item, ++ tree_rmap_item->tree_node->hash); ++ ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); ++ parent = &tree_rmap_item->node; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto put_up_out; ++ ++ rmap_item->tree_node = tree_rmap_item->tree_node; ++ rmap_item->address |= UNSTABLE_FLAG; ++ rmap_item->hash_round = uksm_hash_round; ++ rb_link_node(&rmap_item->node, parent, new); ++ rb_insert_color(&rmap_item->node, ++ &tree_rmap_item->tree_node->sub_root); ++ rmap_item->tree_node->count++; ++ } else { ++ /* ++ * either one of the page has changed or they collide ++ * at the max hash, we consider them as ill items. ++ */ ++ remove_rmap_item_from_tree(tree_rmap_item); ++ } ++put_up_out: ++ put_page(tree_rmap_item->page); ++ up_read(&tree_rmap_item->slot->vma->vm_mm->mmap_sem); ++ } ++} ++ ++ ++ ++ ++static inline unsigned long get_pool_index(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = (sizeof(struct rmap_list_entry *) * index) >> PAGE_SHIFT; ++ if (pool_index >= slot->pool_size) ++ BUG(); ++ return pool_index; ++} ++ ++static inline unsigned long index_page_offset(unsigned long index) ++{ ++ return offset_in_page(sizeof(struct rmap_list_entry *) * index); ++} ++ ++static inline ++struct rmap_list_entry *get_rmap_list_entry(struct vma_slot *slot, ++ unsigned long index, int need_alloc) ++{ ++ unsigned long pool_index; ++ struct page *page; ++ void *addr; ++ ++ ++ pool_index = get_pool_index(slot, index); ++ if (!slot->rmap_list_pool[pool_index]) { ++ if (!need_alloc) ++ return NULL; ++ ++ page = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN); ++ if (!page) ++ return NULL; ++ ++ slot->rmap_list_pool[pool_index] = page; ++ } ++ ++ addr = kmap(slot->rmap_list_pool[pool_index]); ++ addr += index_page_offset(index); ++ ++ return addr; ++} ++ ++static inline void put_rmap_list_entry(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ BUG_ON(!slot->rmap_list_pool[pool_index]); ++ kunmap(slot->rmap_list_pool[pool_index]); ++} ++ ++static inline int entry_is_new(struct rmap_list_entry *entry) ++{ ++ return !entry->item; ++} ++ ++static inline unsigned long get_index_orig_addr(struct vma_slot *slot, ++ unsigned long index) ++{ ++ return slot->vma->vm_start + (index << PAGE_SHIFT); ++} ++ ++static inline unsigned long get_entry_address(struct rmap_list_entry *entry) ++{ ++ unsigned long addr; ++ ++ if (is_addr(entry->addr)) ++ addr = get_clean_addr(entry->addr); ++ else if (entry->item) ++ addr = get_rmap_addr(entry->item); ++ else ++ BUG(); ++ ++ return addr; ++} ++ ++static inline struct rmap_item *get_entry_item(struct rmap_list_entry *entry) ++{ ++ if (is_addr(entry->addr)) ++ return NULL; ++ ++ return entry->item; ++} ++ ++static inline void inc_rmap_list_pool_count(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ BUG_ON(!slot->rmap_list_pool[pool_index]); ++ slot->pool_counts[pool_index]++; ++} ++ ++static inline void dec_rmap_list_pool_count(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ BUG_ON(!slot->rmap_list_pool[pool_index]); ++ BUG_ON(!slot->pool_counts[pool_index]); ++ slot->pool_counts[pool_index]--; ++} ++ ++static inline int entry_has_rmap(struct rmap_list_entry *entry) ++{ ++ return !is_addr(entry->addr) && entry->item; ++} ++ ++static inline void swap_entries(struct rmap_list_entry *entry1, ++ unsigned long index1, ++ struct rmap_list_entry *entry2, ++ unsigned long index2) ++{ ++ struct rmap_list_entry tmp; ++ ++ /* swapping two new entries is meaningless */ ++ BUG_ON(entry_is_new(entry1) && entry_is_new(entry2)); ++ ++ tmp = *entry1; ++ *entry1 = *entry2; ++ *entry2 = tmp; ++ ++ if (entry_has_rmap(entry1)) ++ entry1->item->entry_index = index1; ++ ++ if (entry_has_rmap(entry2)) ++ entry2->item->entry_index = index2; ++ ++ if (entry_has_rmap(entry1) && !entry_has_rmap(entry2)) { ++ inc_rmap_list_pool_count(entry1->item->slot, index1); ++ dec_rmap_list_pool_count(entry1->item->slot, index2); ++ } else if (!entry_has_rmap(entry1) && entry_has_rmap(entry2)) { ++ inc_rmap_list_pool_count(entry2->item->slot, index2); ++ dec_rmap_list_pool_count(entry2->item->slot, index1); ++ } ++} ++ ++static inline void free_entry_item(struct rmap_list_entry *entry) ++{ ++ unsigned long index; ++ struct rmap_item *item; ++ ++ if (!is_addr(entry->addr)) { ++ BUG_ON(!entry->item); ++ item = entry->item; ++ entry->addr = get_rmap_addr(item); ++ set_is_addr(entry->addr); ++ index = item->entry_index; ++ remove_rmap_item_from_tree(item); ++ dec_rmap_list_pool_count(item->slot, index); ++ free_rmap_item(item); ++ } ++} ++ ++static inline int pool_entry_boundary(unsigned long index) ++{ ++ unsigned long linear_addr; ++ ++ linear_addr = sizeof(struct rmap_list_entry *) * index; ++ return index && !offset_in_page(linear_addr); ++} ++ ++static inline void try_free_last_pool(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ if (slot->rmap_list_pool[pool_index] && ++ !slot->pool_counts[pool_index]) { ++ __free_page(slot->rmap_list_pool[pool_index]); ++ slot->rmap_list_pool[pool_index] = NULL; ++ slot->flags |= UKSM_SLOT_NEED_SORT; ++ } ++ ++} ++ ++static inline unsigned long vma_item_index(struct vm_area_struct *vma, ++ struct rmap_item *item) ++{ ++ return (get_rmap_addr(item) - vma->vm_start) >> PAGE_SHIFT; ++} ++ ++static int within_same_pool(struct vma_slot *slot, ++ unsigned long i, unsigned long j) ++{ ++ unsigned long pool_i, pool_j; ++ ++ pool_i = get_pool_index(slot, i); ++ pool_j = get_pool_index(slot, j); ++ ++ return (pool_i == pool_j); ++} ++ ++static void sort_rmap_entry_list(struct vma_slot *slot) ++{ ++ unsigned long i, j; ++ struct rmap_list_entry *entry, *swap_entry; ++ ++ entry = get_rmap_list_entry(slot, 0, 0); ++ for (i = 0; i < slot->pages; ) { ++ ++ if (!entry) ++ goto skip_whole_pool; ++ ++ if (entry_is_new(entry)) ++ goto next_entry; ++ ++ if (is_addr(entry->addr)) { ++ entry->addr = 0; ++ goto next_entry; ++ } ++ ++ j = vma_item_index(slot->vma, entry->item); ++ if (j == i) ++ goto next_entry; ++ ++ if (within_same_pool(slot, i, j)) ++ swap_entry = entry + j - i; ++ else ++ swap_entry = get_rmap_list_entry(slot, j, 1); ++ ++ swap_entries(entry, i, swap_entry, j); ++ if (!within_same_pool(slot, i, j)) ++ put_rmap_list_entry(slot, j); ++ continue; ++ ++skip_whole_pool: ++ i += PAGE_SIZE / sizeof(*entry); ++ if (i < slot->pages) ++ entry = get_rmap_list_entry(slot, i, 0); ++ continue; ++ ++next_entry: ++ if (i >= slot->pages - 1 || ++ !within_same_pool(slot, i, i + 1)) { ++ put_rmap_list_entry(slot, i); ++ if (i + 1 < slot->pages) ++ entry = get_rmap_list_entry(slot, i + 1, 0); ++ } else ++ entry++; ++ i++; ++ continue; ++ } ++ ++ /* free empty pool entries which contain no rmap_item */ ++ /* CAN be simplied to based on only pool_counts when bug freed !!!!! */ ++ for (i = 0; i < slot->pool_size; i++) { ++ unsigned char has_rmap; ++ void *addr; ++ ++ if (!slot->rmap_list_pool[i]) ++ continue; ++ ++ has_rmap = 0; ++ addr = kmap(slot->rmap_list_pool[i]); ++ BUG_ON(!addr); ++ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { ++ entry = (struct rmap_list_entry *)addr + j; ++ if (is_addr(entry->addr)) ++ continue; ++ if (!entry->item) ++ continue; ++ has_rmap = 1; ++ } ++ kunmap(slot->rmap_list_pool[i]); ++ if (!has_rmap) { ++ BUG_ON(slot->pool_counts[i]); ++ __free_page(slot->rmap_list_pool[i]); ++ slot->rmap_list_pool[i] = NULL; ++ } ++ } ++ ++ slot->flags &= ~UKSM_SLOT_NEED_SORT; ++} ++ ++/* ++ * vma_fully_scanned() - if all the pages in this slot have been scanned. ++ */ ++static inline int vma_fully_scanned(struct vma_slot *slot) ++{ ++ return slot->pages_scanned == slot->pages; ++} ++ ++/** ++ * get_next_rmap_item() - Get the next rmap_item in a vma_slot according to ++ * its random permutation. This function is embedded with the random ++ * permutation index management code. ++ */ ++static struct rmap_item *get_next_rmap_item(struct vma_slot *slot, u32 *hash) ++{ ++ unsigned long rand_range, addr, swap_index, scan_index; ++ struct rmap_item *item = NULL; ++ struct rmap_list_entry *scan_entry, *swap_entry = NULL; ++ struct page *page; ++ ++ scan_index = swap_index = slot->pages_scanned % slot->pages; ++ ++ if (pool_entry_boundary(scan_index)) ++ try_free_last_pool(slot, scan_index - 1); ++ ++ if (vma_fully_scanned(slot)) { ++ if (slot->flags & UKSM_SLOT_NEED_SORT) ++ slot->flags |= UKSM_SLOT_NEED_RERAND; ++ else ++ slot->flags &= ~UKSM_SLOT_NEED_RERAND; ++ if (slot->flags & UKSM_SLOT_NEED_SORT) ++ sort_rmap_entry_list(slot); ++ } ++ ++ scan_entry = get_rmap_list_entry(slot, scan_index, 1); ++ if (!scan_entry) ++ return NULL; ++ ++ if (entry_is_new(scan_entry)) { ++ scan_entry->addr = get_index_orig_addr(slot, scan_index); ++ set_is_addr(scan_entry->addr); ++ } ++ ++ if (slot->flags & UKSM_SLOT_NEED_RERAND) { ++ rand_range = slot->pages - scan_index; ++ BUG_ON(!rand_range); ++ swap_index = scan_index + (prandom_u32() % rand_range); ++ } ++ ++ if (swap_index != scan_index) { ++ swap_entry = get_rmap_list_entry(slot, swap_index, 1); ++ if (entry_is_new(swap_entry)) { ++ swap_entry->addr = get_index_orig_addr(slot, ++ swap_index); ++ set_is_addr(swap_entry->addr); ++ } ++ swap_entries(scan_entry, scan_index, swap_entry, swap_index); ++ } ++ ++ addr = get_entry_address(scan_entry); ++ item = get_entry_item(scan_entry); ++ BUG_ON(addr > slot->vma->vm_end || addr < slot->vma->vm_start); ++ ++ page = follow_page(slot->vma, addr, FOLL_GET); ++ if (IS_ERR_OR_NULL(page)) ++ goto nopage; ++ ++ if (!PageAnon(page)) ++ goto putpage; ++ ++ /*check is zero_page pfn or uksm_zero_page*/ ++ if ((page_to_pfn(page) == zero_pfn) ++ || (page_to_pfn(page) == uksm_zero_pfn)) ++ goto putpage; ++ ++ flush_anon_page(slot->vma, page, addr); ++ flush_dcache_page(page); ++ ++ ++ *hash = page_hash(page, hash_strength, 1); ++ inc_uksm_pages_scanned(); ++ /*if the page content all zero, re-map to zero-page*/ ++ if (find_zero_page_hash(hash_strength, *hash)) { ++ if (!cmp_and_merge_zero_page(slot->vma, page)) { ++ slot->pages_merged++; ++ ++ /* For full-zero pages, no need to create rmap item */ ++ goto putpage; ++ } else { ++ inc_rshash_neg(memcmp_cost / 2); ++ } ++ } ++ ++ if (!item) { ++ item = alloc_rmap_item(); ++ if (item) { ++ /* It has already been zeroed */ ++ item->slot = slot; ++ item->address = addr; ++ item->entry_index = scan_index; ++ scan_entry->item = item; ++ inc_rmap_list_pool_count(slot, scan_index); ++ } else ++ goto putpage; ++ } ++ ++ BUG_ON(item->slot != slot); ++ /* the page may have changed */ ++ item->page = page; ++ put_rmap_list_entry(slot, scan_index); ++ if (swap_entry) ++ put_rmap_list_entry(slot, swap_index); ++ return item; ++ ++putpage: ++ put_page(page); ++ page = NULL; ++nopage: ++ /* no page, store addr back and free rmap_item if possible */ ++ free_entry_item(scan_entry); ++ put_rmap_list_entry(slot, scan_index); ++ if (swap_entry) ++ put_rmap_list_entry(slot, swap_index); ++ return NULL; ++} ++ ++static inline int in_stable_tree(struct rmap_item *rmap_item) ++{ ++ return rmap_item->address & STABLE_FLAG; ++} ++ ++/** ++ * scan_vma_one_page() - scan the next page in a vma_slot. Called with ++ * mmap_sem locked. ++ */ ++static noinline void scan_vma_one_page(struct vma_slot *slot) ++{ ++ u32 hash; ++ struct mm_struct *mm; ++ struct rmap_item *rmap_item = NULL; ++ struct vm_area_struct *vma = slot->vma; ++ ++ mm = vma->vm_mm; ++ BUG_ON(!mm); ++ BUG_ON(!slot); ++ ++ rmap_item = get_next_rmap_item(slot, &hash); ++ if (!rmap_item) ++ goto out1; ++ ++ if (PageKsm(rmap_item->page) && in_stable_tree(rmap_item)) ++ goto out2; ++ ++ cmp_and_merge_page(rmap_item, hash); ++out2: ++ put_page(rmap_item->page); ++out1: ++ slot->pages_scanned++; ++ slot->this_sampled++; ++ if (slot->fully_scanned_round != fully_scanned_round) ++ scanned_virtual_pages++; ++ ++ if (vma_fully_scanned(slot)) ++ slot->fully_scanned_round = fully_scanned_round; ++} ++ ++static inline unsigned long rung_get_pages(struct scan_rung *rung) ++{ ++ struct slot_tree_node *node; ++ ++ if (!rung->vma_root.rnode) ++ return 0; ++ ++ node = container_of(rung->vma_root.rnode, struct slot_tree_node, snode); ++ ++ return node->size; ++} ++ ++#define RUNG_SAMPLED_MIN 3 ++ ++static inline ++void uksm_calc_rung_step(struct scan_rung *rung, ++ unsigned long page_time, unsigned long ratio) ++{ ++ unsigned long sampled, pages; ++ ++ /* will be fully scanned ? */ ++ if (!rung->cover_msecs) { ++ rung->step = 1; ++ return; ++ } ++ ++ sampled = rung->cover_msecs * (NSEC_PER_MSEC / TIME_RATIO_SCALE) ++ * ratio / page_time; ++ ++ /* ++ * Before we finsish a scan round and expensive per-round jobs, ++ * we need to have a chance to estimate the per page time. So ++ * the sampled number can not be too small. ++ */ ++ if (sampled < RUNG_SAMPLED_MIN) ++ sampled = RUNG_SAMPLED_MIN; ++ ++ pages = rung_get_pages(rung); ++ if (likely(pages > sampled)) ++ rung->step = pages / sampled; ++ else ++ rung->step = 1; ++} ++ ++static inline int step_need_recalc(struct scan_rung *rung) ++{ ++ unsigned long pages, stepmax; ++ ++ pages = rung_get_pages(rung); ++ stepmax = pages / RUNG_SAMPLED_MIN; ++ ++ return pages && (rung->step > pages || ++ (stepmax && rung->step > stepmax)); ++} ++ ++static inline ++void reset_current_scan(struct scan_rung *rung, int finished, int step_recalc) ++{ ++ struct vma_slot *slot; ++ ++ if (finished) ++ rung->flags |= UKSM_RUNG_ROUND_FINISHED; ++ ++ if (step_recalc || step_need_recalc(rung)) { ++ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); ++ BUG_ON(step_need_recalc(rung)); ++ } ++ ++ slot_iter_index = prandom_u32() % rung->step; ++ BUG_ON(!rung->vma_root.rnode); ++ slot = sradix_tree_next(&rung->vma_root, NULL, 0, slot_iter); ++ BUG_ON(!slot); ++ ++ rung->current_scan = slot; ++ rung->current_offset = slot_iter_index; ++} ++ ++static inline struct sradix_tree_root *slot_get_root(struct vma_slot *slot) ++{ ++ return &slot->rung->vma_root; ++} ++ ++/* ++ * return if resetted. ++ */ ++static int advance_current_scan(struct scan_rung *rung) ++{ ++ unsigned short n; ++ struct vma_slot *slot, *next = NULL; ++ ++ BUG_ON(!rung->vma_root.num); ++ ++ slot = rung->current_scan; ++ n = (slot->pages - rung->current_offset) % rung->step; ++ slot_iter_index = rung->step - n; ++ next = sradix_tree_next(&rung->vma_root, slot->snode, ++ slot->sindex, slot_iter); ++ ++ if (next) { ++ rung->current_offset = slot_iter_index; ++ rung->current_scan = next; ++ return 0; ++ } else { ++ reset_current_scan(rung, 1, 0); ++ return 1; ++ } ++} ++ ++static inline void rung_rm_slot(struct vma_slot *slot) ++{ ++ struct scan_rung *rung = slot->rung; ++ struct sradix_tree_root *root; ++ ++ if (rung->current_scan == slot) ++ advance_current_scan(rung); ++ ++ root = slot_get_root(slot); ++ sradix_tree_delete_from_leaf(root, slot->snode, slot->sindex); ++ slot->snode = NULL; ++ if (step_need_recalc(rung)) { ++ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); ++ BUG_ON(step_need_recalc(rung)); ++ } ++ ++ /* In case advance_current_scan loop back to this slot again */ ++ if (rung->vma_root.num && rung->current_scan == slot) ++ reset_current_scan(slot->rung, 1, 0); ++} ++ ++static inline void rung_add_new_slots(struct scan_rung *rung, ++ struct vma_slot **slots, unsigned long num) ++{ ++ int err; ++ struct vma_slot *slot; ++ unsigned long i; ++ struct sradix_tree_root *root = &rung->vma_root; ++ ++ err = sradix_tree_enter(root, (void **)slots, num); ++ BUG_ON(err); ++ ++ for (i = 0; i < num; i++) { ++ slot = slots[i]; ++ slot->rung = rung; ++ BUG_ON(vma_fully_scanned(slot)); ++ } ++ ++ if (rung->vma_root.num == num) ++ reset_current_scan(rung, 0, 1); ++} ++ ++static inline int rung_add_one_slot(struct scan_rung *rung, ++ struct vma_slot *slot) ++{ ++ int err; ++ ++ err = sradix_tree_enter(&rung->vma_root, (void **)&slot, 1); ++ if (err) ++ return err; ++ ++ slot->rung = rung; ++ if (rung->vma_root.num == 1) ++ reset_current_scan(rung, 0, 1); ++ ++ return 0; ++} ++ ++/* ++ * Return true if the slot is deleted from its rung. ++ */ ++static inline int vma_rung_enter(struct vma_slot *slot, struct scan_rung *rung) ++{ ++ struct scan_rung *old_rung = slot->rung; ++ int err; ++ ++ if (old_rung == rung) ++ return 0; ++ ++ rung_rm_slot(slot); ++ err = rung_add_one_slot(rung, slot); ++ if (err) { ++ err = rung_add_one_slot(old_rung, slot); ++ WARN_ON(err); /* OOPS, badly OOM, we lost this slot */ ++ } ++ ++ return 1; ++} ++ ++static inline int vma_rung_up(struct vma_slot *slot) ++{ ++ struct scan_rung *rung; ++ ++ rung = slot->rung; ++ if (slot->rung != &uksm_scan_ladder[SCAN_LADDER_SIZE-1]) ++ rung++; ++ ++ return vma_rung_enter(slot, rung); ++} ++ ++static inline int vma_rung_down(struct vma_slot *slot) ++{ ++ struct scan_rung *rung; ++ ++ rung = slot->rung; ++ if (slot->rung != &uksm_scan_ladder[0]) ++ rung--; ++ ++ return vma_rung_enter(slot, rung); ++} ++ ++/** ++ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. ++ */ ++static unsigned long cal_dedup_ratio(struct vma_slot *slot) ++{ ++ unsigned long ret; ++ unsigned long pages; ++ ++ pages = slot->this_sampled; ++ if (!pages) ++ return 0; ++ ++ BUG_ON(slot->pages_scanned == slot->last_scanned); ++ ++ ret = slot->pages_merged; ++ ++ /* Thrashing area filtering */ ++ if (ret && uksm_thrash_threshold) { ++ if (slot->pages_cowed * 100 / slot->pages_merged ++ > uksm_thrash_threshold) { ++ ret = 0; ++ } else { ++ ret = slot->pages_merged - slot->pages_cowed; ++ } ++ } ++ ++ return ret * 100 / pages; ++} ++ ++/** ++ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. ++ */ ++static unsigned long cal_dedup_ratio_old(struct vma_slot *slot) ++{ ++ unsigned long ret; ++ unsigned long pages; ++ ++ pages = slot->pages; ++ if (!pages) ++ return 0; ++ ++ ret = slot->pages_bemerged; ++ ++ /* Thrashing area filtering */ ++ if (ret && uksm_thrash_threshold) { ++ if (slot->pages_cowed * 100 / slot->pages_bemerged ++ > uksm_thrash_threshold) { ++ ret = 0; ++ } else { ++ ret = slot->pages_bemerged - slot->pages_cowed; ++ } ++ } ++ ++ return ret * 100 / pages; ++} ++ ++/** ++ * stable_node_reinsert() - When the hash_strength has been adjusted, the ++ * stable tree need to be restructured, this is the function re-inserting the ++ * stable node. ++ */ ++static inline void stable_node_reinsert(struct stable_node *new_node, ++ struct page *page, ++ struct rb_root *root_treep, ++ struct list_head *tree_node_listp, ++ u32 hash) ++{ ++ struct rb_node **new = &root_treep->rb_node; ++ struct rb_node *parent = NULL; ++ struct stable_node *stable_node; ++ struct tree_node *tree_node; ++ struct page *tree_page; ++ int cmp; ++ ++ while (*new) { ++ int cmp; ++ ++ tree_node = rb_entry(*new, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else ++ break; ++ } ++ ++ if (*new) { ++ /* find a stable tree node with same first level hash value */ ++ stable_node_hash_max(new_node, page, hash); ++ if (tree_node->count == 1) { ++ stable_node = rb_entry(tree_node->sub_root.rb_node, ++ struct stable_node, node); ++ tree_page = get_uksm_page(stable_node, 1, 0); ++ if (tree_page) { ++ stable_node_hash_max(stable_node, ++ tree_page, hash); ++ put_page(tree_page); ++ ++ /* prepare for stable node insertion */ ++ ++ cmp = hash_cmp(new_node->hash_max, ++ stable_node->hash_max); ++ parent = &stable_node->node; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto failed; ++ ++ goto add_node; ++ } else { ++ /* the only stable_node deleted, the tree node ++ * was not deleted. ++ */ ++ goto tree_node_reuse; ++ } ++ } ++ ++ /* well, search the collision subtree */ ++ new = &tree_node->sub_root.rb_node; ++ parent = NULL; ++ BUG_ON(!*new); ++ while (*new) { ++ int cmp; ++ ++ stable_node = rb_entry(*new, struct stable_node, node); ++ ++ cmp = hash_cmp(new_node->hash_max, ++ stable_node->hash_max); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else { ++ /* oh, no, still a collision */ ++ goto failed; ++ } ++ } ++ ++ goto add_node; ++ } ++ ++ /* no tree node found */ ++ tree_node = alloc_tree_node(tree_node_listp); ++ if (!tree_node) { ++ pr_err("UKSM: memory allocation error!\n"); ++ goto failed; ++ } else { ++ tree_node->hash = hash; ++ rb_link_node(&tree_node->node, parent, new); ++ rb_insert_color(&tree_node->node, root_treep); ++ ++tree_node_reuse: ++ /* prepare for stable node insertion */ ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ ++add_node: ++ rb_link_node(&new_node->node, parent, new); ++ rb_insert_color(&new_node->node, &tree_node->sub_root); ++ new_node->tree_node = tree_node; ++ tree_node->count++; ++ return; ++ ++failed: ++ /* This can only happen when two nodes have collided ++ * in two levels. ++ */ ++ new_node->tree_node = NULL; ++ return; ++} ++ ++static inline void free_all_tree_nodes(struct list_head *list) ++{ ++ struct tree_node *node, *tmp; ++ ++ list_for_each_entry_safe(node, tmp, list, all_list) { ++ free_tree_node(node); ++ } ++} ++ ++/** ++ * stable_tree_delta_hash() - Delta hash the stable tree from previous hash ++ * strength to the current hash_strength. It re-structures the hole tree. ++ */ ++static inline void stable_tree_delta_hash(u32 prev_hash_strength) ++{ ++ struct stable_node *node, *tmp; ++ struct rb_root *root_new_treep; ++ struct list_head *new_tree_node_listp; ++ ++ stable_tree_index = (stable_tree_index + 1) % 2; ++ root_new_treep = &root_stable_tree[stable_tree_index]; ++ new_tree_node_listp = &stable_tree_node_list[stable_tree_index]; ++ *root_new_treep = RB_ROOT; ++ BUG_ON(!list_empty(new_tree_node_listp)); ++ ++ /* ++ * we need to be safe, the node could be removed by get_uksm_page() ++ */ ++ list_for_each_entry_safe(node, tmp, &stable_node_list, all_list) { ++ void *addr; ++ struct page *node_page; ++ u32 hash; ++ ++ /* ++ * We are completely re-structuring the stable nodes to a new ++ * stable tree. We don't want to touch the old tree unlinks and ++ * old tree_nodes. The old tree_nodes will be freed at once. ++ */ ++ node_page = get_uksm_page(node, 0, 0); ++ if (!node_page) ++ continue; ++ ++ if (node->tree_node) { ++ hash = node->tree_node->hash; ++ ++ addr = kmap_atomic(node_page); ++ ++ hash = delta_hash(addr, prev_hash_strength, ++ hash_strength, hash); ++ kunmap_atomic(addr); ++ } else { ++ /* ++ *it was not inserted to rbtree due to collision in last ++ *round scan. ++ */ ++ hash = page_hash(node_page, hash_strength, 0); ++ } ++ ++ stable_node_reinsert(node, node_page, root_new_treep, ++ new_tree_node_listp, hash); ++ put_page(node_page); ++ } ++ ++ root_stable_treep = root_new_treep; ++ free_all_tree_nodes(stable_tree_node_listp); ++ BUG_ON(!list_empty(stable_tree_node_listp)); ++ stable_tree_node_listp = new_tree_node_listp; ++} ++ ++static inline void inc_hash_strength(unsigned long delta) ++{ ++ hash_strength += 1 << delta; ++ if (hash_strength > HASH_STRENGTH_MAX) ++ hash_strength = HASH_STRENGTH_MAX; ++} ++ ++static inline void dec_hash_strength(unsigned long delta) ++{ ++ unsigned long change = 1 << delta; ++ ++ if (hash_strength <= change + 1) ++ hash_strength = 1; ++ else ++ hash_strength -= change; ++} ++ ++static inline void inc_hash_strength_delta(void) ++{ ++ hash_strength_delta++; ++ if (hash_strength_delta > HASH_STRENGTH_DELTA_MAX) ++ hash_strength_delta = HASH_STRENGTH_DELTA_MAX; ++} ++ ++static inline unsigned long get_current_neg_ratio(void) ++{ ++ u64 pos = benefit.pos; ++ u64 neg = benefit.neg; ++ ++ if (!neg) ++ return 0; ++ ++ if (!pos || neg > pos) ++ return 100; ++ ++ if (neg > div64_u64(U64_MAX, 100)) ++ pos = div64_u64(pos, 100); ++ else ++ neg *= 100; ++ ++ return div64_u64(neg, pos); ++} ++ ++static inline unsigned long get_current_benefit(void) ++{ ++ u64 pos = benefit.pos; ++ u64 neg = benefit.neg; ++ u64 scanned = benefit.scanned; ++ ++ if (neg > pos) ++ return 0; ++ ++ return div64_u64((pos - neg), scanned); ++} ++ ++static inline int judge_rshash_direction(void) ++{ ++ u64 current_neg_ratio, stable_benefit; ++ u64 current_benefit, delta = 0; ++ int ret = STILL; ++ ++ /* ++ * Try to probe a value after the boot, and in case the system ++ * are still for a long time. ++ */ ++ if ((fully_scanned_round & 0xFFULL) == 10) { ++ ret = OBSCURE; ++ goto out; ++ } ++ ++ current_neg_ratio = get_current_neg_ratio(); ++ ++ if (current_neg_ratio == 0) { ++ rshash_neg_cont_zero++; ++ if (rshash_neg_cont_zero > 2) ++ return GO_DOWN; ++ else ++ return STILL; ++ } ++ rshash_neg_cont_zero = 0; ++ ++ if (current_neg_ratio > 90) { ++ ret = GO_UP; ++ goto out; ++ } ++ ++ current_benefit = get_current_benefit(); ++ stable_benefit = rshash_state.stable_benefit; ++ ++ if (!stable_benefit) { ++ ret = OBSCURE; ++ goto out; ++ } ++ ++ if (current_benefit > stable_benefit) ++ delta = current_benefit - stable_benefit; ++ else if (current_benefit < stable_benefit) ++ delta = stable_benefit - current_benefit; ++ ++ delta = div64_u64(100 * delta, stable_benefit); ++ ++ if (delta > 50) { ++ rshash_cont_obscure++; ++ if (rshash_cont_obscure > 2) ++ return OBSCURE; ++ else ++ return STILL; ++ } ++ ++out: ++ rshash_cont_obscure = 0; ++ return ret; ++} ++ ++/** ++ * rshash_adjust() - The main function to control the random sampling state ++ * machine for hash strength adapting. ++ * ++ * return true if hash_strength has changed. ++ */ ++static inline int rshash_adjust(void) ++{ ++ unsigned long prev_hash_strength = hash_strength; ++ ++ if (!encode_benefit()) ++ return 0; ++ ++ switch (rshash_state.state) { ++ case RSHASH_STILL: ++ switch (judge_rshash_direction()) { ++ case GO_UP: ++ if (rshash_state.pre_direct == GO_DOWN) ++ hash_strength_delta = 0; ++ ++ inc_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ rshash_state.stable_benefit = get_current_benefit(); ++ rshash_state.pre_direct = GO_UP; ++ break; ++ ++ case GO_DOWN: ++ if (rshash_state.pre_direct == GO_UP) ++ hash_strength_delta = 0; ++ ++ dec_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ rshash_state.stable_benefit = get_current_benefit(); ++ rshash_state.pre_direct = GO_DOWN; ++ break; ++ ++ case OBSCURE: ++ rshash_state.stable_point = hash_strength; ++ rshash_state.turn_point_down = hash_strength; ++ rshash_state.turn_point_up = hash_strength; ++ rshash_state.turn_benefit_down = get_current_benefit(); ++ rshash_state.turn_benefit_up = get_current_benefit(); ++ rshash_state.lookup_window_index = 0; ++ rshash_state.state = RSHASH_TRYDOWN; ++ dec_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ break; ++ ++ case STILL: ++ break; ++ default: ++ BUG(); ++ } ++ break; ++ ++ case RSHASH_TRYDOWN: ++ if (rshash_state.lookup_window_index++ % 5 == 0) ++ rshash_state.below_count = 0; ++ ++ if (get_current_benefit() < rshash_state.stable_benefit) ++ rshash_state.below_count++; ++ else if (get_current_benefit() > ++ rshash_state.turn_benefit_down) { ++ rshash_state.turn_point_down = hash_strength; ++ rshash_state.turn_benefit_down = get_current_benefit(); ++ } ++ ++ if (rshash_state.below_count >= 3 || ++ judge_rshash_direction() == GO_UP || ++ hash_strength == 1) { ++ hash_strength = rshash_state.stable_point; ++ hash_strength_delta = 0; ++ inc_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ rshash_state.lookup_window_index = 0; ++ rshash_state.state = RSHASH_TRYUP; ++ hash_strength_delta = 0; ++ } else { ++ dec_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ } ++ break; ++ ++ case RSHASH_TRYUP: ++ if (rshash_state.lookup_window_index++ % 5 == 0) ++ rshash_state.below_count = 0; ++ ++ if (get_current_benefit() < rshash_state.turn_benefit_down) ++ rshash_state.below_count++; ++ else if (get_current_benefit() > rshash_state.turn_benefit_up) { ++ rshash_state.turn_point_up = hash_strength; ++ rshash_state.turn_benefit_up = get_current_benefit(); ++ } ++ ++ if (rshash_state.below_count >= 3 || ++ judge_rshash_direction() == GO_DOWN || ++ hash_strength == HASH_STRENGTH_MAX) { ++ hash_strength = rshash_state.turn_benefit_up > ++ rshash_state.turn_benefit_down ? ++ rshash_state.turn_point_up : ++ rshash_state.turn_point_down; ++ ++ rshash_state.state = RSHASH_PRE_STILL; ++ } else { ++ inc_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ } ++ ++ break; ++ ++ case RSHASH_NEW: ++ case RSHASH_PRE_STILL: ++ rshash_state.stable_benefit = get_current_benefit(); ++ rshash_state.state = RSHASH_STILL; ++ hash_strength_delta = 0; ++ break; ++ default: ++ BUG(); ++ } ++ ++ /* rshash_neg = rshash_pos = 0; */ ++ reset_benefit(); ++ ++ if (prev_hash_strength != hash_strength) ++ stable_tree_delta_hash(prev_hash_strength); ++ ++ return prev_hash_strength != hash_strength; ++} ++ ++/** ++ * round_update_ladder() - The main function to do update of all the ++ * adjustments whenever a scan round is finished. ++ */ ++static noinline void round_update_ladder(void) ++{ ++ int i; ++ unsigned long dedup; ++ struct vma_slot *slot, *tmp_slot; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) ++ uksm_scan_ladder[i].flags &= ~UKSM_RUNG_ROUND_FINISHED; ++ ++ list_for_each_entry_safe(slot, tmp_slot, &vma_slot_dedup, dedup_list) { ++ ++ /* slot may be rung_rm_slot() when mm exits */ ++ if (slot->snode) { ++ dedup = cal_dedup_ratio_old(slot); ++ if (dedup && dedup >= uksm_abundant_threshold) ++ vma_rung_up(slot); ++ } ++ ++ slot->pages_bemerged = 0; ++ slot->pages_cowed = 0; ++ ++ list_del_init(&slot->dedup_list); ++ } ++} ++ ++static void uksm_del_vma_slot(struct vma_slot *slot) ++{ ++ int i, j; ++ struct rmap_list_entry *entry; ++ ++ if (slot->snode) { ++ /* ++ * In case it just failed when entering the rung, it's not ++ * necessary. ++ */ ++ rung_rm_slot(slot); ++ } ++ ++ if (!list_empty(&slot->dedup_list)) ++ list_del(&slot->dedup_list); ++ ++ if (!slot->rmap_list_pool || !slot->pool_counts) { ++ /* In case it OOMed in uksm_vma_enter() */ ++ goto out; ++ } ++ ++ for (i = 0; i < slot->pool_size; i++) { ++ void *addr; ++ ++ if (!slot->rmap_list_pool[i]) ++ continue; ++ ++ addr = kmap(slot->rmap_list_pool[i]); ++ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { ++ entry = (struct rmap_list_entry *)addr + j; ++ if (is_addr(entry->addr)) ++ continue; ++ if (!entry->item) ++ continue; ++ ++ remove_rmap_item_from_tree(entry->item); ++ free_rmap_item(entry->item); ++ slot->pool_counts[i]--; ++ } ++ BUG_ON(slot->pool_counts[i]); ++ kunmap(slot->rmap_list_pool[i]); ++ __free_page(slot->rmap_list_pool[i]); ++ } ++ kfree(slot->rmap_list_pool); ++ kfree(slot->pool_counts); ++ ++out: ++ slot->rung = NULL; ++ if (slot->flags & UKSM_SLOT_IN_UKSM) { ++ BUG_ON(uksm_pages_total < slot->pages); ++ uksm_pages_total -= slot->pages; ++ } ++ ++ if (slot->fully_scanned_round == fully_scanned_round) ++ scanned_virtual_pages -= slot->pages; ++ else ++ scanned_virtual_pages -= slot->pages_scanned; ++ free_vma_slot(slot); ++} ++ ++ ++#define SPIN_LOCK_PERIOD 32 ++static struct vma_slot *cleanup_slots[SPIN_LOCK_PERIOD]; ++static inline void cleanup_vma_slots(void) ++{ ++ struct vma_slot *slot; ++ int i; ++ ++ i = 0; ++ spin_lock(&vma_slot_list_lock); ++ while (!list_empty(&vma_slot_del)) { ++ slot = list_entry(vma_slot_del.next, ++ struct vma_slot, slot_list); ++ list_del(&slot->slot_list); ++ cleanup_slots[i++] = slot; ++ if (i == SPIN_LOCK_PERIOD) { ++ spin_unlock(&vma_slot_list_lock); ++ while (--i >= 0) ++ uksm_del_vma_slot(cleanup_slots[i]); ++ i = 0; ++ spin_lock(&vma_slot_list_lock); ++ } ++ } ++ spin_unlock(&vma_slot_list_lock); ++ ++ while (--i >= 0) ++ uksm_del_vma_slot(cleanup_slots[i]); ++} ++ ++/* ++ * Expotional moving average formula ++ */ ++static inline unsigned long ema(unsigned long curr, unsigned long last_ema) ++{ ++ /* ++ * For a very high burst, even the ema cannot work well, a false very ++ * high per-page time estimation can result in feedback in very high ++ * overhead of context switch and rung update -- this will then lead ++ * to higher per-paper time, this may not converge. ++ * ++ * Instead, we try to approach this value in a binary manner. ++ */ ++ if (curr > last_ema * 10) ++ return last_ema * 2; ++ ++ return (EMA_ALPHA * curr + (100 - EMA_ALPHA) * last_ema) / 100; ++} ++ ++/* ++ * convert cpu ratio in 1/TIME_RATIO_SCALE configured by user to ++ * nanoseconds based on current uksm_sleep_jiffies. ++ */ ++static inline unsigned long cpu_ratio_to_nsec(unsigned int ratio) ++{ ++ return NSEC_PER_USEC * jiffies_to_usecs(uksm_sleep_jiffies) / ++ (TIME_RATIO_SCALE - ratio) * ratio; ++} ++ ++ ++static inline unsigned long rung_real_ratio(int cpu_time_ratio) ++{ ++ unsigned long ret; ++ ++ BUG_ON(!cpu_time_ratio); ++ ++ if (cpu_time_ratio > 0) ++ ret = cpu_time_ratio; ++ else ++ ret = (unsigned long)(-cpu_time_ratio) * ++ uksm_max_cpu_percentage / 100UL; ++ ++ return ret ? ret : 1; ++} ++ ++static noinline void uksm_calc_scan_pages(void) ++{ ++ struct scan_rung *ladder = uksm_scan_ladder; ++ unsigned long sleep_usecs, nsecs; ++ unsigned long ratio; ++ int i; ++ unsigned long per_page; ++ ++ if (uksm_ema_page_time > 100000 || ++ (((unsigned long) uksm_eval_round & (256UL - 1)) == 0UL)) ++ uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; ++ ++ per_page = uksm_ema_page_time; ++ BUG_ON(!per_page); ++ ++ /* ++ * For every 8 eval round, we try to probe a uksm_sleep_jiffies value ++ * based on saved user input. ++ */ ++ if (((unsigned long) uksm_eval_round & (8UL - 1)) == 0UL) ++ uksm_sleep_jiffies = uksm_sleep_saved; ++ ++ /* We require a rung scan at least 1 page in a period. */ ++ nsecs = per_page; ++ ratio = rung_real_ratio(ladder[0].cpu_ratio); ++ if (cpu_ratio_to_nsec(ratio) < nsecs) { ++ sleep_usecs = nsecs * (TIME_RATIO_SCALE - ratio) / ratio ++ / NSEC_PER_USEC; ++ uksm_sleep_jiffies = usecs_to_jiffies(sleep_usecs) + 1; ++ } ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ ratio = rung_real_ratio(ladder[i].cpu_ratio); ++ ladder[i].pages_to_scan = cpu_ratio_to_nsec(ratio) / ++ per_page; ++ BUG_ON(!ladder[i].pages_to_scan); ++ uksm_calc_rung_step(&ladder[i], per_page, ratio); ++ } ++} ++ ++/* ++ * From the scan time of this round (ns) to next expected min sleep time ++ * (ms), be careful of the possible overflows. ratio is taken from ++ * rung_real_ratio() ++ */ ++static inline ++unsigned int scan_time_to_sleep(unsigned long long scan_time, unsigned long ratio) ++{ ++ scan_time >>= 20; /* to msec level now */ ++ BUG_ON(scan_time > (ULONG_MAX / TIME_RATIO_SCALE)); ++ ++ return (unsigned int) ((unsigned long) scan_time * ++ (TIME_RATIO_SCALE - ratio) / ratio); ++} ++ ++#define __round_mask(x, y) ((__typeof__(x))((y)-1)) ++#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) ++ ++static void uksm_vma_enter(struct vma_slot **slots, unsigned long num) ++{ ++ struct scan_rung *rung; ++ ++ rung = &uksm_scan_ladder[0]; ++ rung_add_new_slots(rung, slots, num); ++} ++ ++static struct vma_slot *batch_slots[SLOT_TREE_NODE_STORE_SIZE]; ++ ++static void uksm_enter_all_slots(void) ++{ ++ struct vma_slot *slot; ++ unsigned long index; ++ struct list_head empty_vma_list; ++ int i; ++ ++ i = 0; ++ index = 0; ++ INIT_LIST_HEAD(&empty_vma_list); ++ ++ spin_lock(&vma_slot_list_lock); ++ while (!list_empty(&vma_slot_new)) { ++ slot = list_entry(vma_slot_new.next, ++ struct vma_slot, slot_list); ++ ++ if (!slot->vma->anon_vma) { ++ list_move(&slot->slot_list, &empty_vma_list); ++ } else if (vma_can_enter(slot->vma)) { ++ batch_slots[index++] = slot; ++ list_del_init(&slot->slot_list); ++ } else { ++ list_move(&slot->slot_list, &vma_slot_noadd); ++ } ++ ++ if (++i == SPIN_LOCK_PERIOD || ++ (index && !(index % SLOT_TREE_NODE_STORE_SIZE))) { ++ spin_unlock(&vma_slot_list_lock); ++ ++ if (index && !(index % SLOT_TREE_NODE_STORE_SIZE)) { ++ uksm_vma_enter(batch_slots, index); ++ index = 0; ++ } ++ i = 0; ++ cond_resched(); ++ spin_lock(&vma_slot_list_lock); ++ } ++ } ++ ++ list_splice(&empty_vma_list, &vma_slot_new); ++ ++ spin_unlock(&vma_slot_list_lock); ++ ++ if (index) ++ uksm_vma_enter(batch_slots, index); ++ ++} ++ ++static inline int rung_round_finished(struct scan_rung *rung) ++{ ++ return rung->flags & UKSM_RUNG_ROUND_FINISHED; ++} ++ ++static inline void judge_slot(struct vma_slot *slot) ++{ ++ struct scan_rung *rung = slot->rung; ++ unsigned long dedup; ++ int deleted; ++ ++ dedup = cal_dedup_ratio(slot); ++ if (vma_fully_scanned(slot) && uksm_thrash_threshold) ++ deleted = vma_rung_enter(slot, &uksm_scan_ladder[0]); ++ else if (dedup && dedup >= uksm_abundant_threshold) ++ deleted = vma_rung_up(slot); ++ else ++ deleted = vma_rung_down(slot); ++ ++ slot->pages_merged = 0; ++ slot->pages_cowed = 0; ++ slot->this_sampled = 0; ++ ++ if (vma_fully_scanned(slot)) ++ slot->pages_scanned = 0; ++ ++ slot->last_scanned = slot->pages_scanned; ++ ++ /* If its deleted in above, then rung was already advanced. */ ++ if (!deleted) ++ advance_current_scan(rung); ++} ++ ++ ++static inline int hash_round_finished(void) ++{ ++ if (scanned_virtual_pages > (uksm_pages_total >> 2)) { ++ scanned_virtual_pages = 0; ++ if (uksm_pages_scanned) ++ fully_scanned_round++; ++ ++ return 1; ++ } else { ++ return 0; ++ } ++} ++ ++#define UKSM_MMSEM_BATCH 5 ++#define BUSY_RETRY 100 ++ ++/** ++ * uksm_do_scan() - the main worker function. ++ */ ++static noinline void uksm_do_scan(void) ++{ ++ struct vma_slot *slot, *iter; ++ struct mm_struct *busy_mm; ++ unsigned char round_finished, all_rungs_emtpy; ++ int i, err, mmsem_batch; ++ unsigned long pcost; ++ long long delta_exec; ++ unsigned long vpages, max_cpu_ratio; ++ unsigned long long start_time, end_time, scan_time; ++ unsigned int expected_jiffies; ++ ++ might_sleep(); ++ ++ vpages = 0; ++ ++ start_time = task_sched_runtime(current); ++ max_cpu_ratio = 0; ++ mmsem_batch = 0; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE;) { ++ struct scan_rung *rung = &uksm_scan_ladder[i]; ++ unsigned long ratio; ++ int busy_retry; ++ ++ if (!rung->pages_to_scan) { ++ i++; ++ continue; ++ } ++ ++ if (!rung->vma_root.num) { ++ rung->pages_to_scan = 0; ++ i++; ++ continue; ++ } ++ ++ ratio = rung_real_ratio(rung->cpu_ratio); ++ if (ratio > max_cpu_ratio) ++ max_cpu_ratio = ratio; ++ ++ busy_retry = BUSY_RETRY; ++ /* ++ * Do not consider rung_round_finished() here, just used up the ++ * rung->pages_to_scan quota. ++ */ ++ while (rung->pages_to_scan && rung->vma_root.num && ++ likely(!freezing(current))) { ++ int reset = 0; ++ ++ slot = rung->current_scan; ++ ++ BUG_ON(vma_fully_scanned(slot)); ++ ++ if (mmsem_batch) ++ err = 0; ++ else ++ err = try_down_read_slot_mmap_sem(slot); ++ ++ if (err == -ENOENT) { ++rm_slot: ++ rung_rm_slot(slot); ++ continue; ++ } ++ ++ busy_mm = slot->mm; ++ ++ if (err == -EBUSY) { ++ /* skip other vmas on the same mm */ ++ do { ++ reset = advance_current_scan(rung); ++ iter = rung->current_scan; ++ busy_retry--; ++ if (iter->vma->vm_mm != busy_mm || ++ !busy_retry || reset) ++ break; ++ } while (1); ++ ++ if (iter->vma->vm_mm != busy_mm) { ++ continue; ++ } else { ++ /* scan round finsished */ ++ break; ++ } ++ } ++ ++ BUG_ON(!vma_can_enter(slot->vma)); ++ if (uksm_test_exit(slot->vma->vm_mm)) { ++ mmsem_batch = 0; ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ goto rm_slot; ++ } ++ ++ if (mmsem_batch) ++ mmsem_batch--; ++ else ++ mmsem_batch = UKSM_MMSEM_BATCH; ++ ++ /* Ok, we have take the mmap_sem, ready to scan */ ++ scan_vma_one_page(slot); ++ rung->pages_to_scan--; ++ vpages++; ++ ++ if (rung->current_offset + rung->step > slot->pages - 1 ++ || vma_fully_scanned(slot)) { ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ judge_slot(slot); ++ mmsem_batch = 0; ++ } else { ++ rung->current_offset += rung->step; ++ if (!mmsem_batch) ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ } ++ ++ busy_retry = BUSY_RETRY; ++ cond_resched(); ++ } ++ ++ if (mmsem_batch) { ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ mmsem_batch = 0; ++ } ++ ++ if (freezing(current)) ++ break; ++ ++ cond_resched(); ++ } ++ end_time = task_sched_runtime(current); ++ delta_exec = end_time - start_time; ++ ++ if (freezing(current)) ++ return; ++ ++ cleanup_vma_slots(); ++ uksm_enter_all_slots(); ++ ++ round_finished = 1; ++ all_rungs_emtpy = 1; ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ struct scan_rung *rung = &uksm_scan_ladder[i]; ++ ++ if (rung->vma_root.num) { ++ all_rungs_emtpy = 0; ++ if (!rung_round_finished(rung)) ++ round_finished = 0; ++ } ++ } ++ ++ if (all_rungs_emtpy) ++ round_finished = 0; ++ ++ if (round_finished) { ++ round_update_ladder(); ++ uksm_eval_round++; ++ ++ if (hash_round_finished() && rshash_adjust()) { ++ /* Reset the unstable root iff hash strength changed */ ++ uksm_hash_round++; ++ root_unstable_tree = RB_ROOT; ++ free_all_tree_nodes(&unstable_tree_node_list); ++ } ++ ++ /* ++ * A number of pages can hang around indefinitely on per-cpu ++ * pagevecs, raised page count preventing write_protect_page ++ * from merging them. Though it doesn't really matter much, ++ * it is puzzling to see some stuck in pages_volatile until ++ * other activity jostles them out, and they also prevented ++ * LTP's KSM test from succeeding deterministically; so drain ++ * them here (here rather than on entry to uksm_do_scan(), ++ * so we don't IPI too often when pages_to_scan is set low). ++ */ ++ lru_add_drain_all(); ++ } ++ ++ ++ if (vpages && delta_exec > 0) { ++ pcost = (unsigned long) delta_exec / vpages; ++ if (likely(uksm_ema_page_time)) ++ uksm_ema_page_time = ema(pcost, uksm_ema_page_time); ++ else ++ uksm_ema_page_time = pcost; ++ } ++ ++ uksm_calc_scan_pages(); ++ uksm_sleep_real = uksm_sleep_jiffies; ++ /* in case of radical cpu bursts, apply the upper bound */ ++ end_time = task_sched_runtime(current); ++ if (max_cpu_ratio && end_time > start_time) { ++ scan_time = end_time - start_time; ++ expected_jiffies = msecs_to_jiffies( ++ scan_time_to_sleep(scan_time, max_cpu_ratio)); ++ ++ if (expected_jiffies > uksm_sleep_real) ++ uksm_sleep_real = expected_jiffies; ++ ++ /* We have a 1 second up bound for responsiveness. */ ++ if (jiffies_to_msecs(uksm_sleep_real) > MSEC_PER_SEC) ++ uksm_sleep_real = msecs_to_jiffies(1000); ++ } ++ ++ return; ++} ++ ++static int ksmd_should_run(void) ++{ ++ return uksm_run & UKSM_RUN_MERGE; ++} ++ ++static int uksm_scan_thread(void *nothing) ++{ ++ set_freezable(); ++ set_user_nice(current, 5); ++ ++ while (!kthread_should_stop()) { ++ mutex_lock(&uksm_thread_mutex); ++ if (ksmd_should_run()) ++ uksm_do_scan(); ++ mutex_unlock(&uksm_thread_mutex); ++ ++ try_to_freeze(); ++ ++ if (ksmd_should_run()) { ++ schedule_timeout_interruptible(uksm_sleep_real); ++ uksm_sleep_times++; ++ } else { ++ wait_event_freezable(uksm_thread_wait, ++ ksmd_should_run() || kthread_should_stop()); ++ } ++ } ++ return 0; ++} ++ ++void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) ++{ ++ struct stable_node *stable_node; ++ struct node_vma *node_vma; ++ struct rmap_item *rmap_item; ++ int search_new_forks = 0; ++ unsigned long address; ++ ++ VM_BUG_ON_PAGE(!PageKsm(page), page); ++ VM_BUG_ON_PAGE(!PageLocked(page), page); ++ ++ stable_node = page_stable_node(page); ++ if (!stable_node) ++ return; ++again: ++ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { ++ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { ++ struct anon_vma *anon_vma = rmap_item->anon_vma; ++ struct anon_vma_chain *vmac; ++ struct vm_area_struct *vma; ++ ++ cond_resched(); ++ anon_vma_lock_read(anon_vma); ++ anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, ++ 0, ULONG_MAX) { ++ cond_resched(); ++ vma = vmac->vma; ++ address = get_rmap_addr(rmap_item); ++ ++ if (address < vma->vm_start || ++ address >= vma->vm_end) ++ continue; ++ ++ if ((rmap_item->slot->vma == vma) == ++ search_new_forks) ++ continue; ++ ++ if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg)) ++ continue; ++ ++ if (!rwc->rmap_one(page, vma, address, rwc->arg)) { ++ anon_vma_unlock_read(anon_vma); ++ return; ++ } ++ ++ if (rwc->done && rwc->done(page)) { ++ anon_vma_unlock_read(anon_vma); ++ return; ++ } ++ } ++ anon_vma_unlock_read(anon_vma); ++ } ++ } ++ if (!search_new_forks++) ++ goto again; ++} ++ ++#ifdef CONFIG_MIGRATION ++/* Common ksm interface but may be specific to uksm */ ++void ksm_migrate_page(struct page *newpage, struct page *oldpage) ++{ ++ struct stable_node *stable_node; ++ ++ VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage); ++ VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); ++ VM_BUG_ON(newpage->mapping != oldpage->mapping); ++ ++ stable_node = page_stable_node(newpage); ++ if (stable_node) { ++ VM_BUG_ON(stable_node->kpfn != page_to_pfn(oldpage)); ++ stable_node->kpfn = page_to_pfn(newpage); ++ /* ++ * newpage->mapping was set in advance; now we need smp_wmb() ++ * to make sure that the new stable_node->kpfn is visible ++ * to get_ksm_page() before it can see that oldpage->mapping ++ * has gone stale (or that PageSwapCache has been cleared). ++ */ ++ smp_wmb(); ++ set_page_stable_node(oldpage, NULL); ++ } ++} ++#endif /* CONFIG_MIGRATION */ ++ ++#ifdef CONFIG_MEMORY_HOTREMOVE ++static struct stable_node *uksm_check_stable_tree(unsigned long start_pfn, ++ unsigned long end_pfn) ++{ ++ struct rb_node *node; ++ ++ for (node = rb_first(root_stable_treep); node; node = rb_next(node)) { ++ struct stable_node *stable_node; ++ ++ stable_node = rb_entry(node, struct stable_node, node); ++ if (stable_node->kpfn >= start_pfn && ++ stable_node->kpfn < end_pfn) ++ return stable_node; ++ } ++ return NULL; ++} ++ ++static int uksm_memory_callback(struct notifier_block *self, ++ unsigned long action, void *arg) ++{ ++ struct memory_notify *mn = arg; ++ struct stable_node *stable_node; ++ ++ switch (action) { ++ case MEM_GOING_OFFLINE: ++ /* ++ * Keep it very simple for now: just lock out ksmd and ++ * MADV_UNMERGEABLE while any memory is going offline. ++ * mutex_lock_nested() is necessary because lockdep was alarmed ++ * that here we take uksm_thread_mutex inside notifier chain ++ * mutex, and later take notifier chain mutex inside ++ * uksm_thread_mutex to unlock it. But that's safe because both ++ * are inside mem_hotplug_mutex. ++ */ ++ mutex_lock_nested(&uksm_thread_mutex, SINGLE_DEPTH_NESTING); ++ break; ++ ++ case MEM_OFFLINE: ++ /* ++ * Most of the work is done by page migration; but there might ++ * be a few stable_nodes left over, still pointing to struct ++ * pages which have been offlined: prune those from the tree. ++ */ ++ while ((stable_node = uksm_check_stable_tree(mn->start_pfn, ++ mn->start_pfn + mn->nr_pages)) != NULL) ++ remove_node_from_stable_tree(stable_node, 1, 1); ++ /* fallthrough */ ++ ++ case MEM_CANCEL_OFFLINE: ++ mutex_unlock(&uksm_thread_mutex); ++ break; ++ } ++ return NOTIFY_OK; ++} ++#endif /* CONFIG_MEMORY_HOTREMOVE */ ++ ++#ifdef CONFIG_SYSFS ++/* ++ * This all compiles without CONFIG_SYSFS, but is a waste of space. ++ */ ++ ++#define UKSM_ATTR_RO(_name) \ ++ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) ++#define UKSM_ATTR(_name) \ ++ static struct kobj_attribute _name##_attr = \ ++ __ATTR(_name, 0644, _name##_show, _name##_store) ++ ++static ssize_t max_cpu_percentage_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_max_cpu_percentage); ++} ++ ++static ssize_t max_cpu_percentage_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ unsigned long max_cpu_percentage; ++ int err; ++ ++ err = kstrtoul(buf, 10, &max_cpu_percentage); ++ if (err || max_cpu_percentage > 100) ++ return -EINVAL; ++ ++ if (max_cpu_percentage == 100) ++ max_cpu_percentage = 99; ++ else if (max_cpu_percentage < 10) ++ max_cpu_percentage = 10; ++ ++ uksm_max_cpu_percentage = max_cpu_percentage; ++ ++ return count; ++} ++UKSM_ATTR(max_cpu_percentage); ++ ++static ssize_t sleep_millisecs_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", jiffies_to_msecs(uksm_sleep_jiffies)); ++} ++ ++static ssize_t sleep_millisecs_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ unsigned long msecs; ++ int err; ++ ++ err = kstrtoul(buf, 10, &msecs); ++ if (err || msecs > MSEC_PER_SEC) ++ return -EINVAL; ++ ++ uksm_sleep_jiffies = msecs_to_jiffies(msecs); ++ uksm_sleep_saved = uksm_sleep_jiffies; ++ ++ return count; ++} ++UKSM_ATTR(sleep_millisecs); ++ ++ ++static ssize_t cpu_governor_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); ++ int i; ++ ++ buf[0] = '\0'; ++ for (i = 0; i < n ; i++) { ++ if (uksm_cpu_governor == i) ++ strcat(buf, "["); ++ ++ strcat(buf, uksm_cpu_governor_str[i]); ++ ++ if (uksm_cpu_governor == i) ++ strcat(buf, "]"); ++ ++ strcat(buf, " "); ++ } ++ strcat(buf, "\n"); ++ ++ return strlen(buf); ++} ++ ++static inline void init_performance_values(void) ++{ ++ int i; ++ struct scan_rung *rung; ++ struct uksm_cpu_preset_s *preset = uksm_cpu_preset + uksm_cpu_governor; ++ ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = uksm_scan_ladder + i; ++ rung->cpu_ratio = preset->cpu_ratio[i]; ++ rung->cover_msecs = preset->cover_msecs[i]; ++ } ++ ++ uksm_max_cpu_percentage = preset->max_cpu; ++} ++ ++static ssize_t cpu_governor_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); ++ ++ for (n--; n >= 0 ; n--) { ++ if (!strncmp(buf, uksm_cpu_governor_str[n], ++ strlen(uksm_cpu_governor_str[n]))) ++ break; ++ } ++ ++ if (n < 0) ++ return -EINVAL; ++ else ++ uksm_cpu_governor = n; ++ ++ init_performance_values(); ++ ++ return count; ++} ++UKSM_ATTR(cpu_governor); ++ ++static ssize_t run_show(struct kobject *kobj, struct kobj_attribute *attr, ++ char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_run); ++} ++ ++static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int err; ++ unsigned long flags; ++ ++ err = kstrtoul(buf, 10, &flags); ++ if (err || flags > UINT_MAX) ++ return -EINVAL; ++ if (flags > UKSM_RUN_MERGE) ++ return -EINVAL; ++ ++ mutex_lock(&uksm_thread_mutex); ++ if (uksm_run != flags) ++ uksm_run = flags; ++ mutex_unlock(&uksm_thread_mutex); ++ ++ if (flags & UKSM_RUN_MERGE) ++ wake_up_interruptible(&uksm_thread_wait); ++ ++ return count; ++} ++UKSM_ATTR(run); ++ ++static ssize_t abundant_threshold_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_abundant_threshold); ++} ++ ++static ssize_t abundant_threshold_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int err; ++ unsigned long flags; ++ ++ err = kstrtoul(buf, 10, &flags); ++ if (err || flags > 99) ++ return -EINVAL; ++ ++ uksm_abundant_threshold = flags; ++ ++ return count; ++} ++UKSM_ATTR(abundant_threshold); ++ ++static ssize_t thrash_threshold_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_thrash_threshold); ++} ++ ++static ssize_t thrash_threshold_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int err; ++ unsigned long flags; ++ ++ err = kstrtoul(buf, 10, &flags); ++ if (err || flags > 99) ++ return -EINVAL; ++ ++ uksm_thrash_threshold = flags; ++ ++ return count; ++} ++UKSM_ATTR(thrash_threshold); ++ ++static ssize_t cpu_ratios_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ int i, size; ++ struct scan_rung *rung; ++ char *p = buf; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ ++ if (rung->cpu_ratio > 0) ++ size = sprintf(p, "%d ", rung->cpu_ratio); ++ else ++ size = sprintf(p, "MAX/%d ", ++ TIME_RATIO_SCALE / -rung->cpu_ratio); ++ ++ p += size; ++ } ++ ++ *p++ = '\n'; ++ *p = '\0'; ++ ++ return p - buf; ++} ++ ++static ssize_t cpu_ratios_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int i, cpuratios[SCAN_LADDER_SIZE], err; ++ unsigned long value; ++ struct scan_rung *rung; ++ char *p, *end = NULL; ++ ++ p = kzalloc(count, GFP_KERNEL); ++ if (!p) ++ return -ENOMEM; ++ ++ memcpy(p, buf, count); ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ if (i != SCAN_LADDER_SIZE - 1) { ++ end = strchr(p, ' '); ++ if (!end) ++ return -EINVAL; ++ ++ *end = '\0'; ++ } ++ ++ if (strstr(p, "MAX/")) { ++ p = strchr(p, '/') + 1; ++ err = kstrtoul(p, 10, &value); ++ if (err || value > TIME_RATIO_SCALE || !value) ++ return -EINVAL; ++ ++ cpuratios[i] = -(int) (TIME_RATIO_SCALE / value); ++ } else { ++ err = kstrtoul(p, 10, &value); ++ if (err || value > TIME_RATIO_SCALE || !value) ++ return -EINVAL; ++ ++ cpuratios[i] = value; ++ } ++ ++ p = end + 1; ++ } ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ ++ rung->cpu_ratio = cpuratios[i]; ++ } ++ ++ return count; ++} ++UKSM_ATTR(cpu_ratios); ++ ++static ssize_t eval_intervals_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ int i, size; ++ struct scan_rung *rung; ++ char *p = buf; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ size = sprintf(p, "%u ", rung->cover_msecs); ++ p += size; ++ } ++ ++ *p++ = '\n'; ++ *p = '\0'; ++ ++ return p - buf; ++} ++ ++static ssize_t eval_intervals_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int i, err; ++ unsigned long values[SCAN_LADDER_SIZE]; ++ struct scan_rung *rung; ++ char *p, *end = NULL; ++ ssize_t ret = count; ++ ++ p = kzalloc(count + 2, GFP_KERNEL); ++ if (!p) ++ return -ENOMEM; ++ ++ memcpy(p, buf, count); ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ if (i != SCAN_LADDER_SIZE - 1) { ++ end = strchr(p, ' '); ++ if (!end) { ++ ret = -EINVAL; ++ goto out; ++ } ++ ++ *end = '\0'; ++ } ++ ++ err = kstrtoul(p, 10, &values[i]); ++ if (err) { ++ ret = -EINVAL; ++ goto out; ++ } ++ ++ p = end + 1; ++ } ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ ++ rung->cover_msecs = values[i]; ++ } ++ ++out: ++ kfree(p); ++ return ret; ++} ++UKSM_ATTR(eval_intervals); ++ ++static ssize_t ema_per_page_time_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_ema_page_time); ++} ++UKSM_ATTR_RO(ema_per_page_time); ++ ++static ssize_t pages_shared_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_pages_shared); ++} ++UKSM_ATTR_RO(pages_shared); ++ ++static ssize_t pages_sharing_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_pages_sharing); ++} ++UKSM_ATTR_RO(pages_sharing); ++ ++static ssize_t pages_unshared_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_pages_unshared); ++} ++UKSM_ATTR_RO(pages_unshared); ++ ++static ssize_t full_scans_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%llu\n", fully_scanned_round); ++} ++UKSM_ATTR_RO(full_scans); ++ ++static ssize_t pages_scanned_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ unsigned long base = 0; ++ u64 delta, ret; ++ ++ if (pages_scanned_stored) { ++ base = pages_scanned_base; ++ ret = pages_scanned_stored; ++ delta = uksm_pages_scanned >> base; ++ if (CAN_OVERFLOW_U64(ret, delta)) { ++ ret >>= 1; ++ delta >>= 1; ++ base++; ++ ret += delta; ++ } ++ } else { ++ ret = uksm_pages_scanned; ++ } ++ ++ while (ret > ULONG_MAX) { ++ ret >>= 1; ++ base++; ++ } ++ ++ if (base) ++ return sprintf(buf, "%lu * 2^%lu\n", (unsigned long)ret, base); ++ else ++ return sprintf(buf, "%lu\n", (unsigned long)ret); ++} ++UKSM_ATTR_RO(pages_scanned); ++ ++static ssize_t hash_strength_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", hash_strength); ++} ++UKSM_ATTR_RO(hash_strength); ++ ++static ssize_t sleep_times_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%llu\n", uksm_sleep_times); ++} ++UKSM_ATTR_RO(sleep_times); ++ ++ ++static struct attribute *uksm_attrs[] = { ++ &max_cpu_percentage_attr.attr, ++ &sleep_millisecs_attr.attr, ++ &cpu_governor_attr.attr, ++ &run_attr.attr, ++ &ema_per_page_time_attr.attr, ++ &pages_shared_attr.attr, ++ &pages_sharing_attr.attr, ++ &pages_unshared_attr.attr, ++ &full_scans_attr.attr, ++ &pages_scanned_attr.attr, ++ &hash_strength_attr.attr, ++ &sleep_times_attr.attr, ++ &thrash_threshold_attr.attr, ++ &abundant_threshold_attr.attr, ++ &cpu_ratios_attr.attr, ++ &eval_intervals_attr.attr, ++ NULL, ++}; ++ ++static struct attribute_group uksm_attr_group = { ++ .attrs = uksm_attrs, ++ .name = "uksm", ++}; ++#endif /* CONFIG_SYSFS */ ++ ++static inline void init_scan_ladder(void) ++{ ++ int i; ++ struct scan_rung *rung; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = uksm_scan_ladder + i; ++ slot_tree_init_root(&rung->vma_root); ++ } ++ ++ init_performance_values(); ++ uksm_calc_scan_pages(); ++} ++ ++static inline int cal_positive_negative_costs(void) ++{ ++ struct page *p1, *p2; ++ unsigned char *addr1, *addr2; ++ unsigned long i, time_start, hash_cost; ++ unsigned long loopnum = 0; ++ ++ /*IMPORTANT: volatile is needed to prevent over-optimization by gcc. */ ++ volatile u32 hash; ++ volatile int ret; ++ ++ p1 = alloc_page(GFP_KERNEL); ++ if (!p1) ++ return -ENOMEM; ++ ++ p2 = alloc_page(GFP_KERNEL); ++ if (!p2) ++ return -ENOMEM; ++ ++ addr1 = kmap_atomic(p1); ++ addr2 = kmap_atomic(p2); ++ memset(addr1, prandom_u32(), PAGE_SIZE); ++ memcpy(addr2, addr1, PAGE_SIZE); ++ ++ /* make sure that the two pages differ in last byte */ ++ addr2[PAGE_SIZE-1] = ~addr2[PAGE_SIZE-1]; ++ kunmap_atomic(addr2); ++ kunmap_atomic(addr1); ++ ++ time_start = jiffies; ++ while (jiffies - time_start < 100) { ++ for (i = 0; i < 100; i++) ++ hash = page_hash(p1, HASH_STRENGTH_FULL, 0); ++ loopnum += 100; ++ } ++ hash_cost = (jiffies - time_start); ++ ++ time_start = jiffies; ++ for (i = 0; i < loopnum; i++) ++ ret = pages_identical(p1, p2); ++ memcmp_cost = HASH_STRENGTH_FULL * (jiffies - time_start); ++ memcmp_cost /= hash_cost; ++ pr_info("UKSM: relative memcmp_cost = %lu " ++ "hash=%u cmp_ret=%d.\n", ++ memcmp_cost, hash, ret); ++ ++ __free_page(p1); ++ __free_page(p2); ++ return 0; ++} ++ ++static int init_zeropage_hash_table(void) ++{ ++ struct page *page; ++ char *addr; ++ int i; ++ ++ page = alloc_page(GFP_KERNEL); ++ if (!page) ++ return -ENOMEM; ++ ++ addr = kmap_atomic(page); ++ memset(addr, 0, PAGE_SIZE); ++ kunmap_atomic(addr); ++ ++ zero_hash_table = kmalloc_array(HASH_STRENGTH_MAX, sizeof(u32), ++ GFP_KERNEL); ++ if (!zero_hash_table) ++ return -ENOMEM; ++ ++ for (i = 0; i < HASH_STRENGTH_MAX; i++) ++ zero_hash_table[i] = page_hash(page, i, 0); ++ ++ __free_page(page); ++ ++ return 0; ++} ++ ++static inline int init_random_sampling(void) ++{ ++ unsigned long i; ++ ++ random_nums = kmalloc(PAGE_SIZE, GFP_KERNEL); ++ if (!random_nums) ++ return -ENOMEM; ++ ++ for (i = 0; i < HASH_STRENGTH_FULL; i++) ++ random_nums[i] = i; ++ ++ for (i = 0; i < HASH_STRENGTH_FULL; i++) { ++ unsigned long rand_range, swap_index, tmp; ++ ++ rand_range = HASH_STRENGTH_FULL - i; ++ swap_index = i + prandom_u32() % rand_range; ++ tmp = random_nums[i]; ++ random_nums[i] = random_nums[swap_index]; ++ random_nums[swap_index] = tmp; ++ } ++ ++ rshash_state.state = RSHASH_NEW; ++ rshash_state.below_count = 0; ++ rshash_state.lookup_window_index = 0; ++ ++ return cal_positive_negative_costs(); ++} ++ ++static int __init uksm_slab_init(void) ++{ ++ rmap_item_cache = UKSM_KMEM_CACHE(rmap_item, 0); ++ if (!rmap_item_cache) ++ goto out; ++ ++ stable_node_cache = UKSM_KMEM_CACHE(stable_node, 0); ++ if (!stable_node_cache) ++ goto out_free1; ++ ++ node_vma_cache = UKSM_KMEM_CACHE(node_vma, 0); ++ if (!node_vma_cache) ++ goto out_free2; ++ ++ vma_slot_cache = UKSM_KMEM_CACHE(vma_slot, 0); ++ if (!vma_slot_cache) ++ goto out_free3; ++ ++ tree_node_cache = UKSM_KMEM_CACHE(tree_node, 0); ++ if (!tree_node_cache) ++ goto out_free4; ++ ++ return 0; ++ ++out_free4: ++ kmem_cache_destroy(vma_slot_cache); ++out_free3: ++ kmem_cache_destroy(node_vma_cache); ++out_free2: ++ kmem_cache_destroy(stable_node_cache); ++out_free1: ++ kmem_cache_destroy(rmap_item_cache); ++out: ++ return -ENOMEM; ++} ++ ++static void __init uksm_slab_free(void) ++{ ++ kmem_cache_destroy(stable_node_cache); ++ kmem_cache_destroy(rmap_item_cache); ++ kmem_cache_destroy(node_vma_cache); ++ kmem_cache_destroy(vma_slot_cache); ++ kmem_cache_destroy(tree_node_cache); ++} ++ ++/* Common interface to ksm, different to it. */ ++int ksm_madvise(struct vm_area_struct *vma, unsigned long start, ++ unsigned long end, int advice, unsigned long *vm_flags) ++{ ++ int err; ++ ++ switch (advice) { ++ case MADV_MERGEABLE: ++ return 0; /* just ignore the advice */ ++ ++ case MADV_UNMERGEABLE: ++ if (!(*vm_flags & VM_MERGEABLE) || !uksm_flags_can_scan(*vm_flags)) ++ return 0; /* just ignore the advice */ ++ ++ if (vma->anon_vma) { ++ err = unmerge_uksm_pages(vma, start, end); ++ if (err) ++ return err; ++ } ++ ++ uksm_remove_vma(vma); ++ *vm_flags &= ~VM_MERGEABLE; ++ break; ++ } ++ ++ return 0; ++} ++ ++/* Common interface to ksm, actually the same. */ ++struct page *ksm_might_need_to_copy(struct page *page, ++ struct vm_area_struct *vma, unsigned long address) ++{ ++ struct anon_vma *anon_vma = page_anon_vma(page); ++ struct page *new_page; ++ ++ if (PageKsm(page)) { ++ if (page_stable_node(page)) ++ return page; /* no need to copy it */ ++ } else if (!anon_vma) { ++ return page; /* no need to copy it */ ++ } else if (anon_vma->root == vma->anon_vma->root && ++ page->index == linear_page_index(vma, address)) { ++ return page; /* still no need to copy it */ ++ } ++ if (!PageUptodate(page)) ++ return page; /* let do_swap_page report the error */ ++ ++ new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); ++ if (new_page) { ++ copy_user_highpage(new_page, page, address, vma); ++ ++ SetPageDirty(new_page); ++ __SetPageUptodate(new_page); ++ __SetPageLocked(new_page); ++ } ++ ++ return new_page; ++} ++ ++static int __init uksm_init(void) ++{ ++ struct task_struct *uksm_thread; ++ int err; ++ ++ uksm_sleep_jiffies = msecs_to_jiffies(100); ++ uksm_sleep_saved = uksm_sleep_jiffies; ++ ++ slot_tree_init(); ++ init_scan_ladder(); ++ ++ ++ err = init_random_sampling(); ++ if (err) ++ goto out_free2; ++ ++ err = uksm_slab_init(); ++ if (err) ++ goto out_free1; ++ ++ err = init_zeropage_hash_table(); ++ if (err) ++ goto out_free0; ++ ++ uksm_thread = kthread_run(uksm_scan_thread, NULL, "uksmd"); ++ if (IS_ERR(uksm_thread)) { ++ pr_err("uksm: creating kthread failed\n"); ++ err = PTR_ERR(uksm_thread); ++ goto out_free; ++ } ++ ++#ifdef CONFIG_SYSFS ++ err = sysfs_create_group(mm_kobj, &uksm_attr_group); ++ if (err) { ++ pr_err("uksm: register sysfs failed\n"); ++ kthread_stop(uksm_thread); ++ goto out_free; ++ } ++#else ++ uksm_run = UKSM_RUN_MERGE; /* no way for user to start it */ ++ ++#endif /* CONFIG_SYSFS */ ++ ++#ifdef CONFIG_MEMORY_HOTREMOVE ++ /* ++ * Choose a high priority since the callback takes uksm_thread_mutex: ++ * later callbacks could only be taking locks which nest within that. ++ */ ++ hotplug_memory_notifier(uksm_memory_callback, 100); ++#endif ++ return 0; ++ ++out_free: ++ kfree(zero_hash_table); ++out_free0: ++ uksm_slab_free(); ++out_free1: ++ kfree(random_nums); ++out_free2: ++ kfree(uksm_scan_ladder); ++ return err; ++} ++ ++#ifdef MODULE ++subsys_initcall(ksm_init); ++#else ++late_initcall(uksm_init); ++#endif ++ +diff -Nur a/mm/vmstat.c b/mm/vmstat.c +--- a/mm/vmstat.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/vmstat.c 2019-07-07 11:43:00.148837320 +0100 +@@ -1165,6 +1165,9 @@ + "nr_written", + "nr_kernel_misc_reclaimable", + ++#ifdef CONFIG_UKSM ++ "nr_uksm_zero_pages", ++#endif + /* enum writeback_stat_item counters */ + "nr_dirty_threshold", + "nr_dirty_background_threshold", diff --git a/sys-kernel/linux-image-redcore/files/5.1-uksm-linux-hardened.patch b/sys-kernel/linux-image-redcore/files/5.1-uksm-linux-hardened.patch deleted file mode 100644 index a79cb3d5..00000000 --- a/sys-kernel/linux-image-redcore/files/5.1-uksm-linux-hardened.patch +++ /dev/null @@ -1,6901 +0,0 @@ -diff -Nur a/Documentation/vm/uksm.txt b/Documentation/vm/uksm.txt ---- a/Documentation/vm/uksm.txt 1970-01-01 01:00:00.000000000 +0100 -+++ b/Documentation/vm/uksm.txt 2019-07-07 09:32:50.451840235 +0100 -@@ -0,0 +1,61 @@ -+The Ultra Kernel Samepage Merging feature -+---------------------------------------------- -+/* -+ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia -+ * -+ * This is an improvement upon KSM. Some basic data structures and routines -+ * are borrowed from ksm.c . -+ * -+ * Its new features: -+ * 1. Full system scan: -+ * It automatically scans all user processes' anonymous VMAs. Kernel-user -+ * interaction to submit a memory area to KSM is no longer needed. -+ * -+ * 2. Rich area detection: -+ * It automatically detects rich areas containing abundant duplicated -+ * pages based. Rich areas are given a full scan speed. Poor areas are -+ * sampled at a reasonable speed with very low CPU consumption. -+ * -+ * 3. Ultra Per-page scan speed improvement: -+ * A new hash algorithm is proposed. As a result, on a machine with -+ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it -+ * can scan memory areas that does not contain duplicated pages at speed of -+ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of -+ * 477MB/sec ~ 923MB/sec. -+ * -+ * 4. Thrashing area avoidance: -+ * Thrashing area(an VMA that has frequent Ksm page break-out) can be -+ * filtered out. My benchmark shows it's more efficient than KSM's per-page -+ * hash value based volatile page detection. -+ * -+ * -+ * 5. Misc changes upon KSM: -+ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page -+ * comparison. It's much faster than default C version on x86. -+ * * rmap_item now has an struct *page member to loosely cache a -+ * address-->page mapping, which reduces too much time-costly -+ * follow_page(). -+ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. -+ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ -+ * ksm is needed for this case. -+ * -+ * 6. Full Zero Page consideration(contributed by Figo Zhang) -+ * Now uksmd consider full zero pages as special pages and merge them to an -+ * special unswappable uksm zero page. -+ */ -+ -+ChangeLog: -+ -+2012-05-05 The creation of this Doc -+2012-05-08 UKSM 0.1.1.1 libc crash bug fix, api clean up, doc clean up. -+2012-05-28 UKSM 0.1.1.2 bug fix release -+2012-06-26 UKSM 0.1.2-beta1 first beta release for 0.1.2 -+2012-07-2 UKSM 0.1.2-beta2 -+2012-07-10 UKSM 0.1.2-beta3 -+2012-07-26 UKSM 0.1.2 Fine grained speed control, more scan optimization. -+2012-10-13 UKSM 0.1.2.1 Bug fixes. -+2012-12-31 UKSM 0.1.2.2 Minor bug fixes. -+2014-07-02 UKSM 0.1.2.3 Fix a " __this_cpu_read() in preemptible bug". -+2015-04-22 UKSM 0.1.2.4 Fix a race condition that can sometimes trigger anonying warnings. -+2016-09-10 UKSM 0.1.2.5 Fix a bug in dedup ratio calculation. -+2017-02-26 UKSM 0.1.2.6 Fix a bug in hugetlbpage handling and a race bug with page migration. -diff -Nur a/fs/exec.c b/fs/exec.c ---- a/fs/exec.c 2019-07-07 09:08:19.132347946 +0100 -+++ b/fs/exec.c 2019-07-07 09:33:47.653770486 +0100 -@@ -63,6 +63,7 @@ - #include - #include - #include -+#include - - #include - #include -@@ -1385,6 +1386,7 @@ - /* An exec changes our domain. We are no longer part of the thread - group */ - current->self_exec_id++; -+ - flush_signal_handlers(current, 0); - } - EXPORT_SYMBOL(setup_new_exec); -diff -Nur a/fs/proc/meminfo.c b/fs/proc/meminfo.c ---- a/fs/proc/meminfo.c 2019-06-25 04:34:56.000000000 +0100 -+++ b/fs/proc/meminfo.c 2019-07-07 09:32:50.451840235 +0100 -@@ -106,6 +106,10 @@ - global_zone_page_state(NR_KERNEL_STACK_KB)); - show_val_kb(m, "PageTables: ", - global_zone_page_state(NR_PAGETABLE)); -+#ifdef CONFIG_UKSM -+ show_val_kb(m, "KsmZeroPages: ", -+ global_zone_page_state(NR_UKSM_ZERO_PAGES)); -+#endif - #ifdef CONFIG_QUICKLIST - show_val_kb(m, "Quicklists: ", quicklist_total_size()); - #endif -diff -Nur a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h ---- a/include/asm-generic/pgtable.h 2019-06-25 04:34:56.000000000 +0100 -+++ b/include/asm-generic/pgtable.h 2019-07-07 09:32:50.451840235 +0100 -@@ -855,12 +855,25 @@ - extern void untrack_pfn_moved(struct vm_area_struct *vma); - #endif - -+#ifdef CONFIG_UKSM -+static inline int is_uksm_zero_pfn(unsigned long pfn) -+{ -+ extern unsigned long uksm_zero_pfn; -+ return pfn == uksm_zero_pfn; -+} -+#else -+static inline int is_uksm_zero_pfn(unsigned long pfn) -+{ -+ return 0; -+} -+#endif -+ - #ifdef __HAVE_COLOR_ZERO_PAGE - static inline int is_zero_pfn(unsigned long pfn) - { - extern unsigned long zero_pfn; - unsigned long offset_from_zero_pfn = pfn - zero_pfn; -- return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT); -+ return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT) || is_uksm_zero_pfn(pfn); - } - - #define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) -@@ -869,7 +882,7 @@ - static inline int is_zero_pfn(unsigned long pfn) - { - extern unsigned long zero_pfn; -- return pfn == zero_pfn; -+ return (pfn == zero_pfn) || (is_uksm_zero_pfn(pfn)); - } - - static inline unsigned long my_zero_pfn(unsigned long addr) -diff -Nur a/include/linux/ksm.h b/include/linux/ksm.h ---- a/include/linux/ksm.h 2019-06-25 04:34:56.000000000 +0100 -+++ b/include/linux/ksm.h 2019-07-07 09:32:50.451840235 +0100 -@@ -1,4 +1,4 @@ --/* SPDX-License-Identifier: GPL-2.0 */ -+/* SPDX-License-Identifier: GPL-3.0 */ - #ifndef __LINUX_KSM_H - #define __LINUX_KSM_H - /* -@@ -21,20 +21,16 @@ - #ifdef CONFIG_KSM - int ksm_madvise(struct vm_area_struct *vma, unsigned long start, - unsigned long end, int advice, unsigned long *vm_flags); --int __ksm_enter(struct mm_struct *mm); --void __ksm_exit(struct mm_struct *mm); - --static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) -+static inline struct stable_node *page_stable_node(struct page *page) - { -- if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) -- return __ksm_enter(mm); -- return 0; -+ return PageKsm(page) ? page_rmapping(page) : NULL; - } - --static inline void ksm_exit(struct mm_struct *mm) -+static inline void set_page_stable_node(struct page *page, -+ struct stable_node *stable_node) - { -- if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) -- __ksm_exit(mm); -+ page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); - } - - /* -@@ -56,6 +52,33 @@ - bool reuse_ksm_page(struct page *page, - struct vm_area_struct *vma, unsigned long address); - -+#ifdef CONFIG_KSM_LEGACY -+int __ksm_enter(struct mm_struct *mm); -+void __ksm_exit(struct mm_struct *mm); -+static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) -+{ -+ if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) -+ return __ksm_enter(mm); -+ return 0; -+} -+ -+static inline void ksm_exit(struct mm_struct *mm) -+{ -+ if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) -+ __ksm_exit(mm); -+} -+ -+#elif defined(CONFIG_UKSM) -+static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) -+{ -+ return 0; -+} -+ -+static inline void ksm_exit(struct mm_struct *mm) -+{ -+} -+#endif /* !CONFIG_UKSM */ -+ - #else /* !CONFIG_KSM */ - - static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) -@@ -96,4 +119,6 @@ - #endif /* CONFIG_MMU */ - #endif /* !CONFIG_KSM */ - -+#include -+ - #endif /* __LINUX_KSM_H */ -diff -Nur a/include/linux/mm_types.h b/include/linux/mm_types.h ---- a/include/linux/mm_types.h 2019-06-25 04:34:56.000000000 +0100 -+++ b/include/linux/mm_types.h 2019-07-07 09:32:50.451840235 +0100 -@@ -334,6 +334,9 @@ - struct mempolicy *vm_policy; /* NUMA policy for the VMA */ - #endif - struct vm_userfaultfd_ctx vm_userfaultfd_ctx; -+#ifdef CONFIG_UKSM -+ struct vma_slot *uksm_vma_slot; -+#endif - } __randomize_layout; - - struct core_thread { -diff -Nur a/include/linux/mmzone.h b/include/linux/mmzone.h ---- a/include/linux/mmzone.h 2019-06-25 04:34:56.000000000 +0100 -+++ b/include/linux/mmzone.h 2019-07-07 09:32:50.451840235 +0100 -@@ -148,6 +148,9 @@ - NR_ZSPAGES, /* allocated in zsmalloc */ - #endif - NR_FREE_CMA_PAGES, -+#ifdef CONFIG_UKSM -+ NR_UKSM_ZERO_PAGES, -+#endif - NR_VM_ZONE_STAT_ITEMS }; - - enum node_stat_item { -diff -Nur a/include/linux/sradix-tree.h b/include/linux/sradix-tree.h ---- a/include/linux/sradix-tree.h 1970-01-01 01:00:00.000000000 +0100 -+++ b/include/linux/sradix-tree.h 2019-07-07 09:32:50.451840235 +0100 -@@ -0,0 +1,77 @@ -+#ifndef _LINUX_SRADIX_TREE_H -+#define _LINUX_SRADIX_TREE_H -+ -+ -+#define INIT_SRADIX_TREE(root, mask) \ -+do { \ -+ (root)->height = 0; \ -+ (root)->gfp_mask = (mask); \ -+ (root)->rnode = NULL; \ -+} while (0) -+ -+#define ULONG_BITS (sizeof(unsigned long) * 8) -+#define SRADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) -+//#define SRADIX_TREE_MAP_SHIFT 6 -+//#define SRADIX_TREE_MAP_SIZE (1UL << SRADIX_TREE_MAP_SHIFT) -+//#define SRADIX_TREE_MAP_MASK (SRADIX_TREE_MAP_SIZE-1) -+ -+struct sradix_tree_node { -+ unsigned int height; /* Height from the bottom */ -+ unsigned int count; -+ unsigned int fulls; /* Number of full sublevel trees */ -+ struct sradix_tree_node *parent; -+ void *stores[0]; -+}; -+ -+/* A simple radix tree implementation */ -+struct sradix_tree_root { -+ unsigned int height; -+ struct sradix_tree_node *rnode; -+ -+ /* Where found to have available empty stores in its sublevels */ -+ struct sradix_tree_node *enter_node; -+ unsigned int shift; -+ unsigned int stores_size; -+ unsigned int mask; -+ unsigned long min; /* The first hole index */ -+ unsigned long num; -+ //unsigned long *height_to_maxindex; -+ -+ /* How the node is allocated and freed. */ -+ struct sradix_tree_node *(*alloc)(void); -+ void (*free)(struct sradix_tree_node *node); -+ -+ /* When a new node is added and removed */ -+ void (*extend)(struct sradix_tree_node *parent, struct sradix_tree_node *child); -+ void (*assign)(struct sradix_tree_node *node, unsigned int index, void *item); -+ void (*rm)(struct sradix_tree_node *node, unsigned int offset); -+}; -+ -+struct sradix_tree_path { -+ struct sradix_tree_node *node; -+ int offset; -+}; -+ -+static inline -+void init_sradix_tree_root(struct sradix_tree_root *root, unsigned long shift) -+{ -+ root->height = 0; -+ root->rnode = NULL; -+ root->shift = shift; -+ root->stores_size = 1UL << shift; -+ root->mask = root->stores_size - 1; -+} -+ -+ -+extern void *sradix_tree_next(struct sradix_tree_root *root, -+ struct sradix_tree_node *node, unsigned long index, -+ int (*iter)(void *, unsigned long)); -+ -+extern int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num); -+ -+extern void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, -+ struct sradix_tree_node *node, unsigned long index); -+ -+extern void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index); -+ -+#endif /* _LINUX_SRADIX_TREE_H */ -diff -Nur a/include/linux/uksm.h b/include/linux/uksm.h ---- a/include/linux/uksm.h 1970-01-01 01:00:00.000000000 +0100 -+++ b/include/linux/uksm.h 2019-07-07 09:32:50.451840235 +0100 -@@ -0,0 +1,149 @@ -+#ifndef __LINUX_UKSM_H -+#define __LINUX_UKSM_H -+/* -+ * Memory merging support. -+ * -+ * This code enables dynamic sharing of identical pages found in different -+ * memory areas, even if they are not shared by fork(). -+ */ -+ -+/* if !CONFIG_UKSM this file should not be compiled at all. */ -+#ifdef CONFIG_UKSM -+ -+#include -+#include -+#include -+#include -+#include -+ -+extern unsigned long zero_pfn __read_mostly; -+extern unsigned long uksm_zero_pfn __read_mostly; -+extern struct page *empty_uksm_zero_page; -+ -+/* must be done before linked to mm */ -+extern void uksm_vma_add_new(struct vm_area_struct *vma); -+extern void uksm_remove_vma(struct vm_area_struct *vma); -+ -+#define UKSM_SLOT_NEED_SORT (1 << 0) -+#define UKSM_SLOT_NEED_RERAND (1 << 1) -+#define UKSM_SLOT_SCANNED (1 << 2) /* It's scanned in this round */ -+#define UKSM_SLOT_FUL_SCANNED (1 << 3) -+#define UKSM_SLOT_IN_UKSM (1 << 4) -+ -+struct vma_slot { -+ struct sradix_tree_node *snode; -+ unsigned long sindex; -+ -+ struct list_head slot_list; -+ unsigned long fully_scanned_round; -+ unsigned long dedup_num; -+ unsigned long pages_scanned; -+ unsigned long this_sampled; -+ unsigned long last_scanned; -+ unsigned long pages_to_scan; -+ struct scan_rung *rung; -+ struct page **rmap_list_pool; -+ unsigned int *pool_counts; -+ unsigned long pool_size; -+ struct vm_area_struct *vma; -+ struct mm_struct *mm; -+ unsigned long ctime_j; -+ unsigned long pages; -+ unsigned long flags; -+ unsigned long pages_cowed; /* pages cowed this round */ -+ unsigned long pages_merged; /* pages merged this round */ -+ unsigned long pages_bemerged; -+ -+ /* when it has page merged in this eval round */ -+ struct list_head dedup_list; -+}; -+ -+static inline void uksm_unmap_zero_page(pte_t pte) -+{ -+ if (pte_pfn(pte) == uksm_zero_pfn) -+ __dec_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); -+} -+ -+static inline void uksm_map_zero_page(pte_t pte) -+{ -+ if (pte_pfn(pte) == uksm_zero_pfn) -+ __inc_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); -+} -+ -+static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) -+{ -+ if (vma->uksm_vma_slot && PageKsm(page)) -+ vma->uksm_vma_slot->pages_cowed++; -+} -+ -+static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) -+{ -+ if (vma->uksm_vma_slot && pte_pfn(pte) == uksm_zero_pfn) -+ vma->uksm_vma_slot->pages_cowed++; -+} -+ -+static inline int uksm_flags_can_scan(unsigned long vm_flags) -+{ -+#ifdef VM_SAO -+ if (vm_flags & VM_SAO) -+ return 0; -+#endif -+ -+ return !(vm_flags & (VM_PFNMAP | VM_IO | VM_DONTEXPAND | -+ VM_HUGETLB | VM_MIXEDMAP | VM_SHARED -+ | VM_MAYSHARE | VM_GROWSUP | VM_GROWSDOWN)); -+} -+ -+static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) -+{ -+ if (uksm_flags_can_scan(*vm_flags_p)) -+ *vm_flags_p |= VM_MERGEABLE; -+} -+ -+/* -+ * Just a wrapper for BUG_ON for where ksm_zeropage must not be. TODO: it will -+ * be removed when uksm zero page patch is stable enough. -+ */ -+static inline void uksm_bugon_zeropage(pte_t pte) -+{ -+ BUG_ON(pte_pfn(pte) == uksm_zero_pfn); -+} -+#else -+static inline void uksm_vma_add_new(struct vm_area_struct *vma) -+{ -+} -+ -+static inline void uksm_remove_vma(struct vm_area_struct *vma) -+{ -+} -+ -+static inline void uksm_unmap_zero_page(pte_t pte) -+{ -+} -+ -+static inline void uksm_map_zero_page(pte_t pte) -+{ -+} -+ -+static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) -+{ -+} -+ -+static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) -+{ -+} -+ -+static inline int uksm_flags_can_scan(unsigned long vm_flags) -+{ -+ return 0; -+} -+ -+static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) -+{ -+} -+ -+static inline void uksm_bugon_zeropage(pte_t pte) -+{ -+} -+#endif /* !CONFIG_UKSM */ -+#endif /* __LINUX_UKSM_H */ -diff -Nur a/kernel/fork.c b/kernel/fork.c ---- a/kernel/fork.c 2019-07-07 09:08:19.152348621 +0100 -+++ b/kernel/fork.c 2019-07-07 09:32:50.451840235 +0100 -@@ -584,7 +584,7 @@ - __vma_link_rb(mm, tmp, rb_link, rb_parent); - rb_link = &tmp->vm_rb.rb_right; - rb_parent = &tmp->vm_rb; -- -+ uksm_vma_add_new(tmp); - mm->map_count++; - if (!(tmp->vm_flags & VM_WIPEONFORK)) - retval = copy_page_range(mm, oldmm, mpnt); -diff -Nur a/lib/Makefile b/lib/Makefile ---- a/lib/Makefile 2019-06-25 04:34:56.000000000 +0100 -+++ b/lib/Makefile 2019-07-07 09:32:50.451840235 +0100 -@@ -29,7 +29,7 @@ - endif - - lib-y := ctype.o string.o vsprintf.o cmdline.o \ -- rbtree.o radix-tree.o timerqueue.o xarray.o \ -+ rbtree.o radix-tree.o sradix-tree.o timerqueue.o xarray.o \ - idr.o int_sqrt.o extable.o \ - sha1.o chacha.o irq_regs.o argv_split.o \ - flex_proportions.o ratelimit.o show_mem.o \ -diff -Nur a/lib/sradix-tree.c b/lib/sradix-tree.c ---- a/lib/sradix-tree.c 1970-01-01 01:00:00.000000000 +0100 -+++ b/lib/sradix-tree.c 2019-07-07 09:32:50.451840235 +0100 -@@ -0,0 +1,476 @@ -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+ -+static inline int sradix_node_full(struct sradix_tree_root *root, struct sradix_tree_node *node) -+{ -+ return node->fulls == root->stores_size || -+ (node->height == 1 && node->count == root->stores_size); -+} -+ -+/* -+ * Extend a sradix tree so it can store key @index. -+ */ -+static int sradix_tree_extend(struct sradix_tree_root *root, unsigned long index) -+{ -+ struct sradix_tree_node *node; -+ unsigned int height; -+ -+ if (unlikely(root->rnode == NULL)) { -+ if (!(node = root->alloc())) -+ return -ENOMEM; -+ -+ node->height = 1; -+ root->rnode = node; -+ root->height = 1; -+ } -+ -+ /* Figure out what the height should be. */ -+ height = root->height; -+ index >>= root->shift * height; -+ -+ while (index) { -+ index >>= root->shift; -+ height++; -+ } -+ -+ while (height > root->height) { -+ unsigned int newheight; -+ -+ if (!(node = root->alloc())) -+ return -ENOMEM; -+ -+ /* Increase the height. */ -+ node->stores[0] = root->rnode; -+ root->rnode->parent = node; -+ if (root->extend) -+ root->extend(node, root->rnode); -+ -+ newheight = root->height + 1; -+ node->height = newheight; -+ node->count = 1; -+ if (sradix_node_full(root, root->rnode)) -+ node->fulls = 1; -+ -+ root->rnode = node; -+ root->height = newheight; -+ } -+ -+ return 0; -+} -+ -+/* -+ * Search the next item from the current node, that is not NULL -+ * and can satify root->iter(). -+ */ -+void *sradix_tree_next(struct sradix_tree_root *root, -+ struct sradix_tree_node *node, unsigned long index, -+ int (*iter)(void *item, unsigned long height)) -+{ -+ unsigned long offset; -+ void *item; -+ -+ if (unlikely(node == NULL)) { -+ node = root->rnode; -+ for (offset = 0; offset < root->stores_size; offset++) { -+ item = node->stores[offset]; -+ if (item && (!iter || iter(item, node->height))) -+ break; -+ } -+ -+ if (unlikely(offset >= root->stores_size)) -+ return NULL; -+ -+ if (node->height == 1) -+ return item; -+ else -+ goto go_down; -+ } -+ -+ while (node) { -+ offset = (index & root->mask) + 1; -+ for (; offset < root->stores_size; offset++) { -+ item = node->stores[offset]; -+ if (item && (!iter || iter(item, node->height))) -+ break; -+ } -+ -+ if (offset < root->stores_size) -+ break; -+ -+ node = node->parent; -+ index >>= root->shift; -+ } -+ -+ if (!node) -+ return NULL; -+ -+ while (node->height > 1) { -+go_down: -+ node = item; -+ for (offset = 0; offset < root->stores_size; offset++) { -+ item = node->stores[offset]; -+ if (item && (!iter || iter(item, node->height))) -+ break; -+ } -+ -+ if (unlikely(offset >= root->stores_size)) -+ return NULL; -+ } -+ -+ BUG_ON(offset > root->stores_size); -+ -+ return item; -+} -+ -+/* -+ * Blindly insert the item to the tree. Typically, we reuse the -+ * first empty store item. -+ */ -+int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num) -+{ -+ unsigned long index; -+ unsigned int height; -+ struct sradix_tree_node *node, *tmp = NULL; -+ int offset, offset_saved; -+ void **store = NULL; -+ int error, i, j, shift; -+ -+go_on: -+ index = root->min; -+ -+ if (root->enter_node && !sradix_node_full(root, root->enter_node)) { -+ node = root->enter_node; -+ BUG_ON((index >> (root->shift * root->height))); -+ } else { -+ node = root->rnode; -+ if (node == NULL || (index >> (root->shift * root->height)) -+ || sradix_node_full(root, node)) { -+ error = sradix_tree_extend(root, index); -+ if (error) -+ return error; -+ -+ node = root->rnode; -+ } -+ } -+ -+ -+ height = node->height; -+ shift = (height - 1) * root->shift; -+ offset = (index >> shift) & root->mask; -+ while (shift > 0) { -+ offset_saved = offset; -+ for (; offset < root->stores_size; offset++) { -+ store = &node->stores[offset]; -+ tmp = *store; -+ -+ if (!tmp || !sradix_node_full(root, tmp)) -+ break; -+ } -+ BUG_ON(offset >= root->stores_size); -+ -+ if (offset != offset_saved) { -+ index += (offset - offset_saved) << shift; -+ index &= ~((1UL << shift) - 1); -+ } -+ -+ if (!tmp) { -+ if (!(tmp = root->alloc())) -+ return -ENOMEM; -+ -+ tmp->height = shift / root->shift; -+ *store = tmp; -+ tmp->parent = node; -+ node->count++; -+// if (root->extend) -+// root->extend(node, tmp); -+ } -+ -+ node = tmp; -+ shift -= root->shift; -+ offset = (index >> shift) & root->mask; -+ } -+ -+ BUG_ON(node->height != 1); -+ -+ -+ store = &node->stores[offset]; -+ for (i = 0, j = 0; -+ j < root->stores_size - node->count && -+ i < root->stores_size - offset && j < num; i++) { -+ if (!store[i]) { -+ store[i] = item[j]; -+ if (root->assign) -+ root->assign(node, index + i, item[j]); -+ j++; -+ } -+ } -+ -+ node->count += j; -+ root->num += j; -+ num -= j; -+ -+ while (sradix_node_full(root, node)) { -+ node = node->parent; -+ if (!node) -+ break; -+ -+ node->fulls++; -+ } -+ -+ if (unlikely(!node)) { -+ /* All nodes are full */ -+ root->min = 1 << (root->height * root->shift); -+ root->enter_node = NULL; -+ } else { -+ root->min = index + i - 1; -+ root->min |= (1UL << (node->height - 1)) - 1; -+ root->min++; -+ root->enter_node = node; -+ } -+ -+ if (num) { -+ item += j; -+ goto go_on; -+ } -+ -+ return 0; -+} -+ -+ -+/** -+ * sradix_tree_shrink - shrink height of a sradix tree to minimal -+ * @root sradix tree root -+ * -+ */ -+static inline void sradix_tree_shrink(struct sradix_tree_root *root) -+{ -+ /* try to shrink tree height */ -+ while (root->height > 1) { -+ struct sradix_tree_node *to_free = root->rnode; -+ -+ /* -+ * The candidate node has more than one child, or its child -+ * is not at the leftmost store, we cannot shrink. -+ */ -+ if (to_free->count != 1 || !to_free->stores[0]) -+ break; -+ -+ root->rnode = to_free->stores[0]; -+ root->rnode->parent = NULL; -+ root->height--; -+ if (unlikely(root->enter_node == to_free)) -+ root->enter_node = NULL; -+ root->free(to_free); -+ } -+} -+ -+/* -+ * Del the item on the known leaf node and index -+ */ -+void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, -+ struct sradix_tree_node *node, unsigned long index) -+{ -+ unsigned int offset; -+ struct sradix_tree_node *start, *end; -+ -+ BUG_ON(node->height != 1); -+ -+ start = node; -+ while (node && !(--node->count)) -+ node = node->parent; -+ -+ end = node; -+ if (!node) { -+ root->rnode = NULL; -+ root->height = 0; -+ root->min = 0; -+ root->num = 0; -+ root->enter_node = NULL; -+ } else { -+ offset = (index >> (root->shift * (node->height - 1))) & root->mask; -+ if (root->rm) -+ root->rm(node, offset); -+ node->stores[offset] = NULL; -+ root->num--; -+ if (root->min > index) { -+ root->min = index; -+ root->enter_node = node; -+ } -+ } -+ -+ if (start != end) { -+ do { -+ node = start; -+ start = start->parent; -+ if (unlikely(root->enter_node == node)) -+ root->enter_node = end; -+ root->free(node); -+ } while (start != end); -+ -+ /* -+ * Note that shrink may free "end", so enter_node still need to -+ * be checked inside. -+ */ -+ sradix_tree_shrink(root); -+ } else if (node->count == root->stores_size - 1) { -+ /* It WAS a full leaf node. Update the ancestors */ -+ node = node->parent; -+ while (node) { -+ node->fulls--; -+ if (node->fulls != root->stores_size - 1) -+ break; -+ -+ node = node->parent; -+ } -+ } -+} -+ -+void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index) -+{ -+ unsigned int height, offset; -+ struct sradix_tree_node *node; -+ int shift; -+ -+ node = root->rnode; -+ if (node == NULL || (index >> (root->shift * root->height))) -+ return NULL; -+ -+ height = root->height; -+ shift = (height - 1) * root->shift; -+ -+ do { -+ offset = (index >> shift) & root->mask; -+ node = node->stores[offset]; -+ if (!node) -+ return NULL; -+ -+ shift -= root->shift; -+ } while (shift >= 0); -+ -+ return node; -+} -+ -+/* -+ * Return the item if it exists, otherwise create it in place -+ * and return the created item. -+ */ -+void *sradix_tree_lookup_create(struct sradix_tree_root *root, -+ unsigned long index, void *(*item_alloc)(void)) -+{ -+ unsigned int height, offset; -+ struct sradix_tree_node *node, *tmp; -+ void *item; -+ int shift, error; -+ -+ if (root->rnode == NULL || (index >> (root->shift * root->height))) { -+ if (item_alloc) { -+ error = sradix_tree_extend(root, index); -+ if (error) -+ return NULL; -+ } else { -+ return NULL; -+ } -+ } -+ -+ node = root->rnode; -+ height = root->height; -+ shift = (height - 1) * root->shift; -+ -+ do { -+ offset = (index >> shift) & root->mask; -+ if (!node->stores[offset]) { -+ if (!(tmp = root->alloc())) -+ return NULL; -+ -+ tmp->height = shift / root->shift; -+ node->stores[offset] = tmp; -+ tmp->parent = node; -+ node->count++; -+ node = tmp; -+ } else { -+ node = node->stores[offset]; -+ } -+ -+ shift -= root->shift; -+ } while (shift > 0); -+ -+ BUG_ON(node->height != 1); -+ offset = index & root->mask; -+ if (node->stores[offset]) { -+ return node->stores[offset]; -+ } else if (item_alloc) { -+ if (!(item = item_alloc())) -+ return NULL; -+ -+ node->stores[offset] = item; -+ -+ /* -+ * NOTE: we do NOT call root->assign here, since this item is -+ * newly created by us having no meaning. Caller can call this -+ * if it's necessary to do so. -+ */ -+ -+ node->count++; -+ root->num++; -+ -+ while (sradix_node_full(root, node)) { -+ node = node->parent; -+ if (!node) -+ break; -+ -+ node->fulls++; -+ } -+ -+ if (unlikely(!node)) { -+ /* All nodes are full */ -+ root->min = 1 << (root->height * root->shift); -+ } else { -+ if (root->min == index) { -+ root->min |= (1UL << (node->height - 1)) - 1; -+ root->min++; -+ root->enter_node = node; -+ } -+ } -+ -+ return item; -+ } else { -+ return NULL; -+ } -+ -+} -+ -+int sradix_tree_delete(struct sradix_tree_root *root, unsigned long index) -+{ -+ unsigned int height, offset; -+ struct sradix_tree_node *node; -+ int shift; -+ -+ node = root->rnode; -+ if (node == NULL || (index >> (root->shift * root->height))) -+ return -ENOENT; -+ -+ height = root->height; -+ shift = (height - 1) * root->shift; -+ -+ do { -+ offset = (index >> shift) & root->mask; -+ node = node->stores[offset]; -+ if (!node) -+ return -ENOENT; -+ -+ shift -= root->shift; -+ } while (shift > 0); -+ -+ offset = index & root->mask; -+ if (!node->stores[offset]) -+ return -ENOENT; -+ -+ sradix_tree_delete_from_leaf(root, node, index); -+ -+ return 0; -+} -diff -Nur a/mm/Kconfig b/mm/Kconfig ---- a/mm/Kconfig 2019-07-07 09:08:19.162348955 +0100 -+++ b/mm/Kconfig 2019-07-07 09:32:50.451840235 +0100 -@@ -302,6 +302,32 @@ - See Documentation/vm/ksm.rst for more information: KSM is inactive - until a program has madvised that an area is MADV_MERGEABLE, and - root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set). -+choice -+ prompt "Choose UKSM/KSM strategy" -+ default UKSM -+ depends on KSM -+ help -+ This option allows to select a UKSM/KSM stragety. -+ -+config UKSM -+ bool "Ultra-KSM for page merging" -+ depends on KSM -+ help -+ UKSM is inspired by the Linux kernel project \u2014 KSM(Kernel Same -+ page Merging), but with a fundamentally rewritten core algorithm. With -+ an advanced algorithm, UKSM now can transparently scans all anonymously -+ mapped user space applications with an significantly improved scan speed -+ and CPU efficiency. Since KVM is friendly to KSM, KVM can also benefit from -+ UKSM. Now UKSM has its first stable release and first real world enterprise user. -+ For more information, please goto its project page. -+ (www.kerneldedup.org) -+ -+config KSM_LEGACY -+ bool "Legacy KSM implementation" -+ depends on KSM -+ help -+ The legacy KSM implementation from Red Hat. -+endchoice - - config DEFAULT_MMAP_MIN_ADDR - int "Low address space to protect from user allocation" -diff -Nur a/mm/ksm.c b/mm/ksm.c ---- a/mm/ksm.c 2019-06-25 04:34:56.000000000 +0100 -+++ b/mm/ksm.c 2019-07-07 09:32:50.461840572 +0100 -@@ -858,17 +858,6 @@ - return err; - } - --static inline struct stable_node *page_stable_node(struct page *page) --{ -- return PageKsm(page) ? page_rmapping(page) : NULL; --} -- --static inline void set_page_stable_node(struct page *page, -- struct stable_node *stable_node) --{ -- page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); --} -- - #ifdef CONFIG_SYSFS - /* - * Only called through the sysfs control interface: -diff -Nur a/mm/Makefile b/mm/Makefile ---- a/mm/Makefile 2019-06-25 04:34:56.000000000 +0100 -+++ b/mm/Makefile 2019-07-07 09:32:50.451840235 +0100 -@@ -58,7 +58,8 @@ - obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o - obj-$(CONFIG_SLOB) += slob.o - obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o --obj-$(CONFIG_KSM) += ksm.o -+obj-$(CONFIG_KSM_LEGACY) += ksm.o -+obj-$(CONFIG_UKSM) += uksm.o - obj-$(CONFIG_PAGE_POISONING) += page_poison.o - obj-$(CONFIG_SLAB) += slab.o - obj-$(CONFIG_SLUB) += slub.o -diff -Nur a/mm/memory.c b/mm/memory.c ---- a/mm/memory.c 2019-06-25 04:34:56.000000000 +0100 -+++ b/mm/memory.c 2019-07-07 09:32:50.461840572 +0100 -@@ -129,6 +129,25 @@ - - unsigned long highest_memmap_pfn __read_mostly; - -+#ifdef CONFIG_UKSM -+unsigned long uksm_zero_pfn __read_mostly; -+EXPORT_SYMBOL_GPL(uksm_zero_pfn); -+struct page *empty_uksm_zero_page; -+ -+static int __init setup_uksm_zero_page(void) -+{ -+ empty_uksm_zero_page = alloc_pages(__GFP_ZERO & ~__GFP_MOVABLE, 0); -+ if (!empty_uksm_zero_page) -+ panic("Oh boy, that early out of memory?"); -+ -+ SetPageReserved(empty_uksm_zero_page); -+ uksm_zero_pfn = page_to_pfn(empty_uksm_zero_page); -+ -+ return 0; -+} -+core_initcall(setup_uksm_zero_page); -+#endif -+ - /* - * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() - */ -@@ -140,6 +159,7 @@ - core_initcall(init_zero_pfn); - - -+ - #if defined(SPLIT_RSS_COUNTING) - - void sync_mm_rss(struct mm_struct *mm) -@@ -794,6 +814,9 @@ - get_page(page); - page_dup_rmap(page, false); - rss[mm_counter(page)]++; -+ -+ /* Should return NULL in vm_normal_page() */ -+ uksm_bugon_zeropage(pte); - } else if (pte_devmap(pte)) { - page = pte_page(pte); - -@@ -807,6 +830,8 @@ - page_dup_rmap(page, false); - rss[mm_counter(page)]++; - } -+ } else { -+ uksm_map_zero_page(pte); - } - - out_set_pte: -@@ -1075,8 +1100,10 @@ - ptent = ptep_get_and_clear_full(mm, addr, pte, - tlb->fullmm); - tlb_remove_tlb_entry(tlb, pte, addr); -- if (unlikely(!page)) -+ if (unlikely(!page)) { -+ uksm_unmap_zero_page(ptent); - continue; -+ } - - if (!PageAnon(page)) { - if (pte_dirty(ptent)) { -@@ -2117,8 +2144,10 @@ - clear_page(kaddr); - kunmap_atomic(kaddr); - flush_dcache_page(dst); -- } else -+ } else { - copy_user_highpage(dst, src, va, vma); -+ uksm_cow_page(vma, src); -+ } - } - - static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) -@@ -2266,6 +2295,7 @@ - vmf->address); - if (!new_page) - goto oom; -+ uksm_cow_pte(vma, vmf->orig_pte); - } else { - new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, - vmf->address); -@@ -2294,7 +2324,9 @@ - mm_counter_file(old_page)); - inc_mm_counter_fast(mm, MM_ANONPAGES); - } -+ uksm_bugon_zeropage(vmf->orig_pte); - } else { -+ uksm_unmap_zero_page(vmf->orig_pte); - inc_mm_counter_fast(mm, MM_ANONPAGES); - } - flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); -diff -Nur a/mm/mmap.c b/mm/mmap.c ---- a/mm/mmap.c 2019-07-07 09:08:19.162348955 +0100 -+++ b/mm/mmap.c 2019-07-07 09:34:22.544947675 +0100 -@@ -46,6 +46,7 @@ - #include - #include - #include -+#include - - #include - #include -@@ -183,6 +184,7 @@ - if (vma->vm_file) - fput(vma->vm_file); - mpol_put(vma_policy(vma)); -+ uksm_remove_vma(vma); - vm_area_free(vma); - return next; - } -@@ -733,9 +735,16 @@ - long adjust_next = 0; - int remove_next = 0; - -+/* -+ * to avoid deadlock, ksm_remove_vma must be done before any spin_lock is -+ * acquired -+ */ -+ uksm_remove_vma(vma); -+ - if (next && !insert) { - struct vm_area_struct *exporter = NULL, *importer = NULL; - -+ uksm_remove_vma(next); - if (end >= next->vm_end) { - /* - * vma expands, overlapping all the next, and -@@ -868,6 +877,7 @@ - end_changed = true; - } - vma->vm_pgoff = pgoff; -+ - if (adjust_next) { - next->vm_start += adjust_next << PAGE_SHIFT; - next->vm_pgoff += adjust_next; -@@ -973,6 +983,7 @@ - if (remove_next == 2) { - remove_next = 1; - end = next->vm_end; -+ uksm_remove_vma(next); - goto again; - } - else if (next) -@@ -999,10 +1010,14 @@ - */ - VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma)); - } -+ } else { -+ if (next && !insert) -+ uksm_vma_add_new(next); - } - if (insert && file) - uprobe_mmap(insert); - -+ uksm_vma_add_new(vma); - validate_mm(mm); - - return 0; -@@ -1459,6 +1474,9 @@ - vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | - mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; - -+ /* If uksm is enabled, we add VM_MERGEABLE to new VMAs. */ -+ uksm_vm_flags_mod(&vm_flags); -+ - if (flags & MAP_LOCKED) - if (!can_do_mlock()) - return -EPERM; -@@ -1823,6 +1841,7 @@ - allow_write_access(file); - } - file = vma->vm_file; -+ uksm_vma_add_new(vma); - out: - perf_event_mmap(vma); - -@@ -1865,6 +1884,7 @@ - if (vm_flags & VM_DENYWRITE) - allow_write_access(file); - free_vma: -+ uksm_remove_vma(vma); - vm_area_free(vma); - unacct_error: - if (charged) -@@ -2697,6 +2717,8 @@ - else - err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); - -+ uksm_vma_add_new(new); -+ - /* Success. */ - if (!err) - return 0; -@@ -3001,6 +3023,7 @@ - if ((flags & (~VM_EXEC)) != 0) - return -EINVAL; - flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; -+ uksm_vm_flags_mod(&flags); - - error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); - if (offset_in_page(error)) -@@ -3051,6 +3074,7 @@ - vma->vm_flags = flags; - vma->vm_page_prot = vm_get_page_prot(flags); - vma_link(mm, vma, prev, rb_link, rb_parent); -+ uksm_vma_add_new(vma); - out: - perf_event_mmap(vma); - mm->total_vm += len >> PAGE_SHIFT; -@@ -3128,6 +3152,12 @@ - up_write(&mm->mmap_sem); - } - -+ /* -+ * Taking write lock on mmap_sem does not harm others, -+ * but it's crucial for uksm to avoid races. -+ */ -+ down_write(&mm->mmap_sem); -+ - if (mm->locked_vm) { - vma = mm->mmap; - while (vma) { -@@ -3162,6 +3192,11 @@ - vma = remove_vma(vma); - } - vm_unacct_memory(nr_accounted); -+ -+ mm->mmap = NULL; -+ mm->mm_rb = RB_ROOT; -+ vmacache_invalidate(mm); -+ up_write(&mm->mmap_sem); - } - - /* Insert vm structure into process list sorted by address -@@ -3269,6 +3304,7 @@ - new_vma->vm_ops->open(new_vma); - vma_link(mm, new_vma, prev, rb_link, rb_parent); - *need_rmap_locks = false; -+ uksm_vma_add_new(new_vma); - } - return new_vma; - -@@ -3419,6 +3455,7 @@ - vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); - - perf_event_mmap(vma); -+ uksm_vma_add_new(vma); - - return vma; - -diff -Nur a/mm/uksm.c b/mm/uksm.c ---- a/mm/uksm.c 1970-01-01 01:00:00.000000000 +0100 -+++ b/mm/uksm.c 2019-07-07 09:32:50.461840572 +0100 -@@ -0,0 +1,5580 @@ -+/* -+ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia -+ * -+ * This is an improvement upon KSM. Some basic data structures and routines -+ * are borrowed from ksm.c . -+ * -+ * Its new features: -+ * 1. Full system scan: -+ * It automatically scans all user processes' anonymous VMAs. Kernel-user -+ * interaction to submit a memory area to KSM is no longer needed. -+ * -+ * 2. Rich area detection: -+ * It automatically detects rich areas containing abundant duplicated -+ * pages based. Rich areas are given a full scan speed. Poor areas are -+ * sampled at a reasonable speed with very low CPU consumption. -+ * -+ * 3. Ultra Per-page scan speed improvement: -+ * A new hash algorithm is proposed. As a result, on a machine with -+ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it -+ * can scan memory areas that does not contain duplicated pages at speed of -+ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of -+ * 477MB/sec ~ 923MB/sec. -+ * -+ * 4. Thrashing area avoidance: -+ * Thrashing area(an VMA that has frequent Ksm page break-out) can be -+ * filtered out. My benchmark shows it's more efficient than KSM's per-page -+ * hash value based volatile page detection. -+ * -+ * -+ * 5. Misc changes upon KSM: -+ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page -+ * comparison. It's much faster than default C version on x86. -+ * * rmap_item now has an struct *page member to loosely cache a -+ * address-->page mapping, which reduces too much time-costly -+ * follow_page(). -+ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. -+ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ -+ * ksm is needed for this case. -+ * -+ * 6. Full Zero Page consideration(contributed by Figo Zhang) -+ * Now uksmd consider full zero pages as special pages and merge them to an -+ * special unswappable uksm zero page. -+ */ -+ -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+ -+#include -+#include "internal.h" -+ -+#ifdef CONFIG_X86 -+#undef memcmp -+ -+#ifdef CONFIG_X86_32 -+#define memcmp memcmpx86_32 -+/* -+ * Compare 4-byte-aligned address s1 and s2, with length n -+ */ -+int memcmpx86_32(void *s1, void *s2, size_t n) -+{ -+ size_t num = n / 4; -+ register int res; -+ -+ __asm__ __volatile__ -+ ( -+ "testl %3,%3\n\t" -+ "repe; cmpsd\n\t" -+ "je 1f\n\t" -+ "sbbl %0,%0\n\t" -+ "orl $1,%0\n" -+ "1:" -+ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) -+ : "0" (0) -+ : "cc"); -+ -+ return res; -+} -+ -+/* -+ * Check the page is all zero ? -+ */ -+static int is_full_zero(const void *s1, size_t len) -+{ -+ unsigned char same; -+ -+ len /= 4; -+ -+ __asm__ __volatile__ -+ ("repe; scasl;" -+ "sete %0" -+ : "=qm" (same), "+D" (s1), "+c" (len) -+ : "a" (0) -+ : "cc"); -+ -+ return same; -+} -+ -+ -+#elif defined(CONFIG_X86_64) -+#define memcmp memcmpx86_64 -+/* -+ * Compare 8-byte-aligned address s1 and s2, with length n -+ */ -+int memcmpx86_64(void *s1, void *s2, size_t n) -+{ -+ size_t num = n / 8; -+ register int res; -+ -+ __asm__ __volatile__ -+ ( -+ "testq %q3,%q3\n\t" -+ "repe; cmpsq\n\t" -+ "je 1f\n\t" -+ "sbbq %q0,%q0\n\t" -+ "orq $1,%q0\n" -+ "1:" -+ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) -+ : "0" (0) -+ : "cc"); -+ -+ return res; -+} -+ -+static int is_full_zero(const void *s1, size_t len) -+{ -+ unsigned char same; -+ -+ len /= 8; -+ -+ __asm__ __volatile__ -+ ("repe; scasq;" -+ "sete %0" -+ : "=qm" (same), "+D" (s1), "+c" (len) -+ : "a" (0) -+ : "cc"); -+ -+ return same; -+} -+ -+#endif -+#else -+static int is_full_zero(const void *s1, size_t len) -+{ -+ unsigned long *src = s1; -+ int i; -+ -+ len /= sizeof(*src); -+ -+ for (i = 0; i < len; i++) { -+ if (src[i]) -+ return 0; -+ } -+ -+ return 1; -+} -+#endif -+ -+#define UKSM_RUNG_ROUND_FINISHED (1 << 0) -+#define TIME_RATIO_SCALE 10000 -+ -+#define SLOT_TREE_NODE_SHIFT 8 -+#define SLOT_TREE_NODE_STORE_SIZE (1UL << SLOT_TREE_NODE_SHIFT) -+struct slot_tree_node { -+ unsigned long size; -+ struct sradix_tree_node snode; -+ void *stores[SLOT_TREE_NODE_STORE_SIZE]; -+}; -+ -+static struct kmem_cache *slot_tree_node_cachep; -+ -+static struct sradix_tree_node *slot_tree_node_alloc(void) -+{ -+ struct slot_tree_node *p; -+ -+ p = kmem_cache_zalloc(slot_tree_node_cachep, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (!p) -+ return NULL; -+ -+ return &p->snode; -+} -+ -+static void slot_tree_node_free(struct sradix_tree_node *node) -+{ -+ struct slot_tree_node *p; -+ -+ p = container_of(node, struct slot_tree_node, snode); -+ kmem_cache_free(slot_tree_node_cachep, p); -+} -+ -+static void slot_tree_node_extend(struct sradix_tree_node *parent, -+ struct sradix_tree_node *child) -+{ -+ struct slot_tree_node *p, *c; -+ -+ p = container_of(parent, struct slot_tree_node, snode); -+ c = container_of(child, struct slot_tree_node, snode); -+ -+ p->size += c->size; -+} -+ -+void slot_tree_node_assign(struct sradix_tree_node *node, -+ unsigned int index, void *item) -+{ -+ struct vma_slot *slot = item; -+ struct slot_tree_node *cur; -+ -+ slot->snode = node; -+ slot->sindex = index; -+ -+ while (node) { -+ cur = container_of(node, struct slot_tree_node, snode); -+ cur->size += slot->pages; -+ node = node->parent; -+ } -+} -+ -+void slot_tree_node_rm(struct sradix_tree_node *node, unsigned int offset) -+{ -+ struct vma_slot *slot; -+ struct slot_tree_node *cur; -+ unsigned long pages; -+ -+ if (node->height == 1) { -+ slot = node->stores[offset]; -+ pages = slot->pages; -+ } else { -+ cur = container_of(node->stores[offset], -+ struct slot_tree_node, snode); -+ pages = cur->size; -+ } -+ -+ while (node) { -+ cur = container_of(node, struct slot_tree_node, snode); -+ cur->size -= pages; -+ node = node->parent; -+ } -+} -+ -+unsigned long slot_iter_index; -+int slot_iter(void *item, unsigned long height) -+{ -+ struct slot_tree_node *node; -+ struct vma_slot *slot; -+ -+ if (height == 1) { -+ slot = item; -+ if (slot_iter_index < slot->pages) { -+ /*in this one*/ -+ return 1; -+ } else { -+ slot_iter_index -= slot->pages; -+ return 0; -+ } -+ -+ } else { -+ node = container_of(item, struct slot_tree_node, snode); -+ if (slot_iter_index < node->size) { -+ /*in this one*/ -+ return 1; -+ } else { -+ slot_iter_index -= node->size; -+ return 0; -+ } -+ } -+} -+ -+ -+static inline void slot_tree_init_root(struct sradix_tree_root *root) -+{ -+ init_sradix_tree_root(root, SLOT_TREE_NODE_SHIFT); -+ root->alloc = slot_tree_node_alloc; -+ root->free = slot_tree_node_free; -+ root->extend = slot_tree_node_extend; -+ root->assign = slot_tree_node_assign; -+ root->rm = slot_tree_node_rm; -+} -+ -+void slot_tree_init(void) -+{ -+ slot_tree_node_cachep = kmem_cache_create("slot_tree_node", -+ sizeof(struct slot_tree_node), 0, -+ SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, -+ NULL); -+} -+ -+ -+/* Each rung of this ladder is a list of VMAs having a same scan ratio */ -+struct scan_rung { -+ //struct list_head scanned_list; -+ struct sradix_tree_root vma_root; -+ struct sradix_tree_root vma_root2; -+ -+ struct vma_slot *current_scan; -+ unsigned long current_offset; -+ -+ /* -+ * The initial value for current_offset, it should loop over -+ * [0~ step - 1] to let all slot have its chance to be scanned. -+ */ -+ unsigned long offset_init; -+ unsigned long step; /* dynamic step for current_offset */ -+ unsigned int flags; -+ unsigned long pages_to_scan; -+ //unsigned long fully_scanned_slots; -+ /* -+ * a little bit tricky - if cpu_time_ratio > 0, then the value is the -+ * the cpu time ratio it can spend in rung_i for every scan -+ * period. if < 0, then it is the cpu time ratio relative to the -+ * max cpu percentage user specified. Both in unit of -+ * 1/TIME_RATIO_SCALE -+ */ -+ int cpu_ratio; -+ -+ /* -+ * How long it will take for all slots in this rung to be fully -+ * scanned? If it's zero, we don't care about the cover time: -+ * it's fully scanned. -+ */ -+ unsigned int cover_msecs; -+ //unsigned long vma_num; -+ //unsigned long pages; /* Sum of all slot's pages in rung */ -+}; -+ -+/** -+ * node of either the stable or unstale rbtree -+ * -+ */ -+struct tree_node { -+ struct rb_node node; /* link in the main (un)stable rbtree */ -+ struct rb_root sub_root; /* rb_root for sublevel collision rbtree */ -+ u32 hash; -+ unsigned long count; /* TODO: merged with sub_root */ -+ struct list_head all_list; /* all tree nodes in stable/unstable tree */ -+}; -+ -+/** -+ * struct stable_node - node of the stable rbtree -+ * @node: rb node of this ksm page in the stable tree -+ * @hlist: hlist head of rmap_items using this ksm page -+ * @kpfn: page frame number of this ksm page -+ */ -+struct stable_node { -+ struct rb_node node; /* link in sub-rbtree */ -+ struct tree_node *tree_node; /* it's tree node root in stable tree, NULL if it's in hell list */ -+ struct hlist_head hlist; -+ unsigned long kpfn; -+ u32 hash_max; /* if ==0 then it's not been calculated yet */ -+ struct list_head all_list; /* in a list for all stable nodes */ -+}; -+ -+/** -+ * struct node_vma - group rmap_items linked in a same stable -+ * node together. -+ */ -+struct node_vma { -+ union { -+ struct vma_slot *slot; -+ unsigned long key; /* slot is used as key sorted on hlist */ -+ }; -+ struct hlist_node hlist; -+ struct hlist_head rmap_hlist; -+ struct stable_node *head; -+}; -+ -+/** -+ * struct rmap_item - reverse mapping item for virtual addresses -+ * @rmap_list: next rmap_item in mm_slot's singly-linked rmap_list -+ * @anon_vma: pointer to anon_vma for this mm,address, when in stable tree -+ * @mm: the memory structure this rmap_item is pointing into -+ * @address: the virtual address this rmap_item tracks (+ flags in low bits) -+ * @node: rb node of this rmap_item in the unstable tree -+ * @head: pointer to stable_node heading this list in the stable tree -+ * @hlist: link into hlist of rmap_items hanging off that stable_node -+ */ -+struct rmap_item { -+ struct vma_slot *slot; -+ struct page *page; -+ unsigned long address; /* + low bits used for flags below */ -+ unsigned long hash_round; -+ unsigned long entry_index; -+ union { -+ struct {/* when in unstable tree */ -+ struct rb_node node; -+ struct tree_node *tree_node; -+ u32 hash_max; -+ }; -+ struct { /* when in stable tree */ -+ struct node_vma *head; -+ struct hlist_node hlist; -+ struct anon_vma *anon_vma; -+ }; -+ }; -+} __aligned(4); -+ -+struct rmap_list_entry { -+ union { -+ struct rmap_item *item; -+ unsigned long addr; -+ }; -+ /* lowest bit is used for is_addr tag */ -+} __aligned(4); /* 4 aligned to fit in to pages*/ -+ -+ -+/* Basic data structure definition ends */ -+ -+ -+/* -+ * Flags for rmap_item to judge if it's listed in the stable/unstable tree. -+ * The flags use the low bits of rmap_item.address -+ */ -+#define UNSTABLE_FLAG 0x1 -+#define STABLE_FLAG 0x2 -+#define get_rmap_addr(x) ((x)->address & PAGE_MASK) -+ -+/* -+ * rmap_list_entry helpers -+ */ -+#define IS_ADDR_FLAG 1 -+#define is_addr(ptr) ((unsigned long)(ptr) & IS_ADDR_FLAG) -+#define set_is_addr(ptr) ((ptr) |= IS_ADDR_FLAG) -+#define get_clean_addr(ptr) (((ptr) & ~(__typeof__(ptr))IS_ADDR_FLAG)) -+ -+ -+/* -+ * High speed caches for frequently allocated and freed structs -+ */ -+static struct kmem_cache *rmap_item_cache; -+static struct kmem_cache *stable_node_cache; -+static struct kmem_cache *node_vma_cache; -+static struct kmem_cache *vma_slot_cache; -+static struct kmem_cache *tree_node_cache; -+#define UKSM_KMEM_CACHE(__struct, __flags) kmem_cache_create("uksm_"#__struct,\ -+ sizeof(struct __struct), __alignof__(struct __struct),\ -+ (__flags), NULL) -+ -+/* Array of all scan_rung, uksm_scan_ladder[0] having the minimum scan ratio */ -+#define SCAN_LADDER_SIZE 4 -+static struct scan_rung uksm_scan_ladder[SCAN_LADDER_SIZE]; -+ -+/* The evaluation rounds uksmd has finished */ -+static unsigned long long uksm_eval_round = 1; -+ -+/* -+ * we add 1 to this var when we consider we should rebuild the whole -+ * unstable tree. -+ */ -+static unsigned long uksm_hash_round = 1; -+ -+/* -+ * How many times the whole memory is scanned. -+ */ -+static unsigned long long fully_scanned_round = 1; -+ -+/* The total number of virtual pages of all vma slots */ -+static u64 uksm_pages_total; -+ -+/* The number of pages has been scanned since the start up */ -+static u64 uksm_pages_scanned; -+ -+static u64 scanned_virtual_pages; -+ -+/* The number of pages has been scanned since last encode_benefit call */ -+static u64 uksm_pages_scanned_last; -+ -+/* If the scanned number is tooo large, we encode it here */ -+static u64 pages_scanned_stored; -+ -+static unsigned long pages_scanned_base; -+ -+/* The number of nodes in the stable tree */ -+static unsigned long uksm_pages_shared; -+ -+/* The number of page slots additionally sharing those nodes */ -+static unsigned long uksm_pages_sharing; -+ -+/* The number of nodes in the unstable tree */ -+static unsigned long uksm_pages_unshared; -+ -+/* -+ * Milliseconds ksmd should sleep between scans, -+ * >= 100ms to be consistent with -+ * scan_time_to_sleep_msec() -+ */ -+static unsigned int uksm_sleep_jiffies; -+ -+/* The real value for the uksmd next sleep */ -+static unsigned int uksm_sleep_real; -+ -+/* Saved value for user input uksm_sleep_jiffies when it's enlarged */ -+static unsigned int uksm_sleep_saved; -+ -+/* Max percentage of cpu utilization ksmd can take to scan in one batch */ -+static unsigned int uksm_max_cpu_percentage; -+ -+static int uksm_cpu_governor; -+ -+static char *uksm_cpu_governor_str[4] = { "full", "medium", "low", "quiet" }; -+ -+struct uksm_cpu_preset_s { -+ int cpu_ratio[SCAN_LADDER_SIZE]; -+ unsigned int cover_msecs[SCAN_LADDER_SIZE]; -+ unsigned int max_cpu; /* percentage */ -+}; -+ -+struct uksm_cpu_preset_s uksm_cpu_preset[4] = { -+ { {20, 40, -2500, -10000}, {1000, 500, 200, 50}, 95}, -+ { {20, 30, -2500, -10000}, {1000, 500, 400, 100}, 50}, -+ { {10, 20, -5000, -10000}, {1500, 1000, 1000, 250}, 20}, -+ { {10, 20, 40, 75}, {2000, 1000, 1000, 1000}, 1}, -+}; -+ -+/* The default value for uksm_ema_page_time if it's not initialized */ -+#define UKSM_PAGE_TIME_DEFAULT 500 -+ -+/*cost to scan one page by expotional moving average in nsecs */ -+static unsigned long uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; -+ -+/* The expotional moving average alpha weight, in percentage. */ -+#define EMA_ALPHA 20 -+ -+/* -+ * The threshold used to filter out thrashing areas, -+ * If it == 0, filtering is disabled, otherwise it's the percentage up-bound -+ * of the thrashing ratio of all areas. Any area with a bigger thrashing ratio -+ * will be considered as having a zero duplication ratio. -+ */ -+static unsigned int uksm_thrash_threshold = 50; -+ -+/* How much dedup ratio is considered to be abundant*/ -+static unsigned int uksm_abundant_threshold = 10; -+ -+/* All slots having merged pages in this eval round. */ -+struct list_head vma_slot_dedup = LIST_HEAD_INIT(vma_slot_dedup); -+ -+/* How many times the ksmd has slept since startup */ -+static unsigned long long uksm_sleep_times; -+ -+#define UKSM_RUN_STOP 0 -+#define UKSM_RUN_MERGE 1 -+static unsigned int uksm_run = 1; -+ -+static DECLARE_WAIT_QUEUE_HEAD(uksm_thread_wait); -+static DEFINE_MUTEX(uksm_thread_mutex); -+ -+/* -+ * List vma_slot_new is for newly created vma_slot waiting to be added by -+ * ksmd. If one cannot be added(e.g. due to it's too small), it's moved to -+ * vma_slot_noadd. vma_slot_del is the list for vma_slot whose corresponding -+ * VMA has been removed/freed. -+ */ -+struct list_head vma_slot_new = LIST_HEAD_INIT(vma_slot_new); -+struct list_head vma_slot_noadd = LIST_HEAD_INIT(vma_slot_noadd); -+struct list_head vma_slot_del = LIST_HEAD_INIT(vma_slot_del); -+static DEFINE_SPINLOCK(vma_slot_list_lock); -+ -+/* The unstable tree heads */ -+static struct rb_root root_unstable_tree = RB_ROOT; -+ -+/* -+ * All tree_nodes are in a list to be freed at once when unstable tree is -+ * freed after each scan round. -+ */ -+static struct list_head unstable_tree_node_list = -+ LIST_HEAD_INIT(unstable_tree_node_list); -+ -+/* List contains all stable nodes */ -+static struct list_head stable_node_list = LIST_HEAD_INIT(stable_node_list); -+ -+/* -+ * When the hash strength is changed, the stable tree must be delta_hashed and -+ * re-structured. We use two set of below structs to speed up the -+ * re-structuring of stable tree. -+ */ -+static struct list_head -+stable_tree_node_list[2] = {LIST_HEAD_INIT(stable_tree_node_list[0]), -+ LIST_HEAD_INIT(stable_tree_node_list[1])}; -+ -+static struct list_head *stable_tree_node_listp = &stable_tree_node_list[0]; -+static struct rb_root root_stable_tree[2] = {RB_ROOT, RB_ROOT}; -+static struct rb_root *root_stable_treep = &root_stable_tree[0]; -+static unsigned long stable_tree_index; -+ -+/* The hash strength needed to hash a full page */ -+#define HASH_STRENGTH_FULL (PAGE_SIZE / sizeof(u32)) -+ -+/* The hash strength needed for loop-back hashing */ -+#define HASH_STRENGTH_MAX (HASH_STRENGTH_FULL + 10) -+ -+/* The random offsets in a page */ -+static u32 *random_nums; -+ -+/* The hash strength */ -+static unsigned long hash_strength = HASH_STRENGTH_FULL >> 4; -+ -+/* The delta value each time the hash strength increases or decreases */ -+static unsigned long hash_strength_delta; -+#define HASH_STRENGTH_DELTA_MAX 5 -+ -+/* The time we have saved due to random_sample_hash */ -+static u64 rshash_pos; -+ -+/* The time we have wasted due to hash collision */ -+static u64 rshash_neg; -+ -+struct uksm_benefit { -+ u64 pos; -+ u64 neg; -+ u64 scanned; -+ unsigned long base; -+} benefit; -+ -+/* -+ * The relative cost of memcmp, compared to 1 time unit of random sample -+ * hash, this value is tested when ksm module is initialized -+ */ -+static unsigned long memcmp_cost; -+ -+static unsigned long rshash_neg_cont_zero; -+static unsigned long rshash_cont_obscure; -+ -+/* The possible states of hash strength adjustment heuristic */ -+enum rshash_states { -+ RSHASH_STILL, -+ RSHASH_TRYUP, -+ RSHASH_TRYDOWN, -+ RSHASH_NEW, -+ RSHASH_PRE_STILL, -+}; -+ -+/* The possible direction we are about to adjust hash strength */ -+enum rshash_direct { -+ GO_UP, -+ GO_DOWN, -+ OBSCURE, -+ STILL, -+}; -+ -+/* random sampling hash state machine */ -+static struct { -+ enum rshash_states state; -+ enum rshash_direct pre_direct; -+ u8 below_count; -+ /* Keep a lookup window of size 5, iff above_count/below_count > 3 -+ * in this window we stop trying. -+ */ -+ u8 lookup_window_index; -+ u64 stable_benefit; -+ unsigned long turn_point_down; -+ unsigned long turn_benefit_down; -+ unsigned long turn_point_up; -+ unsigned long turn_benefit_up; -+ unsigned long stable_point; -+} rshash_state; -+ -+/*zero page hash table, hash_strength [0 ~ HASH_STRENGTH_MAX]*/ -+static u32 *zero_hash_table; -+ -+static inline struct node_vma *alloc_node_vma(void) -+{ -+ struct node_vma *node_vma; -+ -+ node_vma = kmem_cache_zalloc(node_vma_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (node_vma) { -+ INIT_HLIST_HEAD(&node_vma->rmap_hlist); -+ INIT_HLIST_NODE(&node_vma->hlist); -+ } -+ return node_vma; -+} -+ -+static inline void free_node_vma(struct node_vma *node_vma) -+{ -+ kmem_cache_free(node_vma_cache, node_vma); -+} -+ -+ -+static inline struct vma_slot *alloc_vma_slot(void) -+{ -+ struct vma_slot *slot; -+ -+ /* -+ * In case ksm is not initialized by now. -+ * Oops, we need to consider the call site of uksm_init() in the future. -+ */ -+ if (!vma_slot_cache) -+ return NULL; -+ -+ slot = kmem_cache_zalloc(vma_slot_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (slot) { -+ INIT_LIST_HEAD(&slot->slot_list); -+ INIT_LIST_HEAD(&slot->dedup_list); -+ slot->flags |= UKSM_SLOT_NEED_RERAND; -+ } -+ return slot; -+} -+ -+static inline void free_vma_slot(struct vma_slot *vma_slot) -+{ -+ kmem_cache_free(vma_slot_cache, vma_slot); -+} -+ -+ -+ -+static inline struct rmap_item *alloc_rmap_item(void) -+{ -+ struct rmap_item *rmap_item; -+ -+ rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (rmap_item) { -+ /* bug on lowest bit is not clear for flag use */ -+ BUG_ON(is_addr(rmap_item)); -+ } -+ return rmap_item; -+} -+ -+static inline void free_rmap_item(struct rmap_item *rmap_item) -+{ -+ rmap_item->slot = NULL; /* debug safety */ -+ kmem_cache_free(rmap_item_cache, rmap_item); -+} -+ -+static inline struct stable_node *alloc_stable_node(void) -+{ -+ struct stable_node *node; -+ -+ node = kmem_cache_alloc(stable_node_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (!node) -+ return NULL; -+ -+ INIT_HLIST_HEAD(&node->hlist); -+ list_add(&node->all_list, &stable_node_list); -+ return node; -+} -+ -+static inline void free_stable_node(struct stable_node *stable_node) -+{ -+ list_del(&stable_node->all_list); -+ kmem_cache_free(stable_node_cache, stable_node); -+} -+ -+static inline struct tree_node *alloc_tree_node(struct list_head *list) -+{ -+ struct tree_node *node; -+ -+ node = kmem_cache_zalloc(tree_node_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (!node) -+ return NULL; -+ -+ list_add(&node->all_list, list); -+ return node; -+} -+ -+static inline void free_tree_node(struct tree_node *node) -+{ -+ list_del(&node->all_list); -+ kmem_cache_free(tree_node_cache, node); -+} -+ -+static void uksm_drop_anon_vma(struct rmap_item *rmap_item) -+{ -+ struct anon_vma *anon_vma = rmap_item->anon_vma; -+ -+ put_anon_vma(anon_vma); -+} -+ -+ -+/** -+ * Remove a stable node from stable_tree, may unlink from its tree_node and -+ * may remove its parent tree_node if no other stable node is pending. -+ * -+ * @stable_node The node need to be removed -+ * @unlink_rb Will this node be unlinked from the rbtree? -+ * @remove_tree_ node Will its tree_node be removed if empty? -+ */ -+static void remove_node_from_stable_tree(struct stable_node *stable_node, -+ int unlink_rb, int remove_tree_node) -+{ -+ struct node_vma *node_vma; -+ struct rmap_item *rmap_item; -+ struct hlist_node *n; -+ -+ if (!hlist_empty(&stable_node->hlist)) { -+ hlist_for_each_entry_safe(node_vma, n, -+ &stable_node->hlist, hlist) { -+ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { -+ uksm_pages_sharing--; -+ -+ uksm_drop_anon_vma(rmap_item); -+ rmap_item->address &= PAGE_MASK; -+ } -+ free_node_vma(node_vma); -+ cond_resched(); -+ } -+ -+ /* the last one is counted as shared */ -+ uksm_pages_shared--; -+ uksm_pages_sharing++; -+ } -+ -+ if (stable_node->tree_node && unlink_rb) { -+ rb_erase(&stable_node->node, -+ &stable_node->tree_node->sub_root); -+ -+ if (RB_EMPTY_ROOT(&stable_node->tree_node->sub_root) && -+ remove_tree_node) { -+ rb_erase(&stable_node->tree_node->node, -+ root_stable_treep); -+ free_tree_node(stable_node->tree_node); -+ } else { -+ stable_node->tree_node->count--; -+ } -+ } -+ -+ free_stable_node(stable_node); -+} -+ -+ -+/* -+ * get_uksm_page: checks if the page indicated by the stable node -+ * is still its ksm page, despite having held no reference to it. -+ * In which case we can trust the content of the page, and it -+ * returns the gotten page; but if the page has now been zapped, -+ * remove the stale node from the stable tree and return NULL. -+ * -+ * You would expect the stable_node to hold a reference to the ksm page. -+ * But if it increments the page's count, swapping out has to wait for -+ * ksmd to come around again before it can free the page, which may take -+ * seconds or even minutes: much too unresponsive. So instead we use a -+ * "keyhole reference": access to the ksm page from the stable node peeps -+ * out through its keyhole to see if that page still holds the right key, -+ * pointing back to this stable node. This relies on freeing a PageAnon -+ * page to reset its page->mapping to NULL, and relies on no other use of -+ * a page to put something that might look like our key in page->mapping. -+ * -+ * include/linux/pagemap.h page_cache_get_speculative() is a good reference, -+ * but this is different - made simpler by uksm_thread_mutex being held, but -+ * interesting for assuming that no other use of the struct page could ever -+ * put our expected_mapping into page->mapping (or a field of the union which -+ * coincides with page->mapping). The RCU calls are not for KSM at all, but -+ * to keep the page_count protocol described with page_cache_get_speculative. -+ * -+ * Note: it is possible that get_uksm_page() will return NULL one moment, -+ * then page the next, if the page is in between page_freeze_refs() and -+ * page_unfreeze_refs(): this shouldn't be a problem anywhere, the page -+ * is on its way to being freed; but it is an anomaly to bear in mind. -+ * -+ * @unlink_rb: if the removal of this node will firstly unlink from -+ * its rbtree. stable_node_reinsert will prevent this when restructuring the -+ * node from its old tree. -+ * -+ * @remove_tree_node: if this is the last one of its tree_node, will the -+ * tree_node be freed ? If we are inserting stable node, this tree_node may -+ * be reused, so don't free it. -+ */ -+static struct page *get_uksm_page(struct stable_node *stable_node, -+ int unlink_rb, int remove_tree_node) -+{ -+ struct page *page; -+ void *expected_mapping; -+ unsigned long kpfn; -+ -+ expected_mapping = (void *)((unsigned long)stable_node | -+ PAGE_MAPPING_KSM); -+again: -+ kpfn = READ_ONCE(stable_node->kpfn); -+ page = pfn_to_page(kpfn); -+ -+ /* -+ * page is computed from kpfn, so on most architectures reading -+ * page->mapping is naturally ordered after reading node->kpfn, -+ * but on Alpha we need to be more careful. -+ */ -+ smp_read_barrier_depends(); -+ -+ if (READ_ONCE(page->mapping) != expected_mapping) -+ goto stale; -+ -+ /* -+ * We cannot do anything with the page while its refcount is 0. -+ * Usually 0 means free, or tail of a higher-order page: in which -+ * case this node is no longer referenced, and should be freed; -+ * however, it might mean that the page is under page_freeze_refs(). -+ * The __remove_mapping() case is easy, again the node is now stale; -+ * but if page is swapcache in migrate_page_move_mapping(), it might -+ * still be our page, in which case it's essential to keep the node. -+ */ -+ while (!get_page_unless_zero(page)) { -+ /* -+ * Another check for page->mapping != expected_mapping would -+ * work here too. We have chosen the !PageSwapCache test to -+ * optimize the common case, when the page is or is about to -+ * be freed: PageSwapCache is cleared (under spin_lock_irq) -+ * in the freeze_refs section of __remove_mapping(); but Anon -+ * page->mapping reset to NULL later, in free_pages_prepare(). -+ */ -+ if (!PageSwapCache(page)) -+ goto stale; -+ cpu_relax(); -+ } -+ -+ if (READ_ONCE(page->mapping) != expected_mapping) { -+ put_page(page); -+ goto stale; -+ } -+ -+ lock_page(page); -+ if (READ_ONCE(page->mapping) != expected_mapping) { -+ unlock_page(page); -+ put_page(page); -+ goto stale; -+ } -+ unlock_page(page); -+ return page; -+stale: -+ /* -+ * We come here from above when page->mapping or !PageSwapCache -+ * suggests that the node is stale; but it might be under migration. -+ * We need smp_rmb(), matching the smp_wmb() in ksm_migrate_page(), -+ * before checking whether node->kpfn has been changed. -+ */ -+ smp_rmb(); -+ if (stable_node->kpfn != kpfn) -+ goto again; -+ -+ remove_node_from_stable_tree(stable_node, unlink_rb, remove_tree_node); -+ -+ return NULL; -+} -+ -+/* -+ * Removing rmap_item from stable or unstable tree. -+ * This function will clean the information from the stable/unstable tree. -+ */ -+static inline void remove_rmap_item_from_tree(struct rmap_item *rmap_item) -+{ -+ if (rmap_item->address & STABLE_FLAG) { -+ struct stable_node *stable_node; -+ struct node_vma *node_vma; -+ struct page *page; -+ -+ node_vma = rmap_item->head; -+ stable_node = node_vma->head; -+ page = get_uksm_page(stable_node, 1, 1); -+ if (!page) -+ goto out; -+ -+ /* -+ * page lock is needed because it's racing with -+ * try_to_unmap_ksm(), etc. -+ */ -+ lock_page(page); -+ hlist_del(&rmap_item->hlist); -+ -+ if (hlist_empty(&node_vma->rmap_hlist)) { -+ hlist_del(&node_vma->hlist); -+ free_node_vma(node_vma); -+ } -+ unlock_page(page); -+ -+ put_page(page); -+ if (hlist_empty(&stable_node->hlist)) { -+ /* do NOT call remove_node_from_stable_tree() here, -+ * it's possible for a forked rmap_item not in -+ * stable tree while the in-tree rmap_items were -+ * deleted. -+ */ -+ uksm_pages_shared--; -+ } else -+ uksm_pages_sharing--; -+ -+ -+ uksm_drop_anon_vma(rmap_item); -+ } else if (rmap_item->address & UNSTABLE_FLAG) { -+ if (rmap_item->hash_round == uksm_hash_round) { -+ -+ rb_erase(&rmap_item->node, -+ &rmap_item->tree_node->sub_root); -+ if (RB_EMPTY_ROOT(&rmap_item->tree_node->sub_root)) { -+ rb_erase(&rmap_item->tree_node->node, -+ &root_unstable_tree); -+ -+ free_tree_node(rmap_item->tree_node); -+ } else -+ rmap_item->tree_node->count--; -+ } -+ uksm_pages_unshared--; -+ } -+ -+ rmap_item->address &= PAGE_MASK; -+ rmap_item->hash_max = 0; -+ -+out: -+ cond_resched(); /* we're called from many long loops */ -+} -+ -+static inline int slot_in_uksm(struct vma_slot *slot) -+{ -+ return list_empty(&slot->slot_list); -+} -+ -+/* -+ * Test if the mm is exiting -+ */ -+static inline bool uksm_test_exit(struct mm_struct *mm) -+{ -+ return atomic_read(&mm->mm_users) == 0; -+} -+ -+static inline unsigned long vma_pool_size(struct vma_slot *slot) -+{ -+ return round_up(sizeof(struct rmap_list_entry) * slot->pages, -+ PAGE_SIZE) >> PAGE_SHIFT; -+} -+ -+#define CAN_OVERFLOW_U64(x, delta) (U64_MAX - (x) < (delta)) -+ -+/* must be done with sem locked */ -+static int slot_pool_alloc(struct vma_slot *slot) -+{ -+ unsigned long pool_size; -+ -+ if (slot->rmap_list_pool) -+ return 0; -+ -+ pool_size = vma_pool_size(slot); -+ slot->rmap_list_pool = kcalloc(pool_size, sizeof(struct page *), -+ GFP_KERNEL); -+ if (!slot->rmap_list_pool) -+ return -ENOMEM; -+ -+ slot->pool_counts = kcalloc(pool_size, sizeof(unsigned int), -+ GFP_KERNEL); -+ if (!slot->pool_counts) { -+ kfree(slot->rmap_list_pool); -+ return -ENOMEM; -+ } -+ -+ slot->pool_size = pool_size; -+ BUG_ON(CAN_OVERFLOW_U64(uksm_pages_total, slot->pages)); -+ slot->flags |= UKSM_SLOT_IN_UKSM; -+ uksm_pages_total += slot->pages; -+ -+ return 0; -+} -+ -+/* -+ * Called after vma is unlinked from its mm -+ */ -+void uksm_remove_vma(struct vm_area_struct *vma) -+{ -+ struct vma_slot *slot; -+ -+ if (!vma->uksm_vma_slot) -+ return; -+ -+ spin_lock(&vma_slot_list_lock); -+ slot = vma->uksm_vma_slot; -+ if (!slot) -+ goto out; -+ -+ if (slot_in_uksm(slot)) { -+ /** -+ * This slot has been added by ksmd, so move to the del list -+ * waiting ksmd to free it. -+ */ -+ list_add_tail(&slot->slot_list, &vma_slot_del); -+ } else { -+ /** -+ * It's still on new list. It's ok to free slot directly. -+ */ -+ list_del(&slot->slot_list); -+ free_vma_slot(slot); -+ } -+out: -+ vma->uksm_vma_slot = NULL; -+ spin_unlock(&vma_slot_list_lock); -+} -+ -+/** -+ * Need to do two things: -+ * 1. check if slot was moved to del list -+ * 2. make sure the mmap_sem is manipulated under valid vma. -+ * -+ * My concern here is that in some cases, this may make -+ * vma_slot_list_lock() waiters to serialized further by some -+ * sem->wait_lock, can this really be expensive? -+ * -+ * -+ * @return -+ * 0: if successfully locked mmap_sem -+ * -ENOENT: this slot was moved to del list -+ * -EBUSY: vma lock failed -+ */ -+static int try_down_read_slot_mmap_sem(struct vma_slot *slot) -+{ -+ struct vm_area_struct *vma; -+ struct mm_struct *mm; -+ struct rw_semaphore *sem; -+ -+ spin_lock(&vma_slot_list_lock); -+ -+ /* the slot_list was removed and inited from new list, when it enters -+ * uksm_list. If now it's not empty, then it must be moved to del list -+ */ -+ if (!slot_in_uksm(slot)) { -+ spin_unlock(&vma_slot_list_lock); -+ return -ENOENT; -+ } -+ -+ BUG_ON(slot->pages != vma_pages(slot->vma)); -+ /* Ok, vma still valid */ -+ vma = slot->vma; -+ mm = vma->vm_mm; -+ sem = &mm->mmap_sem; -+ -+ if (uksm_test_exit(mm)) { -+ spin_unlock(&vma_slot_list_lock); -+ return -ENOENT; -+ } -+ -+ if (down_read_trylock(sem)) { -+ spin_unlock(&vma_slot_list_lock); -+ if (slot_pool_alloc(slot)) { -+ uksm_remove_vma(vma); -+ up_read(sem); -+ return -ENOENT; -+ } -+ return 0; -+ } -+ -+ spin_unlock(&vma_slot_list_lock); -+ return -EBUSY; -+} -+ -+static inline unsigned long -+vma_page_address(struct page *page, struct vm_area_struct *vma) -+{ -+ pgoff_t pgoff = page->index; -+ unsigned long address; -+ -+ address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); -+ if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { -+ /* page should be within @vma mapping range */ -+ return -EFAULT; -+ } -+ return address; -+} -+ -+ -+/* return 0 on success with the item's mmap_sem locked */ -+static inline int get_mergeable_page_lock_mmap(struct rmap_item *item) -+{ -+ struct mm_struct *mm; -+ struct vma_slot *slot = item->slot; -+ int err = -EINVAL; -+ -+ struct page *page; -+ -+ /* -+ * try_down_read_slot_mmap_sem() returns non-zero if the slot -+ * has been removed by uksm_remove_vma(). -+ */ -+ if (try_down_read_slot_mmap_sem(slot)) -+ return -EBUSY; -+ -+ mm = slot->vma->vm_mm; -+ -+ if (uksm_test_exit(mm)) -+ goto failout_up; -+ -+ page = item->page; -+ rcu_read_lock(); -+ if (!get_page_unless_zero(page)) { -+ rcu_read_unlock(); -+ goto failout_up; -+ } -+ -+ /* No need to consider huge page here. */ -+ if (item->slot->vma->anon_vma != page_anon_vma(page) || -+ vma_page_address(page, item->slot->vma) != get_rmap_addr(item)) { -+ /* -+ * TODO: -+ * should we release this item becase of its stale page -+ * mapping? -+ */ -+ put_page(page); -+ rcu_read_unlock(); -+ goto failout_up; -+ } -+ rcu_read_unlock(); -+ return 0; -+ -+failout_up: -+ up_read(&mm->mmap_sem); -+ return err; -+} -+ -+/* -+ * What kind of VMA is considered ? -+ */ -+static inline int vma_can_enter(struct vm_area_struct *vma) -+{ -+ return uksm_flags_can_scan(vma->vm_flags); -+} -+ -+/* -+ * Called whenever a fresh new vma is created A new vma_slot. -+ * is created and inserted into a global list Must be called. -+ * after vma is inserted to its mm. -+ */ -+void uksm_vma_add_new(struct vm_area_struct *vma) -+{ -+ struct vma_slot *slot; -+ -+ if (!vma_can_enter(vma)) { -+ vma->uksm_vma_slot = NULL; -+ return; -+ } -+ -+ slot = alloc_vma_slot(); -+ if (!slot) { -+ vma->uksm_vma_slot = NULL; -+ return; -+ } -+ -+ vma->uksm_vma_slot = slot; -+ vma->vm_flags |= VM_MERGEABLE; -+ slot->vma = vma; -+ slot->mm = vma->vm_mm; -+ slot->ctime_j = jiffies; -+ slot->pages = vma_pages(vma); -+ spin_lock(&vma_slot_list_lock); -+ list_add_tail(&slot->slot_list, &vma_slot_new); -+ spin_unlock(&vma_slot_list_lock); -+} -+ -+/* 32/3 < they < 32/2 */ -+#define shiftl 8 -+#define shiftr 12 -+ -+#define HASH_FROM_TO(from, to) \ -+for (index = from; index < to; index++) { \ -+ pos = random_nums[index]; \ -+ hash += key[pos]; \ -+ hash += (hash << shiftl); \ -+ hash ^= (hash >> shiftr); \ -+} -+ -+ -+#define HASH_FROM_DOWN_TO(from, to) \ -+for (index = from - 1; index >= to; index--) { \ -+ hash ^= (hash >> shiftr); \ -+ hash ^= (hash >> (shiftr*2)); \ -+ hash -= (hash << shiftl); \ -+ hash += (hash << (shiftl*2)); \ -+ pos = random_nums[index]; \ -+ hash -= key[pos]; \ -+} -+ -+/* -+ * The main random sample hash function. -+ */ -+static u32 random_sample_hash(void *addr, u32 hash_strength) -+{ -+ u32 hash = 0xdeadbeef; -+ int index, pos, loop = hash_strength; -+ u32 *key = (u32 *)addr; -+ -+ if (loop > HASH_STRENGTH_FULL) -+ loop = HASH_STRENGTH_FULL; -+ -+ HASH_FROM_TO(0, loop); -+ -+ if (hash_strength > HASH_STRENGTH_FULL) { -+ loop = hash_strength - HASH_STRENGTH_FULL; -+ HASH_FROM_TO(0, loop); -+ } -+ -+ return hash; -+} -+ -+ -+/** -+ * It's used when hash strength is adjusted -+ * -+ * @addr The page's virtual address -+ * @from The original hash strength -+ * @to The hash strength changed to -+ * @hash The hash value generated with "from" hash value -+ * -+ * return the hash value -+ */ -+static u32 delta_hash(void *addr, int from, int to, u32 hash) -+{ -+ u32 *key = (u32 *)addr; -+ int index, pos; /* make sure they are int type */ -+ -+ if (to > from) { -+ if (from >= HASH_STRENGTH_FULL) { -+ from -= HASH_STRENGTH_FULL; -+ to -= HASH_STRENGTH_FULL; -+ HASH_FROM_TO(from, to); -+ } else if (to <= HASH_STRENGTH_FULL) { -+ HASH_FROM_TO(from, to); -+ } else { -+ HASH_FROM_TO(from, HASH_STRENGTH_FULL); -+ HASH_FROM_TO(0, to - HASH_STRENGTH_FULL); -+ } -+ } else { -+ if (from <= HASH_STRENGTH_FULL) { -+ HASH_FROM_DOWN_TO(from, to); -+ } else if (to >= HASH_STRENGTH_FULL) { -+ from -= HASH_STRENGTH_FULL; -+ to -= HASH_STRENGTH_FULL; -+ HASH_FROM_DOWN_TO(from, to); -+ } else { -+ HASH_FROM_DOWN_TO(from - HASH_STRENGTH_FULL, 0); -+ HASH_FROM_DOWN_TO(HASH_STRENGTH_FULL, to); -+ } -+ } -+ -+ return hash; -+} -+ -+/** -+ * -+ * Called when: rshash_pos or rshash_neg is about to overflow or a scan round -+ * has finished. -+ * -+ * return 0 if no page has been scanned since last call, 1 otherwise. -+ */ -+static inline int encode_benefit(void) -+{ -+ u64 scanned_delta, pos_delta, neg_delta; -+ unsigned long base = benefit.base; -+ -+ scanned_delta = uksm_pages_scanned - uksm_pages_scanned_last; -+ -+ if (!scanned_delta) -+ return 0; -+ -+ scanned_delta >>= base; -+ pos_delta = rshash_pos >> base; -+ neg_delta = rshash_neg >> base; -+ -+ if (CAN_OVERFLOW_U64(benefit.pos, pos_delta) || -+ CAN_OVERFLOW_U64(benefit.neg, neg_delta) || -+ CAN_OVERFLOW_U64(benefit.scanned, scanned_delta)) { -+ benefit.scanned >>= 1; -+ benefit.neg >>= 1; -+ benefit.pos >>= 1; -+ benefit.base++; -+ scanned_delta >>= 1; -+ pos_delta >>= 1; -+ neg_delta >>= 1; -+ } -+ -+ benefit.pos += pos_delta; -+ benefit.neg += neg_delta; -+ benefit.scanned += scanned_delta; -+ -+ BUG_ON(!benefit.scanned); -+ -+ rshash_pos = rshash_neg = 0; -+ uksm_pages_scanned_last = uksm_pages_scanned; -+ -+ return 1; -+} -+ -+static inline void reset_benefit(void) -+{ -+ benefit.pos = 0; -+ benefit.neg = 0; -+ benefit.base = 0; -+ benefit.scanned = 0; -+} -+ -+static inline void inc_rshash_pos(unsigned long delta) -+{ -+ if (CAN_OVERFLOW_U64(rshash_pos, delta)) -+ encode_benefit(); -+ -+ rshash_pos += delta; -+} -+ -+static inline void inc_rshash_neg(unsigned long delta) -+{ -+ if (CAN_OVERFLOW_U64(rshash_neg, delta)) -+ encode_benefit(); -+ -+ rshash_neg += delta; -+} -+ -+ -+static inline u32 page_hash(struct page *page, unsigned long hash_strength, -+ int cost_accounting) -+{ -+ u32 val; -+ unsigned long delta; -+ -+ void *addr = kmap_atomic(page); -+ -+ val = random_sample_hash(addr, hash_strength); -+ kunmap_atomic(addr); -+ -+ if (cost_accounting) { -+ if (hash_strength < HASH_STRENGTH_FULL) -+ delta = HASH_STRENGTH_FULL - hash_strength; -+ else -+ delta = 0; -+ -+ inc_rshash_pos(delta); -+ } -+ -+ return val; -+} -+ -+static int memcmp_pages(struct page *page1, struct page *page2, -+ int cost_accounting) -+{ -+ char *addr1, *addr2; -+ int ret; -+ -+ addr1 = kmap_atomic(page1); -+ addr2 = kmap_atomic(page2); -+ ret = memcmp(addr1, addr2, PAGE_SIZE); -+ kunmap_atomic(addr2); -+ kunmap_atomic(addr1); -+ -+ if (cost_accounting) -+ inc_rshash_neg(memcmp_cost); -+ -+ return ret; -+} -+ -+static inline int pages_identical(struct page *page1, struct page *page2) -+{ -+ return !memcmp_pages(page1, page2, 0); -+} -+ -+static inline int is_page_full_zero(struct page *page) -+{ -+ char *addr; -+ int ret; -+ -+ addr = kmap_atomic(page); -+ ret = is_full_zero(addr, PAGE_SIZE); -+ kunmap_atomic(addr); -+ -+ return ret; -+} -+ -+static int write_protect_page(struct vm_area_struct *vma, struct page *page, -+ pte_t *orig_pte, pte_t *old_pte) -+{ -+ struct mm_struct *mm = vma->vm_mm; -+ struct page_vma_mapped_walk pvmw = { -+ .page = page, -+ .vma = vma, -+ }; -+ struct mmu_notifier_range range; -+ int swapped; -+ int err = -EFAULT; -+ -+ pvmw.address = page_address_in_vma(page, vma); -+ if (pvmw.address == -EFAULT) -+ goto out; -+ -+ BUG_ON(PageTransCompound(page)); -+ -+ mmu_notifier_range_init(&range, mm, pvmw.address, pvmw.address + PAGE_SIZE); -+ mmu_notifier_invalidate_range_start(&range); -+ -+ if (!page_vma_mapped_walk(&pvmw)) -+ goto out_mn; -+ if (WARN_ONCE(!pvmw.pte, "Unexpected PMD mapping?")) -+ goto out_unlock; -+ -+ if (old_pte) -+ *old_pte = *pvmw.pte; -+ -+ if (pte_write(*pvmw.pte) || pte_dirty(*pvmw.pte) || -+ (pte_protnone(*pvmw.pte) && pte_savedwrite(*pvmw.pte)) || mm_tlb_flush_pending(mm)) { -+ pte_t entry; -+ -+ swapped = PageSwapCache(page); -+ flush_cache_page(vma, pvmw.address, page_to_pfn(page)); -+ /* -+ * Ok this is tricky, when get_user_pages_fast() run it doesn't -+ * take any lock, therefore the check that we are going to make -+ * with the pagecount against the mapcount is racey and -+ * O_DIRECT can happen right after the check. -+ * So we clear the pte and flush the tlb before the check -+ * this assure us that no O_DIRECT can happen after the check -+ * or in the middle of the check. -+ */ -+ entry = ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte); -+ /* -+ * Check that no O_DIRECT or similar I/O is in progress on the -+ * page -+ */ -+ if (page_mapcount(page) + 1 + swapped != page_count(page)) { -+ set_pte_at(mm, pvmw.address, pvmw.pte, entry); -+ goto out_unlock; -+ } -+ if (pte_dirty(entry)) -+ set_page_dirty(page); -+ -+ if (pte_protnone(entry)) -+ entry = pte_mkclean(pte_clear_savedwrite(entry)); -+ else -+ entry = pte_mkclean(pte_wrprotect(entry)); -+ -+ set_pte_at_notify(mm, pvmw.address, pvmw.pte, entry); -+ } -+ *orig_pte = *pvmw.pte; -+ err = 0; -+ -+out_unlock: -+ page_vma_mapped_walk_done(&pvmw); -+out_mn: -+ mmu_notifier_invalidate_range_end(&range); -+out: -+ return err; -+} -+ -+#define MERGE_ERR_PGERR 1 /* the page is invalid cannot continue */ -+#define MERGE_ERR_COLLI 2 /* there is a collision */ -+#define MERGE_ERR_COLLI_MAX 3 /* collision at the max hash strength */ -+#define MERGE_ERR_CHANGED 4 /* the page has changed since last hash */ -+ -+ -+/** -+ * replace_page - replace page in vma by new ksm page -+ * @vma: vma that holds the pte pointing to page -+ * @page: the page we are replacing by kpage -+ * @kpage: the ksm page we replace page by -+ * @orig_pte: the original value of the pte -+ * -+ * Returns 0 on success, MERGE_ERR_PGERR on failure. -+ */ -+static int replace_page(struct vm_area_struct *vma, struct page *page, -+ struct page *kpage, pte_t orig_pte) -+{ -+ struct mm_struct *mm = vma->vm_mm; -+ struct mmu_notifier_range range; -+ pgd_t *pgd; -+ p4d_t *p4d; -+ pud_t *pud; -+ pmd_t *pmd; -+ pte_t *ptep; -+ spinlock_t *ptl; -+ pte_t entry; -+ -+ unsigned long addr; -+ int err = MERGE_ERR_PGERR; -+ -+ addr = page_address_in_vma(page, vma); -+ if (addr == -EFAULT) -+ goto out; -+ -+ pgd = pgd_offset(mm, addr); -+ if (!pgd_present(*pgd)) -+ goto out; -+ -+ p4d = p4d_offset(pgd, addr); -+ pud = pud_offset(p4d, addr); -+ if (!pud_present(*pud)) -+ goto out; -+ -+ pmd = pmd_offset(pud, addr); -+ BUG_ON(pmd_trans_huge(*pmd)); -+ if (!pmd_present(*pmd)) -+ goto out; -+ -+ mmu_notifier_range_init(&range, mm, addr, addr + PAGE_SIZE); -+ mmu_notifier_invalidate_range_start(&range); -+ -+ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); -+ if (!pte_same(*ptep, orig_pte)) { -+ pte_unmap_unlock(ptep, ptl); -+ goto out_mn; -+ } -+ -+ flush_cache_page(vma, addr, pte_pfn(*ptep)); -+ ptep_clear_flush_notify(vma, addr, ptep); -+ entry = mk_pte(kpage, vma->vm_page_prot); -+ -+ /* special treatment is needed for zero_page */ -+ if ((page_to_pfn(kpage) == uksm_zero_pfn) || -+ (page_to_pfn(kpage) == zero_pfn)) { -+ entry = pte_mkspecial(entry); -+ dec_mm_counter(mm, MM_ANONPAGES); -+ inc_zone_page_state(page, NR_UKSM_ZERO_PAGES); -+ } else { -+ get_page(kpage); -+ page_add_anon_rmap(kpage, vma, addr, false); -+ } -+ -+ set_pte_at_notify(mm, addr, ptep, entry); -+ -+ page_remove_rmap(page, false); -+ if (!page_mapped(page)) -+ try_to_free_swap(page); -+ put_page(page); -+ -+ pte_unmap_unlock(ptep, ptl); -+ err = 0; -+out_mn: -+ mmu_notifier_invalidate_range_end(&range); -+out: -+ return err; -+} -+ -+ -+/** -+ * Fully hash a page with HASH_STRENGTH_MAX return a non-zero hash value. The -+ * zero hash value at HASH_STRENGTH_MAX is used to indicated that its -+ * hash_max member has not been calculated. -+ * -+ * @page The page needs to be hashed -+ * @hash_old The hash value calculated with current hash strength -+ * -+ * return the new hash value calculated at HASH_STRENGTH_MAX -+ */ -+static inline u32 page_hash_max(struct page *page, u32 hash_old) -+{ -+ u32 hash_max = 0; -+ void *addr; -+ -+ addr = kmap_atomic(page); -+ hash_max = delta_hash(addr, hash_strength, -+ HASH_STRENGTH_MAX, hash_old); -+ -+ kunmap_atomic(addr); -+ -+ if (!hash_max) -+ hash_max = 1; -+ -+ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); -+ return hash_max; -+} -+ -+/* -+ * We compare the hash again, to ensure that it is really a hash collision -+ * instead of being caused by page write. -+ */ -+static inline int check_collision(struct rmap_item *rmap_item, -+ u32 hash) -+{ -+ int err; -+ struct page *page = rmap_item->page; -+ -+ /* if this rmap_item has already been hash_maxed, then the collision -+ * must appears in the second-level rbtree search. In this case we check -+ * if its hash_max value has been changed. Otherwise, the collision -+ * happens in the first-level rbtree search, so we check against it's -+ * current hash value. -+ */ -+ if (rmap_item->hash_max) { -+ inc_rshash_neg(memcmp_cost); -+ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); -+ -+ if (rmap_item->hash_max == page_hash_max(page, hash)) -+ err = MERGE_ERR_COLLI; -+ else -+ err = MERGE_ERR_CHANGED; -+ } else { -+ inc_rshash_neg(memcmp_cost + hash_strength); -+ -+ if (page_hash(page, hash_strength, 0) == hash) -+ err = MERGE_ERR_COLLI; -+ else -+ err = MERGE_ERR_CHANGED; -+ } -+ -+ return err; -+} -+ -+/** -+ * Try to merge a rmap_item.page with a kpage in stable node. kpage must -+ * already be a ksm page. -+ * -+ * @return 0 if the pages were merged, -EFAULT otherwise. -+ */ -+static int try_to_merge_with_uksm_page(struct rmap_item *rmap_item, -+ struct page *kpage, u32 hash) -+{ -+ struct vm_area_struct *vma = rmap_item->slot->vma; -+ struct mm_struct *mm = vma->vm_mm; -+ pte_t orig_pte = __pte(0); -+ int err = MERGE_ERR_PGERR; -+ struct page *page; -+ -+ if (uksm_test_exit(mm)) -+ goto out; -+ -+ page = rmap_item->page; -+ -+ if (page == kpage) { /* ksm page forked */ -+ err = 0; -+ goto out; -+ } -+ -+ /* -+ * We need the page lock to read a stable PageSwapCache in -+ * write_protect_page(). We use trylock_page() instead of -+ * lock_page() because we don't want to wait here - we -+ * prefer to continue scanning and merging different pages, -+ * then come back to this page when it is unlocked. -+ */ -+ if (!trylock_page(page)) -+ goto out; -+ -+ if (!PageAnon(page) || !PageKsm(kpage)) -+ goto out_unlock; -+ -+ if (PageTransCompound(page)) { -+ err = split_huge_page(page); -+ if (err) -+ goto out_unlock; -+ } -+ -+ /* -+ * If this anonymous page is mapped only here, its pte may need -+ * to be write-protected. If it's mapped elsewhere, all of its -+ * ptes are necessarily already write-protected. But in either -+ * case, we need to lock and check page_count is not raised. -+ */ -+ if (write_protect_page(vma, page, &orig_pte, NULL) == 0) { -+ if (pages_identical(page, kpage)) -+ err = replace_page(vma, page, kpage, orig_pte); -+ else -+ err = check_collision(rmap_item, hash); -+ } -+ -+ if ((vma->vm_flags & VM_LOCKED) && kpage && !err) { -+ munlock_vma_page(page); -+ if (!PageMlocked(kpage)) { -+ unlock_page(page); -+ lock_page(kpage); -+ mlock_vma_page(kpage); -+ page = kpage; /* for final unlock */ -+ } -+ } -+ -+out_unlock: -+ unlock_page(page); -+out: -+ return err; -+} -+ -+ -+ -+/** -+ * If two pages fail to merge in try_to_merge_two_pages, then we have a chance -+ * to restore a page mapping that has been changed in try_to_merge_two_pages. -+ * -+ * @return 0 on success. -+ */ -+static int restore_uksm_page_pte(struct vm_area_struct *vma, unsigned long addr, -+ pte_t orig_pte, pte_t wprt_pte) -+{ -+ struct mm_struct *mm = vma->vm_mm; -+ pgd_t *pgd; -+ p4d_t *p4d; -+ pud_t *pud; -+ pmd_t *pmd; -+ pte_t *ptep; -+ spinlock_t *ptl; -+ -+ int err = -EFAULT; -+ -+ pgd = pgd_offset(mm, addr); -+ if (!pgd_present(*pgd)) -+ goto out; -+ -+ p4d = p4d_offset(pgd, addr); -+ pud = pud_offset(p4d, addr); -+ if (!pud_present(*pud)) -+ goto out; -+ -+ pmd = pmd_offset(pud, addr); -+ if (!pmd_present(*pmd)) -+ goto out; -+ -+ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); -+ if (!pte_same(*ptep, wprt_pte)) { -+ /* already copied, let it be */ -+ pte_unmap_unlock(ptep, ptl); -+ goto out; -+ } -+ -+ /* -+ * Good boy, still here. When we still get the ksm page, it does not -+ * return to the free page pool, there is no way that a pte was changed -+ * to other page and gets back to this page. And remind that ksm page -+ * do not reuse in do_wp_page(). So it's safe to restore the original -+ * pte. -+ */ -+ flush_cache_page(vma, addr, pte_pfn(*ptep)); -+ ptep_clear_flush_notify(vma, addr, ptep); -+ set_pte_at_notify(mm, addr, ptep, orig_pte); -+ -+ pte_unmap_unlock(ptep, ptl); -+ err = 0; -+out: -+ return err; -+} -+ -+/** -+ * try_to_merge_two_pages() - take two identical pages and prepare -+ * them to be merged into one page(rmap_item->page) -+ * -+ * @return 0 if we successfully merged two identical pages into -+ * one ksm page. MERGE_ERR_COLLI if it's only a hash collision -+ * search in rbtree. MERGE_ERR_CHANGED if rmap_item has been -+ * changed since it's hashed. MERGE_ERR_PGERR otherwise. -+ * -+ */ -+static int try_to_merge_two_pages(struct rmap_item *rmap_item, -+ struct rmap_item *tree_rmap_item, -+ u32 hash) -+{ -+ pte_t orig_pte1 = __pte(0), orig_pte2 = __pte(0); -+ pte_t wprt_pte1 = __pte(0), wprt_pte2 = __pte(0); -+ struct vm_area_struct *vma1 = rmap_item->slot->vma; -+ struct vm_area_struct *vma2 = tree_rmap_item->slot->vma; -+ struct page *page = rmap_item->page; -+ struct page *tree_page = tree_rmap_item->page; -+ int err = MERGE_ERR_PGERR; -+ struct address_space *saved_mapping; -+ -+ -+ if (rmap_item->page == tree_rmap_item->page) -+ goto out; -+ -+ if (!trylock_page(page)) -+ goto out; -+ -+ if (!PageAnon(page)) -+ goto out_unlock; -+ -+ if (PageTransCompound(page)) { -+ err = split_huge_page(page); -+ if (err) -+ goto out_unlock; -+ } -+ -+ if (write_protect_page(vma1, page, &wprt_pte1, &orig_pte1) != 0) { -+ unlock_page(page); -+ goto out; -+ } -+ -+ /* -+ * While we hold page lock, upgrade page from -+ * PageAnon+anon_vma to PageKsm+NULL stable_node: -+ * stable_tree_insert() will update stable_node. -+ */ -+ saved_mapping = page->mapping; -+ set_page_stable_node(page, NULL); -+ mark_page_accessed(page); -+ if (!PageDirty(page)) -+ SetPageDirty(page); -+ -+ unlock_page(page); -+ -+ if (!trylock_page(tree_page)) -+ goto restore_out; -+ -+ if (!PageAnon(tree_page)) { -+ unlock_page(tree_page); -+ goto restore_out; -+ } -+ -+ if (PageTransCompound(tree_page)) { -+ err = split_huge_page(tree_page); -+ if (err) { -+ unlock_page(tree_page); -+ goto restore_out; -+ } -+ } -+ -+ if (write_protect_page(vma2, tree_page, &wprt_pte2, &orig_pte2) != 0) { -+ unlock_page(tree_page); -+ goto restore_out; -+ } -+ -+ if (pages_identical(page, tree_page)) { -+ err = replace_page(vma2, tree_page, page, wprt_pte2); -+ if (err) { -+ unlock_page(tree_page); -+ goto restore_out; -+ } -+ -+ if ((vma2->vm_flags & VM_LOCKED)) { -+ munlock_vma_page(tree_page); -+ if (!PageMlocked(page)) { -+ unlock_page(tree_page); -+ lock_page(page); -+ mlock_vma_page(page); -+ tree_page = page; /* for final unlock */ -+ } -+ } -+ -+ unlock_page(tree_page); -+ -+ goto out; /* success */ -+ -+ } else { -+ if (tree_rmap_item->hash_max && -+ tree_rmap_item->hash_max == rmap_item->hash_max) { -+ err = MERGE_ERR_COLLI_MAX; -+ } else if (page_hash(page, hash_strength, 0) == -+ page_hash(tree_page, hash_strength, 0)) { -+ inc_rshash_neg(memcmp_cost + hash_strength * 2); -+ err = MERGE_ERR_COLLI; -+ } else { -+ err = MERGE_ERR_CHANGED; -+ } -+ -+ unlock_page(tree_page); -+ } -+ -+restore_out: -+ lock_page(page); -+ if (!restore_uksm_page_pte(vma1, get_rmap_addr(rmap_item), -+ orig_pte1, wprt_pte1)) -+ page->mapping = saved_mapping; -+ -+out_unlock: -+ unlock_page(page); -+out: -+ return err; -+} -+ -+static inline int hash_cmp(u32 new_val, u32 node_val) -+{ -+ if (new_val > node_val) -+ return 1; -+ else if (new_val < node_val) -+ return -1; -+ else -+ return 0; -+} -+ -+static inline u32 rmap_item_hash_max(struct rmap_item *item, u32 hash) -+{ -+ u32 hash_max = item->hash_max; -+ -+ if (!hash_max) { -+ hash_max = page_hash_max(item->page, hash); -+ -+ item->hash_max = hash_max; -+ } -+ -+ return hash_max; -+} -+ -+ -+ -+/** -+ * stable_tree_search() - search the stable tree for a page -+ * -+ * @item: the rmap_item we are comparing with -+ * @hash: the hash value of this item->page already calculated -+ * -+ * @return the page we have found, NULL otherwise. The page returned has -+ * been gotten. -+ */ -+static struct page *stable_tree_search(struct rmap_item *item, u32 hash) -+{ -+ struct rb_node *node = root_stable_treep->rb_node; -+ struct tree_node *tree_node; -+ unsigned long hash_max; -+ struct page *page = item->page; -+ struct stable_node *stable_node; -+ -+ stable_node = page_stable_node(page); -+ if (stable_node) { -+ /* ksm page forked, that is -+ * if (PageKsm(page) && !in_stable_tree(rmap_item)) -+ * it's actually gotten once outside. -+ */ -+ get_page(page); -+ return page; -+ } -+ -+ while (node) { -+ int cmp; -+ -+ tree_node = rb_entry(node, struct tree_node, node); -+ -+ cmp = hash_cmp(hash, tree_node->hash); -+ -+ if (cmp < 0) -+ node = node->rb_left; -+ else if (cmp > 0) -+ node = node->rb_right; -+ else -+ break; -+ } -+ -+ if (!node) -+ return NULL; -+ -+ if (tree_node->count == 1) { -+ stable_node = rb_entry(tree_node->sub_root.rb_node, -+ struct stable_node, node); -+ BUG_ON(!stable_node); -+ -+ goto get_page_out; -+ } -+ -+ /* -+ * ok, we have to search the second -+ * level subtree, hash the page to a -+ * full strength. -+ */ -+ node = tree_node->sub_root.rb_node; -+ BUG_ON(!node); -+ hash_max = rmap_item_hash_max(item, hash); -+ -+ while (node) { -+ int cmp; -+ -+ stable_node = rb_entry(node, struct stable_node, node); -+ -+ cmp = hash_cmp(hash_max, stable_node->hash_max); -+ -+ if (cmp < 0) -+ node = node->rb_left; -+ else if (cmp > 0) -+ node = node->rb_right; -+ else -+ goto get_page_out; -+ } -+ -+ return NULL; -+ -+get_page_out: -+ page = get_uksm_page(stable_node, 1, 1); -+ return page; -+} -+ -+static int try_merge_rmap_item(struct rmap_item *item, -+ struct page *kpage, -+ struct page *tree_page) -+{ -+ struct vm_area_struct *vma = item->slot->vma; -+ struct page_vma_mapped_walk pvmw = { -+ .page = kpage, -+ .vma = vma, -+ }; -+ -+ pvmw.address = get_rmap_addr(item); -+ if (!page_vma_mapped_walk(&pvmw)) -+ return 0; -+ -+ if (pte_write(*pvmw.pte)) { -+ /* has changed, abort! */ -+ page_vma_mapped_walk_done(&pvmw); -+ return 0; -+ } -+ -+ get_page(tree_page); -+ page_add_anon_rmap(tree_page, vma, pvmw.address, false); -+ -+ flush_cache_page(vma, pvmw.address, page_to_pfn(kpage)); -+ ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte); -+ set_pte_at_notify(vma->vm_mm, pvmw.address, pvmw.pte, -+ mk_pte(tree_page, vma->vm_page_prot)); -+ -+ page_remove_rmap(kpage, false); -+ put_page(kpage); -+ -+ page_vma_mapped_walk_done(&pvmw); -+ -+ return 1; -+} -+ -+/** -+ * try_to_merge_with_stable_page() - when two rmap_items need to be inserted -+ * into stable tree, the page was found to be identical to a stable ksm page, -+ * this is the last chance we can merge them into one. -+ * -+ * @item1: the rmap_item holding the page which we wanted to insert -+ * into stable tree. -+ * @item2: the other rmap_item we found when unstable tree search -+ * @oldpage: the page currently mapped by the two rmap_items -+ * @tree_page: the page we found identical in stable tree node -+ * @success1: return if item1 is successfully merged -+ * @success2: return if item2 is successfully merged -+ */ -+static void try_merge_with_stable(struct rmap_item *item1, -+ struct rmap_item *item2, -+ struct page **kpage, -+ struct page *tree_page, -+ int *success1, int *success2) -+{ -+ struct vm_area_struct *vma1 = item1->slot->vma; -+ struct vm_area_struct *vma2 = item2->slot->vma; -+ *success1 = 0; -+ *success2 = 0; -+ -+ if (unlikely(*kpage == tree_page)) { -+ /* I don't think this can really happen */ -+ pr_warn("UKSM: unexpected condition detected in " -+ "%s -- *kpage == tree_page !\n", __func__); -+ *success1 = 1; -+ *success2 = 1; -+ return; -+ } -+ -+ if (!PageAnon(*kpage) || !PageKsm(*kpage)) -+ goto failed; -+ -+ if (!trylock_page(tree_page)) -+ goto failed; -+ -+ /* If the oldpage is still ksm and still pointed -+ * to in the right place, and still write protected, -+ * we are confident it's not changed, no need to -+ * memcmp anymore. -+ * be ware, we cannot take nested pte locks, -+ * deadlock risk. -+ */ -+ if (!try_merge_rmap_item(item1, *kpage, tree_page)) -+ goto unlock_failed; -+ -+ /* ok, then vma2, remind that pte1 already set */ -+ if (!try_merge_rmap_item(item2, *kpage, tree_page)) -+ goto success_1; -+ -+ *success2 = 1; -+success_1: -+ *success1 = 1; -+ -+ -+ if ((*success1 && vma1->vm_flags & VM_LOCKED) || -+ (*success2 && vma2->vm_flags & VM_LOCKED)) { -+ munlock_vma_page(*kpage); -+ if (!PageMlocked(tree_page)) -+ mlock_vma_page(tree_page); -+ } -+ -+ /* -+ * We do not need oldpage any more in the caller, so can break the lock -+ * now. -+ */ -+ unlock_page(*kpage); -+ *kpage = tree_page; /* Get unlocked outside. */ -+ return; -+ -+unlock_failed: -+ unlock_page(tree_page); -+failed: -+ return; -+} -+ -+static inline void stable_node_hash_max(struct stable_node *node, -+ struct page *page, u32 hash) -+{ -+ u32 hash_max = node->hash_max; -+ -+ if (!hash_max) { -+ hash_max = page_hash_max(page, hash); -+ node->hash_max = hash_max; -+ } -+} -+ -+static inline -+struct stable_node *new_stable_node(struct tree_node *tree_node, -+ struct page *kpage, u32 hash_max) -+{ -+ struct stable_node *new_stable_node; -+ -+ new_stable_node = alloc_stable_node(); -+ if (!new_stable_node) -+ return NULL; -+ -+ new_stable_node->kpfn = page_to_pfn(kpage); -+ new_stable_node->hash_max = hash_max; -+ new_stable_node->tree_node = tree_node; -+ set_page_stable_node(kpage, new_stable_node); -+ -+ return new_stable_node; -+} -+ -+static inline -+struct stable_node *first_level_insert(struct tree_node *tree_node, -+ struct rmap_item *rmap_item, -+ struct rmap_item *tree_rmap_item, -+ struct page **kpage, u32 hash, -+ int *success1, int *success2) -+{ -+ int cmp; -+ struct page *tree_page; -+ u32 hash_max = 0; -+ struct stable_node *stable_node, *new_snode; -+ struct rb_node *parent = NULL, **new; -+ -+ /* this tree node contains no sub-tree yet */ -+ stable_node = rb_entry(tree_node->sub_root.rb_node, -+ struct stable_node, node); -+ -+ tree_page = get_uksm_page(stable_node, 1, 0); -+ if (tree_page) { -+ cmp = memcmp_pages(*kpage, tree_page, 1); -+ if (!cmp) { -+ try_merge_with_stable(rmap_item, tree_rmap_item, kpage, -+ tree_page, success1, success2); -+ put_page(tree_page); -+ if (!*success1 && !*success2) -+ goto failed; -+ -+ return stable_node; -+ -+ } else { -+ /* -+ * collision in first level try to create a subtree. -+ * A new node need to be created. -+ */ -+ put_page(tree_page); -+ -+ stable_node_hash_max(stable_node, tree_page, -+ tree_node->hash); -+ hash_max = rmap_item_hash_max(rmap_item, hash); -+ cmp = hash_cmp(hash_max, stable_node->hash_max); -+ -+ parent = &stable_node->node; -+ if (cmp < 0) -+ new = &parent->rb_left; -+ else if (cmp > 0) -+ new = &parent->rb_right; -+ else -+ goto failed; -+ } -+ -+ } else { -+ /* the only stable_node deleted, we reuse its tree_node. -+ */ -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ } -+ -+ new_snode = new_stable_node(tree_node, *kpage, hash_max); -+ if (!new_snode) -+ goto failed; -+ -+ rb_link_node(&new_snode->node, parent, new); -+ rb_insert_color(&new_snode->node, &tree_node->sub_root); -+ tree_node->count++; -+ *success1 = *success2 = 1; -+ -+ return new_snode; -+ -+failed: -+ return NULL; -+} -+ -+static inline -+struct stable_node *stable_subtree_insert(struct tree_node *tree_node, -+ struct rmap_item *rmap_item, -+ struct rmap_item *tree_rmap_item, -+ struct page **kpage, u32 hash, -+ int *success1, int *success2) -+{ -+ struct page *tree_page; -+ u32 hash_max; -+ struct stable_node *stable_node, *new_snode; -+ struct rb_node *parent, **new; -+ -+research: -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ BUG_ON(!*new); -+ hash_max = rmap_item_hash_max(rmap_item, hash); -+ while (*new) { -+ int cmp; -+ -+ stable_node = rb_entry(*new, struct stable_node, node); -+ -+ cmp = hash_cmp(hash_max, stable_node->hash_max); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else { -+ tree_page = get_uksm_page(stable_node, 1, 0); -+ if (tree_page) { -+ cmp = memcmp_pages(*kpage, tree_page, 1); -+ if (!cmp) { -+ try_merge_with_stable(rmap_item, -+ tree_rmap_item, kpage, -+ tree_page, success1, success2); -+ -+ put_page(tree_page); -+ if (!*success1 && !*success2) -+ goto failed; -+ /* -+ * successfully merged with a stable -+ * node -+ */ -+ return stable_node; -+ } else { -+ put_page(tree_page); -+ goto failed; -+ } -+ } else { -+ /* -+ * stable node may be deleted, -+ * and subtree maybe -+ * restructed, cannot -+ * continue, research it. -+ */ -+ if (tree_node->count) { -+ goto research; -+ } else { -+ /* reuse the tree node*/ -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ } -+ } -+ } -+ } -+ -+ new_snode = new_stable_node(tree_node, *kpage, hash_max); -+ if (!new_snode) -+ goto failed; -+ -+ rb_link_node(&new_snode->node, parent, new); -+ rb_insert_color(&new_snode->node, &tree_node->sub_root); -+ tree_node->count++; -+ *success1 = *success2 = 1; -+ -+ return new_snode; -+ -+failed: -+ return NULL; -+} -+ -+ -+/** -+ * stable_tree_insert() - try to insert a merged page in unstable tree to -+ * the stable tree -+ * -+ * @kpage: the page need to be inserted -+ * @hash: the current hash of this page -+ * @rmap_item: the rmap_item being scanned -+ * @tree_rmap_item: the rmap_item found on unstable tree -+ * @success1: return if rmap_item is merged -+ * @success2: return if tree_rmap_item is merged -+ * -+ * @return the stable_node on stable tree if at least one -+ * rmap_item is inserted into stable tree, NULL -+ * otherwise. -+ */ -+static struct stable_node * -+stable_tree_insert(struct page **kpage, u32 hash, -+ struct rmap_item *rmap_item, -+ struct rmap_item *tree_rmap_item, -+ int *success1, int *success2) -+{ -+ struct rb_node **new = &root_stable_treep->rb_node; -+ struct rb_node *parent = NULL; -+ struct stable_node *stable_node; -+ struct tree_node *tree_node; -+ u32 hash_max = 0; -+ -+ *success1 = *success2 = 0; -+ -+ while (*new) { -+ int cmp; -+ -+ tree_node = rb_entry(*new, struct tree_node, node); -+ -+ cmp = hash_cmp(hash, tree_node->hash); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else -+ break; -+ } -+ -+ if (*new) { -+ if (tree_node->count == 1) { -+ stable_node = first_level_insert(tree_node, rmap_item, -+ tree_rmap_item, kpage, -+ hash, success1, success2); -+ } else { -+ stable_node = stable_subtree_insert(tree_node, -+ rmap_item, tree_rmap_item, kpage, -+ hash, success1, success2); -+ } -+ } else { -+ -+ /* no tree node found */ -+ tree_node = alloc_tree_node(stable_tree_node_listp); -+ if (!tree_node) { -+ stable_node = NULL; -+ goto out; -+ } -+ -+ stable_node = new_stable_node(tree_node, *kpage, hash_max); -+ if (!stable_node) { -+ free_tree_node(tree_node); -+ goto out; -+ } -+ -+ tree_node->hash = hash; -+ rb_link_node(&tree_node->node, parent, new); -+ rb_insert_color(&tree_node->node, root_stable_treep); -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ -+ rb_link_node(&stable_node->node, parent, new); -+ rb_insert_color(&stable_node->node, &tree_node->sub_root); -+ tree_node->count++; -+ *success1 = *success2 = 1; -+ } -+ -+out: -+ return stable_node; -+} -+ -+ -+/** -+ * get_tree_rmap_item_page() - try to get the page and lock the mmap_sem -+ * -+ * @return 0 on success, -EBUSY if unable to lock the mmap_sem, -+ * -EINVAL if the page mapping has been changed. -+ */ -+static inline int get_tree_rmap_item_page(struct rmap_item *tree_rmap_item) -+{ -+ int err; -+ -+ err = get_mergeable_page_lock_mmap(tree_rmap_item); -+ -+ if (err == -EINVAL) { -+ /* its page map has been changed, remove it */ -+ remove_rmap_item_from_tree(tree_rmap_item); -+ } -+ -+ /* The page is gotten and mmap_sem is locked now. */ -+ return err; -+} -+ -+ -+/** -+ * unstable_tree_search_insert() - search an unstable tree rmap_item with the -+ * same hash value. Get its page and trylock the mmap_sem -+ */ -+static inline -+struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, -+ u32 hash) -+ -+{ -+ struct rb_node **new = &root_unstable_tree.rb_node; -+ struct rb_node *parent = NULL; -+ struct tree_node *tree_node; -+ u32 hash_max; -+ struct rmap_item *tree_rmap_item; -+ -+ while (*new) { -+ int cmp; -+ -+ tree_node = rb_entry(*new, struct tree_node, node); -+ -+ cmp = hash_cmp(hash, tree_node->hash); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else -+ break; -+ } -+ -+ if (*new) { -+ /* got the tree_node */ -+ if (tree_node->count == 1) { -+ tree_rmap_item = rb_entry(tree_node->sub_root.rb_node, -+ struct rmap_item, node); -+ BUG_ON(!tree_rmap_item); -+ -+ goto get_page_out; -+ } -+ -+ /* well, search the collision subtree */ -+ new = &tree_node->sub_root.rb_node; -+ BUG_ON(!*new); -+ hash_max = rmap_item_hash_max(rmap_item, hash); -+ -+ while (*new) { -+ int cmp; -+ -+ tree_rmap_item = rb_entry(*new, struct rmap_item, -+ node); -+ -+ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); -+ parent = *new; -+ if (cmp < 0) -+ new = &parent->rb_left; -+ else if (cmp > 0) -+ new = &parent->rb_right; -+ else -+ goto get_page_out; -+ } -+ } else { -+ /* alloc a new tree_node */ -+ tree_node = alloc_tree_node(&unstable_tree_node_list); -+ if (!tree_node) -+ return NULL; -+ -+ tree_node->hash = hash; -+ rb_link_node(&tree_node->node, parent, new); -+ rb_insert_color(&tree_node->node, &root_unstable_tree); -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ } -+ -+ /* did not found even in sub-tree */ -+ rmap_item->tree_node = tree_node; -+ rmap_item->address |= UNSTABLE_FLAG; -+ rmap_item->hash_round = uksm_hash_round; -+ rb_link_node(&rmap_item->node, parent, new); -+ rb_insert_color(&rmap_item->node, &tree_node->sub_root); -+ -+ uksm_pages_unshared++; -+ return NULL; -+ -+get_page_out: -+ if (tree_rmap_item->page == rmap_item->page) -+ return NULL; -+ -+ if (get_tree_rmap_item_page(tree_rmap_item)) -+ return NULL; -+ -+ return tree_rmap_item; -+} -+ -+static void hold_anon_vma(struct rmap_item *rmap_item, -+ struct anon_vma *anon_vma) -+{ -+ rmap_item->anon_vma = anon_vma; -+ get_anon_vma(anon_vma); -+} -+ -+ -+/** -+ * stable_tree_append() - append a rmap_item to a stable node. Deduplication -+ * ratio statistics is done in this function. -+ * -+ */ -+static void stable_tree_append(struct rmap_item *rmap_item, -+ struct stable_node *stable_node, int logdedup) -+{ -+ struct node_vma *node_vma = NULL, *new_node_vma, *node_vma_cont = NULL; -+ unsigned long key = (unsigned long)rmap_item->slot; -+ unsigned long factor = rmap_item->slot->rung->step; -+ -+ BUG_ON(!stable_node); -+ rmap_item->address |= STABLE_FLAG; -+ -+ if (hlist_empty(&stable_node->hlist)) { -+ uksm_pages_shared++; -+ goto node_vma_new; -+ } else { -+ uksm_pages_sharing++; -+ } -+ -+ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { -+ if (node_vma->key >= key) -+ break; -+ -+ if (logdedup) { -+ node_vma->slot->pages_bemerged += factor; -+ if (list_empty(&node_vma->slot->dedup_list)) -+ list_add(&node_vma->slot->dedup_list, -+ &vma_slot_dedup); -+ } -+ } -+ -+ if (node_vma) { -+ if (node_vma->key == key) { -+ node_vma_cont = hlist_entry_safe(node_vma->hlist.next, struct node_vma, hlist); -+ goto node_vma_ok; -+ } else if (node_vma->key > key) { -+ node_vma_cont = node_vma; -+ } -+ } -+ -+node_vma_new: -+ /* no same vma already in node, alloc a new node_vma */ -+ new_node_vma = alloc_node_vma(); -+ BUG_ON(!new_node_vma); -+ new_node_vma->head = stable_node; -+ new_node_vma->slot = rmap_item->slot; -+ -+ if (!node_vma) { -+ hlist_add_head(&new_node_vma->hlist, &stable_node->hlist); -+ } else if (node_vma->key != key) { -+ if (node_vma->key < key) -+ hlist_add_behind(&new_node_vma->hlist, &node_vma->hlist); -+ else { -+ hlist_add_before(&new_node_vma->hlist, -+ &node_vma->hlist); -+ } -+ -+ } -+ node_vma = new_node_vma; -+ -+node_vma_ok: /* ok, ready to add to the list */ -+ rmap_item->head = node_vma; -+ hlist_add_head(&rmap_item->hlist, &node_vma->rmap_hlist); -+ hold_anon_vma(rmap_item, rmap_item->slot->vma->anon_vma); -+ if (logdedup) { -+ rmap_item->slot->pages_merged++; -+ if (node_vma_cont) { -+ node_vma = node_vma_cont; -+ hlist_for_each_entry_continue(node_vma, hlist) { -+ node_vma->slot->pages_bemerged += factor; -+ if (list_empty(&node_vma->slot->dedup_list)) -+ list_add(&node_vma->slot->dedup_list, -+ &vma_slot_dedup); -+ } -+ } -+ } -+} -+ -+/* -+ * We use break_ksm to break COW on a ksm page: it's a stripped down -+ * -+ * if (get_user_pages(addr, 1, 1, 1, &page, NULL) == 1) -+ * put_page(page); -+ * -+ * but taking great care only to touch a ksm page, in a VM_MERGEABLE vma, -+ * in case the application has unmapped and remapped mm,addr meanwhile. -+ * Could a ksm page appear anywhere else? Actually yes, in a VM_PFNMAP -+ * mmap of /dev/mem or /dev/kmem, where we would not want to touch it. -+ */ -+static int break_ksm(struct vm_area_struct *vma, unsigned long addr) -+{ -+ struct page *page; -+ int ret = 0; -+ -+ do { -+ cond_resched(); -+ page = follow_page(vma, addr, FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); -+ if (IS_ERR_OR_NULL(page)) -+ break; -+ if (PageKsm(page)) { -+ ret = handle_mm_fault(vma, addr, -+ FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE); -+ } else -+ ret = VM_FAULT_WRITE; -+ put_page(page); -+ } while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | VM_FAULT_OOM))); -+ /* -+ * We must loop because handle_mm_fault() may back out if there's -+ * any difficulty e.g. if pte accessed bit gets updated concurrently. -+ * -+ * VM_FAULT_WRITE is what we have been hoping for: it indicates that -+ * COW has been broken, even if the vma does not permit VM_WRITE; -+ * but note that a concurrent fault might break PageKsm for us. -+ * -+ * VM_FAULT_SIGBUS could occur if we race with truncation of the -+ * backing file, which also invalidates anonymous pages: that's -+ * okay, that truncation will have unmapped the PageKsm for us. -+ * -+ * VM_FAULT_OOM: at the time of writing (late July 2009), setting -+ * aside mem_cgroup limits, VM_FAULT_OOM would only be set if the -+ * current task has TIF_MEMDIE set, and will be OOM killed on return -+ * to user; and ksmd, having no mm, would never be chosen for that. -+ * -+ * But if the mm is in a limited mem_cgroup, then the fault may fail -+ * with VM_FAULT_OOM even if the current task is not TIF_MEMDIE; and -+ * even ksmd can fail in this way - though it's usually breaking ksm -+ * just to undo a merge it made a moment before, so unlikely to oom. -+ * -+ * That's a pity: we might therefore have more kernel pages allocated -+ * than we're counting as nodes in the stable tree; but uksm_do_scan -+ * will retry to break_cow on each pass, so should recover the page -+ * in due course. The important thing is to not let VM_MERGEABLE -+ * be cleared while any such pages might remain in the area. -+ */ -+ return (ret & VM_FAULT_OOM) ? -ENOMEM : 0; -+} -+ -+static void break_cow(struct rmap_item *rmap_item) -+{ -+ struct vm_area_struct *vma = rmap_item->slot->vma; -+ struct mm_struct *mm = vma->vm_mm; -+ unsigned long addr = get_rmap_addr(rmap_item); -+ -+ if (uksm_test_exit(mm)) -+ goto out; -+ -+ break_ksm(vma, addr); -+out: -+ return; -+} -+ -+/* -+ * Though it's very tempting to unmerge in_stable_tree(rmap_item)s rather -+ * than check every pte of a given vma, the locking doesn't quite work for -+ * that - an rmap_item is assigned to the stable tree after inserting ksm -+ * page and upping mmap_sem. Nor does it fit with the way we skip dup'ing -+ * rmap_items from parent to child at fork time (so as not to waste time -+ * if exit comes before the next scan reaches it). -+ * -+ * Similarly, although we'd like to remove rmap_items (so updating counts -+ * and freeing memory) when unmerging an area, it's easier to leave that -+ * to the next pass of ksmd - consider, for example, how ksmd might be -+ * in cmp_and_merge_page on one of the rmap_items we would be removing. -+ */ -+inline int unmerge_uksm_pages(struct vm_area_struct *vma, -+ unsigned long start, unsigned long end) -+{ -+ unsigned long addr; -+ int err = 0; -+ -+ for (addr = start; addr < end && !err; addr += PAGE_SIZE) { -+ if (uksm_test_exit(vma->vm_mm)) -+ break; -+ if (signal_pending(current)) -+ err = -ERESTARTSYS; -+ else -+ err = break_ksm(vma, addr); -+ } -+ return err; -+} -+ -+static inline void inc_uksm_pages_scanned(void) -+{ -+ u64 delta; -+ -+ -+ if (uksm_pages_scanned == U64_MAX) { -+ encode_benefit(); -+ -+ delta = uksm_pages_scanned >> pages_scanned_base; -+ -+ if (CAN_OVERFLOW_U64(pages_scanned_stored, delta)) { -+ pages_scanned_stored >>= 1; -+ delta >>= 1; -+ pages_scanned_base++; -+ } -+ -+ pages_scanned_stored += delta; -+ -+ uksm_pages_scanned = uksm_pages_scanned_last = 0; -+ } -+ -+ uksm_pages_scanned++; -+} -+ -+static inline int find_zero_page_hash(int strength, u32 hash) -+{ -+ return (zero_hash_table[strength] == hash); -+} -+ -+static -+int cmp_and_merge_zero_page(struct vm_area_struct *vma, struct page *page) -+{ -+ struct page *zero_page = empty_uksm_zero_page; -+ struct mm_struct *mm = vma->vm_mm; -+ pte_t orig_pte = __pte(0); -+ int err = -EFAULT; -+ -+ if (uksm_test_exit(mm)) -+ goto out; -+ -+ if (!trylock_page(page)) -+ goto out; -+ -+ if (!PageAnon(page)) -+ goto out_unlock; -+ -+ if (PageTransCompound(page)) { -+ err = split_huge_page(page); -+ if (err) -+ goto out_unlock; -+ } -+ -+ if (write_protect_page(vma, page, &orig_pte, 0) == 0) { -+ if (is_page_full_zero(page)) -+ err = replace_page(vma, page, zero_page, orig_pte); -+ } -+ -+out_unlock: -+ unlock_page(page); -+out: -+ return err; -+} -+ -+/* -+ * cmp_and_merge_page() - first see if page can be merged into the stable -+ * tree; if not, compare hash to previous and if it's the same, see if page -+ * can be inserted into the unstable tree, or merged with a page already there -+ * and both transferred to the stable tree. -+ * -+ * @page: the page that we are searching identical page to. -+ * @rmap_item: the reverse mapping into the virtual address of this page -+ */ -+static void cmp_and_merge_page(struct rmap_item *rmap_item, u32 hash) -+{ -+ struct rmap_item *tree_rmap_item; -+ struct page *page; -+ struct page *kpage = NULL; -+ u32 hash_max; -+ int err; -+ unsigned int success1, success2; -+ struct stable_node *snode; -+ int cmp; -+ struct rb_node *parent = NULL, **new; -+ -+ remove_rmap_item_from_tree(rmap_item); -+ page = rmap_item->page; -+ -+ /* We first start with searching the page inside the stable tree */ -+ kpage = stable_tree_search(rmap_item, hash); -+ if (kpage) { -+ err = try_to_merge_with_uksm_page(rmap_item, kpage, -+ hash); -+ if (!err) { -+ /* -+ * The page was successfully merged, add -+ * its rmap_item to the stable tree. -+ * page lock is needed because it's -+ * racing with try_to_unmap_ksm(), etc. -+ */ -+ lock_page(kpage); -+ snode = page_stable_node(kpage); -+ stable_tree_append(rmap_item, snode, 1); -+ unlock_page(kpage); -+ put_page(kpage); -+ return; /* success */ -+ } -+ put_page(kpage); -+ -+ /* -+ * if it's a collision and it has been search in sub-rbtree -+ * (hash_max != 0), we want to abort, because if it is -+ * successfully merged in unstable tree, the collision trends to -+ * happen again. -+ */ -+ if (err == MERGE_ERR_COLLI && rmap_item->hash_max) -+ return; -+ } -+ -+ tree_rmap_item = -+ unstable_tree_search_insert(rmap_item, hash); -+ if (tree_rmap_item) { -+ err = try_to_merge_two_pages(rmap_item, tree_rmap_item, hash); -+ /* -+ * As soon as we merge this page, we want to remove the -+ * rmap_item of the page we have merged with from the unstable -+ * tree, and insert it instead as new node in the stable tree. -+ */ -+ if (!err) { -+ kpage = page; -+ remove_rmap_item_from_tree(tree_rmap_item); -+ lock_page(kpage); -+ snode = stable_tree_insert(&kpage, hash, -+ rmap_item, tree_rmap_item, -+ &success1, &success2); -+ -+ /* -+ * Do not log dedup for tree item, it's not counted as -+ * scanned in this round. -+ */ -+ if (success2) -+ stable_tree_append(tree_rmap_item, snode, 0); -+ -+ /* -+ * The order of these two stable append is important: -+ * we are scanning rmap_item. -+ */ -+ if (success1) -+ stable_tree_append(rmap_item, snode, 1); -+ -+ /* -+ * The original kpage may be unlocked inside -+ * stable_tree_insert() already. This page -+ * should be unlocked before doing -+ * break_cow(). -+ */ -+ unlock_page(kpage); -+ -+ if (!success1) -+ break_cow(rmap_item); -+ -+ if (!success2) -+ break_cow(tree_rmap_item); -+ -+ } else if (err == MERGE_ERR_COLLI) { -+ BUG_ON(tree_rmap_item->tree_node->count > 1); -+ -+ rmap_item_hash_max(tree_rmap_item, -+ tree_rmap_item->tree_node->hash); -+ -+ hash_max = rmap_item_hash_max(rmap_item, hash); -+ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); -+ parent = &tree_rmap_item->node; -+ if (cmp < 0) -+ new = &parent->rb_left; -+ else if (cmp > 0) -+ new = &parent->rb_right; -+ else -+ goto put_up_out; -+ -+ rmap_item->tree_node = tree_rmap_item->tree_node; -+ rmap_item->address |= UNSTABLE_FLAG; -+ rmap_item->hash_round = uksm_hash_round; -+ rb_link_node(&rmap_item->node, parent, new); -+ rb_insert_color(&rmap_item->node, -+ &tree_rmap_item->tree_node->sub_root); -+ rmap_item->tree_node->count++; -+ } else { -+ /* -+ * either one of the page has changed or they collide -+ * at the max hash, we consider them as ill items. -+ */ -+ remove_rmap_item_from_tree(tree_rmap_item); -+ } -+put_up_out: -+ put_page(tree_rmap_item->page); -+ up_read(&tree_rmap_item->slot->vma->vm_mm->mmap_sem); -+ } -+} -+ -+ -+ -+ -+static inline unsigned long get_pool_index(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = (sizeof(struct rmap_list_entry *) * index) >> PAGE_SHIFT; -+ if (pool_index >= slot->pool_size) -+ BUG(); -+ return pool_index; -+} -+ -+static inline unsigned long index_page_offset(unsigned long index) -+{ -+ return offset_in_page(sizeof(struct rmap_list_entry *) * index); -+} -+ -+static inline -+struct rmap_list_entry *get_rmap_list_entry(struct vma_slot *slot, -+ unsigned long index, int need_alloc) -+{ -+ unsigned long pool_index; -+ struct page *page; -+ void *addr; -+ -+ -+ pool_index = get_pool_index(slot, index); -+ if (!slot->rmap_list_pool[pool_index]) { -+ if (!need_alloc) -+ return NULL; -+ -+ page = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN); -+ if (!page) -+ return NULL; -+ -+ slot->rmap_list_pool[pool_index] = page; -+ } -+ -+ addr = kmap(slot->rmap_list_pool[pool_index]); -+ addr += index_page_offset(index); -+ -+ return addr; -+} -+ -+static inline void put_rmap_list_entry(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = get_pool_index(slot, index); -+ BUG_ON(!slot->rmap_list_pool[pool_index]); -+ kunmap(slot->rmap_list_pool[pool_index]); -+} -+ -+static inline int entry_is_new(struct rmap_list_entry *entry) -+{ -+ return !entry->item; -+} -+ -+static inline unsigned long get_index_orig_addr(struct vma_slot *slot, -+ unsigned long index) -+{ -+ return slot->vma->vm_start + (index << PAGE_SHIFT); -+} -+ -+static inline unsigned long get_entry_address(struct rmap_list_entry *entry) -+{ -+ unsigned long addr; -+ -+ if (is_addr(entry->addr)) -+ addr = get_clean_addr(entry->addr); -+ else if (entry->item) -+ addr = get_rmap_addr(entry->item); -+ else -+ BUG(); -+ -+ return addr; -+} -+ -+static inline struct rmap_item *get_entry_item(struct rmap_list_entry *entry) -+{ -+ if (is_addr(entry->addr)) -+ return NULL; -+ -+ return entry->item; -+} -+ -+static inline void inc_rmap_list_pool_count(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = get_pool_index(slot, index); -+ BUG_ON(!slot->rmap_list_pool[pool_index]); -+ slot->pool_counts[pool_index]++; -+} -+ -+static inline void dec_rmap_list_pool_count(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = get_pool_index(slot, index); -+ BUG_ON(!slot->rmap_list_pool[pool_index]); -+ BUG_ON(!slot->pool_counts[pool_index]); -+ slot->pool_counts[pool_index]--; -+} -+ -+static inline int entry_has_rmap(struct rmap_list_entry *entry) -+{ -+ return !is_addr(entry->addr) && entry->item; -+} -+ -+static inline void swap_entries(struct rmap_list_entry *entry1, -+ unsigned long index1, -+ struct rmap_list_entry *entry2, -+ unsigned long index2) -+{ -+ struct rmap_list_entry tmp; -+ -+ /* swapping two new entries is meaningless */ -+ BUG_ON(entry_is_new(entry1) && entry_is_new(entry2)); -+ -+ tmp = *entry1; -+ *entry1 = *entry2; -+ *entry2 = tmp; -+ -+ if (entry_has_rmap(entry1)) -+ entry1->item->entry_index = index1; -+ -+ if (entry_has_rmap(entry2)) -+ entry2->item->entry_index = index2; -+ -+ if (entry_has_rmap(entry1) && !entry_has_rmap(entry2)) { -+ inc_rmap_list_pool_count(entry1->item->slot, index1); -+ dec_rmap_list_pool_count(entry1->item->slot, index2); -+ } else if (!entry_has_rmap(entry1) && entry_has_rmap(entry2)) { -+ inc_rmap_list_pool_count(entry2->item->slot, index2); -+ dec_rmap_list_pool_count(entry2->item->slot, index1); -+ } -+} -+ -+static inline void free_entry_item(struct rmap_list_entry *entry) -+{ -+ unsigned long index; -+ struct rmap_item *item; -+ -+ if (!is_addr(entry->addr)) { -+ BUG_ON(!entry->item); -+ item = entry->item; -+ entry->addr = get_rmap_addr(item); -+ set_is_addr(entry->addr); -+ index = item->entry_index; -+ remove_rmap_item_from_tree(item); -+ dec_rmap_list_pool_count(item->slot, index); -+ free_rmap_item(item); -+ } -+} -+ -+static inline int pool_entry_boundary(unsigned long index) -+{ -+ unsigned long linear_addr; -+ -+ linear_addr = sizeof(struct rmap_list_entry *) * index; -+ return index && !offset_in_page(linear_addr); -+} -+ -+static inline void try_free_last_pool(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = get_pool_index(slot, index); -+ if (slot->rmap_list_pool[pool_index] && -+ !slot->pool_counts[pool_index]) { -+ __free_page(slot->rmap_list_pool[pool_index]); -+ slot->rmap_list_pool[pool_index] = NULL; -+ slot->flags |= UKSM_SLOT_NEED_SORT; -+ } -+ -+} -+ -+static inline unsigned long vma_item_index(struct vm_area_struct *vma, -+ struct rmap_item *item) -+{ -+ return (get_rmap_addr(item) - vma->vm_start) >> PAGE_SHIFT; -+} -+ -+static int within_same_pool(struct vma_slot *slot, -+ unsigned long i, unsigned long j) -+{ -+ unsigned long pool_i, pool_j; -+ -+ pool_i = get_pool_index(slot, i); -+ pool_j = get_pool_index(slot, j); -+ -+ return (pool_i == pool_j); -+} -+ -+static void sort_rmap_entry_list(struct vma_slot *slot) -+{ -+ unsigned long i, j; -+ struct rmap_list_entry *entry, *swap_entry; -+ -+ entry = get_rmap_list_entry(slot, 0, 0); -+ for (i = 0; i < slot->pages; ) { -+ -+ if (!entry) -+ goto skip_whole_pool; -+ -+ if (entry_is_new(entry)) -+ goto next_entry; -+ -+ if (is_addr(entry->addr)) { -+ entry->addr = 0; -+ goto next_entry; -+ } -+ -+ j = vma_item_index(slot->vma, entry->item); -+ if (j == i) -+ goto next_entry; -+ -+ if (within_same_pool(slot, i, j)) -+ swap_entry = entry + j - i; -+ else -+ swap_entry = get_rmap_list_entry(slot, j, 1); -+ -+ swap_entries(entry, i, swap_entry, j); -+ if (!within_same_pool(slot, i, j)) -+ put_rmap_list_entry(slot, j); -+ continue; -+ -+skip_whole_pool: -+ i += PAGE_SIZE / sizeof(*entry); -+ if (i < slot->pages) -+ entry = get_rmap_list_entry(slot, i, 0); -+ continue; -+ -+next_entry: -+ if (i >= slot->pages - 1 || -+ !within_same_pool(slot, i, i + 1)) { -+ put_rmap_list_entry(slot, i); -+ if (i + 1 < slot->pages) -+ entry = get_rmap_list_entry(slot, i + 1, 0); -+ } else -+ entry++; -+ i++; -+ continue; -+ } -+ -+ /* free empty pool entries which contain no rmap_item */ -+ /* CAN be simplied to based on only pool_counts when bug freed !!!!! */ -+ for (i = 0; i < slot->pool_size; i++) { -+ unsigned char has_rmap; -+ void *addr; -+ -+ if (!slot->rmap_list_pool[i]) -+ continue; -+ -+ has_rmap = 0; -+ addr = kmap(slot->rmap_list_pool[i]); -+ BUG_ON(!addr); -+ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { -+ entry = (struct rmap_list_entry *)addr + j; -+ if (is_addr(entry->addr)) -+ continue; -+ if (!entry->item) -+ continue; -+ has_rmap = 1; -+ } -+ kunmap(slot->rmap_list_pool[i]); -+ if (!has_rmap) { -+ BUG_ON(slot->pool_counts[i]); -+ __free_page(slot->rmap_list_pool[i]); -+ slot->rmap_list_pool[i] = NULL; -+ } -+ } -+ -+ slot->flags &= ~UKSM_SLOT_NEED_SORT; -+} -+ -+/* -+ * vma_fully_scanned() - if all the pages in this slot have been scanned. -+ */ -+static inline int vma_fully_scanned(struct vma_slot *slot) -+{ -+ return slot->pages_scanned == slot->pages; -+} -+ -+/** -+ * get_next_rmap_item() - Get the next rmap_item in a vma_slot according to -+ * its random permutation. This function is embedded with the random -+ * permutation index management code. -+ */ -+static struct rmap_item *get_next_rmap_item(struct vma_slot *slot, u32 *hash) -+{ -+ unsigned long rand_range, addr, swap_index, scan_index; -+ struct rmap_item *item = NULL; -+ struct rmap_list_entry *scan_entry, *swap_entry = NULL; -+ struct page *page; -+ -+ scan_index = swap_index = slot->pages_scanned % slot->pages; -+ -+ if (pool_entry_boundary(scan_index)) -+ try_free_last_pool(slot, scan_index - 1); -+ -+ if (vma_fully_scanned(slot)) { -+ if (slot->flags & UKSM_SLOT_NEED_SORT) -+ slot->flags |= UKSM_SLOT_NEED_RERAND; -+ else -+ slot->flags &= ~UKSM_SLOT_NEED_RERAND; -+ if (slot->flags & UKSM_SLOT_NEED_SORT) -+ sort_rmap_entry_list(slot); -+ } -+ -+ scan_entry = get_rmap_list_entry(slot, scan_index, 1); -+ if (!scan_entry) -+ return NULL; -+ -+ if (entry_is_new(scan_entry)) { -+ scan_entry->addr = get_index_orig_addr(slot, scan_index); -+ set_is_addr(scan_entry->addr); -+ } -+ -+ if (slot->flags & UKSM_SLOT_NEED_RERAND) { -+ rand_range = slot->pages - scan_index; -+ BUG_ON(!rand_range); -+ swap_index = scan_index + (prandom_u32() % rand_range); -+ } -+ -+ if (swap_index != scan_index) { -+ swap_entry = get_rmap_list_entry(slot, swap_index, 1); -+ if (entry_is_new(swap_entry)) { -+ swap_entry->addr = get_index_orig_addr(slot, -+ swap_index); -+ set_is_addr(swap_entry->addr); -+ } -+ swap_entries(scan_entry, scan_index, swap_entry, swap_index); -+ } -+ -+ addr = get_entry_address(scan_entry); -+ item = get_entry_item(scan_entry); -+ BUG_ON(addr > slot->vma->vm_end || addr < slot->vma->vm_start); -+ -+ page = follow_page(slot->vma, addr, FOLL_GET); -+ if (IS_ERR_OR_NULL(page)) -+ goto nopage; -+ -+ if (!PageAnon(page)) -+ goto putpage; -+ -+ /*check is zero_page pfn or uksm_zero_page*/ -+ if ((page_to_pfn(page) == zero_pfn) -+ || (page_to_pfn(page) == uksm_zero_pfn)) -+ goto putpage; -+ -+ flush_anon_page(slot->vma, page, addr); -+ flush_dcache_page(page); -+ -+ -+ *hash = page_hash(page, hash_strength, 1); -+ inc_uksm_pages_scanned(); -+ /*if the page content all zero, re-map to zero-page*/ -+ if (find_zero_page_hash(hash_strength, *hash)) { -+ if (!cmp_and_merge_zero_page(slot->vma, page)) { -+ slot->pages_merged++; -+ -+ /* For full-zero pages, no need to create rmap item */ -+ goto putpage; -+ } else { -+ inc_rshash_neg(memcmp_cost / 2); -+ } -+ } -+ -+ if (!item) { -+ item = alloc_rmap_item(); -+ if (item) { -+ /* It has already been zeroed */ -+ item->slot = slot; -+ item->address = addr; -+ item->entry_index = scan_index; -+ scan_entry->item = item; -+ inc_rmap_list_pool_count(slot, scan_index); -+ } else -+ goto putpage; -+ } -+ -+ BUG_ON(item->slot != slot); -+ /* the page may have changed */ -+ item->page = page; -+ put_rmap_list_entry(slot, scan_index); -+ if (swap_entry) -+ put_rmap_list_entry(slot, swap_index); -+ return item; -+ -+putpage: -+ put_page(page); -+ page = NULL; -+nopage: -+ /* no page, store addr back and free rmap_item if possible */ -+ free_entry_item(scan_entry); -+ put_rmap_list_entry(slot, scan_index); -+ if (swap_entry) -+ put_rmap_list_entry(slot, swap_index); -+ return NULL; -+} -+ -+static inline int in_stable_tree(struct rmap_item *rmap_item) -+{ -+ return rmap_item->address & STABLE_FLAG; -+} -+ -+/** -+ * scan_vma_one_page() - scan the next page in a vma_slot. Called with -+ * mmap_sem locked. -+ */ -+static noinline void scan_vma_one_page(struct vma_slot *slot) -+{ -+ u32 hash; -+ struct mm_struct *mm; -+ struct rmap_item *rmap_item = NULL; -+ struct vm_area_struct *vma = slot->vma; -+ -+ mm = vma->vm_mm; -+ BUG_ON(!mm); -+ BUG_ON(!slot); -+ -+ rmap_item = get_next_rmap_item(slot, &hash); -+ if (!rmap_item) -+ goto out1; -+ -+ if (PageKsm(rmap_item->page) && in_stable_tree(rmap_item)) -+ goto out2; -+ -+ cmp_and_merge_page(rmap_item, hash); -+out2: -+ put_page(rmap_item->page); -+out1: -+ slot->pages_scanned++; -+ slot->this_sampled++; -+ if (slot->fully_scanned_round != fully_scanned_round) -+ scanned_virtual_pages++; -+ -+ if (vma_fully_scanned(slot)) -+ slot->fully_scanned_round = fully_scanned_round; -+} -+ -+static inline unsigned long rung_get_pages(struct scan_rung *rung) -+{ -+ struct slot_tree_node *node; -+ -+ if (!rung->vma_root.rnode) -+ return 0; -+ -+ node = container_of(rung->vma_root.rnode, struct slot_tree_node, snode); -+ -+ return node->size; -+} -+ -+#define RUNG_SAMPLED_MIN 3 -+ -+static inline -+void uksm_calc_rung_step(struct scan_rung *rung, -+ unsigned long page_time, unsigned long ratio) -+{ -+ unsigned long sampled, pages; -+ -+ /* will be fully scanned ? */ -+ if (!rung->cover_msecs) { -+ rung->step = 1; -+ return; -+ } -+ -+ sampled = rung->cover_msecs * (NSEC_PER_MSEC / TIME_RATIO_SCALE) -+ * ratio / page_time; -+ -+ /* -+ * Before we finsish a scan round and expensive per-round jobs, -+ * we need to have a chance to estimate the per page time. So -+ * the sampled number can not be too small. -+ */ -+ if (sampled < RUNG_SAMPLED_MIN) -+ sampled = RUNG_SAMPLED_MIN; -+ -+ pages = rung_get_pages(rung); -+ if (likely(pages > sampled)) -+ rung->step = pages / sampled; -+ else -+ rung->step = 1; -+} -+ -+static inline int step_need_recalc(struct scan_rung *rung) -+{ -+ unsigned long pages, stepmax; -+ -+ pages = rung_get_pages(rung); -+ stepmax = pages / RUNG_SAMPLED_MIN; -+ -+ return pages && (rung->step > pages || -+ (stepmax && rung->step > stepmax)); -+} -+ -+static inline -+void reset_current_scan(struct scan_rung *rung, int finished, int step_recalc) -+{ -+ struct vma_slot *slot; -+ -+ if (finished) -+ rung->flags |= UKSM_RUNG_ROUND_FINISHED; -+ -+ if (step_recalc || step_need_recalc(rung)) { -+ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); -+ BUG_ON(step_need_recalc(rung)); -+ } -+ -+ slot_iter_index = prandom_u32() % rung->step; -+ BUG_ON(!rung->vma_root.rnode); -+ slot = sradix_tree_next(&rung->vma_root, NULL, 0, slot_iter); -+ BUG_ON(!slot); -+ -+ rung->current_scan = slot; -+ rung->current_offset = slot_iter_index; -+} -+ -+static inline struct sradix_tree_root *slot_get_root(struct vma_slot *slot) -+{ -+ return &slot->rung->vma_root; -+} -+ -+/* -+ * return if resetted. -+ */ -+static int advance_current_scan(struct scan_rung *rung) -+{ -+ unsigned short n; -+ struct vma_slot *slot, *next = NULL; -+ -+ BUG_ON(!rung->vma_root.num); -+ -+ slot = rung->current_scan; -+ n = (slot->pages - rung->current_offset) % rung->step; -+ slot_iter_index = rung->step - n; -+ next = sradix_tree_next(&rung->vma_root, slot->snode, -+ slot->sindex, slot_iter); -+ -+ if (next) { -+ rung->current_offset = slot_iter_index; -+ rung->current_scan = next; -+ return 0; -+ } else { -+ reset_current_scan(rung, 1, 0); -+ return 1; -+ } -+} -+ -+static inline void rung_rm_slot(struct vma_slot *slot) -+{ -+ struct scan_rung *rung = slot->rung; -+ struct sradix_tree_root *root; -+ -+ if (rung->current_scan == slot) -+ advance_current_scan(rung); -+ -+ root = slot_get_root(slot); -+ sradix_tree_delete_from_leaf(root, slot->snode, slot->sindex); -+ slot->snode = NULL; -+ if (step_need_recalc(rung)) { -+ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); -+ BUG_ON(step_need_recalc(rung)); -+ } -+ -+ /* In case advance_current_scan loop back to this slot again */ -+ if (rung->vma_root.num && rung->current_scan == slot) -+ reset_current_scan(slot->rung, 1, 0); -+} -+ -+static inline void rung_add_new_slots(struct scan_rung *rung, -+ struct vma_slot **slots, unsigned long num) -+{ -+ int err; -+ struct vma_slot *slot; -+ unsigned long i; -+ struct sradix_tree_root *root = &rung->vma_root; -+ -+ err = sradix_tree_enter(root, (void **)slots, num); -+ BUG_ON(err); -+ -+ for (i = 0; i < num; i++) { -+ slot = slots[i]; -+ slot->rung = rung; -+ BUG_ON(vma_fully_scanned(slot)); -+ } -+ -+ if (rung->vma_root.num == num) -+ reset_current_scan(rung, 0, 1); -+} -+ -+static inline int rung_add_one_slot(struct scan_rung *rung, -+ struct vma_slot *slot) -+{ -+ int err; -+ -+ err = sradix_tree_enter(&rung->vma_root, (void **)&slot, 1); -+ if (err) -+ return err; -+ -+ slot->rung = rung; -+ if (rung->vma_root.num == 1) -+ reset_current_scan(rung, 0, 1); -+ -+ return 0; -+} -+ -+/* -+ * Return true if the slot is deleted from its rung. -+ */ -+static inline int vma_rung_enter(struct vma_slot *slot, struct scan_rung *rung) -+{ -+ struct scan_rung *old_rung = slot->rung; -+ int err; -+ -+ if (old_rung == rung) -+ return 0; -+ -+ rung_rm_slot(slot); -+ err = rung_add_one_slot(rung, slot); -+ if (err) { -+ err = rung_add_one_slot(old_rung, slot); -+ WARN_ON(err); /* OOPS, badly OOM, we lost this slot */ -+ } -+ -+ return 1; -+} -+ -+static inline int vma_rung_up(struct vma_slot *slot) -+{ -+ struct scan_rung *rung; -+ -+ rung = slot->rung; -+ if (slot->rung != &uksm_scan_ladder[SCAN_LADDER_SIZE-1]) -+ rung++; -+ -+ return vma_rung_enter(slot, rung); -+} -+ -+static inline int vma_rung_down(struct vma_slot *slot) -+{ -+ struct scan_rung *rung; -+ -+ rung = slot->rung; -+ if (slot->rung != &uksm_scan_ladder[0]) -+ rung--; -+ -+ return vma_rung_enter(slot, rung); -+} -+ -+/** -+ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. -+ */ -+static unsigned long cal_dedup_ratio(struct vma_slot *slot) -+{ -+ unsigned long ret; -+ unsigned long pages; -+ -+ pages = slot->this_sampled; -+ if (!pages) -+ return 0; -+ -+ BUG_ON(slot->pages_scanned == slot->last_scanned); -+ -+ ret = slot->pages_merged; -+ -+ /* Thrashing area filtering */ -+ if (ret && uksm_thrash_threshold) { -+ if (slot->pages_cowed * 100 / slot->pages_merged -+ > uksm_thrash_threshold) { -+ ret = 0; -+ } else { -+ ret = slot->pages_merged - slot->pages_cowed; -+ } -+ } -+ -+ return ret * 100 / pages; -+} -+ -+/** -+ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. -+ */ -+static unsigned long cal_dedup_ratio_old(struct vma_slot *slot) -+{ -+ unsigned long ret; -+ unsigned long pages; -+ -+ pages = slot->pages; -+ if (!pages) -+ return 0; -+ -+ ret = slot->pages_bemerged; -+ -+ /* Thrashing area filtering */ -+ if (ret && uksm_thrash_threshold) { -+ if (slot->pages_cowed * 100 / slot->pages_bemerged -+ > uksm_thrash_threshold) { -+ ret = 0; -+ } else { -+ ret = slot->pages_bemerged - slot->pages_cowed; -+ } -+ } -+ -+ return ret * 100 / pages; -+} -+ -+/** -+ * stable_node_reinsert() - When the hash_strength has been adjusted, the -+ * stable tree need to be restructured, this is the function re-inserting the -+ * stable node. -+ */ -+static inline void stable_node_reinsert(struct stable_node *new_node, -+ struct page *page, -+ struct rb_root *root_treep, -+ struct list_head *tree_node_listp, -+ u32 hash) -+{ -+ struct rb_node **new = &root_treep->rb_node; -+ struct rb_node *parent = NULL; -+ struct stable_node *stable_node; -+ struct tree_node *tree_node; -+ struct page *tree_page; -+ int cmp; -+ -+ while (*new) { -+ int cmp; -+ -+ tree_node = rb_entry(*new, struct tree_node, node); -+ -+ cmp = hash_cmp(hash, tree_node->hash); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else -+ break; -+ } -+ -+ if (*new) { -+ /* find a stable tree node with same first level hash value */ -+ stable_node_hash_max(new_node, page, hash); -+ if (tree_node->count == 1) { -+ stable_node = rb_entry(tree_node->sub_root.rb_node, -+ struct stable_node, node); -+ tree_page = get_uksm_page(stable_node, 1, 0); -+ if (tree_page) { -+ stable_node_hash_max(stable_node, -+ tree_page, hash); -+ put_page(tree_page); -+ -+ /* prepare for stable node insertion */ -+ -+ cmp = hash_cmp(new_node->hash_max, -+ stable_node->hash_max); -+ parent = &stable_node->node; -+ if (cmp < 0) -+ new = &parent->rb_left; -+ else if (cmp > 0) -+ new = &parent->rb_right; -+ else -+ goto failed; -+ -+ goto add_node; -+ } else { -+ /* the only stable_node deleted, the tree node -+ * was not deleted. -+ */ -+ goto tree_node_reuse; -+ } -+ } -+ -+ /* well, search the collision subtree */ -+ new = &tree_node->sub_root.rb_node; -+ parent = NULL; -+ BUG_ON(!*new); -+ while (*new) { -+ int cmp; -+ -+ stable_node = rb_entry(*new, struct stable_node, node); -+ -+ cmp = hash_cmp(new_node->hash_max, -+ stable_node->hash_max); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else { -+ /* oh, no, still a collision */ -+ goto failed; -+ } -+ } -+ -+ goto add_node; -+ } -+ -+ /* no tree node found */ -+ tree_node = alloc_tree_node(tree_node_listp); -+ if (!tree_node) { -+ pr_err("UKSM: memory allocation error!\n"); -+ goto failed; -+ } else { -+ tree_node->hash = hash; -+ rb_link_node(&tree_node->node, parent, new); -+ rb_insert_color(&tree_node->node, root_treep); -+ -+tree_node_reuse: -+ /* prepare for stable node insertion */ -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ } -+ -+add_node: -+ rb_link_node(&new_node->node, parent, new); -+ rb_insert_color(&new_node->node, &tree_node->sub_root); -+ new_node->tree_node = tree_node; -+ tree_node->count++; -+ return; -+ -+failed: -+ /* This can only happen when two nodes have collided -+ * in two levels. -+ */ -+ new_node->tree_node = NULL; -+ return; -+} -+ -+static inline void free_all_tree_nodes(struct list_head *list) -+{ -+ struct tree_node *node, *tmp; -+ -+ list_for_each_entry_safe(node, tmp, list, all_list) { -+ free_tree_node(node); -+ } -+} -+ -+/** -+ * stable_tree_delta_hash() - Delta hash the stable tree from previous hash -+ * strength to the current hash_strength. It re-structures the hole tree. -+ */ -+static inline void stable_tree_delta_hash(u32 prev_hash_strength) -+{ -+ struct stable_node *node, *tmp; -+ struct rb_root *root_new_treep; -+ struct list_head *new_tree_node_listp; -+ -+ stable_tree_index = (stable_tree_index + 1) % 2; -+ root_new_treep = &root_stable_tree[stable_tree_index]; -+ new_tree_node_listp = &stable_tree_node_list[stable_tree_index]; -+ *root_new_treep = RB_ROOT; -+ BUG_ON(!list_empty(new_tree_node_listp)); -+ -+ /* -+ * we need to be safe, the node could be removed by get_uksm_page() -+ */ -+ list_for_each_entry_safe(node, tmp, &stable_node_list, all_list) { -+ void *addr; -+ struct page *node_page; -+ u32 hash; -+ -+ /* -+ * We are completely re-structuring the stable nodes to a new -+ * stable tree. We don't want to touch the old tree unlinks and -+ * old tree_nodes. The old tree_nodes will be freed at once. -+ */ -+ node_page = get_uksm_page(node, 0, 0); -+ if (!node_page) -+ continue; -+ -+ if (node->tree_node) { -+ hash = node->tree_node->hash; -+ -+ addr = kmap_atomic(node_page); -+ -+ hash = delta_hash(addr, prev_hash_strength, -+ hash_strength, hash); -+ kunmap_atomic(addr); -+ } else { -+ /* -+ *it was not inserted to rbtree due to collision in last -+ *round scan. -+ */ -+ hash = page_hash(node_page, hash_strength, 0); -+ } -+ -+ stable_node_reinsert(node, node_page, root_new_treep, -+ new_tree_node_listp, hash); -+ put_page(node_page); -+ } -+ -+ root_stable_treep = root_new_treep; -+ free_all_tree_nodes(stable_tree_node_listp); -+ BUG_ON(!list_empty(stable_tree_node_listp)); -+ stable_tree_node_listp = new_tree_node_listp; -+} -+ -+static inline void inc_hash_strength(unsigned long delta) -+{ -+ hash_strength += 1 << delta; -+ if (hash_strength > HASH_STRENGTH_MAX) -+ hash_strength = HASH_STRENGTH_MAX; -+} -+ -+static inline void dec_hash_strength(unsigned long delta) -+{ -+ unsigned long change = 1 << delta; -+ -+ if (hash_strength <= change + 1) -+ hash_strength = 1; -+ else -+ hash_strength -= change; -+} -+ -+static inline void inc_hash_strength_delta(void) -+{ -+ hash_strength_delta++; -+ if (hash_strength_delta > HASH_STRENGTH_DELTA_MAX) -+ hash_strength_delta = HASH_STRENGTH_DELTA_MAX; -+} -+ -+static inline unsigned long get_current_neg_ratio(void) -+{ -+ u64 pos = benefit.pos; -+ u64 neg = benefit.neg; -+ -+ if (!neg) -+ return 0; -+ -+ if (!pos || neg > pos) -+ return 100; -+ -+ if (neg > div64_u64(U64_MAX, 100)) -+ pos = div64_u64(pos, 100); -+ else -+ neg *= 100; -+ -+ return div64_u64(neg, pos); -+} -+ -+static inline unsigned long get_current_benefit(void) -+{ -+ u64 pos = benefit.pos; -+ u64 neg = benefit.neg; -+ u64 scanned = benefit.scanned; -+ -+ if (neg > pos) -+ return 0; -+ -+ return div64_u64((pos - neg), scanned); -+} -+ -+static inline int judge_rshash_direction(void) -+{ -+ u64 current_neg_ratio, stable_benefit; -+ u64 current_benefit, delta = 0; -+ int ret = STILL; -+ -+ /* -+ * Try to probe a value after the boot, and in case the system -+ * are still for a long time. -+ */ -+ if ((fully_scanned_round & 0xFFULL) == 10) { -+ ret = OBSCURE; -+ goto out; -+ } -+ -+ current_neg_ratio = get_current_neg_ratio(); -+ -+ if (current_neg_ratio == 0) { -+ rshash_neg_cont_zero++; -+ if (rshash_neg_cont_zero > 2) -+ return GO_DOWN; -+ else -+ return STILL; -+ } -+ rshash_neg_cont_zero = 0; -+ -+ if (current_neg_ratio > 90) { -+ ret = GO_UP; -+ goto out; -+ } -+ -+ current_benefit = get_current_benefit(); -+ stable_benefit = rshash_state.stable_benefit; -+ -+ if (!stable_benefit) { -+ ret = OBSCURE; -+ goto out; -+ } -+ -+ if (current_benefit > stable_benefit) -+ delta = current_benefit - stable_benefit; -+ else if (current_benefit < stable_benefit) -+ delta = stable_benefit - current_benefit; -+ -+ delta = div64_u64(100 * delta, stable_benefit); -+ -+ if (delta > 50) { -+ rshash_cont_obscure++; -+ if (rshash_cont_obscure > 2) -+ return OBSCURE; -+ else -+ return STILL; -+ } -+ -+out: -+ rshash_cont_obscure = 0; -+ return ret; -+} -+ -+/** -+ * rshash_adjust() - The main function to control the random sampling state -+ * machine for hash strength adapting. -+ * -+ * return true if hash_strength has changed. -+ */ -+static inline int rshash_adjust(void) -+{ -+ unsigned long prev_hash_strength = hash_strength; -+ -+ if (!encode_benefit()) -+ return 0; -+ -+ switch (rshash_state.state) { -+ case RSHASH_STILL: -+ switch (judge_rshash_direction()) { -+ case GO_UP: -+ if (rshash_state.pre_direct == GO_DOWN) -+ hash_strength_delta = 0; -+ -+ inc_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ rshash_state.stable_benefit = get_current_benefit(); -+ rshash_state.pre_direct = GO_UP; -+ break; -+ -+ case GO_DOWN: -+ if (rshash_state.pre_direct == GO_UP) -+ hash_strength_delta = 0; -+ -+ dec_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ rshash_state.stable_benefit = get_current_benefit(); -+ rshash_state.pre_direct = GO_DOWN; -+ break; -+ -+ case OBSCURE: -+ rshash_state.stable_point = hash_strength; -+ rshash_state.turn_point_down = hash_strength; -+ rshash_state.turn_point_up = hash_strength; -+ rshash_state.turn_benefit_down = get_current_benefit(); -+ rshash_state.turn_benefit_up = get_current_benefit(); -+ rshash_state.lookup_window_index = 0; -+ rshash_state.state = RSHASH_TRYDOWN; -+ dec_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ break; -+ -+ case STILL: -+ break; -+ default: -+ BUG(); -+ } -+ break; -+ -+ case RSHASH_TRYDOWN: -+ if (rshash_state.lookup_window_index++ % 5 == 0) -+ rshash_state.below_count = 0; -+ -+ if (get_current_benefit() < rshash_state.stable_benefit) -+ rshash_state.below_count++; -+ else if (get_current_benefit() > -+ rshash_state.turn_benefit_down) { -+ rshash_state.turn_point_down = hash_strength; -+ rshash_state.turn_benefit_down = get_current_benefit(); -+ } -+ -+ if (rshash_state.below_count >= 3 || -+ judge_rshash_direction() == GO_UP || -+ hash_strength == 1) { -+ hash_strength = rshash_state.stable_point; -+ hash_strength_delta = 0; -+ inc_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ rshash_state.lookup_window_index = 0; -+ rshash_state.state = RSHASH_TRYUP; -+ hash_strength_delta = 0; -+ } else { -+ dec_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ } -+ break; -+ -+ case RSHASH_TRYUP: -+ if (rshash_state.lookup_window_index++ % 5 == 0) -+ rshash_state.below_count = 0; -+ -+ if (get_current_benefit() < rshash_state.turn_benefit_down) -+ rshash_state.below_count++; -+ else if (get_current_benefit() > rshash_state.turn_benefit_up) { -+ rshash_state.turn_point_up = hash_strength; -+ rshash_state.turn_benefit_up = get_current_benefit(); -+ } -+ -+ if (rshash_state.below_count >= 3 || -+ judge_rshash_direction() == GO_DOWN || -+ hash_strength == HASH_STRENGTH_MAX) { -+ hash_strength = rshash_state.turn_benefit_up > -+ rshash_state.turn_benefit_down ? -+ rshash_state.turn_point_up : -+ rshash_state.turn_point_down; -+ -+ rshash_state.state = RSHASH_PRE_STILL; -+ } else { -+ inc_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ } -+ -+ break; -+ -+ case RSHASH_NEW: -+ case RSHASH_PRE_STILL: -+ rshash_state.stable_benefit = get_current_benefit(); -+ rshash_state.state = RSHASH_STILL; -+ hash_strength_delta = 0; -+ break; -+ default: -+ BUG(); -+ } -+ -+ /* rshash_neg = rshash_pos = 0; */ -+ reset_benefit(); -+ -+ if (prev_hash_strength != hash_strength) -+ stable_tree_delta_hash(prev_hash_strength); -+ -+ return prev_hash_strength != hash_strength; -+} -+ -+/** -+ * round_update_ladder() - The main function to do update of all the -+ * adjustments whenever a scan round is finished. -+ */ -+static noinline void round_update_ladder(void) -+{ -+ int i; -+ unsigned long dedup; -+ struct vma_slot *slot, *tmp_slot; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) -+ uksm_scan_ladder[i].flags &= ~UKSM_RUNG_ROUND_FINISHED; -+ -+ list_for_each_entry_safe(slot, tmp_slot, &vma_slot_dedup, dedup_list) { -+ -+ /* slot may be rung_rm_slot() when mm exits */ -+ if (slot->snode) { -+ dedup = cal_dedup_ratio_old(slot); -+ if (dedup && dedup >= uksm_abundant_threshold) -+ vma_rung_up(slot); -+ } -+ -+ slot->pages_bemerged = 0; -+ slot->pages_cowed = 0; -+ -+ list_del_init(&slot->dedup_list); -+ } -+} -+ -+static void uksm_del_vma_slot(struct vma_slot *slot) -+{ -+ int i, j; -+ struct rmap_list_entry *entry; -+ -+ if (slot->snode) { -+ /* -+ * In case it just failed when entering the rung, it's not -+ * necessary. -+ */ -+ rung_rm_slot(slot); -+ } -+ -+ if (!list_empty(&slot->dedup_list)) -+ list_del(&slot->dedup_list); -+ -+ if (!slot->rmap_list_pool || !slot->pool_counts) { -+ /* In case it OOMed in uksm_vma_enter() */ -+ goto out; -+ } -+ -+ for (i = 0; i < slot->pool_size; i++) { -+ void *addr; -+ -+ if (!slot->rmap_list_pool[i]) -+ continue; -+ -+ addr = kmap(slot->rmap_list_pool[i]); -+ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { -+ entry = (struct rmap_list_entry *)addr + j; -+ if (is_addr(entry->addr)) -+ continue; -+ if (!entry->item) -+ continue; -+ -+ remove_rmap_item_from_tree(entry->item); -+ free_rmap_item(entry->item); -+ slot->pool_counts[i]--; -+ } -+ BUG_ON(slot->pool_counts[i]); -+ kunmap(slot->rmap_list_pool[i]); -+ __free_page(slot->rmap_list_pool[i]); -+ } -+ kfree(slot->rmap_list_pool); -+ kfree(slot->pool_counts); -+ -+out: -+ slot->rung = NULL; -+ if (slot->flags & UKSM_SLOT_IN_UKSM) { -+ BUG_ON(uksm_pages_total < slot->pages); -+ uksm_pages_total -= slot->pages; -+ } -+ -+ if (slot->fully_scanned_round == fully_scanned_round) -+ scanned_virtual_pages -= slot->pages; -+ else -+ scanned_virtual_pages -= slot->pages_scanned; -+ free_vma_slot(slot); -+} -+ -+ -+#define SPIN_LOCK_PERIOD 32 -+static struct vma_slot *cleanup_slots[SPIN_LOCK_PERIOD]; -+static inline void cleanup_vma_slots(void) -+{ -+ struct vma_slot *slot; -+ int i; -+ -+ i = 0; -+ spin_lock(&vma_slot_list_lock); -+ while (!list_empty(&vma_slot_del)) { -+ slot = list_entry(vma_slot_del.next, -+ struct vma_slot, slot_list); -+ list_del(&slot->slot_list); -+ cleanup_slots[i++] = slot; -+ if (i == SPIN_LOCK_PERIOD) { -+ spin_unlock(&vma_slot_list_lock); -+ while (--i >= 0) -+ uksm_del_vma_slot(cleanup_slots[i]); -+ i = 0; -+ spin_lock(&vma_slot_list_lock); -+ } -+ } -+ spin_unlock(&vma_slot_list_lock); -+ -+ while (--i >= 0) -+ uksm_del_vma_slot(cleanup_slots[i]); -+} -+ -+/* -+ * Expotional moving average formula -+ */ -+static inline unsigned long ema(unsigned long curr, unsigned long last_ema) -+{ -+ /* -+ * For a very high burst, even the ema cannot work well, a false very -+ * high per-page time estimation can result in feedback in very high -+ * overhead of context switch and rung update -- this will then lead -+ * to higher per-paper time, this may not converge. -+ * -+ * Instead, we try to approach this value in a binary manner. -+ */ -+ if (curr > last_ema * 10) -+ return last_ema * 2; -+ -+ return (EMA_ALPHA * curr + (100 - EMA_ALPHA) * last_ema) / 100; -+} -+ -+/* -+ * convert cpu ratio in 1/TIME_RATIO_SCALE configured by user to -+ * nanoseconds based on current uksm_sleep_jiffies. -+ */ -+static inline unsigned long cpu_ratio_to_nsec(unsigned int ratio) -+{ -+ return NSEC_PER_USEC * jiffies_to_usecs(uksm_sleep_jiffies) / -+ (TIME_RATIO_SCALE - ratio) * ratio; -+} -+ -+ -+static inline unsigned long rung_real_ratio(int cpu_time_ratio) -+{ -+ unsigned long ret; -+ -+ BUG_ON(!cpu_time_ratio); -+ -+ if (cpu_time_ratio > 0) -+ ret = cpu_time_ratio; -+ else -+ ret = (unsigned long)(-cpu_time_ratio) * -+ uksm_max_cpu_percentage / 100UL; -+ -+ return ret ? ret : 1; -+} -+ -+static noinline void uksm_calc_scan_pages(void) -+{ -+ struct scan_rung *ladder = uksm_scan_ladder; -+ unsigned long sleep_usecs, nsecs; -+ unsigned long ratio; -+ int i; -+ unsigned long per_page; -+ -+ if (uksm_ema_page_time > 100000 || -+ (((unsigned long) uksm_eval_round & (256UL - 1)) == 0UL)) -+ uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; -+ -+ per_page = uksm_ema_page_time; -+ BUG_ON(!per_page); -+ -+ /* -+ * For every 8 eval round, we try to probe a uksm_sleep_jiffies value -+ * based on saved user input. -+ */ -+ if (((unsigned long) uksm_eval_round & (8UL - 1)) == 0UL) -+ uksm_sleep_jiffies = uksm_sleep_saved; -+ -+ /* We require a rung scan at least 1 page in a period. */ -+ nsecs = per_page; -+ ratio = rung_real_ratio(ladder[0].cpu_ratio); -+ if (cpu_ratio_to_nsec(ratio) < nsecs) { -+ sleep_usecs = nsecs * (TIME_RATIO_SCALE - ratio) / ratio -+ / NSEC_PER_USEC; -+ uksm_sleep_jiffies = usecs_to_jiffies(sleep_usecs) + 1; -+ } -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ ratio = rung_real_ratio(ladder[i].cpu_ratio); -+ ladder[i].pages_to_scan = cpu_ratio_to_nsec(ratio) / -+ per_page; -+ BUG_ON(!ladder[i].pages_to_scan); -+ uksm_calc_rung_step(&ladder[i], per_page, ratio); -+ } -+} -+ -+/* -+ * From the scan time of this round (ns) to next expected min sleep time -+ * (ms), be careful of the possible overflows. ratio is taken from -+ * rung_real_ratio() -+ */ -+static inline -+unsigned int scan_time_to_sleep(unsigned long long scan_time, unsigned long ratio) -+{ -+ scan_time >>= 20; /* to msec level now */ -+ BUG_ON(scan_time > (ULONG_MAX / TIME_RATIO_SCALE)); -+ -+ return (unsigned int) ((unsigned long) scan_time * -+ (TIME_RATIO_SCALE - ratio) / ratio); -+} -+ -+#define __round_mask(x, y) ((__typeof__(x))((y)-1)) -+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) -+ -+static void uksm_vma_enter(struct vma_slot **slots, unsigned long num) -+{ -+ struct scan_rung *rung; -+ -+ rung = &uksm_scan_ladder[0]; -+ rung_add_new_slots(rung, slots, num); -+} -+ -+static struct vma_slot *batch_slots[SLOT_TREE_NODE_STORE_SIZE]; -+ -+static void uksm_enter_all_slots(void) -+{ -+ struct vma_slot *slot; -+ unsigned long index; -+ struct list_head empty_vma_list; -+ int i; -+ -+ i = 0; -+ index = 0; -+ INIT_LIST_HEAD(&empty_vma_list); -+ -+ spin_lock(&vma_slot_list_lock); -+ while (!list_empty(&vma_slot_new)) { -+ slot = list_entry(vma_slot_new.next, -+ struct vma_slot, slot_list); -+ -+ if (!slot->vma->anon_vma) { -+ list_move(&slot->slot_list, &empty_vma_list); -+ } else if (vma_can_enter(slot->vma)) { -+ batch_slots[index++] = slot; -+ list_del_init(&slot->slot_list); -+ } else { -+ list_move(&slot->slot_list, &vma_slot_noadd); -+ } -+ -+ if (++i == SPIN_LOCK_PERIOD || -+ (index && !(index % SLOT_TREE_NODE_STORE_SIZE))) { -+ spin_unlock(&vma_slot_list_lock); -+ -+ if (index && !(index % SLOT_TREE_NODE_STORE_SIZE)) { -+ uksm_vma_enter(batch_slots, index); -+ index = 0; -+ } -+ i = 0; -+ cond_resched(); -+ spin_lock(&vma_slot_list_lock); -+ } -+ } -+ -+ list_splice(&empty_vma_list, &vma_slot_new); -+ -+ spin_unlock(&vma_slot_list_lock); -+ -+ if (index) -+ uksm_vma_enter(batch_slots, index); -+ -+} -+ -+static inline int rung_round_finished(struct scan_rung *rung) -+{ -+ return rung->flags & UKSM_RUNG_ROUND_FINISHED; -+} -+ -+static inline void judge_slot(struct vma_slot *slot) -+{ -+ struct scan_rung *rung = slot->rung; -+ unsigned long dedup; -+ int deleted; -+ -+ dedup = cal_dedup_ratio(slot); -+ if (vma_fully_scanned(slot) && uksm_thrash_threshold) -+ deleted = vma_rung_enter(slot, &uksm_scan_ladder[0]); -+ else if (dedup && dedup >= uksm_abundant_threshold) -+ deleted = vma_rung_up(slot); -+ else -+ deleted = vma_rung_down(slot); -+ -+ slot->pages_merged = 0; -+ slot->pages_cowed = 0; -+ slot->this_sampled = 0; -+ -+ if (vma_fully_scanned(slot)) -+ slot->pages_scanned = 0; -+ -+ slot->last_scanned = slot->pages_scanned; -+ -+ /* If its deleted in above, then rung was already advanced. */ -+ if (!deleted) -+ advance_current_scan(rung); -+} -+ -+ -+static inline int hash_round_finished(void) -+{ -+ if (scanned_virtual_pages > (uksm_pages_total >> 2)) { -+ scanned_virtual_pages = 0; -+ if (uksm_pages_scanned) -+ fully_scanned_round++; -+ -+ return 1; -+ } else { -+ return 0; -+ } -+} -+ -+#define UKSM_MMSEM_BATCH 5 -+#define BUSY_RETRY 100 -+ -+/** -+ * uksm_do_scan() - the main worker function. -+ */ -+static noinline void uksm_do_scan(void) -+{ -+ struct vma_slot *slot, *iter; -+ struct mm_struct *busy_mm; -+ unsigned char round_finished, all_rungs_emtpy; -+ int i, err, mmsem_batch; -+ unsigned long pcost; -+ long long delta_exec; -+ unsigned long vpages, max_cpu_ratio; -+ unsigned long long start_time, end_time, scan_time; -+ unsigned int expected_jiffies; -+ -+ might_sleep(); -+ -+ vpages = 0; -+ -+ start_time = task_sched_runtime(current); -+ max_cpu_ratio = 0; -+ mmsem_batch = 0; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE;) { -+ struct scan_rung *rung = &uksm_scan_ladder[i]; -+ unsigned long ratio; -+ int busy_retry; -+ -+ if (!rung->pages_to_scan) { -+ i++; -+ continue; -+ } -+ -+ if (!rung->vma_root.num) { -+ rung->pages_to_scan = 0; -+ i++; -+ continue; -+ } -+ -+ ratio = rung_real_ratio(rung->cpu_ratio); -+ if (ratio > max_cpu_ratio) -+ max_cpu_ratio = ratio; -+ -+ busy_retry = BUSY_RETRY; -+ /* -+ * Do not consider rung_round_finished() here, just used up the -+ * rung->pages_to_scan quota. -+ */ -+ while (rung->pages_to_scan && rung->vma_root.num && -+ likely(!freezing(current))) { -+ int reset = 0; -+ -+ slot = rung->current_scan; -+ -+ BUG_ON(vma_fully_scanned(slot)); -+ -+ if (mmsem_batch) -+ err = 0; -+ else -+ err = try_down_read_slot_mmap_sem(slot); -+ -+ if (err == -ENOENT) { -+rm_slot: -+ rung_rm_slot(slot); -+ continue; -+ } -+ -+ busy_mm = slot->mm; -+ -+ if (err == -EBUSY) { -+ /* skip other vmas on the same mm */ -+ do { -+ reset = advance_current_scan(rung); -+ iter = rung->current_scan; -+ busy_retry--; -+ if (iter->vma->vm_mm != busy_mm || -+ !busy_retry || reset) -+ break; -+ } while (1); -+ -+ if (iter->vma->vm_mm != busy_mm) { -+ continue; -+ } else { -+ /* scan round finsished */ -+ break; -+ } -+ } -+ -+ BUG_ON(!vma_can_enter(slot->vma)); -+ if (uksm_test_exit(slot->vma->vm_mm)) { -+ mmsem_batch = 0; -+ up_read(&slot->vma->vm_mm->mmap_sem); -+ goto rm_slot; -+ } -+ -+ if (mmsem_batch) -+ mmsem_batch--; -+ else -+ mmsem_batch = UKSM_MMSEM_BATCH; -+ -+ /* Ok, we have take the mmap_sem, ready to scan */ -+ scan_vma_one_page(slot); -+ rung->pages_to_scan--; -+ vpages++; -+ -+ if (rung->current_offset + rung->step > slot->pages - 1 -+ || vma_fully_scanned(slot)) { -+ up_read(&slot->vma->vm_mm->mmap_sem); -+ judge_slot(slot); -+ mmsem_batch = 0; -+ } else { -+ rung->current_offset += rung->step; -+ if (!mmsem_batch) -+ up_read(&slot->vma->vm_mm->mmap_sem); -+ } -+ -+ busy_retry = BUSY_RETRY; -+ cond_resched(); -+ } -+ -+ if (mmsem_batch) { -+ up_read(&slot->vma->vm_mm->mmap_sem); -+ mmsem_batch = 0; -+ } -+ -+ if (freezing(current)) -+ break; -+ -+ cond_resched(); -+ } -+ end_time = task_sched_runtime(current); -+ delta_exec = end_time - start_time; -+ -+ if (freezing(current)) -+ return; -+ -+ cleanup_vma_slots(); -+ uksm_enter_all_slots(); -+ -+ round_finished = 1; -+ all_rungs_emtpy = 1; -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ struct scan_rung *rung = &uksm_scan_ladder[i]; -+ -+ if (rung->vma_root.num) { -+ all_rungs_emtpy = 0; -+ if (!rung_round_finished(rung)) -+ round_finished = 0; -+ } -+ } -+ -+ if (all_rungs_emtpy) -+ round_finished = 0; -+ -+ if (round_finished) { -+ round_update_ladder(); -+ uksm_eval_round++; -+ -+ if (hash_round_finished() && rshash_adjust()) { -+ /* Reset the unstable root iff hash strength changed */ -+ uksm_hash_round++; -+ root_unstable_tree = RB_ROOT; -+ free_all_tree_nodes(&unstable_tree_node_list); -+ } -+ -+ /* -+ * A number of pages can hang around indefinitely on per-cpu -+ * pagevecs, raised page count preventing write_protect_page -+ * from merging them. Though it doesn't really matter much, -+ * it is puzzling to see some stuck in pages_volatile until -+ * other activity jostles them out, and they also prevented -+ * LTP's KSM test from succeeding deterministically; so drain -+ * them here (here rather than on entry to uksm_do_scan(), -+ * so we don't IPI too often when pages_to_scan is set low). -+ */ -+ lru_add_drain_all(); -+ } -+ -+ -+ if (vpages && delta_exec > 0) { -+ pcost = (unsigned long) delta_exec / vpages; -+ if (likely(uksm_ema_page_time)) -+ uksm_ema_page_time = ema(pcost, uksm_ema_page_time); -+ else -+ uksm_ema_page_time = pcost; -+ } -+ -+ uksm_calc_scan_pages(); -+ uksm_sleep_real = uksm_sleep_jiffies; -+ /* in case of radical cpu bursts, apply the upper bound */ -+ end_time = task_sched_runtime(current); -+ if (max_cpu_ratio && end_time > start_time) { -+ scan_time = end_time - start_time; -+ expected_jiffies = msecs_to_jiffies( -+ scan_time_to_sleep(scan_time, max_cpu_ratio)); -+ -+ if (expected_jiffies > uksm_sleep_real) -+ uksm_sleep_real = expected_jiffies; -+ -+ /* We have a 1 second up bound for responsiveness. */ -+ if (jiffies_to_msecs(uksm_sleep_real) > MSEC_PER_SEC) -+ uksm_sleep_real = msecs_to_jiffies(1000); -+ } -+ -+ return; -+} -+ -+static int ksmd_should_run(void) -+{ -+ return uksm_run & UKSM_RUN_MERGE; -+} -+ -+static int uksm_scan_thread(void *nothing) -+{ -+ set_freezable(); -+ set_user_nice(current, 5); -+ -+ while (!kthread_should_stop()) { -+ mutex_lock(&uksm_thread_mutex); -+ if (ksmd_should_run()) -+ uksm_do_scan(); -+ mutex_unlock(&uksm_thread_mutex); -+ -+ try_to_freeze(); -+ -+ if (ksmd_should_run()) { -+ schedule_timeout_interruptible(uksm_sleep_real); -+ uksm_sleep_times++; -+ } else { -+ wait_event_freezable(uksm_thread_wait, -+ ksmd_should_run() || kthread_should_stop()); -+ } -+ } -+ return 0; -+} -+ -+void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) -+{ -+ struct stable_node *stable_node; -+ struct node_vma *node_vma; -+ struct rmap_item *rmap_item; -+ int search_new_forks = 0; -+ unsigned long address; -+ -+ VM_BUG_ON_PAGE(!PageKsm(page), page); -+ VM_BUG_ON_PAGE(!PageLocked(page), page); -+ -+ stable_node = page_stable_node(page); -+ if (!stable_node) -+ return; -+again: -+ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { -+ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { -+ struct anon_vma *anon_vma = rmap_item->anon_vma; -+ struct anon_vma_chain *vmac; -+ struct vm_area_struct *vma; -+ -+ cond_resched(); -+ anon_vma_lock_read(anon_vma); -+ anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, -+ 0, ULONG_MAX) { -+ cond_resched(); -+ vma = vmac->vma; -+ address = get_rmap_addr(rmap_item); -+ -+ if (address < vma->vm_start || -+ address >= vma->vm_end) -+ continue; -+ -+ if ((rmap_item->slot->vma == vma) == -+ search_new_forks) -+ continue; -+ -+ if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg)) -+ continue; -+ -+ if (!rwc->rmap_one(page, vma, address, rwc->arg)) { -+ anon_vma_unlock_read(anon_vma); -+ return; -+ } -+ -+ if (rwc->done && rwc->done(page)) { -+ anon_vma_unlock_read(anon_vma); -+ return; -+ } -+ } -+ anon_vma_unlock_read(anon_vma); -+ } -+ } -+ if (!search_new_forks++) -+ goto again; -+} -+ -+#ifdef CONFIG_MIGRATION -+/* Common ksm interface but may be specific to uksm */ -+void ksm_migrate_page(struct page *newpage, struct page *oldpage) -+{ -+ struct stable_node *stable_node; -+ -+ VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage); -+ VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); -+ VM_BUG_ON(newpage->mapping != oldpage->mapping); -+ -+ stable_node = page_stable_node(newpage); -+ if (stable_node) { -+ VM_BUG_ON(stable_node->kpfn != page_to_pfn(oldpage)); -+ stable_node->kpfn = page_to_pfn(newpage); -+ /* -+ * newpage->mapping was set in advance; now we need smp_wmb() -+ * to make sure that the new stable_node->kpfn is visible -+ * to get_ksm_page() before it can see that oldpage->mapping -+ * has gone stale (or that PageSwapCache has been cleared). -+ */ -+ smp_wmb(); -+ set_page_stable_node(oldpage, NULL); -+ } -+} -+#endif /* CONFIG_MIGRATION */ -+ -+#ifdef CONFIG_MEMORY_HOTREMOVE -+static struct stable_node *uksm_check_stable_tree(unsigned long start_pfn, -+ unsigned long end_pfn) -+{ -+ struct rb_node *node; -+ -+ for (node = rb_first(root_stable_treep); node; node = rb_next(node)) { -+ struct stable_node *stable_node; -+ -+ stable_node = rb_entry(node, struct stable_node, node); -+ if (stable_node->kpfn >= start_pfn && -+ stable_node->kpfn < end_pfn) -+ return stable_node; -+ } -+ return NULL; -+} -+ -+static int uksm_memory_callback(struct notifier_block *self, -+ unsigned long action, void *arg) -+{ -+ struct memory_notify *mn = arg; -+ struct stable_node *stable_node; -+ -+ switch (action) { -+ case MEM_GOING_OFFLINE: -+ /* -+ * Keep it very simple for now: just lock out ksmd and -+ * MADV_UNMERGEABLE while any memory is going offline. -+ * mutex_lock_nested() is necessary because lockdep was alarmed -+ * that here we take uksm_thread_mutex inside notifier chain -+ * mutex, and later take notifier chain mutex inside -+ * uksm_thread_mutex to unlock it. But that's safe because both -+ * are inside mem_hotplug_mutex. -+ */ -+ mutex_lock_nested(&uksm_thread_mutex, SINGLE_DEPTH_NESTING); -+ break; -+ -+ case MEM_OFFLINE: -+ /* -+ * Most of the work is done by page migration; but there might -+ * be a few stable_nodes left over, still pointing to struct -+ * pages which have been offlined: prune those from the tree. -+ */ -+ while ((stable_node = uksm_check_stable_tree(mn->start_pfn, -+ mn->start_pfn + mn->nr_pages)) != NULL) -+ remove_node_from_stable_tree(stable_node, 1, 1); -+ /* fallthrough */ -+ -+ case MEM_CANCEL_OFFLINE: -+ mutex_unlock(&uksm_thread_mutex); -+ break; -+ } -+ return NOTIFY_OK; -+} -+#endif /* CONFIG_MEMORY_HOTREMOVE */ -+ -+#ifdef CONFIG_SYSFS -+/* -+ * This all compiles without CONFIG_SYSFS, but is a waste of space. -+ */ -+ -+#define UKSM_ATTR_RO(_name) \ -+ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) -+#define UKSM_ATTR(_name) \ -+ static struct kobj_attribute _name##_attr = \ -+ __ATTR(_name, 0644, _name##_show, _name##_store) -+ -+static ssize_t max_cpu_percentage_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%u\n", uksm_max_cpu_percentage); -+} -+ -+static ssize_t max_cpu_percentage_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ unsigned long max_cpu_percentage; -+ int err; -+ -+ err = kstrtoul(buf, 10, &max_cpu_percentage); -+ if (err || max_cpu_percentage > 100) -+ return -EINVAL; -+ -+ if (max_cpu_percentage == 100) -+ max_cpu_percentage = 99; -+ else if (max_cpu_percentage < 10) -+ max_cpu_percentage = 10; -+ -+ uksm_max_cpu_percentage = max_cpu_percentage; -+ -+ return count; -+} -+UKSM_ATTR(max_cpu_percentage); -+ -+static ssize_t sleep_millisecs_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%u\n", jiffies_to_msecs(uksm_sleep_jiffies)); -+} -+ -+static ssize_t sleep_millisecs_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ unsigned long msecs; -+ int err; -+ -+ err = kstrtoul(buf, 10, &msecs); -+ if (err || msecs > MSEC_PER_SEC) -+ return -EINVAL; -+ -+ uksm_sleep_jiffies = msecs_to_jiffies(msecs); -+ uksm_sleep_saved = uksm_sleep_jiffies; -+ -+ return count; -+} -+UKSM_ATTR(sleep_millisecs); -+ -+ -+static ssize_t cpu_governor_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); -+ int i; -+ -+ buf[0] = '\0'; -+ for (i = 0; i < n ; i++) { -+ if (uksm_cpu_governor == i) -+ strcat(buf, "["); -+ -+ strcat(buf, uksm_cpu_governor_str[i]); -+ -+ if (uksm_cpu_governor == i) -+ strcat(buf, "]"); -+ -+ strcat(buf, " "); -+ } -+ strcat(buf, "\n"); -+ -+ return strlen(buf); -+} -+ -+static inline void init_performance_values(void) -+{ -+ int i; -+ struct scan_rung *rung; -+ struct uksm_cpu_preset_s *preset = uksm_cpu_preset + uksm_cpu_governor; -+ -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = uksm_scan_ladder + i; -+ rung->cpu_ratio = preset->cpu_ratio[i]; -+ rung->cover_msecs = preset->cover_msecs[i]; -+ } -+ -+ uksm_max_cpu_percentage = preset->max_cpu; -+} -+ -+static ssize_t cpu_governor_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); -+ -+ for (n--; n >= 0 ; n--) { -+ if (!strncmp(buf, uksm_cpu_governor_str[n], -+ strlen(uksm_cpu_governor_str[n]))) -+ break; -+ } -+ -+ if (n < 0) -+ return -EINVAL; -+ else -+ uksm_cpu_governor = n; -+ -+ init_performance_values(); -+ -+ return count; -+} -+UKSM_ATTR(cpu_governor); -+ -+static ssize_t run_show(struct kobject *kobj, struct kobj_attribute *attr, -+ char *buf) -+{ -+ return sprintf(buf, "%u\n", uksm_run); -+} -+ -+static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int err; -+ unsigned long flags; -+ -+ err = kstrtoul(buf, 10, &flags); -+ if (err || flags > UINT_MAX) -+ return -EINVAL; -+ if (flags > UKSM_RUN_MERGE) -+ return -EINVAL; -+ -+ mutex_lock(&uksm_thread_mutex); -+ if (uksm_run != flags) -+ uksm_run = flags; -+ mutex_unlock(&uksm_thread_mutex); -+ -+ if (flags & UKSM_RUN_MERGE) -+ wake_up_interruptible(&uksm_thread_wait); -+ -+ return count; -+} -+UKSM_ATTR(run); -+ -+static ssize_t abundant_threshold_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%u\n", uksm_abundant_threshold); -+} -+ -+static ssize_t abundant_threshold_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int err; -+ unsigned long flags; -+ -+ err = kstrtoul(buf, 10, &flags); -+ if (err || flags > 99) -+ return -EINVAL; -+ -+ uksm_abundant_threshold = flags; -+ -+ return count; -+} -+UKSM_ATTR(abundant_threshold); -+ -+static ssize_t thrash_threshold_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%u\n", uksm_thrash_threshold); -+} -+ -+static ssize_t thrash_threshold_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int err; -+ unsigned long flags; -+ -+ err = kstrtoul(buf, 10, &flags); -+ if (err || flags > 99) -+ return -EINVAL; -+ -+ uksm_thrash_threshold = flags; -+ -+ return count; -+} -+UKSM_ATTR(thrash_threshold); -+ -+static ssize_t cpu_ratios_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ int i, size; -+ struct scan_rung *rung; -+ char *p = buf; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = &uksm_scan_ladder[i]; -+ -+ if (rung->cpu_ratio > 0) -+ size = sprintf(p, "%d ", rung->cpu_ratio); -+ else -+ size = sprintf(p, "MAX/%d ", -+ TIME_RATIO_SCALE / -rung->cpu_ratio); -+ -+ p += size; -+ } -+ -+ *p++ = '\n'; -+ *p = '\0'; -+ -+ return p - buf; -+} -+ -+static ssize_t cpu_ratios_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int i, cpuratios[SCAN_LADDER_SIZE], err; -+ unsigned long value; -+ struct scan_rung *rung; -+ char *p, *end = NULL; -+ -+ p = kzalloc(count, GFP_KERNEL); -+ if (!p) -+ return -ENOMEM; -+ -+ memcpy(p, buf, count); -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ if (i != SCAN_LADDER_SIZE - 1) { -+ end = strchr(p, ' '); -+ if (!end) -+ return -EINVAL; -+ -+ *end = '\0'; -+ } -+ -+ if (strstr(p, "MAX/")) { -+ p = strchr(p, '/') + 1; -+ err = kstrtoul(p, 10, &value); -+ if (err || value > TIME_RATIO_SCALE || !value) -+ return -EINVAL; -+ -+ cpuratios[i] = -(int) (TIME_RATIO_SCALE / value); -+ } else { -+ err = kstrtoul(p, 10, &value); -+ if (err || value > TIME_RATIO_SCALE || !value) -+ return -EINVAL; -+ -+ cpuratios[i] = value; -+ } -+ -+ p = end + 1; -+ } -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = &uksm_scan_ladder[i]; -+ -+ rung->cpu_ratio = cpuratios[i]; -+ } -+ -+ return count; -+} -+UKSM_ATTR(cpu_ratios); -+ -+static ssize_t eval_intervals_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ int i, size; -+ struct scan_rung *rung; -+ char *p = buf; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = &uksm_scan_ladder[i]; -+ size = sprintf(p, "%u ", rung->cover_msecs); -+ p += size; -+ } -+ -+ *p++ = '\n'; -+ *p = '\0'; -+ -+ return p - buf; -+} -+ -+static ssize_t eval_intervals_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int i, err; -+ unsigned long values[SCAN_LADDER_SIZE]; -+ struct scan_rung *rung; -+ char *p, *end = NULL; -+ ssize_t ret = count; -+ -+ p = kzalloc(count + 2, GFP_KERNEL); -+ if (!p) -+ return -ENOMEM; -+ -+ memcpy(p, buf, count); -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ if (i != SCAN_LADDER_SIZE - 1) { -+ end = strchr(p, ' '); -+ if (!end) { -+ ret = -EINVAL; -+ goto out; -+ } -+ -+ *end = '\0'; -+ } -+ -+ err = kstrtoul(p, 10, &values[i]); -+ if (err) { -+ ret = -EINVAL; -+ goto out; -+ } -+ -+ p = end + 1; -+ } -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = &uksm_scan_ladder[i]; -+ -+ rung->cover_msecs = values[i]; -+ } -+ -+out: -+ kfree(p); -+ return ret; -+} -+UKSM_ATTR(eval_intervals); -+ -+static ssize_t ema_per_page_time_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", uksm_ema_page_time); -+} -+UKSM_ATTR_RO(ema_per_page_time); -+ -+static ssize_t pages_shared_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", uksm_pages_shared); -+} -+UKSM_ATTR_RO(pages_shared); -+ -+static ssize_t pages_sharing_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", uksm_pages_sharing); -+} -+UKSM_ATTR_RO(pages_sharing); -+ -+static ssize_t pages_unshared_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", uksm_pages_unshared); -+} -+UKSM_ATTR_RO(pages_unshared); -+ -+static ssize_t full_scans_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%llu\n", fully_scanned_round); -+} -+UKSM_ATTR_RO(full_scans); -+ -+static ssize_t pages_scanned_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ unsigned long base = 0; -+ u64 delta, ret; -+ -+ if (pages_scanned_stored) { -+ base = pages_scanned_base; -+ ret = pages_scanned_stored; -+ delta = uksm_pages_scanned >> base; -+ if (CAN_OVERFLOW_U64(ret, delta)) { -+ ret >>= 1; -+ delta >>= 1; -+ base++; -+ ret += delta; -+ } -+ } else { -+ ret = uksm_pages_scanned; -+ } -+ -+ while (ret > ULONG_MAX) { -+ ret >>= 1; -+ base++; -+ } -+ -+ if (base) -+ return sprintf(buf, "%lu * 2^%lu\n", (unsigned long)ret, base); -+ else -+ return sprintf(buf, "%lu\n", (unsigned long)ret); -+} -+UKSM_ATTR_RO(pages_scanned); -+ -+static ssize_t hash_strength_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", hash_strength); -+} -+UKSM_ATTR_RO(hash_strength); -+ -+static ssize_t sleep_times_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%llu\n", uksm_sleep_times); -+} -+UKSM_ATTR_RO(sleep_times); -+ -+ -+static struct attribute *uksm_attrs[] = { -+ &max_cpu_percentage_attr.attr, -+ &sleep_millisecs_attr.attr, -+ &cpu_governor_attr.attr, -+ &run_attr.attr, -+ &ema_per_page_time_attr.attr, -+ &pages_shared_attr.attr, -+ &pages_sharing_attr.attr, -+ &pages_unshared_attr.attr, -+ &full_scans_attr.attr, -+ &pages_scanned_attr.attr, -+ &hash_strength_attr.attr, -+ &sleep_times_attr.attr, -+ &thrash_threshold_attr.attr, -+ &abundant_threshold_attr.attr, -+ &cpu_ratios_attr.attr, -+ &eval_intervals_attr.attr, -+ NULL, -+}; -+ -+static struct attribute_group uksm_attr_group = { -+ .attrs = uksm_attrs, -+ .name = "uksm", -+}; -+#endif /* CONFIG_SYSFS */ -+ -+static inline void init_scan_ladder(void) -+{ -+ int i; -+ struct scan_rung *rung; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = uksm_scan_ladder + i; -+ slot_tree_init_root(&rung->vma_root); -+ } -+ -+ init_performance_values(); -+ uksm_calc_scan_pages(); -+} -+ -+static inline int cal_positive_negative_costs(void) -+{ -+ struct page *p1, *p2; -+ unsigned char *addr1, *addr2; -+ unsigned long i, time_start, hash_cost; -+ unsigned long loopnum = 0; -+ -+ /*IMPORTANT: volatile is needed to prevent over-optimization by gcc. */ -+ volatile u32 hash; -+ volatile int ret; -+ -+ p1 = alloc_page(GFP_KERNEL); -+ if (!p1) -+ return -ENOMEM; -+ -+ p2 = alloc_page(GFP_KERNEL); -+ if (!p2) -+ return -ENOMEM; -+ -+ addr1 = kmap_atomic(p1); -+ addr2 = kmap_atomic(p2); -+ memset(addr1, prandom_u32(), PAGE_SIZE); -+ memcpy(addr2, addr1, PAGE_SIZE); -+ -+ /* make sure that the two pages differ in last byte */ -+ addr2[PAGE_SIZE-1] = ~addr2[PAGE_SIZE-1]; -+ kunmap_atomic(addr2); -+ kunmap_atomic(addr1); -+ -+ time_start = jiffies; -+ while (jiffies - time_start < 100) { -+ for (i = 0; i < 100; i++) -+ hash = page_hash(p1, HASH_STRENGTH_FULL, 0); -+ loopnum += 100; -+ } -+ hash_cost = (jiffies - time_start); -+ -+ time_start = jiffies; -+ for (i = 0; i < loopnum; i++) -+ ret = pages_identical(p1, p2); -+ memcmp_cost = HASH_STRENGTH_FULL * (jiffies - time_start); -+ memcmp_cost /= hash_cost; -+ pr_info("UKSM: relative memcmp_cost = %lu " -+ "hash=%u cmp_ret=%d.\n", -+ memcmp_cost, hash, ret); -+ -+ __free_page(p1); -+ __free_page(p2); -+ return 0; -+} -+ -+static int init_zeropage_hash_table(void) -+{ -+ struct page *page; -+ char *addr; -+ int i; -+ -+ page = alloc_page(GFP_KERNEL); -+ if (!page) -+ return -ENOMEM; -+ -+ addr = kmap_atomic(page); -+ memset(addr, 0, PAGE_SIZE); -+ kunmap_atomic(addr); -+ -+ zero_hash_table = kmalloc_array(HASH_STRENGTH_MAX, sizeof(u32), -+ GFP_KERNEL); -+ if (!zero_hash_table) -+ return -ENOMEM; -+ -+ for (i = 0; i < HASH_STRENGTH_MAX; i++) -+ zero_hash_table[i] = page_hash(page, i, 0); -+ -+ __free_page(page); -+ -+ return 0; -+} -+ -+static inline int init_random_sampling(void) -+{ -+ unsigned long i; -+ -+ random_nums = kmalloc(PAGE_SIZE, GFP_KERNEL); -+ if (!random_nums) -+ return -ENOMEM; -+ -+ for (i = 0; i < HASH_STRENGTH_FULL; i++) -+ random_nums[i] = i; -+ -+ for (i = 0; i < HASH_STRENGTH_FULL; i++) { -+ unsigned long rand_range, swap_index, tmp; -+ -+ rand_range = HASH_STRENGTH_FULL - i; -+ swap_index = i + prandom_u32() % rand_range; -+ tmp = random_nums[i]; -+ random_nums[i] = random_nums[swap_index]; -+ random_nums[swap_index] = tmp; -+ } -+ -+ rshash_state.state = RSHASH_NEW; -+ rshash_state.below_count = 0; -+ rshash_state.lookup_window_index = 0; -+ -+ return cal_positive_negative_costs(); -+} -+ -+static int __init uksm_slab_init(void) -+{ -+ rmap_item_cache = UKSM_KMEM_CACHE(rmap_item, 0); -+ if (!rmap_item_cache) -+ goto out; -+ -+ stable_node_cache = UKSM_KMEM_CACHE(stable_node, 0); -+ if (!stable_node_cache) -+ goto out_free1; -+ -+ node_vma_cache = UKSM_KMEM_CACHE(node_vma, 0); -+ if (!node_vma_cache) -+ goto out_free2; -+ -+ vma_slot_cache = UKSM_KMEM_CACHE(vma_slot, 0); -+ if (!vma_slot_cache) -+ goto out_free3; -+ -+ tree_node_cache = UKSM_KMEM_CACHE(tree_node, 0); -+ if (!tree_node_cache) -+ goto out_free4; -+ -+ return 0; -+ -+out_free4: -+ kmem_cache_destroy(vma_slot_cache); -+out_free3: -+ kmem_cache_destroy(node_vma_cache); -+out_free2: -+ kmem_cache_destroy(stable_node_cache); -+out_free1: -+ kmem_cache_destroy(rmap_item_cache); -+out: -+ return -ENOMEM; -+} -+ -+static void __init uksm_slab_free(void) -+{ -+ kmem_cache_destroy(stable_node_cache); -+ kmem_cache_destroy(rmap_item_cache); -+ kmem_cache_destroy(node_vma_cache); -+ kmem_cache_destroy(vma_slot_cache); -+ kmem_cache_destroy(tree_node_cache); -+} -+ -+/* Common interface to ksm, different to it. */ -+int ksm_madvise(struct vm_area_struct *vma, unsigned long start, -+ unsigned long end, int advice, unsigned long *vm_flags) -+{ -+ int err; -+ -+ switch (advice) { -+ case MADV_MERGEABLE: -+ return 0; /* just ignore the advice */ -+ -+ case MADV_UNMERGEABLE: -+ if (!(*vm_flags & VM_MERGEABLE) || !uksm_flags_can_scan(*vm_flags)) -+ return 0; /* just ignore the advice */ -+ -+ if (vma->anon_vma) { -+ err = unmerge_uksm_pages(vma, start, end); -+ if (err) -+ return err; -+ } -+ -+ uksm_remove_vma(vma); -+ *vm_flags &= ~VM_MERGEABLE; -+ break; -+ } -+ -+ return 0; -+} -+ -+/* Common interface to ksm, actually the same. */ -+struct page *ksm_might_need_to_copy(struct page *page, -+ struct vm_area_struct *vma, unsigned long address) -+{ -+ struct anon_vma *anon_vma = page_anon_vma(page); -+ struct page *new_page; -+ -+ if (PageKsm(page)) { -+ if (page_stable_node(page)) -+ return page; /* no need to copy it */ -+ } else if (!anon_vma) { -+ return page; /* no need to copy it */ -+ } else if (anon_vma->root == vma->anon_vma->root && -+ page->index == linear_page_index(vma, address)) { -+ return page; /* still no need to copy it */ -+ } -+ if (!PageUptodate(page)) -+ return page; /* let do_swap_page report the error */ -+ -+ new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); -+ if (new_page) { -+ copy_user_highpage(new_page, page, address, vma); -+ -+ SetPageDirty(new_page); -+ __SetPageUptodate(new_page); -+ __SetPageLocked(new_page); -+ } -+ -+ return new_page; -+} -+ -+static int __init uksm_init(void) -+{ -+ struct task_struct *uksm_thread; -+ int err; -+ -+ uksm_sleep_jiffies = msecs_to_jiffies(100); -+ uksm_sleep_saved = uksm_sleep_jiffies; -+ -+ slot_tree_init(); -+ init_scan_ladder(); -+ -+ -+ err = init_random_sampling(); -+ if (err) -+ goto out_free2; -+ -+ err = uksm_slab_init(); -+ if (err) -+ goto out_free1; -+ -+ err = init_zeropage_hash_table(); -+ if (err) -+ goto out_free0; -+ -+ uksm_thread = kthread_run(uksm_scan_thread, NULL, "uksmd"); -+ if (IS_ERR(uksm_thread)) { -+ pr_err("uksm: creating kthread failed\n"); -+ err = PTR_ERR(uksm_thread); -+ goto out_free; -+ } -+ -+#ifdef CONFIG_SYSFS -+ err = sysfs_create_group(mm_kobj, &uksm_attr_group); -+ if (err) { -+ pr_err("uksm: register sysfs failed\n"); -+ kthread_stop(uksm_thread); -+ goto out_free; -+ } -+#else -+ uksm_run = UKSM_RUN_MERGE; /* no way for user to start it */ -+ -+#endif /* CONFIG_SYSFS */ -+ -+#ifdef CONFIG_MEMORY_HOTREMOVE -+ /* -+ * Choose a high priority since the callback takes uksm_thread_mutex: -+ * later callbacks could only be taking locks which nest within that. -+ */ -+ hotplug_memory_notifier(uksm_memory_callback, 100); -+#endif -+ return 0; -+ -+out_free: -+ kfree(zero_hash_table); -+out_free0: -+ uksm_slab_free(); -+out_free1: -+ kfree(random_nums); -+out_free2: -+ kfree(uksm_scan_ladder); -+ return err; -+} -+ -+#ifdef MODULE -+subsys_initcall(ksm_init); -+#else -+late_initcall(uksm_init); -+#endif -+ -diff -Nur a/mm/vmstat.c b/mm/vmstat.c ---- a/mm/vmstat.c 2019-06-25 04:34:56.000000000 +0100 -+++ b/mm/vmstat.c 2019-07-07 09:32:50.461840572 +0100 -@@ -1165,6 +1165,9 @@ - "nr_written", - "nr_kernel_misc_reclaimable", - -+#ifdef CONFIG_UKSM -+ "nr_uksm_zero_pages", -+#endif - /* enum writeback_stat_item counters */ - "nr_dirty_threshold", - "nr_dirty_background_threshold", diff --git a/sys-kernel/linux-image-redcore/linux-image-redcore-5.1.15.ebuild b/sys-kernel/linux-image-redcore/linux-image-redcore-5.1.15.ebuild index 08b6134f..2a190518 100644 --- a/sys-kernel/linux-image-redcore/linux-image-redcore-5.1.15.ebuild +++ b/sys-kernel/linux-image-redcore/linux-image-redcore-5.1.15.ebuild @@ -43,7 +43,8 @@ PATCHES=( "${FILESDIR}"/"${KV_MAJOR}"-radeon_dp_aux_transfer_native-no-ratelimited_debug.patch "${FILESDIR}"/"${KV_MAJOR}"-Unknow-SSD-HFM128GDHTNG-8310B-QUIRK_NO_APST.patch "${FILESDIR}"/"${KV_MAJOR}"-linux-hardened.patch - "${FILESDIR}"/"${KV_MAJOR}"-uksm-linux-hardened.patch + "${FILESDIR}"/"${KV_MAJOR}"-0001-uksm-initial-submission-linux-hardened.patch + "${FILESDIR}"/"${KV_MAJOR}"-0001-uksm-apply-52d1e606ee733.patch "${FILESDIR}"/"${KV_MAJOR}"-0001-MultiQueue-Skiplist-Scheduler-version-0.192-linux-hardened.patch "${FILESDIR}"/"${KV_MAJOR}"-0002-Fix-Werror-build-failure-in-tools.patch "${FILESDIR}"/"${KV_MAJOR}"-0003-Make-preemptible-kernel-default.patch diff --git a/sys-kernel/linux-sources-redcore/files/5.1-0001-uksm-apply-52d1e606ee733.patch b/sys-kernel/linux-sources-redcore/files/5.1-0001-uksm-apply-52d1e606ee733.patch new file mode 100644 index 00000000..dbc5357c --- /dev/null +++ b/sys-kernel/linux-sources-redcore/files/5.1-0001-uksm-apply-52d1e606ee733.patch @@ -0,0 +1,75 @@ +From ea0c9d768bade0bc87046841a3e667f477d90668 Mon Sep 17 00:00:00 2001 +From: Oleksandr Natalenko +Date: Mon, 6 May 2019 22:02:49 +0200 +Subject: [PATCH] uksm-5.1: apply 52d1e606ee733 + +Signed-off-by: Oleksandr Natalenko +--- + mm/uksm.c | 36 +++++++++++++++++++++++++++++++----- + 1 file changed, 31 insertions(+), 5 deletions(-) + +diff --git a/mm/uksm.c b/mm/uksm.c +index 174e1921eade..2531599038b8 100644 +--- a/mm/uksm.c ++++ b/mm/uksm.c +@@ -875,8 +875,8 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node, + * to keep the page_count protocol described with page_cache_get_speculative. + * + * Note: it is possible that get_uksm_page() will return NULL one moment, +- * then page the next, if the page is in between page_freeze_refs() and +- * page_unfreeze_refs(): this shouldn't be a problem anywhere, the page ++ * then page the next, if the page is in between page_ref_freeze() and ++ * page_ref_unfreeze(): this shouldn't be a problem anywhere, the page + * is on its way to being freed; but it is an anomaly to bear in mind. + * + * @unlink_rb: if the removal of this node will firstly unlink from +@@ -914,10 +914,11 @@ static struct page *get_uksm_page(struct stable_node *stable_node, + * We cannot do anything with the page while its refcount is 0. + * Usually 0 means free, or tail of a higher-order page: in which + * case this node is no longer referenced, and should be freed; +- * however, it might mean that the page is under page_freeze_refs(). ++ * however, it might mean that the page is under page_ref_freeze(). + * The __remove_mapping() case is easy, again the node is now stale; +- * but if page is swapcache in migrate_page_move_mapping(), it might +- * still be our page, in which case it's essential to keep the node. ++ * the same is in reuse_ksm_page() case; but if page is swapcache ++ * in migrate_page_move_mapping(), it might still be our page, ++ * in which case it's essential to keep the node. + */ + while (!get_page_unless_zero(page)) { + /* +@@ -4749,6 +4750,31 @@ void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) + goto again; + } + ++bool reuse_ksm_page(struct page *page, ++ struct vm_area_struct *vma, ++ unsigned long address) ++{ ++#ifdef CONFIG_DEBUG_VM ++ if (WARN_ON(is_zero_pfn(page_to_pfn(page))) || ++ WARN_ON(!page_mapped(page)) || ++ WARN_ON(!PageLocked(page))) { ++ dump_page(page, "reuse_ksm_page"); ++ return false; ++ } ++#endif ++ ++ if (PageSwapCache(page) || !page_stable_node(page)) ++ return false; ++ /* Prohibit parallel get_ksm_page() */ ++ if (!page_ref_freeze(page, 1)) ++ return false; ++ ++ page_move_anon_rmap(page, vma); ++ page->index = linear_page_index(vma, address); ++ page_ref_unfreeze(page, 1); ++ ++ return true; ++} + #ifdef CONFIG_MIGRATION + /* Common ksm interface but may be specific to uksm */ + void ksm_migrate_page(struct page *newpage, struct page *oldpage) +-- +2.21.0.777.g83232e3864 + diff --git a/sys-kernel/linux-sources-redcore/files/5.1-0001-uksm-initial-submission-linux-hardened.patch b/sys-kernel/linux-sources-redcore/files/5.1-0001-uksm-initial-submission-linux-hardened.patch new file mode 100644 index 00000000..d2f3a41f --- /dev/null +++ b/sys-kernel/linux-sources-redcore/files/5.1-0001-uksm-initial-submission-linux-hardened.patch @@ -0,0 +1,6922 @@ +diff -Nur a/Documentation/vm/uksm.txt b/Documentation/vm/uksm.txt +--- a/Documentation/vm/uksm.txt 1970-01-01 01:00:00.000000000 +0100 ++++ b/Documentation/vm/uksm.txt 2019-07-07 11:43:00.138836975 +0100 +@@ -0,0 +1,61 @@ ++The Ultra Kernel Samepage Merging feature ++---------------------------------------------- ++/* ++ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia ++ * ++ * This is an improvement upon KSM. Some basic data structures and routines ++ * are borrowed from ksm.c . ++ * ++ * Its new features: ++ * 1. Full system scan: ++ * It automatically scans all user processes' anonymous VMAs. Kernel-user ++ * interaction to submit a memory area to KSM is no longer needed. ++ * ++ * 2. Rich area detection: ++ * It automatically detects rich areas containing abundant duplicated ++ * pages based. Rich areas are given a full scan speed. Poor areas are ++ * sampled at a reasonable speed with very low CPU consumption. ++ * ++ * 3. Ultra Per-page scan speed improvement: ++ * A new hash algorithm is proposed. As a result, on a machine with ++ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it ++ * can scan memory areas that does not contain duplicated pages at speed of ++ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of ++ * 477MB/sec ~ 923MB/sec. ++ * ++ * 4. Thrashing area avoidance: ++ * Thrashing area(an VMA that has frequent Ksm page break-out) can be ++ * filtered out. My benchmark shows it's more efficient than KSM's per-page ++ * hash value based volatile page detection. ++ * ++ * ++ * 5. Misc changes upon KSM: ++ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page ++ * comparison. It's much faster than default C version on x86. ++ * * rmap_item now has an struct *page member to loosely cache a ++ * address-->page mapping, which reduces too much time-costly ++ * follow_page(). ++ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. ++ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ ++ * ksm is needed for this case. ++ * ++ * 6. Full Zero Page consideration(contributed by Figo Zhang) ++ * Now uksmd consider full zero pages as special pages and merge them to an ++ * special unswappable uksm zero page. ++ */ ++ ++ChangeLog: ++ ++2012-05-05 The creation of this Doc ++2012-05-08 UKSM 0.1.1.1 libc crash bug fix, api clean up, doc clean up. ++2012-05-28 UKSM 0.1.1.2 bug fix release ++2012-06-26 UKSM 0.1.2-beta1 first beta release for 0.1.2 ++2012-07-2 UKSM 0.1.2-beta2 ++2012-07-10 UKSM 0.1.2-beta3 ++2012-07-26 UKSM 0.1.2 Fine grained speed control, more scan optimization. ++2012-10-13 UKSM 0.1.2.1 Bug fixes. ++2012-12-31 UKSM 0.1.2.2 Minor bug fixes. ++2014-07-02 UKSM 0.1.2.3 Fix a " __this_cpu_read() in preemptible bug". ++2015-04-22 UKSM 0.1.2.4 Fix a race condition that can sometimes trigger anonying warnings. ++2016-09-10 UKSM 0.1.2.5 Fix a bug in dedup ratio calculation. ++2017-02-26 UKSM 0.1.2.6 Fix a bug in hugetlbpage handling and a race bug with page migration. +diff -Nur a/fs/exec.c b/fs/exec.c +--- a/fs/exec.c 2019-07-07 11:39:06.860827790 +0100 ++++ b/fs/exec.c 2019-07-07 11:44:01.830966115 +0100 +@@ -63,6 +63,8 @@ + #include + #include + #include ++#include ++#include + + #include + #include +@@ -1385,6 +1387,7 @@ + /* An exec changes our domain. We are no longer part of the thread + group */ + current->self_exec_id++; ++ + flush_signal_handlers(current, 0); + } + EXPORT_SYMBOL(setup_new_exec); +diff -Nur a/fs/proc/meminfo.c b/fs/proc/meminfo.c +--- a/fs/proc/meminfo.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/fs/proc/meminfo.c 2019-07-07 11:43:00.138836975 +0100 +@@ -106,6 +106,10 @@ + global_zone_page_state(NR_KERNEL_STACK_KB)); + show_val_kb(m, "PageTables: ", + global_zone_page_state(NR_PAGETABLE)); ++#ifdef CONFIG_UKSM ++ show_val_kb(m, "KsmZeroPages: ", ++ global_zone_page_state(NR_UKSM_ZERO_PAGES)); ++#endif + #ifdef CONFIG_QUICKLIST + show_val_kb(m, "Quicklists: ", quicklist_total_size()); + #endif +diff -Nur a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h +--- a/include/asm-generic/pgtable.h 2019-06-25 04:34:56.000000000 +0100 ++++ b/include/asm-generic/pgtable.h 2019-07-07 11:43:00.138836975 +0100 +@@ -855,12 +855,25 @@ + extern void untrack_pfn_moved(struct vm_area_struct *vma); + #endif + ++#ifdef CONFIG_UKSM ++static inline int is_uksm_zero_pfn(unsigned long pfn) ++{ ++ extern unsigned long uksm_zero_pfn; ++ return pfn == uksm_zero_pfn; ++} ++#else ++static inline int is_uksm_zero_pfn(unsigned long pfn) ++{ ++ return 0; ++} ++#endif ++ + #ifdef __HAVE_COLOR_ZERO_PAGE + static inline int is_zero_pfn(unsigned long pfn) + { + extern unsigned long zero_pfn; + unsigned long offset_from_zero_pfn = pfn - zero_pfn; +- return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT); ++ return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT) || is_uksm_zero_pfn(pfn); + } + + #define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) +@@ -869,7 +882,7 @@ + static inline int is_zero_pfn(unsigned long pfn) + { + extern unsigned long zero_pfn; +- return pfn == zero_pfn; ++ return (pfn == zero_pfn) || (is_uksm_zero_pfn(pfn)); + } + + static inline unsigned long my_zero_pfn(unsigned long addr) +diff -Nur a/include/linux/ksm.h b/include/linux/ksm.h +--- a/include/linux/ksm.h 2019-06-25 04:34:56.000000000 +0100 ++++ b/include/linux/ksm.h 2019-07-07 11:43:00.138836975 +0100 +@@ -21,20 +21,16 @@ + #ifdef CONFIG_KSM + int ksm_madvise(struct vm_area_struct *vma, unsigned long start, + unsigned long end, int advice, unsigned long *vm_flags); +-int __ksm_enter(struct mm_struct *mm); +-void __ksm_exit(struct mm_struct *mm); + +-static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) ++static inline struct stable_node *page_stable_node(struct page *page) + { +- if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) +- return __ksm_enter(mm); +- return 0; ++ return PageKsm(page) ? page_rmapping(page) : NULL; + } + +-static inline void ksm_exit(struct mm_struct *mm) ++static inline void set_page_stable_node(struct page *page, ++ struct stable_node *stable_node) + { +- if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) +- __ksm_exit(mm); ++ page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); + } + + /* +@@ -56,6 +52,33 @@ + bool reuse_ksm_page(struct page *page, + struct vm_area_struct *vma, unsigned long address); + ++#ifdef CONFIG_KSM_LEGACY ++int __ksm_enter(struct mm_struct *mm); ++void __ksm_exit(struct mm_struct *mm); ++static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) ++{ ++ if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) ++ return __ksm_enter(mm); ++ return 0; ++} ++ ++static inline void ksm_exit(struct mm_struct *mm) ++{ ++ if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) ++ __ksm_exit(mm); ++} ++ ++#elif defined(CONFIG_UKSM) ++static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) ++{ ++ return 0; ++} ++ ++static inline void ksm_exit(struct mm_struct *mm) ++{ ++} ++#endif /* !CONFIG_UKSM */ ++ + #else /* !CONFIG_KSM */ + + static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) +@@ -96,4 +119,6 @@ + #endif /* CONFIG_MMU */ + #endif /* !CONFIG_KSM */ + ++#include ++ + #endif /* __LINUX_KSM_H */ +diff -Nur a/include/linux/mm_types.h b/include/linux/mm_types.h +--- a/include/linux/mm_types.h 2019-06-25 04:34:56.000000000 +0100 ++++ b/include/linux/mm_types.h 2019-07-07 11:43:00.138836975 +0100 +@@ -334,6 +334,9 @@ + struct mempolicy *vm_policy; /* NUMA policy for the VMA */ + #endif + struct vm_userfaultfd_ctx vm_userfaultfd_ctx; ++#ifdef CONFIG_UKSM ++ struct vma_slot *uksm_vma_slot; ++#endif + } __randomize_layout; + + struct core_thread { +diff -Nur a/include/linux/mmzone.h b/include/linux/mmzone.h +--- a/include/linux/mmzone.h 2019-06-25 04:34:56.000000000 +0100 ++++ b/include/linux/mmzone.h 2019-07-07 11:43:00.138836975 +0100 +@@ -148,6 +148,9 @@ + NR_ZSPAGES, /* allocated in zsmalloc */ + #endif + NR_FREE_CMA_PAGES, ++#ifdef CONFIG_UKSM ++ NR_UKSM_ZERO_PAGES, ++#endif + NR_VM_ZONE_STAT_ITEMS }; + + enum node_stat_item { +diff -Nur a/include/linux/sradix-tree.h b/include/linux/sradix-tree.h +--- a/include/linux/sradix-tree.h 1970-01-01 01:00:00.000000000 +0100 ++++ b/include/linux/sradix-tree.h 2019-07-07 11:43:00.148837320 +0100 +@@ -0,0 +1,77 @@ ++#ifndef _LINUX_SRADIX_TREE_H ++#define _LINUX_SRADIX_TREE_H ++ ++ ++#define INIT_SRADIX_TREE(root, mask) \ ++do { \ ++ (root)->height = 0; \ ++ (root)->gfp_mask = (mask); \ ++ (root)->rnode = NULL; \ ++} while (0) ++ ++#define ULONG_BITS (sizeof(unsigned long) * 8) ++#define SRADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) ++//#define SRADIX_TREE_MAP_SHIFT 6 ++//#define SRADIX_TREE_MAP_SIZE (1UL << SRADIX_TREE_MAP_SHIFT) ++//#define SRADIX_TREE_MAP_MASK (SRADIX_TREE_MAP_SIZE-1) ++ ++struct sradix_tree_node { ++ unsigned int height; /* Height from the bottom */ ++ unsigned int count; ++ unsigned int fulls; /* Number of full sublevel trees */ ++ struct sradix_tree_node *parent; ++ void *stores[0]; ++}; ++ ++/* A simple radix tree implementation */ ++struct sradix_tree_root { ++ unsigned int height; ++ struct sradix_tree_node *rnode; ++ ++ /* Where found to have available empty stores in its sublevels */ ++ struct sradix_tree_node *enter_node; ++ unsigned int shift; ++ unsigned int stores_size; ++ unsigned int mask; ++ unsigned long min; /* The first hole index */ ++ unsigned long num; ++ //unsigned long *height_to_maxindex; ++ ++ /* How the node is allocated and freed. */ ++ struct sradix_tree_node *(*alloc)(void); ++ void (*free)(struct sradix_tree_node *node); ++ ++ /* When a new node is added and removed */ ++ void (*extend)(struct sradix_tree_node *parent, struct sradix_tree_node *child); ++ void (*assign)(struct sradix_tree_node *node, unsigned int index, void *item); ++ void (*rm)(struct sradix_tree_node *node, unsigned int offset); ++}; ++ ++struct sradix_tree_path { ++ struct sradix_tree_node *node; ++ int offset; ++}; ++ ++static inline ++void init_sradix_tree_root(struct sradix_tree_root *root, unsigned long shift) ++{ ++ root->height = 0; ++ root->rnode = NULL; ++ root->shift = shift; ++ root->stores_size = 1UL << shift; ++ root->mask = root->stores_size - 1; ++} ++ ++ ++extern void *sradix_tree_next(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index, ++ int (*iter)(void *, unsigned long)); ++ ++extern int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num); ++ ++extern void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index); ++ ++extern void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index); ++ ++#endif /* _LINUX_SRADIX_TREE_H */ +diff -Nur a/include/linux/uksm.h b/include/linux/uksm.h +--- a/include/linux/uksm.h 1970-01-01 01:00:00.000000000 +0100 ++++ b/include/linux/uksm.h 2019-07-07 11:43:00.148837320 +0100 +@@ -0,0 +1,149 @@ ++#ifndef __LINUX_UKSM_H ++#define __LINUX_UKSM_H ++/* ++ * Memory merging support. ++ * ++ * This code enables dynamic sharing of identical pages found in different ++ * memory areas, even if they are not shared by fork(). ++ */ ++ ++/* if !CONFIG_UKSM this file should not be compiled at all. */ ++#ifdef CONFIG_UKSM ++ ++#include ++#include ++#include ++#include ++#include ++ ++extern unsigned long zero_pfn __read_mostly; ++extern unsigned long uksm_zero_pfn __read_mostly; ++extern struct page *empty_uksm_zero_page; ++ ++/* must be done before linked to mm */ ++extern void uksm_vma_add_new(struct vm_area_struct *vma); ++extern void uksm_remove_vma(struct vm_area_struct *vma); ++ ++#define UKSM_SLOT_NEED_SORT (1 << 0) ++#define UKSM_SLOT_NEED_RERAND (1 << 1) ++#define UKSM_SLOT_SCANNED (1 << 2) /* It's scanned in this round */ ++#define UKSM_SLOT_FUL_SCANNED (1 << 3) ++#define UKSM_SLOT_IN_UKSM (1 << 4) ++ ++struct vma_slot { ++ struct sradix_tree_node *snode; ++ unsigned long sindex; ++ ++ struct list_head slot_list; ++ unsigned long fully_scanned_round; ++ unsigned long dedup_num; ++ unsigned long pages_scanned; ++ unsigned long this_sampled; ++ unsigned long last_scanned; ++ unsigned long pages_to_scan; ++ struct scan_rung *rung; ++ struct page **rmap_list_pool; ++ unsigned int *pool_counts; ++ unsigned long pool_size; ++ struct vm_area_struct *vma; ++ struct mm_struct *mm; ++ unsigned long ctime_j; ++ unsigned long pages; ++ unsigned long flags; ++ unsigned long pages_cowed; /* pages cowed this round */ ++ unsigned long pages_merged; /* pages merged this round */ ++ unsigned long pages_bemerged; ++ ++ /* when it has page merged in this eval round */ ++ struct list_head dedup_list; ++}; ++ ++static inline void uksm_unmap_zero_page(pte_t pte) ++{ ++ if (pte_pfn(pte) == uksm_zero_pfn) ++ __dec_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); ++} ++ ++static inline void uksm_map_zero_page(pte_t pte) ++{ ++ if (pte_pfn(pte) == uksm_zero_pfn) ++ __inc_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); ++} ++ ++static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) ++{ ++ if (vma->uksm_vma_slot && PageKsm(page)) ++ vma->uksm_vma_slot->pages_cowed++; ++} ++ ++static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) ++{ ++ if (vma->uksm_vma_slot && pte_pfn(pte) == uksm_zero_pfn) ++ vma->uksm_vma_slot->pages_cowed++; ++} ++ ++static inline int uksm_flags_can_scan(unsigned long vm_flags) ++{ ++#ifdef VM_SAO ++ if (vm_flags & VM_SAO) ++ return 0; ++#endif ++ ++ return !(vm_flags & (VM_PFNMAP | VM_IO | VM_DONTEXPAND | ++ VM_HUGETLB | VM_MIXEDMAP | VM_SHARED ++ | VM_MAYSHARE | VM_GROWSUP | VM_GROWSDOWN)); ++} ++ ++static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) ++{ ++ if (uksm_flags_can_scan(*vm_flags_p)) ++ *vm_flags_p |= VM_MERGEABLE; ++} ++ ++/* ++ * Just a wrapper for BUG_ON for where ksm_zeropage must not be. TODO: it will ++ * be removed when uksm zero page patch is stable enough. ++ */ ++static inline void uksm_bugon_zeropage(pte_t pte) ++{ ++ BUG_ON(pte_pfn(pte) == uksm_zero_pfn); ++} ++#else ++static inline void uksm_vma_add_new(struct vm_area_struct *vma) ++{ ++} ++ ++static inline void uksm_remove_vma(struct vm_area_struct *vma) ++{ ++} ++ ++static inline void uksm_unmap_zero_page(pte_t pte) ++{ ++} ++ ++static inline void uksm_map_zero_page(pte_t pte) ++{ ++} ++ ++static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) ++{ ++} ++ ++static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) ++{ ++} ++ ++static inline int uksm_flags_can_scan(unsigned long vm_flags) ++{ ++ return 0; ++} ++ ++static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) ++{ ++} ++ ++static inline void uksm_bugon_zeropage(pte_t pte) ++{ ++} ++#endif /* !CONFIG_UKSM */ ++#endif /* __LINUX_UKSM_H */ +diff -Nur a/kernel/fork.c b/kernel/fork.c +--- a/kernel/fork.c 2019-07-07 11:39:06.870828132 +0100 ++++ b/kernel/fork.c 2019-07-07 11:43:00.148837320 +0100 +@@ -584,7 +584,7 @@ + __vma_link_rb(mm, tmp, rb_link, rb_parent); + rb_link = &tmp->vm_rb.rb_right; + rb_parent = &tmp->vm_rb; +- ++ uksm_vma_add_new(tmp); + mm->map_count++; + if (!(tmp->vm_flags & VM_WIPEONFORK)) + retval = copy_page_range(mm, oldmm, mpnt); +diff -Nur a/lib/Makefile b/lib/Makefile +--- a/lib/Makefile 2019-06-25 04:34:56.000000000 +0100 ++++ b/lib/Makefile 2019-07-07 11:43:00.148837320 +0100 +@@ -29,7 +29,7 @@ + endif + + lib-y := ctype.o string.o vsprintf.o cmdline.o \ +- rbtree.o radix-tree.o timerqueue.o xarray.o \ ++ rbtree.o radix-tree.o sradix-tree.o timerqueue.o xarray.o \ + idr.o int_sqrt.o extable.o \ + sha1.o chacha.o irq_regs.o argv_split.o \ + flex_proportions.o ratelimit.o show_mem.o \ +diff -Nur a/lib/sradix-tree.c b/lib/sradix-tree.c +--- a/lib/sradix-tree.c 1970-01-01 01:00:00.000000000 +0100 ++++ b/lib/sradix-tree.c 2019-07-07 11:43:00.148837320 +0100 +@@ -0,0 +1,476 @@ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++ ++static inline int sradix_node_full(struct sradix_tree_root *root, struct sradix_tree_node *node) ++{ ++ return node->fulls == root->stores_size || ++ (node->height == 1 && node->count == root->stores_size); ++} ++ ++/* ++ * Extend a sradix tree so it can store key @index. ++ */ ++static int sradix_tree_extend(struct sradix_tree_root *root, unsigned long index) ++{ ++ struct sradix_tree_node *node; ++ unsigned int height; ++ ++ if (unlikely(root->rnode == NULL)) { ++ if (!(node = root->alloc())) ++ return -ENOMEM; ++ ++ node->height = 1; ++ root->rnode = node; ++ root->height = 1; ++ } ++ ++ /* Figure out what the height should be. */ ++ height = root->height; ++ index >>= root->shift * height; ++ ++ while (index) { ++ index >>= root->shift; ++ height++; ++ } ++ ++ while (height > root->height) { ++ unsigned int newheight; ++ ++ if (!(node = root->alloc())) ++ return -ENOMEM; ++ ++ /* Increase the height. */ ++ node->stores[0] = root->rnode; ++ root->rnode->parent = node; ++ if (root->extend) ++ root->extend(node, root->rnode); ++ ++ newheight = root->height + 1; ++ node->height = newheight; ++ node->count = 1; ++ if (sradix_node_full(root, root->rnode)) ++ node->fulls = 1; ++ ++ root->rnode = node; ++ root->height = newheight; ++ } ++ ++ return 0; ++} ++ ++/* ++ * Search the next item from the current node, that is not NULL ++ * and can satify root->iter(). ++ */ ++void *sradix_tree_next(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index, ++ int (*iter)(void *item, unsigned long height)) ++{ ++ unsigned long offset; ++ void *item; ++ ++ if (unlikely(node == NULL)) { ++ node = root->rnode; ++ for (offset = 0; offset < root->stores_size; offset++) { ++ item = node->stores[offset]; ++ if (item && (!iter || iter(item, node->height))) ++ break; ++ } ++ ++ if (unlikely(offset >= root->stores_size)) ++ return NULL; ++ ++ if (node->height == 1) ++ return item; ++ else ++ goto go_down; ++ } ++ ++ while (node) { ++ offset = (index & root->mask) + 1; ++ for (; offset < root->stores_size; offset++) { ++ item = node->stores[offset]; ++ if (item && (!iter || iter(item, node->height))) ++ break; ++ } ++ ++ if (offset < root->stores_size) ++ break; ++ ++ node = node->parent; ++ index >>= root->shift; ++ } ++ ++ if (!node) ++ return NULL; ++ ++ while (node->height > 1) { ++go_down: ++ node = item; ++ for (offset = 0; offset < root->stores_size; offset++) { ++ item = node->stores[offset]; ++ if (item && (!iter || iter(item, node->height))) ++ break; ++ } ++ ++ if (unlikely(offset >= root->stores_size)) ++ return NULL; ++ } ++ ++ BUG_ON(offset > root->stores_size); ++ ++ return item; ++} ++ ++/* ++ * Blindly insert the item to the tree. Typically, we reuse the ++ * first empty store item. ++ */ ++int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num) ++{ ++ unsigned long index; ++ unsigned int height; ++ struct sradix_tree_node *node, *tmp = NULL; ++ int offset, offset_saved; ++ void **store = NULL; ++ int error, i, j, shift; ++ ++go_on: ++ index = root->min; ++ ++ if (root->enter_node && !sradix_node_full(root, root->enter_node)) { ++ node = root->enter_node; ++ BUG_ON((index >> (root->shift * root->height))); ++ } else { ++ node = root->rnode; ++ if (node == NULL || (index >> (root->shift * root->height)) ++ || sradix_node_full(root, node)) { ++ error = sradix_tree_extend(root, index); ++ if (error) ++ return error; ++ ++ node = root->rnode; ++ } ++ } ++ ++ ++ height = node->height; ++ shift = (height - 1) * root->shift; ++ offset = (index >> shift) & root->mask; ++ while (shift > 0) { ++ offset_saved = offset; ++ for (; offset < root->stores_size; offset++) { ++ store = &node->stores[offset]; ++ tmp = *store; ++ ++ if (!tmp || !sradix_node_full(root, tmp)) ++ break; ++ } ++ BUG_ON(offset >= root->stores_size); ++ ++ if (offset != offset_saved) { ++ index += (offset - offset_saved) << shift; ++ index &= ~((1UL << shift) - 1); ++ } ++ ++ if (!tmp) { ++ if (!(tmp = root->alloc())) ++ return -ENOMEM; ++ ++ tmp->height = shift / root->shift; ++ *store = tmp; ++ tmp->parent = node; ++ node->count++; ++// if (root->extend) ++// root->extend(node, tmp); ++ } ++ ++ node = tmp; ++ shift -= root->shift; ++ offset = (index >> shift) & root->mask; ++ } ++ ++ BUG_ON(node->height != 1); ++ ++ ++ store = &node->stores[offset]; ++ for (i = 0, j = 0; ++ j < root->stores_size - node->count && ++ i < root->stores_size - offset && j < num; i++) { ++ if (!store[i]) { ++ store[i] = item[j]; ++ if (root->assign) ++ root->assign(node, index + i, item[j]); ++ j++; ++ } ++ } ++ ++ node->count += j; ++ root->num += j; ++ num -= j; ++ ++ while (sradix_node_full(root, node)) { ++ node = node->parent; ++ if (!node) ++ break; ++ ++ node->fulls++; ++ } ++ ++ if (unlikely(!node)) { ++ /* All nodes are full */ ++ root->min = 1 << (root->height * root->shift); ++ root->enter_node = NULL; ++ } else { ++ root->min = index + i - 1; ++ root->min |= (1UL << (node->height - 1)) - 1; ++ root->min++; ++ root->enter_node = node; ++ } ++ ++ if (num) { ++ item += j; ++ goto go_on; ++ } ++ ++ return 0; ++} ++ ++ ++/** ++ * sradix_tree_shrink - shrink height of a sradix tree to minimal ++ * @root sradix tree root ++ * ++ */ ++static inline void sradix_tree_shrink(struct sradix_tree_root *root) ++{ ++ /* try to shrink tree height */ ++ while (root->height > 1) { ++ struct sradix_tree_node *to_free = root->rnode; ++ ++ /* ++ * The candidate node has more than one child, or its child ++ * is not at the leftmost store, we cannot shrink. ++ */ ++ if (to_free->count != 1 || !to_free->stores[0]) ++ break; ++ ++ root->rnode = to_free->stores[0]; ++ root->rnode->parent = NULL; ++ root->height--; ++ if (unlikely(root->enter_node == to_free)) ++ root->enter_node = NULL; ++ root->free(to_free); ++ } ++} ++ ++/* ++ * Del the item on the known leaf node and index ++ */ ++void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index) ++{ ++ unsigned int offset; ++ struct sradix_tree_node *start, *end; ++ ++ BUG_ON(node->height != 1); ++ ++ start = node; ++ while (node && !(--node->count)) ++ node = node->parent; ++ ++ end = node; ++ if (!node) { ++ root->rnode = NULL; ++ root->height = 0; ++ root->min = 0; ++ root->num = 0; ++ root->enter_node = NULL; ++ } else { ++ offset = (index >> (root->shift * (node->height - 1))) & root->mask; ++ if (root->rm) ++ root->rm(node, offset); ++ node->stores[offset] = NULL; ++ root->num--; ++ if (root->min > index) { ++ root->min = index; ++ root->enter_node = node; ++ } ++ } ++ ++ if (start != end) { ++ do { ++ node = start; ++ start = start->parent; ++ if (unlikely(root->enter_node == node)) ++ root->enter_node = end; ++ root->free(node); ++ } while (start != end); ++ ++ /* ++ * Note that shrink may free "end", so enter_node still need to ++ * be checked inside. ++ */ ++ sradix_tree_shrink(root); ++ } else if (node->count == root->stores_size - 1) { ++ /* It WAS a full leaf node. Update the ancestors */ ++ node = node->parent; ++ while (node) { ++ node->fulls--; ++ if (node->fulls != root->stores_size - 1) ++ break; ++ ++ node = node->parent; ++ } ++ } ++} ++ ++void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index) ++{ ++ unsigned int height, offset; ++ struct sradix_tree_node *node; ++ int shift; ++ ++ node = root->rnode; ++ if (node == NULL || (index >> (root->shift * root->height))) ++ return NULL; ++ ++ height = root->height; ++ shift = (height - 1) * root->shift; ++ ++ do { ++ offset = (index >> shift) & root->mask; ++ node = node->stores[offset]; ++ if (!node) ++ return NULL; ++ ++ shift -= root->shift; ++ } while (shift >= 0); ++ ++ return node; ++} ++ ++/* ++ * Return the item if it exists, otherwise create it in place ++ * and return the created item. ++ */ ++void *sradix_tree_lookup_create(struct sradix_tree_root *root, ++ unsigned long index, void *(*item_alloc)(void)) ++{ ++ unsigned int height, offset; ++ struct sradix_tree_node *node, *tmp; ++ void *item; ++ int shift, error; ++ ++ if (root->rnode == NULL || (index >> (root->shift * root->height))) { ++ if (item_alloc) { ++ error = sradix_tree_extend(root, index); ++ if (error) ++ return NULL; ++ } else { ++ return NULL; ++ } ++ } ++ ++ node = root->rnode; ++ height = root->height; ++ shift = (height - 1) * root->shift; ++ ++ do { ++ offset = (index >> shift) & root->mask; ++ if (!node->stores[offset]) { ++ if (!(tmp = root->alloc())) ++ return NULL; ++ ++ tmp->height = shift / root->shift; ++ node->stores[offset] = tmp; ++ tmp->parent = node; ++ node->count++; ++ node = tmp; ++ } else { ++ node = node->stores[offset]; ++ } ++ ++ shift -= root->shift; ++ } while (shift > 0); ++ ++ BUG_ON(node->height != 1); ++ offset = index & root->mask; ++ if (node->stores[offset]) { ++ return node->stores[offset]; ++ } else if (item_alloc) { ++ if (!(item = item_alloc())) ++ return NULL; ++ ++ node->stores[offset] = item; ++ ++ /* ++ * NOTE: we do NOT call root->assign here, since this item is ++ * newly created by us having no meaning. Caller can call this ++ * if it's necessary to do so. ++ */ ++ ++ node->count++; ++ root->num++; ++ ++ while (sradix_node_full(root, node)) { ++ node = node->parent; ++ if (!node) ++ break; ++ ++ node->fulls++; ++ } ++ ++ if (unlikely(!node)) { ++ /* All nodes are full */ ++ root->min = 1 << (root->height * root->shift); ++ } else { ++ if (root->min == index) { ++ root->min |= (1UL << (node->height - 1)) - 1; ++ root->min++; ++ root->enter_node = node; ++ } ++ } ++ ++ return item; ++ } else { ++ return NULL; ++ } ++ ++} ++ ++int sradix_tree_delete(struct sradix_tree_root *root, unsigned long index) ++{ ++ unsigned int height, offset; ++ struct sradix_tree_node *node; ++ int shift; ++ ++ node = root->rnode; ++ if (node == NULL || (index >> (root->shift * root->height))) ++ return -ENOENT; ++ ++ height = root->height; ++ shift = (height - 1) * root->shift; ++ ++ do { ++ offset = (index >> shift) & root->mask; ++ node = node->stores[offset]; ++ if (!node) ++ return -ENOENT; ++ ++ shift -= root->shift; ++ } while (shift > 0); ++ ++ offset = index & root->mask; ++ if (!node->stores[offset]) ++ return -ENOENT; ++ ++ sradix_tree_delete_from_leaf(root, node, index); ++ ++ return 0; ++} +diff -Nur a/mm/Kconfig b/mm/Kconfig +--- a/mm/Kconfig 2019-07-07 11:39:06.880828472 +0100 ++++ b/mm/Kconfig 2019-07-07 11:43:00.148837320 +0100 +@@ -302,6 +302,32 @@ + See Documentation/vm/ksm.rst for more information: KSM is inactive + until a program has madvised that an area is MADV_MERGEABLE, and + root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set). ++choice ++ prompt "Choose UKSM/KSM strategy" ++ default UKSM ++ depends on KSM ++ help ++ This option allows to select a UKSM/KSM stragety. ++ ++config UKSM ++ bool "Ultra-KSM for page merging" ++ depends on KSM ++ help ++ UKSM is inspired by the Linux kernel project \u2014 KSM(Kernel Same ++ page Merging), but with a fundamentally rewritten core algorithm. With ++ an advanced algorithm, UKSM now can transparently scans all anonymously ++ mapped user space applications with an significantly improved scan speed ++ and CPU efficiency. Since KVM is friendly to KSM, KVM can also benefit from ++ UKSM. Now UKSM has its first stable release and first real world enterprise user. ++ For more information, please goto its project page. ++ (www.kerneldedup.org) ++ ++config KSM_LEGACY ++ bool "Legacy KSM implementation" ++ depends on KSM ++ help ++ The legacy KSM implementation from Red Hat. ++endchoice + + config DEFAULT_MMAP_MIN_ADDR + int "Low address space to protect from user allocation" +diff -Nur a/mm/ksm.c b/mm/ksm.c +--- a/mm/ksm.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/ksm.c 2019-07-07 11:43:00.148837320 +0100 +@@ -858,17 +858,6 @@ + return err; + } + +-static inline struct stable_node *page_stable_node(struct page *page) +-{ +- return PageKsm(page) ? page_rmapping(page) : NULL; +-} +- +-static inline void set_page_stable_node(struct page *page, +- struct stable_node *stable_node) +-{ +- page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); +-} +- + #ifdef CONFIG_SYSFS + /* + * Only called through the sysfs control interface: +diff -Nur a/mm/Makefile b/mm/Makefile +--- a/mm/Makefile 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/Makefile 2019-07-07 11:43:00.148837320 +0100 +@@ -58,7 +58,8 @@ + obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o + obj-$(CONFIG_SLOB) += slob.o + obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o +-obj-$(CONFIG_KSM) += ksm.o ++obj-$(CONFIG_KSM_LEGACY) += ksm.o ++obj-$(CONFIG_UKSM) += uksm.o + obj-$(CONFIG_PAGE_POISONING) += page_poison.o + obj-$(CONFIG_SLAB) += slab.o + obj-$(CONFIG_SLUB) += slub.o +diff -Nur a/mm/memory.c b/mm/memory.c +--- a/mm/memory.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/memory.c 2019-07-07 11:43:00.148837320 +0100 +@@ -129,6 +129,25 @@ + + unsigned long highest_memmap_pfn __read_mostly; + ++#ifdef CONFIG_UKSM ++unsigned long uksm_zero_pfn __read_mostly; ++EXPORT_SYMBOL_GPL(uksm_zero_pfn); ++struct page *empty_uksm_zero_page; ++ ++static int __init setup_uksm_zero_page(void) ++{ ++ empty_uksm_zero_page = alloc_pages(__GFP_ZERO & ~__GFP_MOVABLE, 0); ++ if (!empty_uksm_zero_page) ++ panic("Oh boy, that early out of memory?"); ++ ++ SetPageReserved(empty_uksm_zero_page); ++ uksm_zero_pfn = page_to_pfn(empty_uksm_zero_page); ++ ++ return 0; ++} ++core_initcall(setup_uksm_zero_page); ++#endif ++ + /* + * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() + */ +@@ -140,6 +159,7 @@ + core_initcall(init_zero_pfn); + + ++ + #if defined(SPLIT_RSS_COUNTING) + + void sync_mm_rss(struct mm_struct *mm) +@@ -794,6 +814,9 @@ + get_page(page); + page_dup_rmap(page, false); + rss[mm_counter(page)]++; ++ ++ /* Should return NULL in vm_normal_page() */ ++ uksm_bugon_zeropage(pte); + } else if (pte_devmap(pte)) { + page = pte_page(pte); + +@@ -807,6 +830,8 @@ + page_dup_rmap(page, false); + rss[mm_counter(page)]++; + } ++ } else { ++ uksm_map_zero_page(pte); + } + + out_set_pte: +@@ -1075,8 +1100,10 @@ + ptent = ptep_get_and_clear_full(mm, addr, pte, + tlb->fullmm); + tlb_remove_tlb_entry(tlb, pte, addr); +- if (unlikely(!page)) ++ if (unlikely(!page)) { ++ uksm_unmap_zero_page(ptent); + continue; ++ } + + if (!PageAnon(page)) { + if (pte_dirty(ptent)) { +@@ -2117,8 +2144,10 @@ + clear_page(kaddr); + kunmap_atomic(kaddr); + flush_dcache_page(dst); +- } else ++ } else { + copy_user_highpage(dst, src, va, vma); ++ uksm_cow_page(vma, src); ++ } + } + + static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) +@@ -2266,6 +2295,7 @@ + vmf->address); + if (!new_page) + goto oom; ++ uksm_cow_pte(vma, vmf->orig_pte); + } else { + new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, + vmf->address); +@@ -2294,7 +2324,9 @@ + mm_counter_file(old_page)); + inc_mm_counter_fast(mm, MM_ANONPAGES); + } ++ uksm_bugon_zeropage(vmf->orig_pte); + } else { ++ uksm_unmap_zero_page(vmf->orig_pte); + inc_mm_counter_fast(mm, MM_ANONPAGES); + } + flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); +diff -Nur a/mm/mmap.c b/mm/mmap.c +--- a/mm/mmap.c 2019-07-07 11:39:06.880828472 +0100 ++++ b/mm/mmap.c 2019-07-07 11:43:00.148837320 +0100 +@@ -46,6 +46,7 @@ + #include + #include + #include ++#include + + #include + #include +@@ -183,6 +184,7 @@ + if (vma->vm_file) + fput(vma->vm_file); + mpol_put(vma_policy(vma)); ++ uksm_remove_vma(vma); + vm_area_free(vma); + return next; + } +@@ -733,9 +735,16 @@ + long adjust_next = 0; + int remove_next = 0; + ++/* ++ * to avoid deadlock, ksm_remove_vma must be done before any spin_lock is ++ * acquired ++ */ ++ uksm_remove_vma(vma); ++ + if (next && !insert) { + struct vm_area_struct *exporter = NULL, *importer = NULL; + ++ uksm_remove_vma(next); + if (end >= next->vm_end) { + /* + * vma expands, overlapping all the next, and +@@ -868,6 +877,7 @@ + end_changed = true; + } + vma->vm_pgoff = pgoff; ++ + if (adjust_next) { + next->vm_start += adjust_next << PAGE_SHIFT; + next->vm_pgoff += adjust_next; +@@ -973,6 +983,7 @@ + if (remove_next == 2) { + remove_next = 1; + end = next->vm_end; ++ uksm_remove_vma(next); + goto again; + } + else if (next) +@@ -999,10 +1010,14 @@ + */ + VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma)); + } ++ } else { ++ if (next && !insert) ++ uksm_vma_add_new(next); + } + if (insert && file) + uprobe_mmap(insert); + ++ uksm_vma_add_new(vma); + validate_mm(mm); + + return 0; +@@ -1459,6 +1474,9 @@ + vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | + mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; + ++ /* If uksm is enabled, we add VM_MERGEABLE to new VMAs. */ ++ uksm_vm_flags_mod(&vm_flags); ++ + if (flags & MAP_LOCKED) + if (!can_do_mlock()) + return -EPERM; +@@ -1823,6 +1841,7 @@ + allow_write_access(file); + } + file = vma->vm_file; ++ uksm_vma_add_new(vma); + out: + perf_event_mmap(vma); + +@@ -1865,6 +1884,7 @@ + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); + free_vma: ++ uksm_remove_vma(vma); + vm_area_free(vma); + unacct_error: + if (charged) +@@ -2697,6 +2717,8 @@ + else + err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); + ++ uksm_vma_add_new(new); ++ + /* Success. */ + if (!err) + return 0; +@@ -3001,6 +3023,7 @@ + if ((flags & (~VM_EXEC)) != 0) + return -EINVAL; + flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; ++ uksm_vm_flags_mod(&flags); + + error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); + if (offset_in_page(error)) +@@ -3051,6 +3074,7 @@ + vma->vm_flags = flags; + vma->vm_page_prot = vm_get_page_prot(flags); + vma_link(mm, vma, prev, rb_link, rb_parent); ++ uksm_vma_add_new(vma); + out: + perf_event_mmap(vma); + mm->total_vm += len >> PAGE_SHIFT; +@@ -3128,6 +3152,12 @@ + up_write(&mm->mmap_sem); + } + ++ /* ++ * Taking write lock on mmap_sem does not harm others, ++ * but it's crucial for uksm to avoid races. ++ */ ++ down_write(&mm->mmap_sem); ++ + if (mm->locked_vm) { + vma = mm->mmap; + while (vma) { +@@ -3140,8 +3170,12 @@ + arch_exit_mmap(mm); + + vma = mm->mmap; +- if (!vma) /* Can happen if dup_mmap() received an OOM */ ++ /* Can happen if dup_mmap() received an OOM */ ++ if (!vma) { ++ /* Release write lock previously taken for UKSM */ ++ up_write(&mm->mmap_sem); + return; ++ } + + lru_add_drain(); + flush_cache_mm(mm); +@@ -3162,6 +3196,11 @@ + vma = remove_vma(vma); + } + vm_unacct_memory(nr_accounted); ++ ++ mm->mmap = NULL; ++ mm->mm_rb = RB_ROOT; ++ vmacache_invalidate(mm); ++ up_write(&mm->mmap_sem); + } + + /* Insert vm structure into process list sorted by address +@@ -3269,6 +3308,7 @@ + new_vma->vm_ops->open(new_vma); + vma_link(mm, new_vma, prev, rb_link, rb_parent); + *need_rmap_locks = false; ++ uksm_vma_add_new(new_vma); + } + return new_vma; + +@@ -3419,6 +3459,7 @@ + vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); + + perf_event_mmap(vma); ++ uksm_vma_add_new(vma); + + return vma; + +diff -Nur a/mm/rmap.c b/mm/rmap.c +--- a/mm/rmap.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/rmap.c 2019-07-07 11:43:00.148837320 +0100 +@@ -1021,7 +1021,7 @@ + * __page_set_anon_rmap - set up new anonymous rmap + * @page: Page or Hugepage to add to rmap + * @vma: VM area to add page to. +- * @address: User virtual address of the mapping ++ * @address: User virtual address of the mapping + * @exclusive: the page is exclusively owned by the current process + */ + static void __page_set_anon_rmap(struct page *page, +diff -Nur a/mm/uksm.c b/mm/uksm.c +--- a/mm/uksm.c 1970-01-01 01:00:00.000000000 +0100 ++++ b/mm/uksm.c 2019-07-07 11:43:00.148837320 +0100 +@@ -0,0 +1,5580 @@ ++/* ++ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia ++ * ++ * This is an improvement upon KSM. Some basic data structures and routines ++ * are borrowed from ksm.c . ++ * ++ * Its new features: ++ * 1. Full system scan: ++ * It automatically scans all user processes' anonymous VMAs. Kernel-user ++ * interaction to submit a memory area to KSM is no longer needed. ++ * ++ * 2. Rich area detection: ++ * It automatically detects rich areas containing abundant duplicated ++ * pages based. Rich areas are given a full scan speed. Poor areas are ++ * sampled at a reasonable speed with very low CPU consumption. ++ * ++ * 3. Ultra Per-page scan speed improvement: ++ * A new hash algorithm is proposed. As a result, on a machine with ++ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it ++ * can scan memory areas that does not contain duplicated pages at speed of ++ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of ++ * 477MB/sec ~ 923MB/sec. ++ * ++ * 4. Thrashing area avoidance: ++ * Thrashing area(an VMA that has frequent Ksm page break-out) can be ++ * filtered out. My benchmark shows it's more efficient than KSM's per-page ++ * hash value based volatile page detection. ++ * ++ * ++ * 5. Misc changes upon KSM: ++ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page ++ * comparison. It's much faster than default C version on x86. ++ * * rmap_item now has an struct *page member to loosely cache a ++ * address-->page mapping, which reduces too much time-costly ++ * follow_page(). ++ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. ++ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ ++ * ksm is needed for this case. ++ * ++ * 6. Full Zero Page consideration(contributed by Figo Zhang) ++ * Now uksmd consider full zero pages as special pages and merge them to an ++ * special unswappable uksm zero page. ++ */ ++ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++ ++#include ++#include "internal.h" ++ ++#ifdef CONFIG_X86 ++#undef memcmp ++ ++#ifdef CONFIG_X86_32 ++#define memcmp memcmpx86_32 ++/* ++ * Compare 4-byte-aligned address s1 and s2, with length n ++ */ ++int memcmpx86_32(void *s1, void *s2, size_t n) ++{ ++ size_t num = n / 4; ++ register int res; ++ ++ __asm__ __volatile__ ++ ( ++ "testl %3,%3\n\t" ++ "repe; cmpsd\n\t" ++ "je 1f\n\t" ++ "sbbl %0,%0\n\t" ++ "orl $1,%0\n" ++ "1:" ++ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) ++ : "0" (0) ++ : "cc"); ++ ++ return res; ++} ++ ++/* ++ * Check the page is all zero ? ++ */ ++static int is_full_zero(const void *s1, size_t len) ++{ ++ unsigned char same; ++ ++ len /= 4; ++ ++ __asm__ __volatile__ ++ ("repe; scasl;" ++ "sete %0" ++ : "=qm" (same), "+D" (s1), "+c" (len) ++ : "a" (0) ++ : "cc"); ++ ++ return same; ++} ++ ++ ++#elif defined(CONFIG_X86_64) ++#define memcmp memcmpx86_64 ++/* ++ * Compare 8-byte-aligned address s1 and s2, with length n ++ */ ++int memcmpx86_64(void *s1, void *s2, size_t n) ++{ ++ size_t num = n / 8; ++ register int res; ++ ++ __asm__ __volatile__ ++ ( ++ "testq %q3,%q3\n\t" ++ "repe; cmpsq\n\t" ++ "je 1f\n\t" ++ "sbbq %q0,%q0\n\t" ++ "orq $1,%q0\n" ++ "1:" ++ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) ++ : "0" (0) ++ : "cc"); ++ ++ return res; ++} ++ ++static int is_full_zero(const void *s1, size_t len) ++{ ++ unsigned char same; ++ ++ len /= 8; ++ ++ __asm__ __volatile__ ++ ("repe; scasq;" ++ "sete %0" ++ : "=qm" (same), "+D" (s1), "+c" (len) ++ : "a" (0) ++ : "cc"); ++ ++ return same; ++} ++ ++#endif ++#else ++static int is_full_zero(const void *s1, size_t len) ++{ ++ unsigned long *src = s1; ++ int i; ++ ++ len /= sizeof(*src); ++ ++ for (i = 0; i < len; i++) { ++ if (src[i]) ++ return 0; ++ } ++ ++ return 1; ++} ++#endif ++ ++#define UKSM_RUNG_ROUND_FINISHED (1 << 0) ++#define TIME_RATIO_SCALE 10000 ++ ++#define SLOT_TREE_NODE_SHIFT 8 ++#define SLOT_TREE_NODE_STORE_SIZE (1UL << SLOT_TREE_NODE_SHIFT) ++struct slot_tree_node { ++ unsigned long size; ++ struct sradix_tree_node snode; ++ void *stores[SLOT_TREE_NODE_STORE_SIZE]; ++}; ++ ++static struct kmem_cache *slot_tree_node_cachep; ++ ++static struct sradix_tree_node *slot_tree_node_alloc(void) ++{ ++ struct slot_tree_node *p; ++ ++ p = kmem_cache_zalloc(slot_tree_node_cachep, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (!p) ++ return NULL; ++ ++ return &p->snode; ++} ++ ++static void slot_tree_node_free(struct sradix_tree_node *node) ++{ ++ struct slot_tree_node *p; ++ ++ p = container_of(node, struct slot_tree_node, snode); ++ kmem_cache_free(slot_tree_node_cachep, p); ++} ++ ++static void slot_tree_node_extend(struct sradix_tree_node *parent, ++ struct sradix_tree_node *child) ++{ ++ struct slot_tree_node *p, *c; ++ ++ p = container_of(parent, struct slot_tree_node, snode); ++ c = container_of(child, struct slot_tree_node, snode); ++ ++ p->size += c->size; ++} ++ ++void slot_tree_node_assign(struct sradix_tree_node *node, ++ unsigned int index, void *item) ++{ ++ struct vma_slot *slot = item; ++ struct slot_tree_node *cur; ++ ++ slot->snode = node; ++ slot->sindex = index; ++ ++ while (node) { ++ cur = container_of(node, struct slot_tree_node, snode); ++ cur->size += slot->pages; ++ node = node->parent; ++ } ++} ++ ++void slot_tree_node_rm(struct sradix_tree_node *node, unsigned int offset) ++{ ++ struct vma_slot *slot; ++ struct slot_tree_node *cur; ++ unsigned long pages; ++ ++ if (node->height == 1) { ++ slot = node->stores[offset]; ++ pages = slot->pages; ++ } else { ++ cur = container_of(node->stores[offset], ++ struct slot_tree_node, snode); ++ pages = cur->size; ++ } ++ ++ while (node) { ++ cur = container_of(node, struct slot_tree_node, snode); ++ cur->size -= pages; ++ node = node->parent; ++ } ++} ++ ++unsigned long slot_iter_index; ++int slot_iter(void *item, unsigned long height) ++{ ++ struct slot_tree_node *node; ++ struct vma_slot *slot; ++ ++ if (height == 1) { ++ slot = item; ++ if (slot_iter_index < slot->pages) { ++ /*in this one*/ ++ return 1; ++ } else { ++ slot_iter_index -= slot->pages; ++ return 0; ++ } ++ ++ } else { ++ node = container_of(item, struct slot_tree_node, snode); ++ if (slot_iter_index < node->size) { ++ /*in this one*/ ++ return 1; ++ } else { ++ slot_iter_index -= node->size; ++ return 0; ++ } ++ } ++} ++ ++ ++static inline void slot_tree_init_root(struct sradix_tree_root *root) ++{ ++ init_sradix_tree_root(root, SLOT_TREE_NODE_SHIFT); ++ root->alloc = slot_tree_node_alloc; ++ root->free = slot_tree_node_free; ++ root->extend = slot_tree_node_extend; ++ root->assign = slot_tree_node_assign; ++ root->rm = slot_tree_node_rm; ++} ++ ++void slot_tree_init(void) ++{ ++ slot_tree_node_cachep = kmem_cache_create("slot_tree_node", ++ sizeof(struct slot_tree_node), 0, ++ SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, ++ NULL); ++} ++ ++ ++/* Each rung of this ladder is a list of VMAs having a same scan ratio */ ++struct scan_rung { ++ //struct list_head scanned_list; ++ struct sradix_tree_root vma_root; ++ struct sradix_tree_root vma_root2; ++ ++ struct vma_slot *current_scan; ++ unsigned long current_offset; ++ ++ /* ++ * The initial value for current_offset, it should loop over ++ * [0~ step - 1] to let all slot have its chance to be scanned. ++ */ ++ unsigned long offset_init; ++ unsigned long step; /* dynamic step for current_offset */ ++ unsigned int flags; ++ unsigned long pages_to_scan; ++ //unsigned long fully_scanned_slots; ++ /* ++ * a little bit tricky - if cpu_time_ratio > 0, then the value is the ++ * the cpu time ratio it can spend in rung_i for every scan ++ * period. if < 0, then it is the cpu time ratio relative to the ++ * max cpu percentage user specified. Both in unit of ++ * 1/TIME_RATIO_SCALE ++ */ ++ int cpu_ratio; ++ ++ /* ++ * How long it will take for all slots in this rung to be fully ++ * scanned? If it's zero, we don't care about the cover time: ++ * it's fully scanned. ++ */ ++ unsigned int cover_msecs; ++ //unsigned long vma_num; ++ //unsigned long pages; /* Sum of all slot's pages in rung */ ++}; ++ ++/** ++ * node of either the stable or unstale rbtree ++ * ++ */ ++struct tree_node { ++ struct rb_node node; /* link in the main (un)stable rbtree */ ++ struct rb_root sub_root; /* rb_root for sublevel collision rbtree */ ++ u32 hash; ++ unsigned long count; /* TODO: merged with sub_root */ ++ struct list_head all_list; /* all tree nodes in stable/unstable tree */ ++}; ++ ++/** ++ * struct stable_node - node of the stable rbtree ++ * @node: rb node of this ksm page in the stable tree ++ * @hlist: hlist head of rmap_items using this ksm page ++ * @kpfn: page frame number of this ksm page ++ */ ++struct stable_node { ++ struct rb_node node; /* link in sub-rbtree */ ++ struct tree_node *tree_node; /* it's tree node root in stable tree, NULL if it's in hell list */ ++ struct hlist_head hlist; ++ unsigned long kpfn; ++ u32 hash_max; /* if ==0 then it's not been calculated yet */ ++ struct list_head all_list; /* in a list for all stable nodes */ ++}; ++ ++/** ++ * struct node_vma - group rmap_items linked in a same stable ++ * node together. ++ */ ++struct node_vma { ++ union { ++ struct vma_slot *slot; ++ unsigned long key; /* slot is used as key sorted on hlist */ ++ }; ++ struct hlist_node hlist; ++ struct hlist_head rmap_hlist; ++ struct stable_node *head; ++}; ++ ++/** ++ * struct rmap_item - reverse mapping item for virtual addresses ++ * @rmap_list: next rmap_item in mm_slot's singly-linked rmap_list ++ * @anon_vma: pointer to anon_vma for this mm,address, when in stable tree ++ * @mm: the memory structure this rmap_item is pointing into ++ * @address: the virtual address this rmap_item tracks (+ flags in low bits) ++ * @node: rb node of this rmap_item in the unstable tree ++ * @head: pointer to stable_node heading this list in the stable tree ++ * @hlist: link into hlist of rmap_items hanging off that stable_node ++ */ ++struct rmap_item { ++ struct vma_slot *slot; ++ struct page *page; ++ unsigned long address; /* + low bits used for flags below */ ++ unsigned long hash_round; ++ unsigned long entry_index; ++ union { ++ struct {/* when in unstable tree */ ++ struct rb_node node; ++ struct tree_node *tree_node; ++ u32 hash_max; ++ }; ++ struct { /* when in stable tree */ ++ struct node_vma *head; ++ struct hlist_node hlist; ++ struct anon_vma *anon_vma; ++ }; ++ }; ++} __aligned(4); ++ ++struct rmap_list_entry { ++ union { ++ struct rmap_item *item; ++ unsigned long addr; ++ }; ++ /* lowest bit is used for is_addr tag */ ++} __aligned(4); /* 4 aligned to fit in to pages*/ ++ ++ ++/* Basic data structure definition ends */ ++ ++ ++/* ++ * Flags for rmap_item to judge if it's listed in the stable/unstable tree. ++ * The flags use the low bits of rmap_item.address ++ */ ++#define UNSTABLE_FLAG 0x1 ++#define STABLE_FLAG 0x2 ++#define get_rmap_addr(x) ((x)->address & PAGE_MASK) ++ ++/* ++ * rmap_list_entry helpers ++ */ ++#define IS_ADDR_FLAG 1 ++#define is_addr(ptr) ((unsigned long)(ptr) & IS_ADDR_FLAG) ++#define set_is_addr(ptr) ((ptr) |= IS_ADDR_FLAG) ++#define get_clean_addr(ptr) (((ptr) & ~(__typeof__(ptr))IS_ADDR_FLAG)) ++ ++ ++/* ++ * High speed caches for frequently allocated and freed structs ++ */ ++static struct kmem_cache *rmap_item_cache; ++static struct kmem_cache *stable_node_cache; ++static struct kmem_cache *node_vma_cache; ++static struct kmem_cache *vma_slot_cache; ++static struct kmem_cache *tree_node_cache; ++#define UKSM_KMEM_CACHE(__struct, __flags) kmem_cache_create("uksm_"#__struct,\ ++ sizeof(struct __struct), __alignof__(struct __struct),\ ++ (__flags), NULL) ++ ++/* Array of all scan_rung, uksm_scan_ladder[0] having the minimum scan ratio */ ++#define SCAN_LADDER_SIZE 4 ++static struct scan_rung uksm_scan_ladder[SCAN_LADDER_SIZE]; ++ ++/* The evaluation rounds uksmd has finished */ ++static unsigned long long uksm_eval_round = 1; ++ ++/* ++ * we add 1 to this var when we consider we should rebuild the whole ++ * unstable tree. ++ */ ++static unsigned long uksm_hash_round = 1; ++ ++/* ++ * How many times the whole memory is scanned. ++ */ ++static unsigned long long fully_scanned_round = 1; ++ ++/* The total number of virtual pages of all vma slots */ ++static u64 uksm_pages_total; ++ ++/* The number of pages has been scanned since the start up */ ++static u64 uksm_pages_scanned; ++ ++static u64 scanned_virtual_pages; ++ ++/* The number of pages has been scanned since last encode_benefit call */ ++static u64 uksm_pages_scanned_last; ++ ++/* If the scanned number is tooo large, we encode it here */ ++static u64 pages_scanned_stored; ++ ++static unsigned long pages_scanned_base; ++ ++/* The number of nodes in the stable tree */ ++static unsigned long uksm_pages_shared; ++ ++/* The number of page slots additionally sharing those nodes */ ++static unsigned long uksm_pages_sharing; ++ ++/* The number of nodes in the unstable tree */ ++static unsigned long uksm_pages_unshared; ++ ++/* ++ * Milliseconds ksmd should sleep between scans, ++ * >= 100ms to be consistent with ++ * scan_time_to_sleep_msec() ++ */ ++static unsigned int uksm_sleep_jiffies; ++ ++/* The real value for the uksmd next sleep */ ++static unsigned int uksm_sleep_real; ++ ++/* Saved value for user input uksm_sleep_jiffies when it's enlarged */ ++static unsigned int uksm_sleep_saved; ++ ++/* Max percentage of cpu utilization ksmd can take to scan in one batch */ ++static unsigned int uksm_max_cpu_percentage; ++ ++static int uksm_cpu_governor; ++ ++static char *uksm_cpu_governor_str[4] = { "full", "medium", "low", "quiet" }; ++ ++struct uksm_cpu_preset_s { ++ int cpu_ratio[SCAN_LADDER_SIZE]; ++ unsigned int cover_msecs[SCAN_LADDER_SIZE]; ++ unsigned int max_cpu; /* percentage */ ++}; ++ ++struct uksm_cpu_preset_s uksm_cpu_preset[4] = { ++ { {20, 40, -2500, -10000}, {1000, 500, 200, 50}, 95}, ++ { {20, 30, -2500, -10000}, {1000, 500, 400, 100}, 50}, ++ { {10, 20, -5000, -10000}, {1500, 1000, 1000, 250}, 20}, ++ { {10, 20, 40, 75}, {2000, 1000, 1000, 1000}, 1}, ++}; ++ ++/* The default value for uksm_ema_page_time if it's not initialized */ ++#define UKSM_PAGE_TIME_DEFAULT 500 ++ ++/*cost to scan one page by expotional moving average in nsecs */ ++static unsigned long uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; ++ ++/* The expotional moving average alpha weight, in percentage. */ ++#define EMA_ALPHA 20 ++ ++/* ++ * The threshold used to filter out thrashing areas, ++ * If it == 0, filtering is disabled, otherwise it's the percentage up-bound ++ * of the thrashing ratio of all areas. Any area with a bigger thrashing ratio ++ * will be considered as having a zero duplication ratio. ++ */ ++static unsigned int uksm_thrash_threshold = 50; ++ ++/* How much dedup ratio is considered to be abundant*/ ++static unsigned int uksm_abundant_threshold = 10; ++ ++/* All slots having merged pages in this eval round. */ ++struct list_head vma_slot_dedup = LIST_HEAD_INIT(vma_slot_dedup); ++ ++/* How many times the ksmd has slept since startup */ ++static unsigned long long uksm_sleep_times; ++ ++#define UKSM_RUN_STOP 0 ++#define UKSM_RUN_MERGE 1 ++static unsigned int uksm_run = 1; ++ ++static DECLARE_WAIT_QUEUE_HEAD(uksm_thread_wait); ++static DEFINE_MUTEX(uksm_thread_mutex); ++ ++/* ++ * List vma_slot_new is for newly created vma_slot waiting to be added by ++ * ksmd. If one cannot be added(e.g. due to it's too small), it's moved to ++ * vma_slot_noadd. vma_slot_del is the list for vma_slot whose corresponding ++ * VMA has been removed/freed. ++ */ ++struct list_head vma_slot_new = LIST_HEAD_INIT(vma_slot_new); ++struct list_head vma_slot_noadd = LIST_HEAD_INIT(vma_slot_noadd); ++struct list_head vma_slot_del = LIST_HEAD_INIT(vma_slot_del); ++static DEFINE_SPINLOCK(vma_slot_list_lock); ++ ++/* The unstable tree heads */ ++static struct rb_root root_unstable_tree = RB_ROOT; ++ ++/* ++ * All tree_nodes are in a list to be freed at once when unstable tree is ++ * freed after each scan round. ++ */ ++static struct list_head unstable_tree_node_list = ++ LIST_HEAD_INIT(unstable_tree_node_list); ++ ++/* List contains all stable nodes */ ++static struct list_head stable_node_list = LIST_HEAD_INIT(stable_node_list); ++ ++/* ++ * When the hash strength is changed, the stable tree must be delta_hashed and ++ * re-structured. We use two set of below structs to speed up the ++ * re-structuring of stable tree. ++ */ ++static struct list_head ++stable_tree_node_list[2] = {LIST_HEAD_INIT(stable_tree_node_list[0]), ++ LIST_HEAD_INIT(stable_tree_node_list[1])}; ++ ++static struct list_head *stable_tree_node_listp = &stable_tree_node_list[0]; ++static struct rb_root root_stable_tree[2] = {RB_ROOT, RB_ROOT}; ++static struct rb_root *root_stable_treep = &root_stable_tree[0]; ++static unsigned long stable_tree_index; ++ ++/* The hash strength needed to hash a full page */ ++#define HASH_STRENGTH_FULL (PAGE_SIZE / sizeof(u32)) ++ ++/* The hash strength needed for loop-back hashing */ ++#define HASH_STRENGTH_MAX (HASH_STRENGTH_FULL + 10) ++ ++/* The random offsets in a page */ ++static u32 *random_nums; ++ ++/* The hash strength */ ++static unsigned long hash_strength = HASH_STRENGTH_FULL >> 4; ++ ++/* The delta value each time the hash strength increases or decreases */ ++static unsigned long hash_strength_delta; ++#define HASH_STRENGTH_DELTA_MAX 5 ++ ++/* The time we have saved due to random_sample_hash */ ++static u64 rshash_pos; ++ ++/* The time we have wasted due to hash collision */ ++static u64 rshash_neg; ++ ++struct uksm_benefit { ++ u64 pos; ++ u64 neg; ++ u64 scanned; ++ unsigned long base; ++} benefit; ++ ++/* ++ * The relative cost of memcmp, compared to 1 time unit of random sample ++ * hash, this value is tested when ksm module is initialized ++ */ ++static unsigned long memcmp_cost; ++ ++static unsigned long rshash_neg_cont_zero; ++static unsigned long rshash_cont_obscure; ++ ++/* The possible states of hash strength adjustment heuristic */ ++enum rshash_states { ++ RSHASH_STILL, ++ RSHASH_TRYUP, ++ RSHASH_TRYDOWN, ++ RSHASH_NEW, ++ RSHASH_PRE_STILL, ++}; ++ ++/* The possible direction we are about to adjust hash strength */ ++enum rshash_direct { ++ GO_UP, ++ GO_DOWN, ++ OBSCURE, ++ STILL, ++}; ++ ++/* random sampling hash state machine */ ++static struct { ++ enum rshash_states state; ++ enum rshash_direct pre_direct; ++ u8 below_count; ++ /* Keep a lookup window of size 5, iff above_count/below_count > 3 ++ * in this window we stop trying. ++ */ ++ u8 lookup_window_index; ++ u64 stable_benefit; ++ unsigned long turn_point_down; ++ unsigned long turn_benefit_down; ++ unsigned long turn_point_up; ++ unsigned long turn_benefit_up; ++ unsigned long stable_point; ++} rshash_state; ++ ++/*zero page hash table, hash_strength [0 ~ HASH_STRENGTH_MAX]*/ ++static u32 *zero_hash_table; ++ ++static inline struct node_vma *alloc_node_vma(void) ++{ ++ struct node_vma *node_vma; ++ ++ node_vma = kmem_cache_zalloc(node_vma_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (node_vma) { ++ INIT_HLIST_HEAD(&node_vma->rmap_hlist); ++ INIT_HLIST_NODE(&node_vma->hlist); ++ } ++ return node_vma; ++} ++ ++static inline void free_node_vma(struct node_vma *node_vma) ++{ ++ kmem_cache_free(node_vma_cache, node_vma); ++} ++ ++ ++static inline struct vma_slot *alloc_vma_slot(void) ++{ ++ struct vma_slot *slot; ++ ++ /* ++ * In case ksm is not initialized by now. ++ * Oops, we need to consider the call site of uksm_init() in the future. ++ */ ++ if (!vma_slot_cache) ++ return NULL; ++ ++ slot = kmem_cache_zalloc(vma_slot_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (slot) { ++ INIT_LIST_HEAD(&slot->slot_list); ++ INIT_LIST_HEAD(&slot->dedup_list); ++ slot->flags |= UKSM_SLOT_NEED_RERAND; ++ } ++ return slot; ++} ++ ++static inline void free_vma_slot(struct vma_slot *vma_slot) ++{ ++ kmem_cache_free(vma_slot_cache, vma_slot); ++} ++ ++ ++ ++static inline struct rmap_item *alloc_rmap_item(void) ++{ ++ struct rmap_item *rmap_item; ++ ++ rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (rmap_item) { ++ /* bug on lowest bit is not clear for flag use */ ++ BUG_ON(is_addr(rmap_item)); ++ } ++ return rmap_item; ++} ++ ++static inline void free_rmap_item(struct rmap_item *rmap_item) ++{ ++ rmap_item->slot = NULL; /* debug safety */ ++ kmem_cache_free(rmap_item_cache, rmap_item); ++} ++ ++static inline struct stable_node *alloc_stable_node(void) ++{ ++ struct stable_node *node; ++ ++ node = kmem_cache_alloc(stable_node_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (!node) ++ return NULL; ++ ++ INIT_HLIST_HEAD(&node->hlist); ++ list_add(&node->all_list, &stable_node_list); ++ return node; ++} ++ ++static inline void free_stable_node(struct stable_node *stable_node) ++{ ++ list_del(&stable_node->all_list); ++ kmem_cache_free(stable_node_cache, stable_node); ++} ++ ++static inline struct tree_node *alloc_tree_node(struct list_head *list) ++{ ++ struct tree_node *node; ++ ++ node = kmem_cache_zalloc(tree_node_cache, GFP_KERNEL | ++ __GFP_NORETRY | __GFP_NOWARN); ++ if (!node) ++ return NULL; ++ ++ list_add(&node->all_list, list); ++ return node; ++} ++ ++static inline void free_tree_node(struct tree_node *node) ++{ ++ list_del(&node->all_list); ++ kmem_cache_free(tree_node_cache, node); ++} ++ ++static void uksm_drop_anon_vma(struct rmap_item *rmap_item) ++{ ++ struct anon_vma *anon_vma = rmap_item->anon_vma; ++ ++ put_anon_vma(anon_vma); ++} ++ ++ ++/** ++ * Remove a stable node from stable_tree, may unlink from its tree_node and ++ * may remove its parent tree_node if no other stable node is pending. ++ * ++ * @stable_node The node need to be removed ++ * @unlink_rb Will this node be unlinked from the rbtree? ++ * @remove_tree_ node Will its tree_node be removed if empty? ++ */ ++static void remove_node_from_stable_tree(struct stable_node *stable_node, ++ int unlink_rb, int remove_tree_node) ++{ ++ struct node_vma *node_vma; ++ struct rmap_item *rmap_item; ++ struct hlist_node *n; ++ ++ if (!hlist_empty(&stable_node->hlist)) { ++ hlist_for_each_entry_safe(node_vma, n, ++ &stable_node->hlist, hlist) { ++ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { ++ uksm_pages_sharing--; ++ ++ uksm_drop_anon_vma(rmap_item); ++ rmap_item->address &= PAGE_MASK; ++ } ++ free_node_vma(node_vma); ++ cond_resched(); ++ } ++ ++ /* the last one is counted as shared */ ++ uksm_pages_shared--; ++ uksm_pages_sharing++; ++ } ++ ++ if (stable_node->tree_node && unlink_rb) { ++ rb_erase(&stable_node->node, ++ &stable_node->tree_node->sub_root); ++ ++ if (RB_EMPTY_ROOT(&stable_node->tree_node->sub_root) && ++ remove_tree_node) { ++ rb_erase(&stable_node->tree_node->node, ++ root_stable_treep); ++ free_tree_node(stable_node->tree_node); ++ } else { ++ stable_node->tree_node->count--; ++ } ++ } ++ ++ free_stable_node(stable_node); ++} ++ ++ ++/* ++ * get_uksm_page: checks if the page indicated by the stable node ++ * is still its ksm page, despite having held no reference to it. ++ * In which case we can trust the content of the page, and it ++ * returns the gotten page; but if the page has now been zapped, ++ * remove the stale node from the stable tree and return NULL. ++ * ++ * You would expect the stable_node to hold a reference to the ksm page. ++ * But if it increments the page's count, swapping out has to wait for ++ * ksmd to come around again before it can free the page, which may take ++ * seconds or even minutes: much too unresponsive. So instead we use a ++ * "keyhole reference": access to the ksm page from the stable node peeps ++ * out through its keyhole to see if that page still holds the right key, ++ * pointing back to this stable node. This relies on freeing a PageAnon ++ * page to reset its page->mapping to NULL, and relies on no other use of ++ * a page to put something that might look like our key in page->mapping. ++ * ++ * include/linux/pagemap.h page_cache_get_speculative() is a good reference, ++ * but this is different - made simpler by uksm_thread_mutex being held, but ++ * interesting for assuming that no other use of the struct page could ever ++ * put our expected_mapping into page->mapping (or a field of the union which ++ * coincides with page->mapping). The RCU calls are not for KSM at all, but ++ * to keep the page_count protocol described with page_cache_get_speculative. ++ * ++ * Note: it is possible that get_uksm_page() will return NULL one moment, ++ * then page the next, if the page is in between page_freeze_refs() and ++ * page_unfreeze_refs(): this shouldn't be a problem anywhere, the page ++ * is on its way to being freed; but it is an anomaly to bear in mind. ++ * ++ * @unlink_rb: if the removal of this node will firstly unlink from ++ * its rbtree. stable_node_reinsert will prevent this when restructuring the ++ * node from its old tree. ++ * ++ * @remove_tree_node: if this is the last one of its tree_node, will the ++ * tree_node be freed ? If we are inserting stable node, this tree_node may ++ * be reused, so don't free it. ++ */ ++static struct page *get_uksm_page(struct stable_node *stable_node, ++ int unlink_rb, int remove_tree_node) ++{ ++ struct page *page; ++ void *expected_mapping; ++ unsigned long kpfn; ++ ++ expected_mapping = (void *)((unsigned long)stable_node | ++ PAGE_MAPPING_KSM); ++again: ++ kpfn = READ_ONCE(stable_node->kpfn); ++ page = pfn_to_page(kpfn); ++ ++ /* ++ * page is computed from kpfn, so on most architectures reading ++ * page->mapping is naturally ordered after reading node->kpfn, ++ * but on Alpha we need to be more careful. ++ */ ++ smp_read_barrier_depends(); ++ ++ if (READ_ONCE(page->mapping) != expected_mapping) ++ goto stale; ++ ++ /* ++ * We cannot do anything with the page while its refcount is 0. ++ * Usually 0 means free, or tail of a higher-order page: in which ++ * case this node is no longer referenced, and should be freed; ++ * however, it might mean that the page is under page_freeze_refs(). ++ * The __remove_mapping() case is easy, again the node is now stale; ++ * but if page is swapcache in migrate_page_move_mapping(), it might ++ * still be our page, in which case it's essential to keep the node. ++ */ ++ while (!get_page_unless_zero(page)) { ++ /* ++ * Another check for page->mapping != expected_mapping would ++ * work here too. We have chosen the !PageSwapCache test to ++ * optimize the common case, when the page is or is about to ++ * be freed: PageSwapCache is cleared (under spin_lock_irq) ++ * in the freeze_refs section of __remove_mapping(); but Anon ++ * page->mapping reset to NULL later, in free_pages_prepare(). ++ */ ++ if (!PageSwapCache(page)) ++ goto stale; ++ cpu_relax(); ++ } ++ ++ if (READ_ONCE(page->mapping) != expected_mapping) { ++ put_page(page); ++ goto stale; ++ } ++ ++ lock_page(page); ++ if (READ_ONCE(page->mapping) != expected_mapping) { ++ unlock_page(page); ++ put_page(page); ++ goto stale; ++ } ++ unlock_page(page); ++ return page; ++stale: ++ /* ++ * We come here from above when page->mapping or !PageSwapCache ++ * suggests that the node is stale; but it might be under migration. ++ * We need smp_rmb(), matching the smp_wmb() in ksm_migrate_page(), ++ * before checking whether node->kpfn has been changed. ++ */ ++ smp_rmb(); ++ if (stable_node->kpfn != kpfn) ++ goto again; ++ ++ remove_node_from_stable_tree(stable_node, unlink_rb, remove_tree_node); ++ ++ return NULL; ++} ++ ++/* ++ * Removing rmap_item from stable or unstable tree. ++ * This function will clean the information from the stable/unstable tree. ++ */ ++static inline void remove_rmap_item_from_tree(struct rmap_item *rmap_item) ++{ ++ if (rmap_item->address & STABLE_FLAG) { ++ struct stable_node *stable_node; ++ struct node_vma *node_vma; ++ struct page *page; ++ ++ node_vma = rmap_item->head; ++ stable_node = node_vma->head; ++ page = get_uksm_page(stable_node, 1, 1); ++ if (!page) ++ goto out; ++ ++ /* ++ * page lock is needed because it's racing with ++ * try_to_unmap_ksm(), etc. ++ */ ++ lock_page(page); ++ hlist_del(&rmap_item->hlist); ++ ++ if (hlist_empty(&node_vma->rmap_hlist)) { ++ hlist_del(&node_vma->hlist); ++ free_node_vma(node_vma); ++ } ++ unlock_page(page); ++ ++ put_page(page); ++ if (hlist_empty(&stable_node->hlist)) { ++ /* do NOT call remove_node_from_stable_tree() here, ++ * it's possible for a forked rmap_item not in ++ * stable tree while the in-tree rmap_items were ++ * deleted. ++ */ ++ uksm_pages_shared--; ++ } else ++ uksm_pages_sharing--; ++ ++ ++ uksm_drop_anon_vma(rmap_item); ++ } else if (rmap_item->address & UNSTABLE_FLAG) { ++ if (rmap_item->hash_round == uksm_hash_round) { ++ ++ rb_erase(&rmap_item->node, ++ &rmap_item->tree_node->sub_root); ++ if (RB_EMPTY_ROOT(&rmap_item->tree_node->sub_root)) { ++ rb_erase(&rmap_item->tree_node->node, ++ &root_unstable_tree); ++ ++ free_tree_node(rmap_item->tree_node); ++ } else ++ rmap_item->tree_node->count--; ++ } ++ uksm_pages_unshared--; ++ } ++ ++ rmap_item->address &= PAGE_MASK; ++ rmap_item->hash_max = 0; ++ ++out: ++ cond_resched(); /* we're called from many long loops */ ++} ++ ++static inline int slot_in_uksm(struct vma_slot *slot) ++{ ++ return list_empty(&slot->slot_list); ++} ++ ++/* ++ * Test if the mm is exiting ++ */ ++static inline bool uksm_test_exit(struct mm_struct *mm) ++{ ++ return atomic_read(&mm->mm_users) == 0; ++} ++ ++static inline unsigned long vma_pool_size(struct vma_slot *slot) ++{ ++ return round_up(sizeof(struct rmap_list_entry) * slot->pages, ++ PAGE_SIZE) >> PAGE_SHIFT; ++} ++ ++#define CAN_OVERFLOW_U64(x, delta) (U64_MAX - (x) < (delta)) ++ ++/* must be done with sem locked */ ++static int slot_pool_alloc(struct vma_slot *slot) ++{ ++ unsigned long pool_size; ++ ++ if (slot->rmap_list_pool) ++ return 0; ++ ++ pool_size = vma_pool_size(slot); ++ slot->rmap_list_pool = kcalloc(pool_size, sizeof(struct page *), ++ GFP_KERNEL); ++ if (!slot->rmap_list_pool) ++ return -ENOMEM; ++ ++ slot->pool_counts = kcalloc(pool_size, sizeof(unsigned int), ++ GFP_KERNEL); ++ if (!slot->pool_counts) { ++ kfree(slot->rmap_list_pool); ++ return -ENOMEM; ++ } ++ ++ slot->pool_size = pool_size; ++ BUG_ON(CAN_OVERFLOW_U64(uksm_pages_total, slot->pages)); ++ slot->flags |= UKSM_SLOT_IN_UKSM; ++ uksm_pages_total += slot->pages; ++ ++ return 0; ++} ++ ++/* ++ * Called after vma is unlinked from its mm ++ */ ++void uksm_remove_vma(struct vm_area_struct *vma) ++{ ++ struct vma_slot *slot; ++ ++ if (!vma->uksm_vma_slot) ++ return; ++ ++ spin_lock(&vma_slot_list_lock); ++ slot = vma->uksm_vma_slot; ++ if (!slot) ++ goto out; ++ ++ if (slot_in_uksm(slot)) { ++ /** ++ * This slot has been added by ksmd, so move to the del list ++ * waiting ksmd to free it. ++ */ ++ list_add_tail(&slot->slot_list, &vma_slot_del); ++ } else { ++ /** ++ * It's still on new list. It's ok to free slot directly. ++ */ ++ list_del(&slot->slot_list); ++ free_vma_slot(slot); ++ } ++out: ++ vma->uksm_vma_slot = NULL; ++ spin_unlock(&vma_slot_list_lock); ++} ++ ++/** ++ * Need to do two things: ++ * 1. check if slot was moved to del list ++ * 2. make sure the mmap_sem is manipulated under valid vma. ++ * ++ * My concern here is that in some cases, this may make ++ * vma_slot_list_lock() waiters to serialized further by some ++ * sem->wait_lock, can this really be expensive? ++ * ++ * ++ * @return ++ * 0: if successfully locked mmap_sem ++ * -ENOENT: this slot was moved to del list ++ * -EBUSY: vma lock failed ++ */ ++static int try_down_read_slot_mmap_sem(struct vma_slot *slot) ++{ ++ struct vm_area_struct *vma; ++ struct mm_struct *mm; ++ struct rw_semaphore *sem; ++ ++ spin_lock(&vma_slot_list_lock); ++ ++ /* the slot_list was removed and inited from new list, when it enters ++ * uksm_list. If now it's not empty, then it must be moved to del list ++ */ ++ if (!slot_in_uksm(slot)) { ++ spin_unlock(&vma_slot_list_lock); ++ return -ENOENT; ++ } ++ ++ BUG_ON(slot->pages != vma_pages(slot->vma)); ++ /* Ok, vma still valid */ ++ vma = slot->vma; ++ mm = vma->vm_mm; ++ sem = &mm->mmap_sem; ++ ++ if (uksm_test_exit(mm)) { ++ spin_unlock(&vma_slot_list_lock); ++ return -ENOENT; ++ } ++ ++ if (down_read_trylock(sem)) { ++ spin_unlock(&vma_slot_list_lock); ++ if (slot_pool_alloc(slot)) { ++ uksm_remove_vma(vma); ++ up_read(sem); ++ return -ENOENT; ++ } ++ return 0; ++ } ++ ++ spin_unlock(&vma_slot_list_lock); ++ return -EBUSY; ++} ++ ++static inline unsigned long ++vma_page_address(struct page *page, struct vm_area_struct *vma) ++{ ++ pgoff_t pgoff = page->index; ++ unsigned long address; ++ ++ address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); ++ if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { ++ /* page should be within @vma mapping range */ ++ return -EFAULT; ++ } ++ return address; ++} ++ ++ ++/* return 0 on success with the item's mmap_sem locked */ ++static inline int get_mergeable_page_lock_mmap(struct rmap_item *item) ++{ ++ struct mm_struct *mm; ++ struct vma_slot *slot = item->slot; ++ int err = -EINVAL; ++ ++ struct page *page; ++ ++ /* ++ * try_down_read_slot_mmap_sem() returns non-zero if the slot ++ * has been removed by uksm_remove_vma(). ++ */ ++ if (try_down_read_slot_mmap_sem(slot)) ++ return -EBUSY; ++ ++ mm = slot->vma->vm_mm; ++ ++ if (uksm_test_exit(mm)) ++ goto failout_up; ++ ++ page = item->page; ++ rcu_read_lock(); ++ if (!get_page_unless_zero(page)) { ++ rcu_read_unlock(); ++ goto failout_up; ++ } ++ ++ /* No need to consider huge page here. */ ++ if (item->slot->vma->anon_vma != page_anon_vma(page) || ++ vma_page_address(page, item->slot->vma) != get_rmap_addr(item)) { ++ /* ++ * TODO: ++ * should we release this item becase of its stale page ++ * mapping? ++ */ ++ put_page(page); ++ rcu_read_unlock(); ++ goto failout_up; ++ } ++ rcu_read_unlock(); ++ return 0; ++ ++failout_up: ++ up_read(&mm->mmap_sem); ++ return err; ++} ++ ++/* ++ * What kind of VMA is considered ? ++ */ ++static inline int vma_can_enter(struct vm_area_struct *vma) ++{ ++ return uksm_flags_can_scan(vma->vm_flags); ++} ++ ++/* ++ * Called whenever a fresh new vma is created A new vma_slot. ++ * is created and inserted into a global list Must be called. ++ * after vma is inserted to its mm. ++ */ ++void uksm_vma_add_new(struct vm_area_struct *vma) ++{ ++ struct vma_slot *slot; ++ ++ if (!vma_can_enter(vma)) { ++ vma->uksm_vma_slot = NULL; ++ return; ++ } ++ ++ slot = alloc_vma_slot(); ++ if (!slot) { ++ vma->uksm_vma_slot = NULL; ++ return; ++ } ++ ++ vma->uksm_vma_slot = slot; ++ vma->vm_flags |= VM_MERGEABLE; ++ slot->vma = vma; ++ slot->mm = vma->vm_mm; ++ slot->ctime_j = jiffies; ++ slot->pages = vma_pages(vma); ++ spin_lock(&vma_slot_list_lock); ++ list_add_tail(&slot->slot_list, &vma_slot_new); ++ spin_unlock(&vma_slot_list_lock); ++} ++ ++/* 32/3 < they < 32/2 */ ++#define shiftl 8 ++#define shiftr 12 ++ ++#define HASH_FROM_TO(from, to) \ ++for (index = from; index < to; index++) { \ ++ pos = random_nums[index]; \ ++ hash += key[pos]; \ ++ hash += (hash << shiftl); \ ++ hash ^= (hash >> shiftr); \ ++} ++ ++ ++#define HASH_FROM_DOWN_TO(from, to) \ ++for (index = from - 1; index >= to; index--) { \ ++ hash ^= (hash >> shiftr); \ ++ hash ^= (hash >> (shiftr*2)); \ ++ hash -= (hash << shiftl); \ ++ hash += (hash << (shiftl*2)); \ ++ pos = random_nums[index]; \ ++ hash -= key[pos]; \ ++} ++ ++/* ++ * The main random sample hash function. ++ */ ++static u32 random_sample_hash(void *addr, u32 hash_strength) ++{ ++ u32 hash = 0xdeadbeef; ++ int index, pos, loop = hash_strength; ++ u32 *key = (u32 *)addr; ++ ++ if (loop > HASH_STRENGTH_FULL) ++ loop = HASH_STRENGTH_FULL; ++ ++ HASH_FROM_TO(0, loop); ++ ++ if (hash_strength > HASH_STRENGTH_FULL) { ++ loop = hash_strength - HASH_STRENGTH_FULL; ++ HASH_FROM_TO(0, loop); ++ } ++ ++ return hash; ++} ++ ++ ++/** ++ * It's used when hash strength is adjusted ++ * ++ * @addr The page's virtual address ++ * @from The original hash strength ++ * @to The hash strength changed to ++ * @hash The hash value generated with "from" hash value ++ * ++ * return the hash value ++ */ ++static u32 delta_hash(void *addr, int from, int to, u32 hash) ++{ ++ u32 *key = (u32 *)addr; ++ int index, pos; /* make sure they are int type */ ++ ++ if (to > from) { ++ if (from >= HASH_STRENGTH_FULL) { ++ from -= HASH_STRENGTH_FULL; ++ to -= HASH_STRENGTH_FULL; ++ HASH_FROM_TO(from, to); ++ } else if (to <= HASH_STRENGTH_FULL) { ++ HASH_FROM_TO(from, to); ++ } else { ++ HASH_FROM_TO(from, HASH_STRENGTH_FULL); ++ HASH_FROM_TO(0, to - HASH_STRENGTH_FULL); ++ } ++ } else { ++ if (from <= HASH_STRENGTH_FULL) { ++ HASH_FROM_DOWN_TO(from, to); ++ } else if (to >= HASH_STRENGTH_FULL) { ++ from -= HASH_STRENGTH_FULL; ++ to -= HASH_STRENGTH_FULL; ++ HASH_FROM_DOWN_TO(from, to); ++ } else { ++ HASH_FROM_DOWN_TO(from - HASH_STRENGTH_FULL, 0); ++ HASH_FROM_DOWN_TO(HASH_STRENGTH_FULL, to); ++ } ++ } ++ ++ return hash; ++} ++ ++/** ++ * ++ * Called when: rshash_pos or rshash_neg is about to overflow or a scan round ++ * has finished. ++ * ++ * return 0 if no page has been scanned since last call, 1 otherwise. ++ */ ++static inline int encode_benefit(void) ++{ ++ u64 scanned_delta, pos_delta, neg_delta; ++ unsigned long base = benefit.base; ++ ++ scanned_delta = uksm_pages_scanned - uksm_pages_scanned_last; ++ ++ if (!scanned_delta) ++ return 0; ++ ++ scanned_delta >>= base; ++ pos_delta = rshash_pos >> base; ++ neg_delta = rshash_neg >> base; ++ ++ if (CAN_OVERFLOW_U64(benefit.pos, pos_delta) || ++ CAN_OVERFLOW_U64(benefit.neg, neg_delta) || ++ CAN_OVERFLOW_U64(benefit.scanned, scanned_delta)) { ++ benefit.scanned >>= 1; ++ benefit.neg >>= 1; ++ benefit.pos >>= 1; ++ benefit.base++; ++ scanned_delta >>= 1; ++ pos_delta >>= 1; ++ neg_delta >>= 1; ++ } ++ ++ benefit.pos += pos_delta; ++ benefit.neg += neg_delta; ++ benefit.scanned += scanned_delta; ++ ++ BUG_ON(!benefit.scanned); ++ ++ rshash_pos = rshash_neg = 0; ++ uksm_pages_scanned_last = uksm_pages_scanned; ++ ++ return 1; ++} ++ ++static inline void reset_benefit(void) ++{ ++ benefit.pos = 0; ++ benefit.neg = 0; ++ benefit.base = 0; ++ benefit.scanned = 0; ++} ++ ++static inline void inc_rshash_pos(unsigned long delta) ++{ ++ if (CAN_OVERFLOW_U64(rshash_pos, delta)) ++ encode_benefit(); ++ ++ rshash_pos += delta; ++} ++ ++static inline void inc_rshash_neg(unsigned long delta) ++{ ++ if (CAN_OVERFLOW_U64(rshash_neg, delta)) ++ encode_benefit(); ++ ++ rshash_neg += delta; ++} ++ ++ ++static inline u32 page_hash(struct page *page, unsigned long hash_strength, ++ int cost_accounting) ++{ ++ u32 val; ++ unsigned long delta; ++ ++ void *addr = kmap_atomic(page); ++ ++ val = random_sample_hash(addr, hash_strength); ++ kunmap_atomic(addr); ++ ++ if (cost_accounting) { ++ if (hash_strength < HASH_STRENGTH_FULL) ++ delta = HASH_STRENGTH_FULL - hash_strength; ++ else ++ delta = 0; ++ ++ inc_rshash_pos(delta); ++ } ++ ++ return val; ++} ++ ++static int memcmp_pages(struct page *page1, struct page *page2, ++ int cost_accounting) ++{ ++ char *addr1, *addr2; ++ int ret; ++ ++ addr1 = kmap_atomic(page1); ++ addr2 = kmap_atomic(page2); ++ ret = memcmp(addr1, addr2, PAGE_SIZE); ++ kunmap_atomic(addr2); ++ kunmap_atomic(addr1); ++ ++ if (cost_accounting) ++ inc_rshash_neg(memcmp_cost); ++ ++ return ret; ++} ++ ++static inline int pages_identical(struct page *page1, struct page *page2) ++{ ++ return !memcmp_pages(page1, page2, 0); ++} ++ ++static inline int is_page_full_zero(struct page *page) ++{ ++ char *addr; ++ int ret; ++ ++ addr = kmap_atomic(page); ++ ret = is_full_zero(addr, PAGE_SIZE); ++ kunmap_atomic(addr); ++ ++ return ret; ++} ++ ++static int write_protect_page(struct vm_area_struct *vma, struct page *page, ++ pte_t *orig_pte, pte_t *old_pte) ++{ ++ struct mm_struct *mm = vma->vm_mm; ++ struct page_vma_mapped_walk pvmw = { ++ .page = page, ++ .vma = vma, ++ }; ++ int swapped; ++ int err = -EFAULT; ++ struct mmu_notifier_range range; ++ ++ pvmw.address = page_address_in_vma(page, vma); ++ if (pvmw.address == -EFAULT) ++ goto out; ++ ++ BUG_ON(PageTransCompound(page)); ++ ++ mmu_notifier_range_init(&range, mm, pvmw.address, pvmw.address + PAGE_SIZE); ++ mmu_notifier_invalidate_range_start(&range); ++ ++ if (!page_vma_mapped_walk(&pvmw)) ++ goto out_mn; ++ if (WARN_ONCE(!pvmw.pte, "Unexpected PMD mapping?")) ++ goto out_unlock; ++ ++ if (old_pte) ++ *old_pte = *pvmw.pte; ++ ++ if (pte_write(*pvmw.pte) || pte_dirty(*pvmw.pte) || ++ (pte_protnone(*pvmw.pte) && pte_savedwrite(*pvmw.pte)) || mm_tlb_flush_pending(mm)) { ++ pte_t entry; ++ ++ swapped = PageSwapCache(page); ++ flush_cache_page(vma, pvmw.address, page_to_pfn(page)); ++ /* ++ * Ok this is tricky, when get_user_pages_fast() run it doesn't ++ * take any lock, therefore the check that we are going to make ++ * with the pagecount against the mapcount is racey and ++ * O_DIRECT can happen right after the check. ++ * So we clear the pte and flush the tlb before the check ++ * this assure us that no O_DIRECT can happen after the check ++ * or in the middle of the check. ++ */ ++ entry = ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte); ++ /* ++ * Check that no O_DIRECT or similar I/O is in progress on the ++ * page ++ */ ++ if (page_mapcount(page) + 1 + swapped != page_count(page)) { ++ set_pte_at(mm, pvmw.address, pvmw.pte, entry); ++ goto out_unlock; ++ } ++ if (pte_dirty(entry)) ++ set_page_dirty(page); ++ ++ if (pte_protnone(entry)) ++ entry = pte_mkclean(pte_clear_savedwrite(entry)); ++ else ++ entry = pte_mkclean(pte_wrprotect(entry)); ++ ++ set_pte_at_notify(mm, pvmw.address, pvmw.pte, entry); ++ } ++ *orig_pte = *pvmw.pte; ++ err = 0; ++ ++out_unlock: ++ page_vma_mapped_walk_done(&pvmw); ++out_mn: ++ mmu_notifier_invalidate_range_end(&range); ++out: ++ return err; ++} ++ ++#define MERGE_ERR_PGERR 1 /* the page is invalid cannot continue */ ++#define MERGE_ERR_COLLI 2 /* there is a collision */ ++#define MERGE_ERR_COLLI_MAX 3 /* collision at the max hash strength */ ++#define MERGE_ERR_CHANGED 4 /* the page has changed since last hash */ ++ ++ ++/** ++ * replace_page - replace page in vma by new ksm page ++ * @vma: vma that holds the pte pointing to page ++ * @page: the page we are replacing by kpage ++ * @kpage: the ksm page we replace page by ++ * @orig_pte: the original value of the pte ++ * ++ * Returns 0 on success, MERGE_ERR_PGERR on failure. ++ */ ++static int replace_page(struct vm_area_struct *vma, struct page *page, ++ struct page *kpage, pte_t orig_pte) ++{ ++ struct mm_struct *mm = vma->vm_mm; ++ pgd_t *pgd; ++ p4d_t *p4d; ++ pud_t *pud; ++ pmd_t *pmd; ++ pte_t *ptep; ++ spinlock_t *ptl; ++ pte_t entry; ++ ++ unsigned long addr; ++ int err = MERGE_ERR_PGERR; ++ struct mmu_notifier_range range; ++ ++ addr = page_address_in_vma(page, vma); ++ if (addr == -EFAULT) ++ goto out; ++ ++ pgd = pgd_offset(mm, addr); ++ if (!pgd_present(*pgd)) ++ goto out; ++ ++ p4d = p4d_offset(pgd, addr); ++ pud = pud_offset(p4d, addr); ++ if (!pud_present(*pud)) ++ goto out; ++ ++ pmd = pmd_offset(pud, addr); ++ BUG_ON(pmd_trans_huge(*pmd)); ++ if (!pmd_present(*pmd)) ++ goto out; ++ ++ mmu_notifier_range_init(&range, mm, addr, addr + PAGE_SIZE); ++ mmu_notifier_invalidate_range_start(&range); ++ ++ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); ++ if (!pte_same(*ptep, orig_pte)) { ++ pte_unmap_unlock(ptep, ptl); ++ goto out_mn; ++ } ++ ++ flush_cache_page(vma, addr, pte_pfn(*ptep)); ++ ptep_clear_flush_notify(vma, addr, ptep); ++ entry = mk_pte(kpage, vma->vm_page_prot); ++ ++ /* special treatment is needed for zero_page */ ++ if ((page_to_pfn(kpage) == uksm_zero_pfn) || ++ (page_to_pfn(kpage) == zero_pfn)) { ++ entry = pte_mkspecial(entry); ++ dec_mm_counter(mm, MM_ANONPAGES); ++ inc_zone_page_state(page, NR_UKSM_ZERO_PAGES); ++ } else { ++ get_page(kpage); ++ page_add_anon_rmap(kpage, vma, addr, false); ++ } ++ ++ set_pte_at_notify(mm, addr, ptep, entry); ++ ++ page_remove_rmap(page, false); ++ if (!page_mapped(page)) ++ try_to_free_swap(page); ++ put_page(page); ++ ++ pte_unmap_unlock(ptep, ptl); ++ err = 0; ++out_mn: ++ mmu_notifier_invalidate_range_end(&range); ++out: ++ return err; ++} ++ ++ ++/** ++ * Fully hash a page with HASH_STRENGTH_MAX return a non-zero hash value. The ++ * zero hash value at HASH_STRENGTH_MAX is used to indicated that its ++ * hash_max member has not been calculated. ++ * ++ * @page The page needs to be hashed ++ * @hash_old The hash value calculated with current hash strength ++ * ++ * return the new hash value calculated at HASH_STRENGTH_MAX ++ */ ++static inline u32 page_hash_max(struct page *page, u32 hash_old) ++{ ++ u32 hash_max = 0; ++ void *addr; ++ ++ addr = kmap_atomic(page); ++ hash_max = delta_hash(addr, hash_strength, ++ HASH_STRENGTH_MAX, hash_old); ++ ++ kunmap_atomic(addr); ++ ++ if (!hash_max) ++ hash_max = 1; ++ ++ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); ++ return hash_max; ++} ++ ++/* ++ * We compare the hash again, to ensure that it is really a hash collision ++ * instead of being caused by page write. ++ */ ++static inline int check_collision(struct rmap_item *rmap_item, ++ u32 hash) ++{ ++ int err; ++ struct page *page = rmap_item->page; ++ ++ /* if this rmap_item has already been hash_maxed, then the collision ++ * must appears in the second-level rbtree search. In this case we check ++ * if its hash_max value has been changed. Otherwise, the collision ++ * happens in the first-level rbtree search, so we check against it's ++ * current hash value. ++ */ ++ if (rmap_item->hash_max) { ++ inc_rshash_neg(memcmp_cost); ++ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); ++ ++ if (rmap_item->hash_max == page_hash_max(page, hash)) ++ err = MERGE_ERR_COLLI; ++ else ++ err = MERGE_ERR_CHANGED; ++ } else { ++ inc_rshash_neg(memcmp_cost + hash_strength); ++ ++ if (page_hash(page, hash_strength, 0) == hash) ++ err = MERGE_ERR_COLLI; ++ else ++ err = MERGE_ERR_CHANGED; ++ } ++ ++ return err; ++} ++ ++/** ++ * Try to merge a rmap_item.page with a kpage in stable node. kpage must ++ * already be a ksm page. ++ * ++ * @return 0 if the pages were merged, -EFAULT otherwise. ++ */ ++static int try_to_merge_with_uksm_page(struct rmap_item *rmap_item, ++ struct page *kpage, u32 hash) ++{ ++ struct vm_area_struct *vma = rmap_item->slot->vma; ++ struct mm_struct *mm = vma->vm_mm; ++ pte_t orig_pte = __pte(0); ++ int err = MERGE_ERR_PGERR; ++ struct page *page; ++ ++ if (uksm_test_exit(mm)) ++ goto out; ++ ++ page = rmap_item->page; ++ ++ if (page == kpage) { /* ksm page forked */ ++ err = 0; ++ goto out; ++ } ++ ++ /* ++ * We need the page lock to read a stable PageSwapCache in ++ * write_protect_page(). We use trylock_page() instead of ++ * lock_page() because we don't want to wait here - we ++ * prefer to continue scanning and merging different pages, ++ * then come back to this page when it is unlocked. ++ */ ++ if (!trylock_page(page)) ++ goto out; ++ ++ if (!PageAnon(page) || !PageKsm(kpage)) ++ goto out_unlock; ++ ++ if (PageTransCompound(page)) { ++ err = split_huge_page(page); ++ if (err) ++ goto out_unlock; ++ } ++ ++ /* ++ * If this anonymous page is mapped only here, its pte may need ++ * to be write-protected. If it's mapped elsewhere, all of its ++ * ptes are necessarily already write-protected. But in either ++ * case, we need to lock and check page_count is not raised. ++ */ ++ if (write_protect_page(vma, page, &orig_pte, NULL) == 0) { ++ if (pages_identical(page, kpage)) ++ err = replace_page(vma, page, kpage, orig_pte); ++ else ++ err = check_collision(rmap_item, hash); ++ } ++ ++ if ((vma->vm_flags & VM_LOCKED) && kpage && !err) { ++ munlock_vma_page(page); ++ if (!PageMlocked(kpage)) { ++ unlock_page(page); ++ lock_page(kpage); ++ mlock_vma_page(kpage); ++ page = kpage; /* for final unlock */ ++ } ++ } ++ ++out_unlock: ++ unlock_page(page); ++out: ++ return err; ++} ++ ++ ++ ++/** ++ * If two pages fail to merge in try_to_merge_two_pages, then we have a chance ++ * to restore a page mapping that has been changed in try_to_merge_two_pages. ++ * ++ * @return 0 on success. ++ */ ++static int restore_uksm_page_pte(struct vm_area_struct *vma, unsigned long addr, ++ pte_t orig_pte, pte_t wprt_pte) ++{ ++ struct mm_struct *mm = vma->vm_mm; ++ pgd_t *pgd; ++ p4d_t *p4d; ++ pud_t *pud; ++ pmd_t *pmd; ++ pte_t *ptep; ++ spinlock_t *ptl; ++ ++ int err = -EFAULT; ++ ++ pgd = pgd_offset(mm, addr); ++ if (!pgd_present(*pgd)) ++ goto out; ++ ++ p4d = p4d_offset(pgd, addr); ++ pud = pud_offset(p4d, addr); ++ if (!pud_present(*pud)) ++ goto out; ++ ++ pmd = pmd_offset(pud, addr); ++ if (!pmd_present(*pmd)) ++ goto out; ++ ++ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); ++ if (!pte_same(*ptep, wprt_pte)) { ++ /* already copied, let it be */ ++ pte_unmap_unlock(ptep, ptl); ++ goto out; ++ } ++ ++ /* ++ * Good boy, still here. When we still get the ksm page, it does not ++ * return to the free page pool, there is no way that a pte was changed ++ * to other page and gets back to this page. And remind that ksm page ++ * do not reuse in do_wp_page(). So it's safe to restore the original ++ * pte. ++ */ ++ flush_cache_page(vma, addr, pte_pfn(*ptep)); ++ ptep_clear_flush_notify(vma, addr, ptep); ++ set_pte_at_notify(mm, addr, ptep, orig_pte); ++ ++ pte_unmap_unlock(ptep, ptl); ++ err = 0; ++out: ++ return err; ++} ++ ++/** ++ * try_to_merge_two_pages() - take two identical pages and prepare ++ * them to be merged into one page(rmap_item->page) ++ * ++ * @return 0 if we successfully merged two identical pages into ++ * one ksm page. MERGE_ERR_COLLI if it's only a hash collision ++ * search in rbtree. MERGE_ERR_CHANGED if rmap_item has been ++ * changed since it's hashed. MERGE_ERR_PGERR otherwise. ++ * ++ */ ++static int try_to_merge_two_pages(struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ u32 hash) ++{ ++ pte_t orig_pte1 = __pte(0), orig_pte2 = __pte(0); ++ pte_t wprt_pte1 = __pte(0), wprt_pte2 = __pte(0); ++ struct vm_area_struct *vma1 = rmap_item->slot->vma; ++ struct vm_area_struct *vma2 = tree_rmap_item->slot->vma; ++ struct page *page = rmap_item->page; ++ struct page *tree_page = tree_rmap_item->page; ++ int err = MERGE_ERR_PGERR; ++ struct address_space *saved_mapping; ++ ++ ++ if (rmap_item->page == tree_rmap_item->page) ++ goto out; ++ ++ if (!trylock_page(page)) ++ goto out; ++ ++ if (!PageAnon(page)) ++ goto out_unlock; ++ ++ if (PageTransCompound(page)) { ++ err = split_huge_page(page); ++ if (err) ++ goto out_unlock; ++ } ++ ++ if (write_protect_page(vma1, page, &wprt_pte1, &orig_pte1) != 0) { ++ unlock_page(page); ++ goto out; ++ } ++ ++ /* ++ * While we hold page lock, upgrade page from ++ * PageAnon+anon_vma to PageKsm+NULL stable_node: ++ * stable_tree_insert() will update stable_node. ++ */ ++ saved_mapping = page->mapping; ++ set_page_stable_node(page, NULL); ++ mark_page_accessed(page); ++ if (!PageDirty(page)) ++ SetPageDirty(page); ++ ++ unlock_page(page); ++ ++ if (!trylock_page(tree_page)) ++ goto restore_out; ++ ++ if (!PageAnon(tree_page)) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ ++ if (PageTransCompound(tree_page)) { ++ err = split_huge_page(tree_page); ++ if (err) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ } ++ ++ if (write_protect_page(vma2, tree_page, &wprt_pte2, &orig_pte2) != 0) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ ++ if (pages_identical(page, tree_page)) { ++ err = replace_page(vma2, tree_page, page, wprt_pte2); ++ if (err) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ ++ if ((vma2->vm_flags & VM_LOCKED)) { ++ munlock_vma_page(tree_page); ++ if (!PageMlocked(page)) { ++ unlock_page(tree_page); ++ lock_page(page); ++ mlock_vma_page(page); ++ tree_page = page; /* for final unlock */ ++ } ++ } ++ ++ unlock_page(tree_page); ++ ++ goto out; /* success */ ++ ++ } else { ++ if (tree_rmap_item->hash_max && ++ tree_rmap_item->hash_max == rmap_item->hash_max) { ++ err = MERGE_ERR_COLLI_MAX; ++ } else if (page_hash(page, hash_strength, 0) == ++ page_hash(tree_page, hash_strength, 0)) { ++ inc_rshash_neg(memcmp_cost + hash_strength * 2); ++ err = MERGE_ERR_COLLI; ++ } else { ++ err = MERGE_ERR_CHANGED; ++ } ++ ++ unlock_page(tree_page); ++ } ++ ++restore_out: ++ lock_page(page); ++ if (!restore_uksm_page_pte(vma1, get_rmap_addr(rmap_item), ++ orig_pte1, wprt_pte1)) ++ page->mapping = saved_mapping; ++ ++out_unlock: ++ unlock_page(page); ++out: ++ return err; ++} ++ ++static inline int hash_cmp(u32 new_val, u32 node_val) ++{ ++ if (new_val > node_val) ++ return 1; ++ else if (new_val < node_val) ++ return -1; ++ else ++ return 0; ++} ++ ++static inline u32 rmap_item_hash_max(struct rmap_item *item, u32 hash) ++{ ++ u32 hash_max = item->hash_max; ++ ++ if (!hash_max) { ++ hash_max = page_hash_max(item->page, hash); ++ ++ item->hash_max = hash_max; ++ } ++ ++ return hash_max; ++} ++ ++ ++ ++/** ++ * stable_tree_search() - search the stable tree for a page ++ * ++ * @item: the rmap_item we are comparing with ++ * @hash: the hash value of this item->page already calculated ++ * ++ * @return the page we have found, NULL otherwise. The page returned has ++ * been gotten. ++ */ ++static struct page *stable_tree_search(struct rmap_item *item, u32 hash) ++{ ++ struct rb_node *node = root_stable_treep->rb_node; ++ struct tree_node *tree_node; ++ unsigned long hash_max; ++ struct page *page = item->page; ++ struct stable_node *stable_node; ++ ++ stable_node = page_stable_node(page); ++ if (stable_node) { ++ /* ksm page forked, that is ++ * if (PageKsm(page) && !in_stable_tree(rmap_item)) ++ * it's actually gotten once outside. ++ */ ++ get_page(page); ++ return page; ++ } ++ ++ while (node) { ++ int cmp; ++ ++ tree_node = rb_entry(node, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) ++ node = node->rb_left; ++ else if (cmp > 0) ++ node = node->rb_right; ++ else ++ break; ++ } ++ ++ if (!node) ++ return NULL; ++ ++ if (tree_node->count == 1) { ++ stable_node = rb_entry(tree_node->sub_root.rb_node, ++ struct stable_node, node); ++ BUG_ON(!stable_node); ++ ++ goto get_page_out; ++ } ++ ++ /* ++ * ok, we have to search the second ++ * level subtree, hash the page to a ++ * full strength. ++ */ ++ node = tree_node->sub_root.rb_node; ++ BUG_ON(!node); ++ hash_max = rmap_item_hash_max(item, hash); ++ ++ while (node) { ++ int cmp; ++ ++ stable_node = rb_entry(node, struct stable_node, node); ++ ++ cmp = hash_cmp(hash_max, stable_node->hash_max); ++ ++ if (cmp < 0) ++ node = node->rb_left; ++ else if (cmp > 0) ++ node = node->rb_right; ++ else ++ goto get_page_out; ++ } ++ ++ return NULL; ++ ++get_page_out: ++ page = get_uksm_page(stable_node, 1, 1); ++ return page; ++} ++ ++static int try_merge_rmap_item(struct rmap_item *item, ++ struct page *kpage, ++ struct page *tree_page) ++{ ++ struct vm_area_struct *vma = item->slot->vma; ++ struct page_vma_mapped_walk pvmw = { ++ .page = kpage, ++ .vma = vma, ++ }; ++ ++ pvmw.address = get_rmap_addr(item); ++ if (!page_vma_mapped_walk(&pvmw)) ++ return 0; ++ ++ if (pte_write(*pvmw.pte)) { ++ /* has changed, abort! */ ++ page_vma_mapped_walk_done(&pvmw); ++ return 0; ++ } ++ ++ get_page(tree_page); ++ page_add_anon_rmap(tree_page, vma, pvmw.address, false); ++ ++ flush_cache_page(vma, pvmw.address, page_to_pfn(kpage)); ++ ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte); ++ set_pte_at_notify(vma->vm_mm, pvmw.address, pvmw.pte, ++ mk_pte(tree_page, vma->vm_page_prot)); ++ ++ page_remove_rmap(kpage, false); ++ put_page(kpage); ++ ++ page_vma_mapped_walk_done(&pvmw); ++ ++ return 1; ++} ++ ++/** ++ * try_to_merge_with_stable_page() - when two rmap_items need to be inserted ++ * into stable tree, the page was found to be identical to a stable ksm page, ++ * this is the last chance we can merge them into one. ++ * ++ * @item1: the rmap_item holding the page which we wanted to insert ++ * into stable tree. ++ * @item2: the other rmap_item we found when unstable tree search ++ * @oldpage: the page currently mapped by the two rmap_items ++ * @tree_page: the page we found identical in stable tree node ++ * @success1: return if item1 is successfully merged ++ * @success2: return if item2 is successfully merged ++ */ ++static void try_merge_with_stable(struct rmap_item *item1, ++ struct rmap_item *item2, ++ struct page **kpage, ++ struct page *tree_page, ++ int *success1, int *success2) ++{ ++ struct vm_area_struct *vma1 = item1->slot->vma; ++ struct vm_area_struct *vma2 = item2->slot->vma; ++ *success1 = 0; ++ *success2 = 0; ++ ++ if (unlikely(*kpage == tree_page)) { ++ /* I don't think this can really happen */ ++ pr_warn("UKSM: unexpected condition detected in " ++ "%s -- *kpage == tree_page !\n", __func__); ++ *success1 = 1; ++ *success2 = 1; ++ return; ++ } ++ ++ if (!PageAnon(*kpage) || !PageKsm(*kpage)) ++ goto failed; ++ ++ if (!trylock_page(tree_page)) ++ goto failed; ++ ++ /* If the oldpage is still ksm and still pointed ++ * to in the right place, and still write protected, ++ * we are confident it's not changed, no need to ++ * memcmp anymore. ++ * be ware, we cannot take nested pte locks, ++ * deadlock risk. ++ */ ++ if (!try_merge_rmap_item(item1, *kpage, tree_page)) ++ goto unlock_failed; ++ ++ /* ok, then vma2, remind that pte1 already set */ ++ if (!try_merge_rmap_item(item2, *kpage, tree_page)) ++ goto success_1; ++ ++ *success2 = 1; ++success_1: ++ *success1 = 1; ++ ++ ++ if ((*success1 && vma1->vm_flags & VM_LOCKED) || ++ (*success2 && vma2->vm_flags & VM_LOCKED)) { ++ munlock_vma_page(*kpage); ++ if (!PageMlocked(tree_page)) ++ mlock_vma_page(tree_page); ++ } ++ ++ /* ++ * We do not need oldpage any more in the caller, so can break the lock ++ * now. ++ */ ++ unlock_page(*kpage); ++ *kpage = tree_page; /* Get unlocked outside. */ ++ return; ++ ++unlock_failed: ++ unlock_page(tree_page); ++failed: ++ return; ++} ++ ++static inline void stable_node_hash_max(struct stable_node *node, ++ struct page *page, u32 hash) ++{ ++ u32 hash_max = node->hash_max; ++ ++ if (!hash_max) { ++ hash_max = page_hash_max(page, hash); ++ node->hash_max = hash_max; ++ } ++} ++ ++static inline ++struct stable_node *new_stable_node(struct tree_node *tree_node, ++ struct page *kpage, u32 hash_max) ++{ ++ struct stable_node *new_stable_node; ++ ++ new_stable_node = alloc_stable_node(); ++ if (!new_stable_node) ++ return NULL; ++ ++ new_stable_node->kpfn = page_to_pfn(kpage); ++ new_stable_node->hash_max = hash_max; ++ new_stable_node->tree_node = tree_node; ++ set_page_stable_node(kpage, new_stable_node); ++ ++ return new_stable_node; ++} ++ ++static inline ++struct stable_node *first_level_insert(struct tree_node *tree_node, ++ struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ struct page **kpage, u32 hash, ++ int *success1, int *success2) ++{ ++ int cmp; ++ struct page *tree_page; ++ u32 hash_max = 0; ++ struct stable_node *stable_node, *new_snode; ++ struct rb_node *parent = NULL, **new; ++ ++ /* this tree node contains no sub-tree yet */ ++ stable_node = rb_entry(tree_node->sub_root.rb_node, ++ struct stable_node, node); ++ ++ tree_page = get_uksm_page(stable_node, 1, 0); ++ if (tree_page) { ++ cmp = memcmp_pages(*kpage, tree_page, 1); ++ if (!cmp) { ++ try_merge_with_stable(rmap_item, tree_rmap_item, kpage, ++ tree_page, success1, success2); ++ put_page(tree_page); ++ if (!*success1 && !*success2) ++ goto failed; ++ ++ return stable_node; ++ ++ } else { ++ /* ++ * collision in first level try to create a subtree. ++ * A new node need to be created. ++ */ ++ put_page(tree_page); ++ ++ stable_node_hash_max(stable_node, tree_page, ++ tree_node->hash); ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ cmp = hash_cmp(hash_max, stable_node->hash_max); ++ ++ parent = &stable_node->node; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto failed; ++ } ++ ++ } else { ++ /* the only stable_node deleted, we reuse its tree_node. ++ */ ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ ++ new_snode = new_stable_node(tree_node, *kpage, hash_max); ++ if (!new_snode) ++ goto failed; ++ ++ rb_link_node(&new_snode->node, parent, new); ++ rb_insert_color(&new_snode->node, &tree_node->sub_root); ++ tree_node->count++; ++ *success1 = *success2 = 1; ++ ++ return new_snode; ++ ++failed: ++ return NULL; ++} ++ ++static inline ++struct stable_node *stable_subtree_insert(struct tree_node *tree_node, ++ struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ struct page **kpage, u32 hash, ++ int *success1, int *success2) ++{ ++ struct page *tree_page; ++ u32 hash_max; ++ struct stable_node *stable_node, *new_snode; ++ struct rb_node *parent, **new; ++ ++research: ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ BUG_ON(!*new); ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ while (*new) { ++ int cmp; ++ ++ stable_node = rb_entry(*new, struct stable_node, node); ++ ++ cmp = hash_cmp(hash_max, stable_node->hash_max); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else { ++ tree_page = get_uksm_page(stable_node, 1, 0); ++ if (tree_page) { ++ cmp = memcmp_pages(*kpage, tree_page, 1); ++ if (!cmp) { ++ try_merge_with_stable(rmap_item, ++ tree_rmap_item, kpage, ++ tree_page, success1, success2); ++ ++ put_page(tree_page); ++ if (!*success1 && !*success2) ++ goto failed; ++ /* ++ * successfully merged with a stable ++ * node ++ */ ++ return stable_node; ++ } else { ++ put_page(tree_page); ++ goto failed; ++ } ++ } else { ++ /* ++ * stable node may be deleted, ++ * and subtree maybe ++ * restructed, cannot ++ * continue, research it. ++ */ ++ if (tree_node->count) { ++ goto research; ++ } else { ++ /* reuse the tree node*/ ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ } ++ } ++ } ++ ++ new_snode = new_stable_node(tree_node, *kpage, hash_max); ++ if (!new_snode) ++ goto failed; ++ ++ rb_link_node(&new_snode->node, parent, new); ++ rb_insert_color(&new_snode->node, &tree_node->sub_root); ++ tree_node->count++; ++ *success1 = *success2 = 1; ++ ++ return new_snode; ++ ++failed: ++ return NULL; ++} ++ ++ ++/** ++ * stable_tree_insert() - try to insert a merged page in unstable tree to ++ * the stable tree ++ * ++ * @kpage: the page need to be inserted ++ * @hash: the current hash of this page ++ * @rmap_item: the rmap_item being scanned ++ * @tree_rmap_item: the rmap_item found on unstable tree ++ * @success1: return if rmap_item is merged ++ * @success2: return if tree_rmap_item is merged ++ * ++ * @return the stable_node on stable tree if at least one ++ * rmap_item is inserted into stable tree, NULL ++ * otherwise. ++ */ ++static struct stable_node * ++stable_tree_insert(struct page **kpage, u32 hash, ++ struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ int *success1, int *success2) ++{ ++ struct rb_node **new = &root_stable_treep->rb_node; ++ struct rb_node *parent = NULL; ++ struct stable_node *stable_node; ++ struct tree_node *tree_node; ++ u32 hash_max = 0; ++ ++ *success1 = *success2 = 0; ++ ++ while (*new) { ++ int cmp; ++ ++ tree_node = rb_entry(*new, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else ++ break; ++ } ++ ++ if (*new) { ++ if (tree_node->count == 1) { ++ stable_node = first_level_insert(tree_node, rmap_item, ++ tree_rmap_item, kpage, ++ hash, success1, success2); ++ } else { ++ stable_node = stable_subtree_insert(tree_node, ++ rmap_item, tree_rmap_item, kpage, ++ hash, success1, success2); ++ } ++ } else { ++ ++ /* no tree node found */ ++ tree_node = alloc_tree_node(stable_tree_node_listp); ++ if (!tree_node) { ++ stable_node = NULL; ++ goto out; ++ } ++ ++ stable_node = new_stable_node(tree_node, *kpage, hash_max); ++ if (!stable_node) { ++ free_tree_node(tree_node); ++ goto out; ++ } ++ ++ tree_node->hash = hash; ++ rb_link_node(&tree_node->node, parent, new); ++ rb_insert_color(&tree_node->node, root_stable_treep); ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ ++ rb_link_node(&stable_node->node, parent, new); ++ rb_insert_color(&stable_node->node, &tree_node->sub_root); ++ tree_node->count++; ++ *success1 = *success2 = 1; ++ } ++ ++out: ++ return stable_node; ++} ++ ++ ++/** ++ * get_tree_rmap_item_page() - try to get the page and lock the mmap_sem ++ * ++ * @return 0 on success, -EBUSY if unable to lock the mmap_sem, ++ * -EINVAL if the page mapping has been changed. ++ */ ++static inline int get_tree_rmap_item_page(struct rmap_item *tree_rmap_item) ++{ ++ int err; ++ ++ err = get_mergeable_page_lock_mmap(tree_rmap_item); ++ ++ if (err == -EINVAL) { ++ /* its page map has been changed, remove it */ ++ remove_rmap_item_from_tree(tree_rmap_item); ++ } ++ ++ /* The page is gotten and mmap_sem is locked now. */ ++ return err; ++} ++ ++ ++/** ++ * unstable_tree_search_insert() - search an unstable tree rmap_item with the ++ * same hash value. Get its page and trylock the mmap_sem ++ */ ++static inline ++struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, ++ u32 hash) ++ ++{ ++ struct rb_node **new = &root_unstable_tree.rb_node; ++ struct rb_node *parent = NULL; ++ struct tree_node *tree_node; ++ u32 hash_max; ++ struct rmap_item *tree_rmap_item; ++ ++ while (*new) { ++ int cmp; ++ ++ tree_node = rb_entry(*new, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else ++ break; ++ } ++ ++ if (*new) { ++ /* got the tree_node */ ++ if (tree_node->count == 1) { ++ tree_rmap_item = rb_entry(tree_node->sub_root.rb_node, ++ struct rmap_item, node); ++ BUG_ON(!tree_rmap_item); ++ ++ goto get_page_out; ++ } ++ ++ /* well, search the collision subtree */ ++ new = &tree_node->sub_root.rb_node; ++ BUG_ON(!*new); ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ ++ while (*new) { ++ int cmp; ++ ++ tree_rmap_item = rb_entry(*new, struct rmap_item, ++ node); ++ ++ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); ++ parent = *new; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto get_page_out; ++ } ++ } else { ++ /* alloc a new tree_node */ ++ tree_node = alloc_tree_node(&unstable_tree_node_list); ++ if (!tree_node) ++ return NULL; ++ ++ tree_node->hash = hash; ++ rb_link_node(&tree_node->node, parent, new); ++ rb_insert_color(&tree_node->node, &root_unstable_tree); ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ ++ /* did not found even in sub-tree */ ++ rmap_item->tree_node = tree_node; ++ rmap_item->address |= UNSTABLE_FLAG; ++ rmap_item->hash_round = uksm_hash_round; ++ rb_link_node(&rmap_item->node, parent, new); ++ rb_insert_color(&rmap_item->node, &tree_node->sub_root); ++ ++ uksm_pages_unshared++; ++ return NULL; ++ ++get_page_out: ++ if (tree_rmap_item->page == rmap_item->page) ++ return NULL; ++ ++ if (get_tree_rmap_item_page(tree_rmap_item)) ++ return NULL; ++ ++ return tree_rmap_item; ++} ++ ++static void hold_anon_vma(struct rmap_item *rmap_item, ++ struct anon_vma *anon_vma) ++{ ++ rmap_item->anon_vma = anon_vma; ++ get_anon_vma(anon_vma); ++} ++ ++ ++/** ++ * stable_tree_append() - append a rmap_item to a stable node. Deduplication ++ * ratio statistics is done in this function. ++ * ++ */ ++static void stable_tree_append(struct rmap_item *rmap_item, ++ struct stable_node *stable_node, int logdedup) ++{ ++ struct node_vma *node_vma = NULL, *new_node_vma, *node_vma_cont = NULL; ++ unsigned long key = (unsigned long)rmap_item->slot; ++ unsigned long factor = rmap_item->slot->rung->step; ++ ++ BUG_ON(!stable_node); ++ rmap_item->address |= STABLE_FLAG; ++ ++ if (hlist_empty(&stable_node->hlist)) { ++ uksm_pages_shared++; ++ goto node_vma_new; ++ } else { ++ uksm_pages_sharing++; ++ } ++ ++ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { ++ if (node_vma->key >= key) ++ break; ++ ++ if (logdedup) { ++ node_vma->slot->pages_bemerged += factor; ++ if (list_empty(&node_vma->slot->dedup_list)) ++ list_add(&node_vma->slot->dedup_list, ++ &vma_slot_dedup); ++ } ++ } ++ ++ if (node_vma) { ++ if (node_vma->key == key) { ++ node_vma_cont = hlist_entry_safe(node_vma->hlist.next, struct node_vma, hlist); ++ goto node_vma_ok; ++ } else if (node_vma->key > key) { ++ node_vma_cont = node_vma; ++ } ++ } ++ ++node_vma_new: ++ /* no same vma already in node, alloc a new node_vma */ ++ new_node_vma = alloc_node_vma(); ++ BUG_ON(!new_node_vma); ++ new_node_vma->head = stable_node; ++ new_node_vma->slot = rmap_item->slot; ++ ++ if (!node_vma) { ++ hlist_add_head(&new_node_vma->hlist, &stable_node->hlist); ++ } else if (node_vma->key != key) { ++ if (node_vma->key < key) ++ hlist_add_behind(&new_node_vma->hlist, &node_vma->hlist); ++ else { ++ hlist_add_before(&new_node_vma->hlist, ++ &node_vma->hlist); ++ } ++ ++ } ++ node_vma = new_node_vma; ++ ++node_vma_ok: /* ok, ready to add to the list */ ++ rmap_item->head = node_vma; ++ hlist_add_head(&rmap_item->hlist, &node_vma->rmap_hlist); ++ hold_anon_vma(rmap_item, rmap_item->slot->vma->anon_vma); ++ if (logdedup) { ++ rmap_item->slot->pages_merged++; ++ if (node_vma_cont) { ++ node_vma = node_vma_cont; ++ hlist_for_each_entry_continue(node_vma, hlist) { ++ node_vma->slot->pages_bemerged += factor; ++ if (list_empty(&node_vma->slot->dedup_list)) ++ list_add(&node_vma->slot->dedup_list, ++ &vma_slot_dedup); ++ } ++ } ++ } ++} ++ ++/* ++ * We use break_ksm to break COW on a ksm page: it's a stripped down ++ * ++ * if (get_user_pages(addr, 1, 1, 1, &page, NULL) == 1) ++ * put_page(page); ++ * ++ * but taking great care only to touch a ksm page, in a VM_MERGEABLE vma, ++ * in case the application has unmapped and remapped mm,addr meanwhile. ++ * Could a ksm page appear anywhere else? Actually yes, in a VM_PFNMAP ++ * mmap of /dev/mem or /dev/kmem, where we would not want to touch it. ++ */ ++static int break_ksm(struct vm_area_struct *vma, unsigned long addr) ++{ ++ struct page *page; ++ int ret = 0; ++ ++ do { ++ cond_resched(); ++ page = follow_page(vma, addr, FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); ++ if (IS_ERR_OR_NULL(page)) ++ break; ++ if (PageKsm(page)) { ++ ret = handle_mm_fault(vma, addr, ++ FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE); ++ } else ++ ret = VM_FAULT_WRITE; ++ put_page(page); ++ } while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | VM_FAULT_OOM))); ++ /* ++ * We must loop because handle_mm_fault() may back out if there's ++ * any difficulty e.g. if pte accessed bit gets updated concurrently. ++ * ++ * VM_FAULT_WRITE is what we have been hoping for: it indicates that ++ * COW has been broken, even if the vma does not permit VM_WRITE; ++ * but note that a concurrent fault might break PageKsm for us. ++ * ++ * VM_FAULT_SIGBUS could occur if we race with truncation of the ++ * backing file, which also invalidates anonymous pages: that's ++ * okay, that truncation will have unmapped the PageKsm for us. ++ * ++ * VM_FAULT_OOM: at the time of writing (late July 2009), setting ++ * aside mem_cgroup limits, VM_FAULT_OOM would only be set if the ++ * current task has TIF_MEMDIE set, and will be OOM killed on return ++ * to user; and ksmd, having no mm, would never be chosen for that. ++ * ++ * But if the mm is in a limited mem_cgroup, then the fault may fail ++ * with VM_FAULT_OOM even if the current task is not TIF_MEMDIE; and ++ * even ksmd can fail in this way - though it's usually breaking ksm ++ * just to undo a merge it made a moment before, so unlikely to oom. ++ * ++ * That's a pity: we might therefore have more kernel pages allocated ++ * than we're counting as nodes in the stable tree; but uksm_do_scan ++ * will retry to break_cow on each pass, so should recover the page ++ * in due course. The important thing is to not let VM_MERGEABLE ++ * be cleared while any such pages might remain in the area. ++ */ ++ return (ret & VM_FAULT_OOM) ? -ENOMEM : 0; ++} ++ ++static void break_cow(struct rmap_item *rmap_item) ++{ ++ struct vm_area_struct *vma = rmap_item->slot->vma; ++ struct mm_struct *mm = vma->vm_mm; ++ unsigned long addr = get_rmap_addr(rmap_item); ++ ++ if (uksm_test_exit(mm)) ++ goto out; ++ ++ break_ksm(vma, addr); ++out: ++ return; ++} ++ ++/* ++ * Though it's very tempting to unmerge in_stable_tree(rmap_item)s rather ++ * than check every pte of a given vma, the locking doesn't quite work for ++ * that - an rmap_item is assigned to the stable tree after inserting ksm ++ * page and upping mmap_sem. Nor does it fit with the way we skip dup'ing ++ * rmap_items from parent to child at fork time (so as not to waste time ++ * if exit comes before the next scan reaches it). ++ * ++ * Similarly, although we'd like to remove rmap_items (so updating counts ++ * and freeing memory) when unmerging an area, it's easier to leave that ++ * to the next pass of ksmd - consider, for example, how ksmd might be ++ * in cmp_and_merge_page on one of the rmap_items we would be removing. ++ */ ++inline int unmerge_uksm_pages(struct vm_area_struct *vma, ++ unsigned long start, unsigned long end) ++{ ++ unsigned long addr; ++ int err = 0; ++ ++ for (addr = start; addr < end && !err; addr += PAGE_SIZE) { ++ if (uksm_test_exit(vma->vm_mm)) ++ break; ++ if (signal_pending(current)) ++ err = -ERESTARTSYS; ++ else ++ err = break_ksm(vma, addr); ++ } ++ return err; ++} ++ ++static inline void inc_uksm_pages_scanned(void) ++{ ++ u64 delta; ++ ++ ++ if (uksm_pages_scanned == U64_MAX) { ++ encode_benefit(); ++ ++ delta = uksm_pages_scanned >> pages_scanned_base; ++ ++ if (CAN_OVERFLOW_U64(pages_scanned_stored, delta)) { ++ pages_scanned_stored >>= 1; ++ delta >>= 1; ++ pages_scanned_base++; ++ } ++ ++ pages_scanned_stored += delta; ++ ++ uksm_pages_scanned = uksm_pages_scanned_last = 0; ++ } ++ ++ uksm_pages_scanned++; ++} ++ ++static inline int find_zero_page_hash(int strength, u32 hash) ++{ ++ return (zero_hash_table[strength] == hash); ++} ++ ++static ++int cmp_and_merge_zero_page(struct vm_area_struct *vma, struct page *page) ++{ ++ struct page *zero_page = empty_uksm_zero_page; ++ struct mm_struct *mm = vma->vm_mm; ++ pte_t orig_pte = __pte(0); ++ int err = -EFAULT; ++ ++ if (uksm_test_exit(mm)) ++ goto out; ++ ++ if (!trylock_page(page)) ++ goto out; ++ ++ if (!PageAnon(page)) ++ goto out_unlock; ++ ++ if (PageTransCompound(page)) { ++ err = split_huge_page(page); ++ if (err) ++ goto out_unlock; ++ } ++ ++ if (write_protect_page(vma, page, &orig_pte, 0) == 0) { ++ if (is_page_full_zero(page)) ++ err = replace_page(vma, page, zero_page, orig_pte); ++ } ++ ++out_unlock: ++ unlock_page(page); ++out: ++ return err; ++} ++ ++/* ++ * cmp_and_merge_page() - first see if page can be merged into the stable ++ * tree; if not, compare hash to previous and if it's the same, see if page ++ * can be inserted into the unstable tree, or merged with a page already there ++ * and both transferred to the stable tree. ++ * ++ * @page: the page that we are searching identical page to. ++ * @rmap_item: the reverse mapping into the virtual address of this page ++ */ ++static void cmp_and_merge_page(struct rmap_item *rmap_item, u32 hash) ++{ ++ struct rmap_item *tree_rmap_item; ++ struct page *page; ++ struct page *kpage = NULL; ++ u32 hash_max; ++ int err; ++ unsigned int success1, success2; ++ struct stable_node *snode; ++ int cmp; ++ struct rb_node *parent = NULL, **new; ++ ++ remove_rmap_item_from_tree(rmap_item); ++ page = rmap_item->page; ++ ++ /* We first start with searching the page inside the stable tree */ ++ kpage = stable_tree_search(rmap_item, hash); ++ if (kpage) { ++ err = try_to_merge_with_uksm_page(rmap_item, kpage, ++ hash); ++ if (!err) { ++ /* ++ * The page was successfully merged, add ++ * its rmap_item to the stable tree. ++ * page lock is needed because it's ++ * racing with try_to_unmap_ksm(), etc. ++ */ ++ lock_page(kpage); ++ snode = page_stable_node(kpage); ++ stable_tree_append(rmap_item, snode, 1); ++ unlock_page(kpage); ++ put_page(kpage); ++ return; /* success */ ++ } ++ put_page(kpage); ++ ++ /* ++ * if it's a collision and it has been search in sub-rbtree ++ * (hash_max != 0), we want to abort, because if it is ++ * successfully merged in unstable tree, the collision trends to ++ * happen again. ++ */ ++ if (err == MERGE_ERR_COLLI && rmap_item->hash_max) ++ return; ++ } ++ ++ tree_rmap_item = ++ unstable_tree_search_insert(rmap_item, hash); ++ if (tree_rmap_item) { ++ err = try_to_merge_two_pages(rmap_item, tree_rmap_item, hash); ++ /* ++ * As soon as we merge this page, we want to remove the ++ * rmap_item of the page we have merged with from the unstable ++ * tree, and insert it instead as new node in the stable tree. ++ */ ++ if (!err) { ++ kpage = page; ++ remove_rmap_item_from_tree(tree_rmap_item); ++ lock_page(kpage); ++ snode = stable_tree_insert(&kpage, hash, ++ rmap_item, tree_rmap_item, ++ &success1, &success2); ++ ++ /* ++ * Do not log dedup for tree item, it's not counted as ++ * scanned in this round. ++ */ ++ if (success2) ++ stable_tree_append(tree_rmap_item, snode, 0); ++ ++ /* ++ * The order of these two stable append is important: ++ * we are scanning rmap_item. ++ */ ++ if (success1) ++ stable_tree_append(rmap_item, snode, 1); ++ ++ /* ++ * The original kpage may be unlocked inside ++ * stable_tree_insert() already. This page ++ * should be unlocked before doing ++ * break_cow(). ++ */ ++ unlock_page(kpage); ++ ++ if (!success1) ++ break_cow(rmap_item); ++ ++ if (!success2) ++ break_cow(tree_rmap_item); ++ ++ } else if (err == MERGE_ERR_COLLI) { ++ BUG_ON(tree_rmap_item->tree_node->count > 1); ++ ++ rmap_item_hash_max(tree_rmap_item, ++ tree_rmap_item->tree_node->hash); ++ ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); ++ parent = &tree_rmap_item->node; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto put_up_out; ++ ++ rmap_item->tree_node = tree_rmap_item->tree_node; ++ rmap_item->address |= UNSTABLE_FLAG; ++ rmap_item->hash_round = uksm_hash_round; ++ rb_link_node(&rmap_item->node, parent, new); ++ rb_insert_color(&rmap_item->node, ++ &tree_rmap_item->tree_node->sub_root); ++ rmap_item->tree_node->count++; ++ } else { ++ /* ++ * either one of the page has changed or they collide ++ * at the max hash, we consider them as ill items. ++ */ ++ remove_rmap_item_from_tree(tree_rmap_item); ++ } ++put_up_out: ++ put_page(tree_rmap_item->page); ++ up_read(&tree_rmap_item->slot->vma->vm_mm->mmap_sem); ++ } ++} ++ ++ ++ ++ ++static inline unsigned long get_pool_index(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = (sizeof(struct rmap_list_entry *) * index) >> PAGE_SHIFT; ++ if (pool_index >= slot->pool_size) ++ BUG(); ++ return pool_index; ++} ++ ++static inline unsigned long index_page_offset(unsigned long index) ++{ ++ return offset_in_page(sizeof(struct rmap_list_entry *) * index); ++} ++ ++static inline ++struct rmap_list_entry *get_rmap_list_entry(struct vma_slot *slot, ++ unsigned long index, int need_alloc) ++{ ++ unsigned long pool_index; ++ struct page *page; ++ void *addr; ++ ++ ++ pool_index = get_pool_index(slot, index); ++ if (!slot->rmap_list_pool[pool_index]) { ++ if (!need_alloc) ++ return NULL; ++ ++ page = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN); ++ if (!page) ++ return NULL; ++ ++ slot->rmap_list_pool[pool_index] = page; ++ } ++ ++ addr = kmap(slot->rmap_list_pool[pool_index]); ++ addr += index_page_offset(index); ++ ++ return addr; ++} ++ ++static inline void put_rmap_list_entry(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ BUG_ON(!slot->rmap_list_pool[pool_index]); ++ kunmap(slot->rmap_list_pool[pool_index]); ++} ++ ++static inline int entry_is_new(struct rmap_list_entry *entry) ++{ ++ return !entry->item; ++} ++ ++static inline unsigned long get_index_orig_addr(struct vma_slot *slot, ++ unsigned long index) ++{ ++ return slot->vma->vm_start + (index << PAGE_SHIFT); ++} ++ ++static inline unsigned long get_entry_address(struct rmap_list_entry *entry) ++{ ++ unsigned long addr; ++ ++ if (is_addr(entry->addr)) ++ addr = get_clean_addr(entry->addr); ++ else if (entry->item) ++ addr = get_rmap_addr(entry->item); ++ else ++ BUG(); ++ ++ return addr; ++} ++ ++static inline struct rmap_item *get_entry_item(struct rmap_list_entry *entry) ++{ ++ if (is_addr(entry->addr)) ++ return NULL; ++ ++ return entry->item; ++} ++ ++static inline void inc_rmap_list_pool_count(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ BUG_ON(!slot->rmap_list_pool[pool_index]); ++ slot->pool_counts[pool_index]++; ++} ++ ++static inline void dec_rmap_list_pool_count(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ BUG_ON(!slot->rmap_list_pool[pool_index]); ++ BUG_ON(!slot->pool_counts[pool_index]); ++ slot->pool_counts[pool_index]--; ++} ++ ++static inline int entry_has_rmap(struct rmap_list_entry *entry) ++{ ++ return !is_addr(entry->addr) && entry->item; ++} ++ ++static inline void swap_entries(struct rmap_list_entry *entry1, ++ unsigned long index1, ++ struct rmap_list_entry *entry2, ++ unsigned long index2) ++{ ++ struct rmap_list_entry tmp; ++ ++ /* swapping two new entries is meaningless */ ++ BUG_ON(entry_is_new(entry1) && entry_is_new(entry2)); ++ ++ tmp = *entry1; ++ *entry1 = *entry2; ++ *entry2 = tmp; ++ ++ if (entry_has_rmap(entry1)) ++ entry1->item->entry_index = index1; ++ ++ if (entry_has_rmap(entry2)) ++ entry2->item->entry_index = index2; ++ ++ if (entry_has_rmap(entry1) && !entry_has_rmap(entry2)) { ++ inc_rmap_list_pool_count(entry1->item->slot, index1); ++ dec_rmap_list_pool_count(entry1->item->slot, index2); ++ } else if (!entry_has_rmap(entry1) && entry_has_rmap(entry2)) { ++ inc_rmap_list_pool_count(entry2->item->slot, index2); ++ dec_rmap_list_pool_count(entry2->item->slot, index1); ++ } ++} ++ ++static inline void free_entry_item(struct rmap_list_entry *entry) ++{ ++ unsigned long index; ++ struct rmap_item *item; ++ ++ if (!is_addr(entry->addr)) { ++ BUG_ON(!entry->item); ++ item = entry->item; ++ entry->addr = get_rmap_addr(item); ++ set_is_addr(entry->addr); ++ index = item->entry_index; ++ remove_rmap_item_from_tree(item); ++ dec_rmap_list_pool_count(item->slot, index); ++ free_rmap_item(item); ++ } ++} ++ ++static inline int pool_entry_boundary(unsigned long index) ++{ ++ unsigned long linear_addr; ++ ++ linear_addr = sizeof(struct rmap_list_entry *) * index; ++ return index && !offset_in_page(linear_addr); ++} ++ ++static inline void try_free_last_pool(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ if (slot->rmap_list_pool[pool_index] && ++ !slot->pool_counts[pool_index]) { ++ __free_page(slot->rmap_list_pool[pool_index]); ++ slot->rmap_list_pool[pool_index] = NULL; ++ slot->flags |= UKSM_SLOT_NEED_SORT; ++ } ++ ++} ++ ++static inline unsigned long vma_item_index(struct vm_area_struct *vma, ++ struct rmap_item *item) ++{ ++ return (get_rmap_addr(item) - vma->vm_start) >> PAGE_SHIFT; ++} ++ ++static int within_same_pool(struct vma_slot *slot, ++ unsigned long i, unsigned long j) ++{ ++ unsigned long pool_i, pool_j; ++ ++ pool_i = get_pool_index(slot, i); ++ pool_j = get_pool_index(slot, j); ++ ++ return (pool_i == pool_j); ++} ++ ++static void sort_rmap_entry_list(struct vma_slot *slot) ++{ ++ unsigned long i, j; ++ struct rmap_list_entry *entry, *swap_entry; ++ ++ entry = get_rmap_list_entry(slot, 0, 0); ++ for (i = 0; i < slot->pages; ) { ++ ++ if (!entry) ++ goto skip_whole_pool; ++ ++ if (entry_is_new(entry)) ++ goto next_entry; ++ ++ if (is_addr(entry->addr)) { ++ entry->addr = 0; ++ goto next_entry; ++ } ++ ++ j = vma_item_index(slot->vma, entry->item); ++ if (j == i) ++ goto next_entry; ++ ++ if (within_same_pool(slot, i, j)) ++ swap_entry = entry + j - i; ++ else ++ swap_entry = get_rmap_list_entry(slot, j, 1); ++ ++ swap_entries(entry, i, swap_entry, j); ++ if (!within_same_pool(slot, i, j)) ++ put_rmap_list_entry(slot, j); ++ continue; ++ ++skip_whole_pool: ++ i += PAGE_SIZE / sizeof(*entry); ++ if (i < slot->pages) ++ entry = get_rmap_list_entry(slot, i, 0); ++ continue; ++ ++next_entry: ++ if (i >= slot->pages - 1 || ++ !within_same_pool(slot, i, i + 1)) { ++ put_rmap_list_entry(slot, i); ++ if (i + 1 < slot->pages) ++ entry = get_rmap_list_entry(slot, i + 1, 0); ++ } else ++ entry++; ++ i++; ++ continue; ++ } ++ ++ /* free empty pool entries which contain no rmap_item */ ++ /* CAN be simplied to based on only pool_counts when bug freed !!!!! */ ++ for (i = 0; i < slot->pool_size; i++) { ++ unsigned char has_rmap; ++ void *addr; ++ ++ if (!slot->rmap_list_pool[i]) ++ continue; ++ ++ has_rmap = 0; ++ addr = kmap(slot->rmap_list_pool[i]); ++ BUG_ON(!addr); ++ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { ++ entry = (struct rmap_list_entry *)addr + j; ++ if (is_addr(entry->addr)) ++ continue; ++ if (!entry->item) ++ continue; ++ has_rmap = 1; ++ } ++ kunmap(slot->rmap_list_pool[i]); ++ if (!has_rmap) { ++ BUG_ON(slot->pool_counts[i]); ++ __free_page(slot->rmap_list_pool[i]); ++ slot->rmap_list_pool[i] = NULL; ++ } ++ } ++ ++ slot->flags &= ~UKSM_SLOT_NEED_SORT; ++} ++ ++/* ++ * vma_fully_scanned() - if all the pages in this slot have been scanned. ++ */ ++static inline int vma_fully_scanned(struct vma_slot *slot) ++{ ++ return slot->pages_scanned == slot->pages; ++} ++ ++/** ++ * get_next_rmap_item() - Get the next rmap_item in a vma_slot according to ++ * its random permutation. This function is embedded with the random ++ * permutation index management code. ++ */ ++static struct rmap_item *get_next_rmap_item(struct vma_slot *slot, u32 *hash) ++{ ++ unsigned long rand_range, addr, swap_index, scan_index; ++ struct rmap_item *item = NULL; ++ struct rmap_list_entry *scan_entry, *swap_entry = NULL; ++ struct page *page; ++ ++ scan_index = swap_index = slot->pages_scanned % slot->pages; ++ ++ if (pool_entry_boundary(scan_index)) ++ try_free_last_pool(slot, scan_index - 1); ++ ++ if (vma_fully_scanned(slot)) { ++ if (slot->flags & UKSM_SLOT_NEED_SORT) ++ slot->flags |= UKSM_SLOT_NEED_RERAND; ++ else ++ slot->flags &= ~UKSM_SLOT_NEED_RERAND; ++ if (slot->flags & UKSM_SLOT_NEED_SORT) ++ sort_rmap_entry_list(slot); ++ } ++ ++ scan_entry = get_rmap_list_entry(slot, scan_index, 1); ++ if (!scan_entry) ++ return NULL; ++ ++ if (entry_is_new(scan_entry)) { ++ scan_entry->addr = get_index_orig_addr(slot, scan_index); ++ set_is_addr(scan_entry->addr); ++ } ++ ++ if (slot->flags & UKSM_SLOT_NEED_RERAND) { ++ rand_range = slot->pages - scan_index; ++ BUG_ON(!rand_range); ++ swap_index = scan_index + (prandom_u32() % rand_range); ++ } ++ ++ if (swap_index != scan_index) { ++ swap_entry = get_rmap_list_entry(slot, swap_index, 1); ++ if (entry_is_new(swap_entry)) { ++ swap_entry->addr = get_index_orig_addr(slot, ++ swap_index); ++ set_is_addr(swap_entry->addr); ++ } ++ swap_entries(scan_entry, scan_index, swap_entry, swap_index); ++ } ++ ++ addr = get_entry_address(scan_entry); ++ item = get_entry_item(scan_entry); ++ BUG_ON(addr > slot->vma->vm_end || addr < slot->vma->vm_start); ++ ++ page = follow_page(slot->vma, addr, FOLL_GET); ++ if (IS_ERR_OR_NULL(page)) ++ goto nopage; ++ ++ if (!PageAnon(page)) ++ goto putpage; ++ ++ /*check is zero_page pfn or uksm_zero_page*/ ++ if ((page_to_pfn(page) == zero_pfn) ++ || (page_to_pfn(page) == uksm_zero_pfn)) ++ goto putpage; ++ ++ flush_anon_page(slot->vma, page, addr); ++ flush_dcache_page(page); ++ ++ ++ *hash = page_hash(page, hash_strength, 1); ++ inc_uksm_pages_scanned(); ++ /*if the page content all zero, re-map to zero-page*/ ++ if (find_zero_page_hash(hash_strength, *hash)) { ++ if (!cmp_and_merge_zero_page(slot->vma, page)) { ++ slot->pages_merged++; ++ ++ /* For full-zero pages, no need to create rmap item */ ++ goto putpage; ++ } else { ++ inc_rshash_neg(memcmp_cost / 2); ++ } ++ } ++ ++ if (!item) { ++ item = alloc_rmap_item(); ++ if (item) { ++ /* It has already been zeroed */ ++ item->slot = slot; ++ item->address = addr; ++ item->entry_index = scan_index; ++ scan_entry->item = item; ++ inc_rmap_list_pool_count(slot, scan_index); ++ } else ++ goto putpage; ++ } ++ ++ BUG_ON(item->slot != slot); ++ /* the page may have changed */ ++ item->page = page; ++ put_rmap_list_entry(slot, scan_index); ++ if (swap_entry) ++ put_rmap_list_entry(slot, swap_index); ++ return item; ++ ++putpage: ++ put_page(page); ++ page = NULL; ++nopage: ++ /* no page, store addr back and free rmap_item if possible */ ++ free_entry_item(scan_entry); ++ put_rmap_list_entry(slot, scan_index); ++ if (swap_entry) ++ put_rmap_list_entry(slot, swap_index); ++ return NULL; ++} ++ ++static inline int in_stable_tree(struct rmap_item *rmap_item) ++{ ++ return rmap_item->address & STABLE_FLAG; ++} ++ ++/** ++ * scan_vma_one_page() - scan the next page in a vma_slot. Called with ++ * mmap_sem locked. ++ */ ++static noinline void scan_vma_one_page(struct vma_slot *slot) ++{ ++ u32 hash; ++ struct mm_struct *mm; ++ struct rmap_item *rmap_item = NULL; ++ struct vm_area_struct *vma = slot->vma; ++ ++ mm = vma->vm_mm; ++ BUG_ON(!mm); ++ BUG_ON(!slot); ++ ++ rmap_item = get_next_rmap_item(slot, &hash); ++ if (!rmap_item) ++ goto out1; ++ ++ if (PageKsm(rmap_item->page) && in_stable_tree(rmap_item)) ++ goto out2; ++ ++ cmp_and_merge_page(rmap_item, hash); ++out2: ++ put_page(rmap_item->page); ++out1: ++ slot->pages_scanned++; ++ slot->this_sampled++; ++ if (slot->fully_scanned_round != fully_scanned_round) ++ scanned_virtual_pages++; ++ ++ if (vma_fully_scanned(slot)) ++ slot->fully_scanned_round = fully_scanned_round; ++} ++ ++static inline unsigned long rung_get_pages(struct scan_rung *rung) ++{ ++ struct slot_tree_node *node; ++ ++ if (!rung->vma_root.rnode) ++ return 0; ++ ++ node = container_of(rung->vma_root.rnode, struct slot_tree_node, snode); ++ ++ return node->size; ++} ++ ++#define RUNG_SAMPLED_MIN 3 ++ ++static inline ++void uksm_calc_rung_step(struct scan_rung *rung, ++ unsigned long page_time, unsigned long ratio) ++{ ++ unsigned long sampled, pages; ++ ++ /* will be fully scanned ? */ ++ if (!rung->cover_msecs) { ++ rung->step = 1; ++ return; ++ } ++ ++ sampled = rung->cover_msecs * (NSEC_PER_MSEC / TIME_RATIO_SCALE) ++ * ratio / page_time; ++ ++ /* ++ * Before we finsish a scan round and expensive per-round jobs, ++ * we need to have a chance to estimate the per page time. So ++ * the sampled number can not be too small. ++ */ ++ if (sampled < RUNG_SAMPLED_MIN) ++ sampled = RUNG_SAMPLED_MIN; ++ ++ pages = rung_get_pages(rung); ++ if (likely(pages > sampled)) ++ rung->step = pages / sampled; ++ else ++ rung->step = 1; ++} ++ ++static inline int step_need_recalc(struct scan_rung *rung) ++{ ++ unsigned long pages, stepmax; ++ ++ pages = rung_get_pages(rung); ++ stepmax = pages / RUNG_SAMPLED_MIN; ++ ++ return pages && (rung->step > pages || ++ (stepmax && rung->step > stepmax)); ++} ++ ++static inline ++void reset_current_scan(struct scan_rung *rung, int finished, int step_recalc) ++{ ++ struct vma_slot *slot; ++ ++ if (finished) ++ rung->flags |= UKSM_RUNG_ROUND_FINISHED; ++ ++ if (step_recalc || step_need_recalc(rung)) { ++ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); ++ BUG_ON(step_need_recalc(rung)); ++ } ++ ++ slot_iter_index = prandom_u32() % rung->step; ++ BUG_ON(!rung->vma_root.rnode); ++ slot = sradix_tree_next(&rung->vma_root, NULL, 0, slot_iter); ++ BUG_ON(!slot); ++ ++ rung->current_scan = slot; ++ rung->current_offset = slot_iter_index; ++} ++ ++static inline struct sradix_tree_root *slot_get_root(struct vma_slot *slot) ++{ ++ return &slot->rung->vma_root; ++} ++ ++/* ++ * return if resetted. ++ */ ++static int advance_current_scan(struct scan_rung *rung) ++{ ++ unsigned short n; ++ struct vma_slot *slot, *next = NULL; ++ ++ BUG_ON(!rung->vma_root.num); ++ ++ slot = rung->current_scan; ++ n = (slot->pages - rung->current_offset) % rung->step; ++ slot_iter_index = rung->step - n; ++ next = sradix_tree_next(&rung->vma_root, slot->snode, ++ slot->sindex, slot_iter); ++ ++ if (next) { ++ rung->current_offset = slot_iter_index; ++ rung->current_scan = next; ++ return 0; ++ } else { ++ reset_current_scan(rung, 1, 0); ++ return 1; ++ } ++} ++ ++static inline void rung_rm_slot(struct vma_slot *slot) ++{ ++ struct scan_rung *rung = slot->rung; ++ struct sradix_tree_root *root; ++ ++ if (rung->current_scan == slot) ++ advance_current_scan(rung); ++ ++ root = slot_get_root(slot); ++ sradix_tree_delete_from_leaf(root, slot->snode, slot->sindex); ++ slot->snode = NULL; ++ if (step_need_recalc(rung)) { ++ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); ++ BUG_ON(step_need_recalc(rung)); ++ } ++ ++ /* In case advance_current_scan loop back to this slot again */ ++ if (rung->vma_root.num && rung->current_scan == slot) ++ reset_current_scan(slot->rung, 1, 0); ++} ++ ++static inline void rung_add_new_slots(struct scan_rung *rung, ++ struct vma_slot **slots, unsigned long num) ++{ ++ int err; ++ struct vma_slot *slot; ++ unsigned long i; ++ struct sradix_tree_root *root = &rung->vma_root; ++ ++ err = sradix_tree_enter(root, (void **)slots, num); ++ BUG_ON(err); ++ ++ for (i = 0; i < num; i++) { ++ slot = slots[i]; ++ slot->rung = rung; ++ BUG_ON(vma_fully_scanned(slot)); ++ } ++ ++ if (rung->vma_root.num == num) ++ reset_current_scan(rung, 0, 1); ++} ++ ++static inline int rung_add_one_slot(struct scan_rung *rung, ++ struct vma_slot *slot) ++{ ++ int err; ++ ++ err = sradix_tree_enter(&rung->vma_root, (void **)&slot, 1); ++ if (err) ++ return err; ++ ++ slot->rung = rung; ++ if (rung->vma_root.num == 1) ++ reset_current_scan(rung, 0, 1); ++ ++ return 0; ++} ++ ++/* ++ * Return true if the slot is deleted from its rung. ++ */ ++static inline int vma_rung_enter(struct vma_slot *slot, struct scan_rung *rung) ++{ ++ struct scan_rung *old_rung = slot->rung; ++ int err; ++ ++ if (old_rung == rung) ++ return 0; ++ ++ rung_rm_slot(slot); ++ err = rung_add_one_slot(rung, slot); ++ if (err) { ++ err = rung_add_one_slot(old_rung, slot); ++ WARN_ON(err); /* OOPS, badly OOM, we lost this slot */ ++ } ++ ++ return 1; ++} ++ ++static inline int vma_rung_up(struct vma_slot *slot) ++{ ++ struct scan_rung *rung; ++ ++ rung = slot->rung; ++ if (slot->rung != &uksm_scan_ladder[SCAN_LADDER_SIZE-1]) ++ rung++; ++ ++ return vma_rung_enter(slot, rung); ++} ++ ++static inline int vma_rung_down(struct vma_slot *slot) ++{ ++ struct scan_rung *rung; ++ ++ rung = slot->rung; ++ if (slot->rung != &uksm_scan_ladder[0]) ++ rung--; ++ ++ return vma_rung_enter(slot, rung); ++} ++ ++/** ++ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. ++ */ ++static unsigned long cal_dedup_ratio(struct vma_slot *slot) ++{ ++ unsigned long ret; ++ unsigned long pages; ++ ++ pages = slot->this_sampled; ++ if (!pages) ++ return 0; ++ ++ BUG_ON(slot->pages_scanned == slot->last_scanned); ++ ++ ret = slot->pages_merged; ++ ++ /* Thrashing area filtering */ ++ if (ret && uksm_thrash_threshold) { ++ if (slot->pages_cowed * 100 / slot->pages_merged ++ > uksm_thrash_threshold) { ++ ret = 0; ++ } else { ++ ret = slot->pages_merged - slot->pages_cowed; ++ } ++ } ++ ++ return ret * 100 / pages; ++} ++ ++/** ++ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. ++ */ ++static unsigned long cal_dedup_ratio_old(struct vma_slot *slot) ++{ ++ unsigned long ret; ++ unsigned long pages; ++ ++ pages = slot->pages; ++ if (!pages) ++ return 0; ++ ++ ret = slot->pages_bemerged; ++ ++ /* Thrashing area filtering */ ++ if (ret && uksm_thrash_threshold) { ++ if (slot->pages_cowed * 100 / slot->pages_bemerged ++ > uksm_thrash_threshold) { ++ ret = 0; ++ } else { ++ ret = slot->pages_bemerged - slot->pages_cowed; ++ } ++ } ++ ++ return ret * 100 / pages; ++} ++ ++/** ++ * stable_node_reinsert() - When the hash_strength has been adjusted, the ++ * stable tree need to be restructured, this is the function re-inserting the ++ * stable node. ++ */ ++static inline void stable_node_reinsert(struct stable_node *new_node, ++ struct page *page, ++ struct rb_root *root_treep, ++ struct list_head *tree_node_listp, ++ u32 hash) ++{ ++ struct rb_node **new = &root_treep->rb_node; ++ struct rb_node *parent = NULL; ++ struct stable_node *stable_node; ++ struct tree_node *tree_node; ++ struct page *tree_page; ++ int cmp; ++ ++ while (*new) { ++ int cmp; ++ ++ tree_node = rb_entry(*new, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else ++ break; ++ } ++ ++ if (*new) { ++ /* find a stable tree node with same first level hash value */ ++ stable_node_hash_max(new_node, page, hash); ++ if (tree_node->count == 1) { ++ stable_node = rb_entry(tree_node->sub_root.rb_node, ++ struct stable_node, node); ++ tree_page = get_uksm_page(stable_node, 1, 0); ++ if (tree_page) { ++ stable_node_hash_max(stable_node, ++ tree_page, hash); ++ put_page(tree_page); ++ ++ /* prepare for stable node insertion */ ++ ++ cmp = hash_cmp(new_node->hash_max, ++ stable_node->hash_max); ++ parent = &stable_node->node; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto failed; ++ ++ goto add_node; ++ } else { ++ /* the only stable_node deleted, the tree node ++ * was not deleted. ++ */ ++ goto tree_node_reuse; ++ } ++ } ++ ++ /* well, search the collision subtree */ ++ new = &tree_node->sub_root.rb_node; ++ parent = NULL; ++ BUG_ON(!*new); ++ while (*new) { ++ int cmp; ++ ++ stable_node = rb_entry(*new, struct stable_node, node); ++ ++ cmp = hash_cmp(new_node->hash_max, ++ stable_node->hash_max); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else { ++ /* oh, no, still a collision */ ++ goto failed; ++ } ++ } ++ ++ goto add_node; ++ } ++ ++ /* no tree node found */ ++ tree_node = alloc_tree_node(tree_node_listp); ++ if (!tree_node) { ++ pr_err("UKSM: memory allocation error!\n"); ++ goto failed; ++ } else { ++ tree_node->hash = hash; ++ rb_link_node(&tree_node->node, parent, new); ++ rb_insert_color(&tree_node->node, root_treep); ++ ++tree_node_reuse: ++ /* prepare for stable node insertion */ ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ ++add_node: ++ rb_link_node(&new_node->node, parent, new); ++ rb_insert_color(&new_node->node, &tree_node->sub_root); ++ new_node->tree_node = tree_node; ++ tree_node->count++; ++ return; ++ ++failed: ++ /* This can only happen when two nodes have collided ++ * in two levels. ++ */ ++ new_node->tree_node = NULL; ++ return; ++} ++ ++static inline void free_all_tree_nodes(struct list_head *list) ++{ ++ struct tree_node *node, *tmp; ++ ++ list_for_each_entry_safe(node, tmp, list, all_list) { ++ free_tree_node(node); ++ } ++} ++ ++/** ++ * stable_tree_delta_hash() - Delta hash the stable tree from previous hash ++ * strength to the current hash_strength. It re-structures the hole tree. ++ */ ++static inline void stable_tree_delta_hash(u32 prev_hash_strength) ++{ ++ struct stable_node *node, *tmp; ++ struct rb_root *root_new_treep; ++ struct list_head *new_tree_node_listp; ++ ++ stable_tree_index = (stable_tree_index + 1) % 2; ++ root_new_treep = &root_stable_tree[stable_tree_index]; ++ new_tree_node_listp = &stable_tree_node_list[stable_tree_index]; ++ *root_new_treep = RB_ROOT; ++ BUG_ON(!list_empty(new_tree_node_listp)); ++ ++ /* ++ * we need to be safe, the node could be removed by get_uksm_page() ++ */ ++ list_for_each_entry_safe(node, tmp, &stable_node_list, all_list) { ++ void *addr; ++ struct page *node_page; ++ u32 hash; ++ ++ /* ++ * We are completely re-structuring the stable nodes to a new ++ * stable tree. We don't want to touch the old tree unlinks and ++ * old tree_nodes. The old tree_nodes will be freed at once. ++ */ ++ node_page = get_uksm_page(node, 0, 0); ++ if (!node_page) ++ continue; ++ ++ if (node->tree_node) { ++ hash = node->tree_node->hash; ++ ++ addr = kmap_atomic(node_page); ++ ++ hash = delta_hash(addr, prev_hash_strength, ++ hash_strength, hash); ++ kunmap_atomic(addr); ++ } else { ++ /* ++ *it was not inserted to rbtree due to collision in last ++ *round scan. ++ */ ++ hash = page_hash(node_page, hash_strength, 0); ++ } ++ ++ stable_node_reinsert(node, node_page, root_new_treep, ++ new_tree_node_listp, hash); ++ put_page(node_page); ++ } ++ ++ root_stable_treep = root_new_treep; ++ free_all_tree_nodes(stable_tree_node_listp); ++ BUG_ON(!list_empty(stable_tree_node_listp)); ++ stable_tree_node_listp = new_tree_node_listp; ++} ++ ++static inline void inc_hash_strength(unsigned long delta) ++{ ++ hash_strength += 1 << delta; ++ if (hash_strength > HASH_STRENGTH_MAX) ++ hash_strength = HASH_STRENGTH_MAX; ++} ++ ++static inline void dec_hash_strength(unsigned long delta) ++{ ++ unsigned long change = 1 << delta; ++ ++ if (hash_strength <= change + 1) ++ hash_strength = 1; ++ else ++ hash_strength -= change; ++} ++ ++static inline void inc_hash_strength_delta(void) ++{ ++ hash_strength_delta++; ++ if (hash_strength_delta > HASH_STRENGTH_DELTA_MAX) ++ hash_strength_delta = HASH_STRENGTH_DELTA_MAX; ++} ++ ++static inline unsigned long get_current_neg_ratio(void) ++{ ++ u64 pos = benefit.pos; ++ u64 neg = benefit.neg; ++ ++ if (!neg) ++ return 0; ++ ++ if (!pos || neg > pos) ++ return 100; ++ ++ if (neg > div64_u64(U64_MAX, 100)) ++ pos = div64_u64(pos, 100); ++ else ++ neg *= 100; ++ ++ return div64_u64(neg, pos); ++} ++ ++static inline unsigned long get_current_benefit(void) ++{ ++ u64 pos = benefit.pos; ++ u64 neg = benefit.neg; ++ u64 scanned = benefit.scanned; ++ ++ if (neg > pos) ++ return 0; ++ ++ return div64_u64((pos - neg), scanned); ++} ++ ++static inline int judge_rshash_direction(void) ++{ ++ u64 current_neg_ratio, stable_benefit; ++ u64 current_benefit, delta = 0; ++ int ret = STILL; ++ ++ /* ++ * Try to probe a value after the boot, and in case the system ++ * are still for a long time. ++ */ ++ if ((fully_scanned_round & 0xFFULL) == 10) { ++ ret = OBSCURE; ++ goto out; ++ } ++ ++ current_neg_ratio = get_current_neg_ratio(); ++ ++ if (current_neg_ratio == 0) { ++ rshash_neg_cont_zero++; ++ if (rshash_neg_cont_zero > 2) ++ return GO_DOWN; ++ else ++ return STILL; ++ } ++ rshash_neg_cont_zero = 0; ++ ++ if (current_neg_ratio > 90) { ++ ret = GO_UP; ++ goto out; ++ } ++ ++ current_benefit = get_current_benefit(); ++ stable_benefit = rshash_state.stable_benefit; ++ ++ if (!stable_benefit) { ++ ret = OBSCURE; ++ goto out; ++ } ++ ++ if (current_benefit > stable_benefit) ++ delta = current_benefit - stable_benefit; ++ else if (current_benefit < stable_benefit) ++ delta = stable_benefit - current_benefit; ++ ++ delta = div64_u64(100 * delta, stable_benefit); ++ ++ if (delta > 50) { ++ rshash_cont_obscure++; ++ if (rshash_cont_obscure > 2) ++ return OBSCURE; ++ else ++ return STILL; ++ } ++ ++out: ++ rshash_cont_obscure = 0; ++ return ret; ++} ++ ++/** ++ * rshash_adjust() - The main function to control the random sampling state ++ * machine for hash strength adapting. ++ * ++ * return true if hash_strength has changed. ++ */ ++static inline int rshash_adjust(void) ++{ ++ unsigned long prev_hash_strength = hash_strength; ++ ++ if (!encode_benefit()) ++ return 0; ++ ++ switch (rshash_state.state) { ++ case RSHASH_STILL: ++ switch (judge_rshash_direction()) { ++ case GO_UP: ++ if (rshash_state.pre_direct == GO_DOWN) ++ hash_strength_delta = 0; ++ ++ inc_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ rshash_state.stable_benefit = get_current_benefit(); ++ rshash_state.pre_direct = GO_UP; ++ break; ++ ++ case GO_DOWN: ++ if (rshash_state.pre_direct == GO_UP) ++ hash_strength_delta = 0; ++ ++ dec_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ rshash_state.stable_benefit = get_current_benefit(); ++ rshash_state.pre_direct = GO_DOWN; ++ break; ++ ++ case OBSCURE: ++ rshash_state.stable_point = hash_strength; ++ rshash_state.turn_point_down = hash_strength; ++ rshash_state.turn_point_up = hash_strength; ++ rshash_state.turn_benefit_down = get_current_benefit(); ++ rshash_state.turn_benefit_up = get_current_benefit(); ++ rshash_state.lookup_window_index = 0; ++ rshash_state.state = RSHASH_TRYDOWN; ++ dec_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ break; ++ ++ case STILL: ++ break; ++ default: ++ BUG(); ++ } ++ break; ++ ++ case RSHASH_TRYDOWN: ++ if (rshash_state.lookup_window_index++ % 5 == 0) ++ rshash_state.below_count = 0; ++ ++ if (get_current_benefit() < rshash_state.stable_benefit) ++ rshash_state.below_count++; ++ else if (get_current_benefit() > ++ rshash_state.turn_benefit_down) { ++ rshash_state.turn_point_down = hash_strength; ++ rshash_state.turn_benefit_down = get_current_benefit(); ++ } ++ ++ if (rshash_state.below_count >= 3 || ++ judge_rshash_direction() == GO_UP || ++ hash_strength == 1) { ++ hash_strength = rshash_state.stable_point; ++ hash_strength_delta = 0; ++ inc_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ rshash_state.lookup_window_index = 0; ++ rshash_state.state = RSHASH_TRYUP; ++ hash_strength_delta = 0; ++ } else { ++ dec_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ } ++ break; ++ ++ case RSHASH_TRYUP: ++ if (rshash_state.lookup_window_index++ % 5 == 0) ++ rshash_state.below_count = 0; ++ ++ if (get_current_benefit() < rshash_state.turn_benefit_down) ++ rshash_state.below_count++; ++ else if (get_current_benefit() > rshash_state.turn_benefit_up) { ++ rshash_state.turn_point_up = hash_strength; ++ rshash_state.turn_benefit_up = get_current_benefit(); ++ } ++ ++ if (rshash_state.below_count >= 3 || ++ judge_rshash_direction() == GO_DOWN || ++ hash_strength == HASH_STRENGTH_MAX) { ++ hash_strength = rshash_state.turn_benefit_up > ++ rshash_state.turn_benefit_down ? ++ rshash_state.turn_point_up : ++ rshash_state.turn_point_down; ++ ++ rshash_state.state = RSHASH_PRE_STILL; ++ } else { ++ inc_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ } ++ ++ break; ++ ++ case RSHASH_NEW: ++ case RSHASH_PRE_STILL: ++ rshash_state.stable_benefit = get_current_benefit(); ++ rshash_state.state = RSHASH_STILL; ++ hash_strength_delta = 0; ++ break; ++ default: ++ BUG(); ++ } ++ ++ /* rshash_neg = rshash_pos = 0; */ ++ reset_benefit(); ++ ++ if (prev_hash_strength != hash_strength) ++ stable_tree_delta_hash(prev_hash_strength); ++ ++ return prev_hash_strength != hash_strength; ++} ++ ++/** ++ * round_update_ladder() - The main function to do update of all the ++ * adjustments whenever a scan round is finished. ++ */ ++static noinline void round_update_ladder(void) ++{ ++ int i; ++ unsigned long dedup; ++ struct vma_slot *slot, *tmp_slot; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) ++ uksm_scan_ladder[i].flags &= ~UKSM_RUNG_ROUND_FINISHED; ++ ++ list_for_each_entry_safe(slot, tmp_slot, &vma_slot_dedup, dedup_list) { ++ ++ /* slot may be rung_rm_slot() when mm exits */ ++ if (slot->snode) { ++ dedup = cal_dedup_ratio_old(slot); ++ if (dedup && dedup >= uksm_abundant_threshold) ++ vma_rung_up(slot); ++ } ++ ++ slot->pages_bemerged = 0; ++ slot->pages_cowed = 0; ++ ++ list_del_init(&slot->dedup_list); ++ } ++} ++ ++static void uksm_del_vma_slot(struct vma_slot *slot) ++{ ++ int i, j; ++ struct rmap_list_entry *entry; ++ ++ if (slot->snode) { ++ /* ++ * In case it just failed when entering the rung, it's not ++ * necessary. ++ */ ++ rung_rm_slot(slot); ++ } ++ ++ if (!list_empty(&slot->dedup_list)) ++ list_del(&slot->dedup_list); ++ ++ if (!slot->rmap_list_pool || !slot->pool_counts) { ++ /* In case it OOMed in uksm_vma_enter() */ ++ goto out; ++ } ++ ++ for (i = 0; i < slot->pool_size; i++) { ++ void *addr; ++ ++ if (!slot->rmap_list_pool[i]) ++ continue; ++ ++ addr = kmap(slot->rmap_list_pool[i]); ++ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { ++ entry = (struct rmap_list_entry *)addr + j; ++ if (is_addr(entry->addr)) ++ continue; ++ if (!entry->item) ++ continue; ++ ++ remove_rmap_item_from_tree(entry->item); ++ free_rmap_item(entry->item); ++ slot->pool_counts[i]--; ++ } ++ BUG_ON(slot->pool_counts[i]); ++ kunmap(slot->rmap_list_pool[i]); ++ __free_page(slot->rmap_list_pool[i]); ++ } ++ kfree(slot->rmap_list_pool); ++ kfree(slot->pool_counts); ++ ++out: ++ slot->rung = NULL; ++ if (slot->flags & UKSM_SLOT_IN_UKSM) { ++ BUG_ON(uksm_pages_total < slot->pages); ++ uksm_pages_total -= slot->pages; ++ } ++ ++ if (slot->fully_scanned_round == fully_scanned_round) ++ scanned_virtual_pages -= slot->pages; ++ else ++ scanned_virtual_pages -= slot->pages_scanned; ++ free_vma_slot(slot); ++} ++ ++ ++#define SPIN_LOCK_PERIOD 32 ++static struct vma_slot *cleanup_slots[SPIN_LOCK_PERIOD]; ++static inline void cleanup_vma_slots(void) ++{ ++ struct vma_slot *slot; ++ int i; ++ ++ i = 0; ++ spin_lock(&vma_slot_list_lock); ++ while (!list_empty(&vma_slot_del)) { ++ slot = list_entry(vma_slot_del.next, ++ struct vma_slot, slot_list); ++ list_del(&slot->slot_list); ++ cleanup_slots[i++] = slot; ++ if (i == SPIN_LOCK_PERIOD) { ++ spin_unlock(&vma_slot_list_lock); ++ while (--i >= 0) ++ uksm_del_vma_slot(cleanup_slots[i]); ++ i = 0; ++ spin_lock(&vma_slot_list_lock); ++ } ++ } ++ spin_unlock(&vma_slot_list_lock); ++ ++ while (--i >= 0) ++ uksm_del_vma_slot(cleanup_slots[i]); ++} ++ ++/* ++ * Expotional moving average formula ++ */ ++static inline unsigned long ema(unsigned long curr, unsigned long last_ema) ++{ ++ /* ++ * For a very high burst, even the ema cannot work well, a false very ++ * high per-page time estimation can result in feedback in very high ++ * overhead of context switch and rung update -- this will then lead ++ * to higher per-paper time, this may not converge. ++ * ++ * Instead, we try to approach this value in a binary manner. ++ */ ++ if (curr > last_ema * 10) ++ return last_ema * 2; ++ ++ return (EMA_ALPHA * curr + (100 - EMA_ALPHA) * last_ema) / 100; ++} ++ ++/* ++ * convert cpu ratio in 1/TIME_RATIO_SCALE configured by user to ++ * nanoseconds based on current uksm_sleep_jiffies. ++ */ ++static inline unsigned long cpu_ratio_to_nsec(unsigned int ratio) ++{ ++ return NSEC_PER_USEC * jiffies_to_usecs(uksm_sleep_jiffies) / ++ (TIME_RATIO_SCALE - ratio) * ratio; ++} ++ ++ ++static inline unsigned long rung_real_ratio(int cpu_time_ratio) ++{ ++ unsigned long ret; ++ ++ BUG_ON(!cpu_time_ratio); ++ ++ if (cpu_time_ratio > 0) ++ ret = cpu_time_ratio; ++ else ++ ret = (unsigned long)(-cpu_time_ratio) * ++ uksm_max_cpu_percentage / 100UL; ++ ++ return ret ? ret : 1; ++} ++ ++static noinline void uksm_calc_scan_pages(void) ++{ ++ struct scan_rung *ladder = uksm_scan_ladder; ++ unsigned long sleep_usecs, nsecs; ++ unsigned long ratio; ++ int i; ++ unsigned long per_page; ++ ++ if (uksm_ema_page_time > 100000 || ++ (((unsigned long) uksm_eval_round & (256UL - 1)) == 0UL)) ++ uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; ++ ++ per_page = uksm_ema_page_time; ++ BUG_ON(!per_page); ++ ++ /* ++ * For every 8 eval round, we try to probe a uksm_sleep_jiffies value ++ * based on saved user input. ++ */ ++ if (((unsigned long) uksm_eval_round & (8UL - 1)) == 0UL) ++ uksm_sleep_jiffies = uksm_sleep_saved; ++ ++ /* We require a rung scan at least 1 page in a period. */ ++ nsecs = per_page; ++ ratio = rung_real_ratio(ladder[0].cpu_ratio); ++ if (cpu_ratio_to_nsec(ratio) < nsecs) { ++ sleep_usecs = nsecs * (TIME_RATIO_SCALE - ratio) / ratio ++ / NSEC_PER_USEC; ++ uksm_sleep_jiffies = usecs_to_jiffies(sleep_usecs) + 1; ++ } ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ ratio = rung_real_ratio(ladder[i].cpu_ratio); ++ ladder[i].pages_to_scan = cpu_ratio_to_nsec(ratio) / ++ per_page; ++ BUG_ON(!ladder[i].pages_to_scan); ++ uksm_calc_rung_step(&ladder[i], per_page, ratio); ++ } ++} ++ ++/* ++ * From the scan time of this round (ns) to next expected min sleep time ++ * (ms), be careful of the possible overflows. ratio is taken from ++ * rung_real_ratio() ++ */ ++static inline ++unsigned int scan_time_to_sleep(unsigned long long scan_time, unsigned long ratio) ++{ ++ scan_time >>= 20; /* to msec level now */ ++ BUG_ON(scan_time > (ULONG_MAX / TIME_RATIO_SCALE)); ++ ++ return (unsigned int) ((unsigned long) scan_time * ++ (TIME_RATIO_SCALE - ratio) / ratio); ++} ++ ++#define __round_mask(x, y) ((__typeof__(x))((y)-1)) ++#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) ++ ++static void uksm_vma_enter(struct vma_slot **slots, unsigned long num) ++{ ++ struct scan_rung *rung; ++ ++ rung = &uksm_scan_ladder[0]; ++ rung_add_new_slots(rung, slots, num); ++} ++ ++static struct vma_slot *batch_slots[SLOT_TREE_NODE_STORE_SIZE]; ++ ++static void uksm_enter_all_slots(void) ++{ ++ struct vma_slot *slot; ++ unsigned long index; ++ struct list_head empty_vma_list; ++ int i; ++ ++ i = 0; ++ index = 0; ++ INIT_LIST_HEAD(&empty_vma_list); ++ ++ spin_lock(&vma_slot_list_lock); ++ while (!list_empty(&vma_slot_new)) { ++ slot = list_entry(vma_slot_new.next, ++ struct vma_slot, slot_list); ++ ++ if (!slot->vma->anon_vma) { ++ list_move(&slot->slot_list, &empty_vma_list); ++ } else if (vma_can_enter(slot->vma)) { ++ batch_slots[index++] = slot; ++ list_del_init(&slot->slot_list); ++ } else { ++ list_move(&slot->slot_list, &vma_slot_noadd); ++ } ++ ++ if (++i == SPIN_LOCK_PERIOD || ++ (index && !(index % SLOT_TREE_NODE_STORE_SIZE))) { ++ spin_unlock(&vma_slot_list_lock); ++ ++ if (index && !(index % SLOT_TREE_NODE_STORE_SIZE)) { ++ uksm_vma_enter(batch_slots, index); ++ index = 0; ++ } ++ i = 0; ++ cond_resched(); ++ spin_lock(&vma_slot_list_lock); ++ } ++ } ++ ++ list_splice(&empty_vma_list, &vma_slot_new); ++ ++ spin_unlock(&vma_slot_list_lock); ++ ++ if (index) ++ uksm_vma_enter(batch_slots, index); ++ ++} ++ ++static inline int rung_round_finished(struct scan_rung *rung) ++{ ++ return rung->flags & UKSM_RUNG_ROUND_FINISHED; ++} ++ ++static inline void judge_slot(struct vma_slot *slot) ++{ ++ struct scan_rung *rung = slot->rung; ++ unsigned long dedup; ++ int deleted; ++ ++ dedup = cal_dedup_ratio(slot); ++ if (vma_fully_scanned(slot) && uksm_thrash_threshold) ++ deleted = vma_rung_enter(slot, &uksm_scan_ladder[0]); ++ else if (dedup && dedup >= uksm_abundant_threshold) ++ deleted = vma_rung_up(slot); ++ else ++ deleted = vma_rung_down(slot); ++ ++ slot->pages_merged = 0; ++ slot->pages_cowed = 0; ++ slot->this_sampled = 0; ++ ++ if (vma_fully_scanned(slot)) ++ slot->pages_scanned = 0; ++ ++ slot->last_scanned = slot->pages_scanned; ++ ++ /* If its deleted in above, then rung was already advanced. */ ++ if (!deleted) ++ advance_current_scan(rung); ++} ++ ++ ++static inline int hash_round_finished(void) ++{ ++ if (scanned_virtual_pages > (uksm_pages_total >> 2)) { ++ scanned_virtual_pages = 0; ++ if (uksm_pages_scanned) ++ fully_scanned_round++; ++ ++ return 1; ++ } else { ++ return 0; ++ } ++} ++ ++#define UKSM_MMSEM_BATCH 5 ++#define BUSY_RETRY 100 ++ ++/** ++ * uksm_do_scan() - the main worker function. ++ */ ++static noinline void uksm_do_scan(void) ++{ ++ struct vma_slot *slot, *iter; ++ struct mm_struct *busy_mm; ++ unsigned char round_finished, all_rungs_emtpy; ++ int i, err, mmsem_batch; ++ unsigned long pcost; ++ long long delta_exec; ++ unsigned long vpages, max_cpu_ratio; ++ unsigned long long start_time, end_time, scan_time; ++ unsigned int expected_jiffies; ++ ++ might_sleep(); ++ ++ vpages = 0; ++ ++ start_time = task_sched_runtime(current); ++ max_cpu_ratio = 0; ++ mmsem_batch = 0; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE;) { ++ struct scan_rung *rung = &uksm_scan_ladder[i]; ++ unsigned long ratio; ++ int busy_retry; ++ ++ if (!rung->pages_to_scan) { ++ i++; ++ continue; ++ } ++ ++ if (!rung->vma_root.num) { ++ rung->pages_to_scan = 0; ++ i++; ++ continue; ++ } ++ ++ ratio = rung_real_ratio(rung->cpu_ratio); ++ if (ratio > max_cpu_ratio) ++ max_cpu_ratio = ratio; ++ ++ busy_retry = BUSY_RETRY; ++ /* ++ * Do not consider rung_round_finished() here, just used up the ++ * rung->pages_to_scan quota. ++ */ ++ while (rung->pages_to_scan && rung->vma_root.num && ++ likely(!freezing(current))) { ++ int reset = 0; ++ ++ slot = rung->current_scan; ++ ++ BUG_ON(vma_fully_scanned(slot)); ++ ++ if (mmsem_batch) ++ err = 0; ++ else ++ err = try_down_read_slot_mmap_sem(slot); ++ ++ if (err == -ENOENT) { ++rm_slot: ++ rung_rm_slot(slot); ++ continue; ++ } ++ ++ busy_mm = slot->mm; ++ ++ if (err == -EBUSY) { ++ /* skip other vmas on the same mm */ ++ do { ++ reset = advance_current_scan(rung); ++ iter = rung->current_scan; ++ busy_retry--; ++ if (iter->vma->vm_mm != busy_mm || ++ !busy_retry || reset) ++ break; ++ } while (1); ++ ++ if (iter->vma->vm_mm != busy_mm) { ++ continue; ++ } else { ++ /* scan round finsished */ ++ break; ++ } ++ } ++ ++ BUG_ON(!vma_can_enter(slot->vma)); ++ if (uksm_test_exit(slot->vma->vm_mm)) { ++ mmsem_batch = 0; ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ goto rm_slot; ++ } ++ ++ if (mmsem_batch) ++ mmsem_batch--; ++ else ++ mmsem_batch = UKSM_MMSEM_BATCH; ++ ++ /* Ok, we have take the mmap_sem, ready to scan */ ++ scan_vma_one_page(slot); ++ rung->pages_to_scan--; ++ vpages++; ++ ++ if (rung->current_offset + rung->step > slot->pages - 1 ++ || vma_fully_scanned(slot)) { ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ judge_slot(slot); ++ mmsem_batch = 0; ++ } else { ++ rung->current_offset += rung->step; ++ if (!mmsem_batch) ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ } ++ ++ busy_retry = BUSY_RETRY; ++ cond_resched(); ++ } ++ ++ if (mmsem_batch) { ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ mmsem_batch = 0; ++ } ++ ++ if (freezing(current)) ++ break; ++ ++ cond_resched(); ++ } ++ end_time = task_sched_runtime(current); ++ delta_exec = end_time - start_time; ++ ++ if (freezing(current)) ++ return; ++ ++ cleanup_vma_slots(); ++ uksm_enter_all_slots(); ++ ++ round_finished = 1; ++ all_rungs_emtpy = 1; ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ struct scan_rung *rung = &uksm_scan_ladder[i]; ++ ++ if (rung->vma_root.num) { ++ all_rungs_emtpy = 0; ++ if (!rung_round_finished(rung)) ++ round_finished = 0; ++ } ++ } ++ ++ if (all_rungs_emtpy) ++ round_finished = 0; ++ ++ if (round_finished) { ++ round_update_ladder(); ++ uksm_eval_round++; ++ ++ if (hash_round_finished() && rshash_adjust()) { ++ /* Reset the unstable root iff hash strength changed */ ++ uksm_hash_round++; ++ root_unstable_tree = RB_ROOT; ++ free_all_tree_nodes(&unstable_tree_node_list); ++ } ++ ++ /* ++ * A number of pages can hang around indefinitely on per-cpu ++ * pagevecs, raised page count preventing write_protect_page ++ * from merging them. Though it doesn't really matter much, ++ * it is puzzling to see some stuck in pages_volatile until ++ * other activity jostles them out, and they also prevented ++ * LTP's KSM test from succeeding deterministically; so drain ++ * them here (here rather than on entry to uksm_do_scan(), ++ * so we don't IPI too often when pages_to_scan is set low). ++ */ ++ lru_add_drain_all(); ++ } ++ ++ ++ if (vpages && delta_exec > 0) { ++ pcost = (unsigned long) delta_exec / vpages; ++ if (likely(uksm_ema_page_time)) ++ uksm_ema_page_time = ema(pcost, uksm_ema_page_time); ++ else ++ uksm_ema_page_time = pcost; ++ } ++ ++ uksm_calc_scan_pages(); ++ uksm_sleep_real = uksm_sleep_jiffies; ++ /* in case of radical cpu bursts, apply the upper bound */ ++ end_time = task_sched_runtime(current); ++ if (max_cpu_ratio && end_time > start_time) { ++ scan_time = end_time - start_time; ++ expected_jiffies = msecs_to_jiffies( ++ scan_time_to_sleep(scan_time, max_cpu_ratio)); ++ ++ if (expected_jiffies > uksm_sleep_real) ++ uksm_sleep_real = expected_jiffies; ++ ++ /* We have a 1 second up bound for responsiveness. */ ++ if (jiffies_to_msecs(uksm_sleep_real) > MSEC_PER_SEC) ++ uksm_sleep_real = msecs_to_jiffies(1000); ++ } ++ ++ return; ++} ++ ++static int ksmd_should_run(void) ++{ ++ return uksm_run & UKSM_RUN_MERGE; ++} ++ ++static int uksm_scan_thread(void *nothing) ++{ ++ set_freezable(); ++ set_user_nice(current, 5); ++ ++ while (!kthread_should_stop()) { ++ mutex_lock(&uksm_thread_mutex); ++ if (ksmd_should_run()) ++ uksm_do_scan(); ++ mutex_unlock(&uksm_thread_mutex); ++ ++ try_to_freeze(); ++ ++ if (ksmd_should_run()) { ++ schedule_timeout_interruptible(uksm_sleep_real); ++ uksm_sleep_times++; ++ } else { ++ wait_event_freezable(uksm_thread_wait, ++ ksmd_should_run() || kthread_should_stop()); ++ } ++ } ++ return 0; ++} ++ ++void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) ++{ ++ struct stable_node *stable_node; ++ struct node_vma *node_vma; ++ struct rmap_item *rmap_item; ++ int search_new_forks = 0; ++ unsigned long address; ++ ++ VM_BUG_ON_PAGE(!PageKsm(page), page); ++ VM_BUG_ON_PAGE(!PageLocked(page), page); ++ ++ stable_node = page_stable_node(page); ++ if (!stable_node) ++ return; ++again: ++ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { ++ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { ++ struct anon_vma *anon_vma = rmap_item->anon_vma; ++ struct anon_vma_chain *vmac; ++ struct vm_area_struct *vma; ++ ++ cond_resched(); ++ anon_vma_lock_read(anon_vma); ++ anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, ++ 0, ULONG_MAX) { ++ cond_resched(); ++ vma = vmac->vma; ++ address = get_rmap_addr(rmap_item); ++ ++ if (address < vma->vm_start || ++ address >= vma->vm_end) ++ continue; ++ ++ if ((rmap_item->slot->vma == vma) == ++ search_new_forks) ++ continue; ++ ++ if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg)) ++ continue; ++ ++ if (!rwc->rmap_one(page, vma, address, rwc->arg)) { ++ anon_vma_unlock_read(anon_vma); ++ return; ++ } ++ ++ if (rwc->done && rwc->done(page)) { ++ anon_vma_unlock_read(anon_vma); ++ return; ++ } ++ } ++ anon_vma_unlock_read(anon_vma); ++ } ++ } ++ if (!search_new_forks++) ++ goto again; ++} ++ ++#ifdef CONFIG_MIGRATION ++/* Common ksm interface but may be specific to uksm */ ++void ksm_migrate_page(struct page *newpage, struct page *oldpage) ++{ ++ struct stable_node *stable_node; ++ ++ VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage); ++ VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); ++ VM_BUG_ON(newpage->mapping != oldpage->mapping); ++ ++ stable_node = page_stable_node(newpage); ++ if (stable_node) { ++ VM_BUG_ON(stable_node->kpfn != page_to_pfn(oldpage)); ++ stable_node->kpfn = page_to_pfn(newpage); ++ /* ++ * newpage->mapping was set in advance; now we need smp_wmb() ++ * to make sure that the new stable_node->kpfn is visible ++ * to get_ksm_page() before it can see that oldpage->mapping ++ * has gone stale (or that PageSwapCache has been cleared). ++ */ ++ smp_wmb(); ++ set_page_stable_node(oldpage, NULL); ++ } ++} ++#endif /* CONFIG_MIGRATION */ ++ ++#ifdef CONFIG_MEMORY_HOTREMOVE ++static struct stable_node *uksm_check_stable_tree(unsigned long start_pfn, ++ unsigned long end_pfn) ++{ ++ struct rb_node *node; ++ ++ for (node = rb_first(root_stable_treep); node; node = rb_next(node)) { ++ struct stable_node *stable_node; ++ ++ stable_node = rb_entry(node, struct stable_node, node); ++ if (stable_node->kpfn >= start_pfn && ++ stable_node->kpfn < end_pfn) ++ return stable_node; ++ } ++ return NULL; ++} ++ ++static int uksm_memory_callback(struct notifier_block *self, ++ unsigned long action, void *arg) ++{ ++ struct memory_notify *mn = arg; ++ struct stable_node *stable_node; ++ ++ switch (action) { ++ case MEM_GOING_OFFLINE: ++ /* ++ * Keep it very simple for now: just lock out ksmd and ++ * MADV_UNMERGEABLE while any memory is going offline. ++ * mutex_lock_nested() is necessary because lockdep was alarmed ++ * that here we take uksm_thread_mutex inside notifier chain ++ * mutex, and later take notifier chain mutex inside ++ * uksm_thread_mutex to unlock it. But that's safe because both ++ * are inside mem_hotplug_mutex. ++ */ ++ mutex_lock_nested(&uksm_thread_mutex, SINGLE_DEPTH_NESTING); ++ break; ++ ++ case MEM_OFFLINE: ++ /* ++ * Most of the work is done by page migration; but there might ++ * be a few stable_nodes left over, still pointing to struct ++ * pages which have been offlined: prune those from the tree. ++ */ ++ while ((stable_node = uksm_check_stable_tree(mn->start_pfn, ++ mn->start_pfn + mn->nr_pages)) != NULL) ++ remove_node_from_stable_tree(stable_node, 1, 1); ++ /* fallthrough */ ++ ++ case MEM_CANCEL_OFFLINE: ++ mutex_unlock(&uksm_thread_mutex); ++ break; ++ } ++ return NOTIFY_OK; ++} ++#endif /* CONFIG_MEMORY_HOTREMOVE */ ++ ++#ifdef CONFIG_SYSFS ++/* ++ * This all compiles without CONFIG_SYSFS, but is a waste of space. ++ */ ++ ++#define UKSM_ATTR_RO(_name) \ ++ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) ++#define UKSM_ATTR(_name) \ ++ static struct kobj_attribute _name##_attr = \ ++ __ATTR(_name, 0644, _name##_show, _name##_store) ++ ++static ssize_t max_cpu_percentage_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_max_cpu_percentage); ++} ++ ++static ssize_t max_cpu_percentage_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ unsigned long max_cpu_percentage; ++ int err; ++ ++ err = kstrtoul(buf, 10, &max_cpu_percentage); ++ if (err || max_cpu_percentage > 100) ++ return -EINVAL; ++ ++ if (max_cpu_percentage == 100) ++ max_cpu_percentage = 99; ++ else if (max_cpu_percentage < 10) ++ max_cpu_percentage = 10; ++ ++ uksm_max_cpu_percentage = max_cpu_percentage; ++ ++ return count; ++} ++UKSM_ATTR(max_cpu_percentage); ++ ++static ssize_t sleep_millisecs_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", jiffies_to_msecs(uksm_sleep_jiffies)); ++} ++ ++static ssize_t sleep_millisecs_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ unsigned long msecs; ++ int err; ++ ++ err = kstrtoul(buf, 10, &msecs); ++ if (err || msecs > MSEC_PER_SEC) ++ return -EINVAL; ++ ++ uksm_sleep_jiffies = msecs_to_jiffies(msecs); ++ uksm_sleep_saved = uksm_sleep_jiffies; ++ ++ return count; ++} ++UKSM_ATTR(sleep_millisecs); ++ ++ ++static ssize_t cpu_governor_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); ++ int i; ++ ++ buf[0] = '\0'; ++ for (i = 0; i < n ; i++) { ++ if (uksm_cpu_governor == i) ++ strcat(buf, "["); ++ ++ strcat(buf, uksm_cpu_governor_str[i]); ++ ++ if (uksm_cpu_governor == i) ++ strcat(buf, "]"); ++ ++ strcat(buf, " "); ++ } ++ strcat(buf, "\n"); ++ ++ return strlen(buf); ++} ++ ++static inline void init_performance_values(void) ++{ ++ int i; ++ struct scan_rung *rung; ++ struct uksm_cpu_preset_s *preset = uksm_cpu_preset + uksm_cpu_governor; ++ ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = uksm_scan_ladder + i; ++ rung->cpu_ratio = preset->cpu_ratio[i]; ++ rung->cover_msecs = preset->cover_msecs[i]; ++ } ++ ++ uksm_max_cpu_percentage = preset->max_cpu; ++} ++ ++static ssize_t cpu_governor_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); ++ ++ for (n--; n >= 0 ; n--) { ++ if (!strncmp(buf, uksm_cpu_governor_str[n], ++ strlen(uksm_cpu_governor_str[n]))) ++ break; ++ } ++ ++ if (n < 0) ++ return -EINVAL; ++ else ++ uksm_cpu_governor = n; ++ ++ init_performance_values(); ++ ++ return count; ++} ++UKSM_ATTR(cpu_governor); ++ ++static ssize_t run_show(struct kobject *kobj, struct kobj_attribute *attr, ++ char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_run); ++} ++ ++static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int err; ++ unsigned long flags; ++ ++ err = kstrtoul(buf, 10, &flags); ++ if (err || flags > UINT_MAX) ++ return -EINVAL; ++ if (flags > UKSM_RUN_MERGE) ++ return -EINVAL; ++ ++ mutex_lock(&uksm_thread_mutex); ++ if (uksm_run != flags) ++ uksm_run = flags; ++ mutex_unlock(&uksm_thread_mutex); ++ ++ if (flags & UKSM_RUN_MERGE) ++ wake_up_interruptible(&uksm_thread_wait); ++ ++ return count; ++} ++UKSM_ATTR(run); ++ ++static ssize_t abundant_threshold_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_abundant_threshold); ++} ++ ++static ssize_t abundant_threshold_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int err; ++ unsigned long flags; ++ ++ err = kstrtoul(buf, 10, &flags); ++ if (err || flags > 99) ++ return -EINVAL; ++ ++ uksm_abundant_threshold = flags; ++ ++ return count; ++} ++UKSM_ATTR(abundant_threshold); ++ ++static ssize_t thrash_threshold_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_thrash_threshold); ++} ++ ++static ssize_t thrash_threshold_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int err; ++ unsigned long flags; ++ ++ err = kstrtoul(buf, 10, &flags); ++ if (err || flags > 99) ++ return -EINVAL; ++ ++ uksm_thrash_threshold = flags; ++ ++ return count; ++} ++UKSM_ATTR(thrash_threshold); ++ ++static ssize_t cpu_ratios_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ int i, size; ++ struct scan_rung *rung; ++ char *p = buf; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ ++ if (rung->cpu_ratio > 0) ++ size = sprintf(p, "%d ", rung->cpu_ratio); ++ else ++ size = sprintf(p, "MAX/%d ", ++ TIME_RATIO_SCALE / -rung->cpu_ratio); ++ ++ p += size; ++ } ++ ++ *p++ = '\n'; ++ *p = '\0'; ++ ++ return p - buf; ++} ++ ++static ssize_t cpu_ratios_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int i, cpuratios[SCAN_LADDER_SIZE], err; ++ unsigned long value; ++ struct scan_rung *rung; ++ char *p, *end = NULL; ++ ++ p = kzalloc(count, GFP_KERNEL); ++ if (!p) ++ return -ENOMEM; ++ ++ memcpy(p, buf, count); ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ if (i != SCAN_LADDER_SIZE - 1) { ++ end = strchr(p, ' '); ++ if (!end) ++ return -EINVAL; ++ ++ *end = '\0'; ++ } ++ ++ if (strstr(p, "MAX/")) { ++ p = strchr(p, '/') + 1; ++ err = kstrtoul(p, 10, &value); ++ if (err || value > TIME_RATIO_SCALE || !value) ++ return -EINVAL; ++ ++ cpuratios[i] = -(int) (TIME_RATIO_SCALE / value); ++ } else { ++ err = kstrtoul(p, 10, &value); ++ if (err || value > TIME_RATIO_SCALE || !value) ++ return -EINVAL; ++ ++ cpuratios[i] = value; ++ } ++ ++ p = end + 1; ++ } ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ ++ rung->cpu_ratio = cpuratios[i]; ++ } ++ ++ return count; ++} ++UKSM_ATTR(cpu_ratios); ++ ++static ssize_t eval_intervals_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ int i, size; ++ struct scan_rung *rung; ++ char *p = buf; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ size = sprintf(p, "%u ", rung->cover_msecs); ++ p += size; ++ } ++ ++ *p++ = '\n'; ++ *p = '\0'; ++ ++ return p - buf; ++} ++ ++static ssize_t eval_intervals_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int i, err; ++ unsigned long values[SCAN_LADDER_SIZE]; ++ struct scan_rung *rung; ++ char *p, *end = NULL; ++ ssize_t ret = count; ++ ++ p = kzalloc(count + 2, GFP_KERNEL); ++ if (!p) ++ return -ENOMEM; ++ ++ memcpy(p, buf, count); ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ if (i != SCAN_LADDER_SIZE - 1) { ++ end = strchr(p, ' '); ++ if (!end) { ++ ret = -EINVAL; ++ goto out; ++ } ++ ++ *end = '\0'; ++ } ++ ++ err = kstrtoul(p, 10, &values[i]); ++ if (err) { ++ ret = -EINVAL; ++ goto out; ++ } ++ ++ p = end + 1; ++ } ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ ++ rung->cover_msecs = values[i]; ++ } ++ ++out: ++ kfree(p); ++ return ret; ++} ++UKSM_ATTR(eval_intervals); ++ ++static ssize_t ema_per_page_time_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_ema_page_time); ++} ++UKSM_ATTR_RO(ema_per_page_time); ++ ++static ssize_t pages_shared_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_pages_shared); ++} ++UKSM_ATTR_RO(pages_shared); ++ ++static ssize_t pages_sharing_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_pages_sharing); ++} ++UKSM_ATTR_RO(pages_sharing); ++ ++static ssize_t pages_unshared_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_pages_unshared); ++} ++UKSM_ATTR_RO(pages_unshared); ++ ++static ssize_t full_scans_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%llu\n", fully_scanned_round); ++} ++UKSM_ATTR_RO(full_scans); ++ ++static ssize_t pages_scanned_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ unsigned long base = 0; ++ u64 delta, ret; ++ ++ if (pages_scanned_stored) { ++ base = pages_scanned_base; ++ ret = pages_scanned_stored; ++ delta = uksm_pages_scanned >> base; ++ if (CAN_OVERFLOW_U64(ret, delta)) { ++ ret >>= 1; ++ delta >>= 1; ++ base++; ++ ret += delta; ++ } ++ } else { ++ ret = uksm_pages_scanned; ++ } ++ ++ while (ret > ULONG_MAX) { ++ ret >>= 1; ++ base++; ++ } ++ ++ if (base) ++ return sprintf(buf, "%lu * 2^%lu\n", (unsigned long)ret, base); ++ else ++ return sprintf(buf, "%lu\n", (unsigned long)ret); ++} ++UKSM_ATTR_RO(pages_scanned); ++ ++static ssize_t hash_strength_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", hash_strength); ++} ++UKSM_ATTR_RO(hash_strength); ++ ++static ssize_t sleep_times_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%llu\n", uksm_sleep_times); ++} ++UKSM_ATTR_RO(sleep_times); ++ ++ ++static struct attribute *uksm_attrs[] = { ++ &max_cpu_percentage_attr.attr, ++ &sleep_millisecs_attr.attr, ++ &cpu_governor_attr.attr, ++ &run_attr.attr, ++ &ema_per_page_time_attr.attr, ++ &pages_shared_attr.attr, ++ &pages_sharing_attr.attr, ++ &pages_unshared_attr.attr, ++ &full_scans_attr.attr, ++ &pages_scanned_attr.attr, ++ &hash_strength_attr.attr, ++ &sleep_times_attr.attr, ++ &thrash_threshold_attr.attr, ++ &abundant_threshold_attr.attr, ++ &cpu_ratios_attr.attr, ++ &eval_intervals_attr.attr, ++ NULL, ++}; ++ ++static struct attribute_group uksm_attr_group = { ++ .attrs = uksm_attrs, ++ .name = "uksm", ++}; ++#endif /* CONFIG_SYSFS */ ++ ++static inline void init_scan_ladder(void) ++{ ++ int i; ++ struct scan_rung *rung; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = uksm_scan_ladder + i; ++ slot_tree_init_root(&rung->vma_root); ++ } ++ ++ init_performance_values(); ++ uksm_calc_scan_pages(); ++} ++ ++static inline int cal_positive_negative_costs(void) ++{ ++ struct page *p1, *p2; ++ unsigned char *addr1, *addr2; ++ unsigned long i, time_start, hash_cost; ++ unsigned long loopnum = 0; ++ ++ /*IMPORTANT: volatile is needed to prevent over-optimization by gcc. */ ++ volatile u32 hash; ++ volatile int ret; ++ ++ p1 = alloc_page(GFP_KERNEL); ++ if (!p1) ++ return -ENOMEM; ++ ++ p2 = alloc_page(GFP_KERNEL); ++ if (!p2) ++ return -ENOMEM; ++ ++ addr1 = kmap_atomic(p1); ++ addr2 = kmap_atomic(p2); ++ memset(addr1, prandom_u32(), PAGE_SIZE); ++ memcpy(addr2, addr1, PAGE_SIZE); ++ ++ /* make sure that the two pages differ in last byte */ ++ addr2[PAGE_SIZE-1] = ~addr2[PAGE_SIZE-1]; ++ kunmap_atomic(addr2); ++ kunmap_atomic(addr1); ++ ++ time_start = jiffies; ++ while (jiffies - time_start < 100) { ++ for (i = 0; i < 100; i++) ++ hash = page_hash(p1, HASH_STRENGTH_FULL, 0); ++ loopnum += 100; ++ } ++ hash_cost = (jiffies - time_start); ++ ++ time_start = jiffies; ++ for (i = 0; i < loopnum; i++) ++ ret = pages_identical(p1, p2); ++ memcmp_cost = HASH_STRENGTH_FULL * (jiffies - time_start); ++ memcmp_cost /= hash_cost; ++ pr_info("UKSM: relative memcmp_cost = %lu " ++ "hash=%u cmp_ret=%d.\n", ++ memcmp_cost, hash, ret); ++ ++ __free_page(p1); ++ __free_page(p2); ++ return 0; ++} ++ ++static int init_zeropage_hash_table(void) ++{ ++ struct page *page; ++ char *addr; ++ int i; ++ ++ page = alloc_page(GFP_KERNEL); ++ if (!page) ++ return -ENOMEM; ++ ++ addr = kmap_atomic(page); ++ memset(addr, 0, PAGE_SIZE); ++ kunmap_atomic(addr); ++ ++ zero_hash_table = kmalloc_array(HASH_STRENGTH_MAX, sizeof(u32), ++ GFP_KERNEL); ++ if (!zero_hash_table) ++ return -ENOMEM; ++ ++ for (i = 0; i < HASH_STRENGTH_MAX; i++) ++ zero_hash_table[i] = page_hash(page, i, 0); ++ ++ __free_page(page); ++ ++ return 0; ++} ++ ++static inline int init_random_sampling(void) ++{ ++ unsigned long i; ++ ++ random_nums = kmalloc(PAGE_SIZE, GFP_KERNEL); ++ if (!random_nums) ++ return -ENOMEM; ++ ++ for (i = 0; i < HASH_STRENGTH_FULL; i++) ++ random_nums[i] = i; ++ ++ for (i = 0; i < HASH_STRENGTH_FULL; i++) { ++ unsigned long rand_range, swap_index, tmp; ++ ++ rand_range = HASH_STRENGTH_FULL - i; ++ swap_index = i + prandom_u32() % rand_range; ++ tmp = random_nums[i]; ++ random_nums[i] = random_nums[swap_index]; ++ random_nums[swap_index] = tmp; ++ } ++ ++ rshash_state.state = RSHASH_NEW; ++ rshash_state.below_count = 0; ++ rshash_state.lookup_window_index = 0; ++ ++ return cal_positive_negative_costs(); ++} ++ ++static int __init uksm_slab_init(void) ++{ ++ rmap_item_cache = UKSM_KMEM_CACHE(rmap_item, 0); ++ if (!rmap_item_cache) ++ goto out; ++ ++ stable_node_cache = UKSM_KMEM_CACHE(stable_node, 0); ++ if (!stable_node_cache) ++ goto out_free1; ++ ++ node_vma_cache = UKSM_KMEM_CACHE(node_vma, 0); ++ if (!node_vma_cache) ++ goto out_free2; ++ ++ vma_slot_cache = UKSM_KMEM_CACHE(vma_slot, 0); ++ if (!vma_slot_cache) ++ goto out_free3; ++ ++ tree_node_cache = UKSM_KMEM_CACHE(tree_node, 0); ++ if (!tree_node_cache) ++ goto out_free4; ++ ++ return 0; ++ ++out_free4: ++ kmem_cache_destroy(vma_slot_cache); ++out_free3: ++ kmem_cache_destroy(node_vma_cache); ++out_free2: ++ kmem_cache_destroy(stable_node_cache); ++out_free1: ++ kmem_cache_destroy(rmap_item_cache); ++out: ++ return -ENOMEM; ++} ++ ++static void __init uksm_slab_free(void) ++{ ++ kmem_cache_destroy(stable_node_cache); ++ kmem_cache_destroy(rmap_item_cache); ++ kmem_cache_destroy(node_vma_cache); ++ kmem_cache_destroy(vma_slot_cache); ++ kmem_cache_destroy(tree_node_cache); ++} ++ ++/* Common interface to ksm, different to it. */ ++int ksm_madvise(struct vm_area_struct *vma, unsigned long start, ++ unsigned long end, int advice, unsigned long *vm_flags) ++{ ++ int err; ++ ++ switch (advice) { ++ case MADV_MERGEABLE: ++ return 0; /* just ignore the advice */ ++ ++ case MADV_UNMERGEABLE: ++ if (!(*vm_flags & VM_MERGEABLE) || !uksm_flags_can_scan(*vm_flags)) ++ return 0; /* just ignore the advice */ ++ ++ if (vma->anon_vma) { ++ err = unmerge_uksm_pages(vma, start, end); ++ if (err) ++ return err; ++ } ++ ++ uksm_remove_vma(vma); ++ *vm_flags &= ~VM_MERGEABLE; ++ break; ++ } ++ ++ return 0; ++} ++ ++/* Common interface to ksm, actually the same. */ ++struct page *ksm_might_need_to_copy(struct page *page, ++ struct vm_area_struct *vma, unsigned long address) ++{ ++ struct anon_vma *anon_vma = page_anon_vma(page); ++ struct page *new_page; ++ ++ if (PageKsm(page)) { ++ if (page_stable_node(page)) ++ return page; /* no need to copy it */ ++ } else if (!anon_vma) { ++ return page; /* no need to copy it */ ++ } else if (anon_vma->root == vma->anon_vma->root && ++ page->index == linear_page_index(vma, address)) { ++ return page; /* still no need to copy it */ ++ } ++ if (!PageUptodate(page)) ++ return page; /* let do_swap_page report the error */ ++ ++ new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); ++ if (new_page) { ++ copy_user_highpage(new_page, page, address, vma); ++ ++ SetPageDirty(new_page); ++ __SetPageUptodate(new_page); ++ __SetPageLocked(new_page); ++ } ++ ++ return new_page; ++} ++ ++static int __init uksm_init(void) ++{ ++ struct task_struct *uksm_thread; ++ int err; ++ ++ uksm_sleep_jiffies = msecs_to_jiffies(100); ++ uksm_sleep_saved = uksm_sleep_jiffies; ++ ++ slot_tree_init(); ++ init_scan_ladder(); ++ ++ ++ err = init_random_sampling(); ++ if (err) ++ goto out_free2; ++ ++ err = uksm_slab_init(); ++ if (err) ++ goto out_free1; ++ ++ err = init_zeropage_hash_table(); ++ if (err) ++ goto out_free0; ++ ++ uksm_thread = kthread_run(uksm_scan_thread, NULL, "uksmd"); ++ if (IS_ERR(uksm_thread)) { ++ pr_err("uksm: creating kthread failed\n"); ++ err = PTR_ERR(uksm_thread); ++ goto out_free; ++ } ++ ++#ifdef CONFIG_SYSFS ++ err = sysfs_create_group(mm_kobj, &uksm_attr_group); ++ if (err) { ++ pr_err("uksm: register sysfs failed\n"); ++ kthread_stop(uksm_thread); ++ goto out_free; ++ } ++#else ++ uksm_run = UKSM_RUN_MERGE; /* no way for user to start it */ ++ ++#endif /* CONFIG_SYSFS */ ++ ++#ifdef CONFIG_MEMORY_HOTREMOVE ++ /* ++ * Choose a high priority since the callback takes uksm_thread_mutex: ++ * later callbacks could only be taking locks which nest within that. ++ */ ++ hotplug_memory_notifier(uksm_memory_callback, 100); ++#endif ++ return 0; ++ ++out_free: ++ kfree(zero_hash_table); ++out_free0: ++ uksm_slab_free(); ++out_free1: ++ kfree(random_nums); ++out_free2: ++ kfree(uksm_scan_ladder); ++ return err; ++} ++ ++#ifdef MODULE ++subsys_initcall(ksm_init); ++#else ++late_initcall(uksm_init); ++#endif ++ +diff -Nur a/mm/vmstat.c b/mm/vmstat.c +--- a/mm/vmstat.c 2019-06-25 04:34:56.000000000 +0100 ++++ b/mm/vmstat.c 2019-07-07 11:43:00.148837320 +0100 +@@ -1165,6 +1165,9 @@ + "nr_written", + "nr_kernel_misc_reclaimable", + ++#ifdef CONFIG_UKSM ++ "nr_uksm_zero_pages", ++#endif + /* enum writeback_stat_item counters */ + "nr_dirty_threshold", + "nr_dirty_background_threshold", diff --git a/sys-kernel/linux-sources-redcore/files/5.1-uksm-linux-hardened.patch b/sys-kernel/linux-sources-redcore/files/5.1-uksm-linux-hardened.patch deleted file mode 100644 index a79cb3d5..00000000 --- a/sys-kernel/linux-sources-redcore/files/5.1-uksm-linux-hardened.patch +++ /dev/null @@ -1,6901 +0,0 @@ -diff -Nur a/Documentation/vm/uksm.txt b/Documentation/vm/uksm.txt ---- a/Documentation/vm/uksm.txt 1970-01-01 01:00:00.000000000 +0100 -+++ b/Documentation/vm/uksm.txt 2019-07-07 09:32:50.451840235 +0100 -@@ -0,0 +1,61 @@ -+The Ultra Kernel Samepage Merging feature -+---------------------------------------------- -+/* -+ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia -+ * -+ * This is an improvement upon KSM. Some basic data structures and routines -+ * are borrowed from ksm.c . -+ * -+ * Its new features: -+ * 1. Full system scan: -+ * It automatically scans all user processes' anonymous VMAs. Kernel-user -+ * interaction to submit a memory area to KSM is no longer needed. -+ * -+ * 2. Rich area detection: -+ * It automatically detects rich areas containing abundant duplicated -+ * pages based. Rich areas are given a full scan speed. Poor areas are -+ * sampled at a reasonable speed with very low CPU consumption. -+ * -+ * 3. Ultra Per-page scan speed improvement: -+ * A new hash algorithm is proposed. As a result, on a machine with -+ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it -+ * can scan memory areas that does not contain duplicated pages at speed of -+ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of -+ * 477MB/sec ~ 923MB/sec. -+ * -+ * 4. Thrashing area avoidance: -+ * Thrashing area(an VMA that has frequent Ksm page break-out) can be -+ * filtered out. My benchmark shows it's more efficient than KSM's per-page -+ * hash value based volatile page detection. -+ * -+ * -+ * 5. Misc changes upon KSM: -+ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page -+ * comparison. It's much faster than default C version on x86. -+ * * rmap_item now has an struct *page member to loosely cache a -+ * address-->page mapping, which reduces too much time-costly -+ * follow_page(). -+ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. -+ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ -+ * ksm is needed for this case. -+ * -+ * 6. Full Zero Page consideration(contributed by Figo Zhang) -+ * Now uksmd consider full zero pages as special pages and merge them to an -+ * special unswappable uksm zero page. -+ */ -+ -+ChangeLog: -+ -+2012-05-05 The creation of this Doc -+2012-05-08 UKSM 0.1.1.1 libc crash bug fix, api clean up, doc clean up. -+2012-05-28 UKSM 0.1.1.2 bug fix release -+2012-06-26 UKSM 0.1.2-beta1 first beta release for 0.1.2 -+2012-07-2 UKSM 0.1.2-beta2 -+2012-07-10 UKSM 0.1.2-beta3 -+2012-07-26 UKSM 0.1.2 Fine grained speed control, more scan optimization. -+2012-10-13 UKSM 0.1.2.1 Bug fixes. -+2012-12-31 UKSM 0.1.2.2 Minor bug fixes. -+2014-07-02 UKSM 0.1.2.3 Fix a " __this_cpu_read() in preemptible bug". -+2015-04-22 UKSM 0.1.2.4 Fix a race condition that can sometimes trigger anonying warnings. -+2016-09-10 UKSM 0.1.2.5 Fix a bug in dedup ratio calculation. -+2017-02-26 UKSM 0.1.2.6 Fix a bug in hugetlbpage handling and a race bug with page migration. -diff -Nur a/fs/exec.c b/fs/exec.c ---- a/fs/exec.c 2019-07-07 09:08:19.132347946 +0100 -+++ b/fs/exec.c 2019-07-07 09:33:47.653770486 +0100 -@@ -63,6 +63,7 @@ - #include - #include - #include -+#include - - #include - #include -@@ -1385,6 +1386,7 @@ - /* An exec changes our domain. We are no longer part of the thread - group */ - current->self_exec_id++; -+ - flush_signal_handlers(current, 0); - } - EXPORT_SYMBOL(setup_new_exec); -diff -Nur a/fs/proc/meminfo.c b/fs/proc/meminfo.c ---- a/fs/proc/meminfo.c 2019-06-25 04:34:56.000000000 +0100 -+++ b/fs/proc/meminfo.c 2019-07-07 09:32:50.451840235 +0100 -@@ -106,6 +106,10 @@ - global_zone_page_state(NR_KERNEL_STACK_KB)); - show_val_kb(m, "PageTables: ", - global_zone_page_state(NR_PAGETABLE)); -+#ifdef CONFIG_UKSM -+ show_val_kb(m, "KsmZeroPages: ", -+ global_zone_page_state(NR_UKSM_ZERO_PAGES)); -+#endif - #ifdef CONFIG_QUICKLIST - show_val_kb(m, "Quicklists: ", quicklist_total_size()); - #endif -diff -Nur a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h ---- a/include/asm-generic/pgtable.h 2019-06-25 04:34:56.000000000 +0100 -+++ b/include/asm-generic/pgtable.h 2019-07-07 09:32:50.451840235 +0100 -@@ -855,12 +855,25 @@ - extern void untrack_pfn_moved(struct vm_area_struct *vma); - #endif - -+#ifdef CONFIG_UKSM -+static inline int is_uksm_zero_pfn(unsigned long pfn) -+{ -+ extern unsigned long uksm_zero_pfn; -+ return pfn == uksm_zero_pfn; -+} -+#else -+static inline int is_uksm_zero_pfn(unsigned long pfn) -+{ -+ return 0; -+} -+#endif -+ - #ifdef __HAVE_COLOR_ZERO_PAGE - static inline int is_zero_pfn(unsigned long pfn) - { - extern unsigned long zero_pfn; - unsigned long offset_from_zero_pfn = pfn - zero_pfn; -- return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT); -+ return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT) || is_uksm_zero_pfn(pfn); - } - - #define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) -@@ -869,7 +882,7 @@ - static inline int is_zero_pfn(unsigned long pfn) - { - extern unsigned long zero_pfn; -- return pfn == zero_pfn; -+ return (pfn == zero_pfn) || (is_uksm_zero_pfn(pfn)); - } - - static inline unsigned long my_zero_pfn(unsigned long addr) -diff -Nur a/include/linux/ksm.h b/include/linux/ksm.h ---- a/include/linux/ksm.h 2019-06-25 04:34:56.000000000 +0100 -+++ b/include/linux/ksm.h 2019-07-07 09:32:50.451840235 +0100 -@@ -1,4 +1,4 @@ --/* SPDX-License-Identifier: GPL-2.0 */ -+/* SPDX-License-Identifier: GPL-3.0 */ - #ifndef __LINUX_KSM_H - #define __LINUX_KSM_H - /* -@@ -21,20 +21,16 @@ - #ifdef CONFIG_KSM - int ksm_madvise(struct vm_area_struct *vma, unsigned long start, - unsigned long end, int advice, unsigned long *vm_flags); --int __ksm_enter(struct mm_struct *mm); --void __ksm_exit(struct mm_struct *mm); - --static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) -+static inline struct stable_node *page_stable_node(struct page *page) - { -- if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) -- return __ksm_enter(mm); -- return 0; -+ return PageKsm(page) ? page_rmapping(page) : NULL; - } - --static inline void ksm_exit(struct mm_struct *mm) -+static inline void set_page_stable_node(struct page *page, -+ struct stable_node *stable_node) - { -- if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) -- __ksm_exit(mm); -+ page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); - } - - /* -@@ -56,6 +52,33 @@ - bool reuse_ksm_page(struct page *page, - struct vm_area_struct *vma, unsigned long address); - -+#ifdef CONFIG_KSM_LEGACY -+int __ksm_enter(struct mm_struct *mm); -+void __ksm_exit(struct mm_struct *mm); -+static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) -+{ -+ if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) -+ return __ksm_enter(mm); -+ return 0; -+} -+ -+static inline void ksm_exit(struct mm_struct *mm) -+{ -+ if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) -+ __ksm_exit(mm); -+} -+ -+#elif defined(CONFIG_UKSM) -+static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) -+{ -+ return 0; -+} -+ -+static inline void ksm_exit(struct mm_struct *mm) -+{ -+} -+#endif /* !CONFIG_UKSM */ -+ - #else /* !CONFIG_KSM */ - - static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) -@@ -96,4 +119,6 @@ - #endif /* CONFIG_MMU */ - #endif /* !CONFIG_KSM */ - -+#include -+ - #endif /* __LINUX_KSM_H */ -diff -Nur a/include/linux/mm_types.h b/include/linux/mm_types.h ---- a/include/linux/mm_types.h 2019-06-25 04:34:56.000000000 +0100 -+++ b/include/linux/mm_types.h 2019-07-07 09:32:50.451840235 +0100 -@@ -334,6 +334,9 @@ - struct mempolicy *vm_policy; /* NUMA policy for the VMA */ - #endif - struct vm_userfaultfd_ctx vm_userfaultfd_ctx; -+#ifdef CONFIG_UKSM -+ struct vma_slot *uksm_vma_slot; -+#endif - } __randomize_layout; - - struct core_thread { -diff -Nur a/include/linux/mmzone.h b/include/linux/mmzone.h ---- a/include/linux/mmzone.h 2019-06-25 04:34:56.000000000 +0100 -+++ b/include/linux/mmzone.h 2019-07-07 09:32:50.451840235 +0100 -@@ -148,6 +148,9 @@ - NR_ZSPAGES, /* allocated in zsmalloc */ - #endif - NR_FREE_CMA_PAGES, -+#ifdef CONFIG_UKSM -+ NR_UKSM_ZERO_PAGES, -+#endif - NR_VM_ZONE_STAT_ITEMS }; - - enum node_stat_item { -diff -Nur a/include/linux/sradix-tree.h b/include/linux/sradix-tree.h ---- a/include/linux/sradix-tree.h 1970-01-01 01:00:00.000000000 +0100 -+++ b/include/linux/sradix-tree.h 2019-07-07 09:32:50.451840235 +0100 -@@ -0,0 +1,77 @@ -+#ifndef _LINUX_SRADIX_TREE_H -+#define _LINUX_SRADIX_TREE_H -+ -+ -+#define INIT_SRADIX_TREE(root, mask) \ -+do { \ -+ (root)->height = 0; \ -+ (root)->gfp_mask = (mask); \ -+ (root)->rnode = NULL; \ -+} while (0) -+ -+#define ULONG_BITS (sizeof(unsigned long) * 8) -+#define SRADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) -+//#define SRADIX_TREE_MAP_SHIFT 6 -+//#define SRADIX_TREE_MAP_SIZE (1UL << SRADIX_TREE_MAP_SHIFT) -+//#define SRADIX_TREE_MAP_MASK (SRADIX_TREE_MAP_SIZE-1) -+ -+struct sradix_tree_node { -+ unsigned int height; /* Height from the bottom */ -+ unsigned int count; -+ unsigned int fulls; /* Number of full sublevel trees */ -+ struct sradix_tree_node *parent; -+ void *stores[0]; -+}; -+ -+/* A simple radix tree implementation */ -+struct sradix_tree_root { -+ unsigned int height; -+ struct sradix_tree_node *rnode; -+ -+ /* Where found to have available empty stores in its sublevels */ -+ struct sradix_tree_node *enter_node; -+ unsigned int shift; -+ unsigned int stores_size; -+ unsigned int mask; -+ unsigned long min; /* The first hole index */ -+ unsigned long num; -+ //unsigned long *height_to_maxindex; -+ -+ /* How the node is allocated and freed. */ -+ struct sradix_tree_node *(*alloc)(void); -+ void (*free)(struct sradix_tree_node *node); -+ -+ /* When a new node is added and removed */ -+ void (*extend)(struct sradix_tree_node *parent, struct sradix_tree_node *child); -+ void (*assign)(struct sradix_tree_node *node, unsigned int index, void *item); -+ void (*rm)(struct sradix_tree_node *node, unsigned int offset); -+}; -+ -+struct sradix_tree_path { -+ struct sradix_tree_node *node; -+ int offset; -+}; -+ -+static inline -+void init_sradix_tree_root(struct sradix_tree_root *root, unsigned long shift) -+{ -+ root->height = 0; -+ root->rnode = NULL; -+ root->shift = shift; -+ root->stores_size = 1UL << shift; -+ root->mask = root->stores_size - 1; -+} -+ -+ -+extern void *sradix_tree_next(struct sradix_tree_root *root, -+ struct sradix_tree_node *node, unsigned long index, -+ int (*iter)(void *, unsigned long)); -+ -+extern int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num); -+ -+extern void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, -+ struct sradix_tree_node *node, unsigned long index); -+ -+extern void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index); -+ -+#endif /* _LINUX_SRADIX_TREE_H */ -diff -Nur a/include/linux/uksm.h b/include/linux/uksm.h ---- a/include/linux/uksm.h 1970-01-01 01:00:00.000000000 +0100 -+++ b/include/linux/uksm.h 2019-07-07 09:32:50.451840235 +0100 -@@ -0,0 +1,149 @@ -+#ifndef __LINUX_UKSM_H -+#define __LINUX_UKSM_H -+/* -+ * Memory merging support. -+ * -+ * This code enables dynamic sharing of identical pages found in different -+ * memory areas, even if they are not shared by fork(). -+ */ -+ -+/* if !CONFIG_UKSM this file should not be compiled at all. */ -+#ifdef CONFIG_UKSM -+ -+#include -+#include -+#include -+#include -+#include -+ -+extern unsigned long zero_pfn __read_mostly; -+extern unsigned long uksm_zero_pfn __read_mostly; -+extern struct page *empty_uksm_zero_page; -+ -+/* must be done before linked to mm */ -+extern void uksm_vma_add_new(struct vm_area_struct *vma); -+extern void uksm_remove_vma(struct vm_area_struct *vma); -+ -+#define UKSM_SLOT_NEED_SORT (1 << 0) -+#define UKSM_SLOT_NEED_RERAND (1 << 1) -+#define UKSM_SLOT_SCANNED (1 << 2) /* It's scanned in this round */ -+#define UKSM_SLOT_FUL_SCANNED (1 << 3) -+#define UKSM_SLOT_IN_UKSM (1 << 4) -+ -+struct vma_slot { -+ struct sradix_tree_node *snode; -+ unsigned long sindex; -+ -+ struct list_head slot_list; -+ unsigned long fully_scanned_round; -+ unsigned long dedup_num; -+ unsigned long pages_scanned; -+ unsigned long this_sampled; -+ unsigned long last_scanned; -+ unsigned long pages_to_scan; -+ struct scan_rung *rung; -+ struct page **rmap_list_pool; -+ unsigned int *pool_counts; -+ unsigned long pool_size; -+ struct vm_area_struct *vma; -+ struct mm_struct *mm; -+ unsigned long ctime_j; -+ unsigned long pages; -+ unsigned long flags; -+ unsigned long pages_cowed; /* pages cowed this round */ -+ unsigned long pages_merged; /* pages merged this round */ -+ unsigned long pages_bemerged; -+ -+ /* when it has page merged in this eval round */ -+ struct list_head dedup_list; -+}; -+ -+static inline void uksm_unmap_zero_page(pte_t pte) -+{ -+ if (pte_pfn(pte) == uksm_zero_pfn) -+ __dec_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); -+} -+ -+static inline void uksm_map_zero_page(pte_t pte) -+{ -+ if (pte_pfn(pte) == uksm_zero_pfn) -+ __inc_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); -+} -+ -+static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) -+{ -+ if (vma->uksm_vma_slot && PageKsm(page)) -+ vma->uksm_vma_slot->pages_cowed++; -+} -+ -+static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) -+{ -+ if (vma->uksm_vma_slot && pte_pfn(pte) == uksm_zero_pfn) -+ vma->uksm_vma_slot->pages_cowed++; -+} -+ -+static inline int uksm_flags_can_scan(unsigned long vm_flags) -+{ -+#ifdef VM_SAO -+ if (vm_flags & VM_SAO) -+ return 0; -+#endif -+ -+ return !(vm_flags & (VM_PFNMAP | VM_IO | VM_DONTEXPAND | -+ VM_HUGETLB | VM_MIXEDMAP | VM_SHARED -+ | VM_MAYSHARE | VM_GROWSUP | VM_GROWSDOWN)); -+} -+ -+static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) -+{ -+ if (uksm_flags_can_scan(*vm_flags_p)) -+ *vm_flags_p |= VM_MERGEABLE; -+} -+ -+/* -+ * Just a wrapper for BUG_ON for where ksm_zeropage must not be. TODO: it will -+ * be removed when uksm zero page patch is stable enough. -+ */ -+static inline void uksm_bugon_zeropage(pte_t pte) -+{ -+ BUG_ON(pte_pfn(pte) == uksm_zero_pfn); -+} -+#else -+static inline void uksm_vma_add_new(struct vm_area_struct *vma) -+{ -+} -+ -+static inline void uksm_remove_vma(struct vm_area_struct *vma) -+{ -+} -+ -+static inline void uksm_unmap_zero_page(pte_t pte) -+{ -+} -+ -+static inline void uksm_map_zero_page(pte_t pte) -+{ -+} -+ -+static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) -+{ -+} -+ -+static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) -+{ -+} -+ -+static inline int uksm_flags_can_scan(unsigned long vm_flags) -+{ -+ return 0; -+} -+ -+static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) -+{ -+} -+ -+static inline void uksm_bugon_zeropage(pte_t pte) -+{ -+} -+#endif /* !CONFIG_UKSM */ -+#endif /* __LINUX_UKSM_H */ -diff -Nur a/kernel/fork.c b/kernel/fork.c ---- a/kernel/fork.c 2019-07-07 09:08:19.152348621 +0100 -+++ b/kernel/fork.c 2019-07-07 09:32:50.451840235 +0100 -@@ -584,7 +584,7 @@ - __vma_link_rb(mm, tmp, rb_link, rb_parent); - rb_link = &tmp->vm_rb.rb_right; - rb_parent = &tmp->vm_rb; -- -+ uksm_vma_add_new(tmp); - mm->map_count++; - if (!(tmp->vm_flags & VM_WIPEONFORK)) - retval = copy_page_range(mm, oldmm, mpnt); -diff -Nur a/lib/Makefile b/lib/Makefile ---- a/lib/Makefile 2019-06-25 04:34:56.000000000 +0100 -+++ b/lib/Makefile 2019-07-07 09:32:50.451840235 +0100 -@@ -29,7 +29,7 @@ - endif - - lib-y := ctype.o string.o vsprintf.o cmdline.o \ -- rbtree.o radix-tree.o timerqueue.o xarray.o \ -+ rbtree.o radix-tree.o sradix-tree.o timerqueue.o xarray.o \ - idr.o int_sqrt.o extable.o \ - sha1.o chacha.o irq_regs.o argv_split.o \ - flex_proportions.o ratelimit.o show_mem.o \ -diff -Nur a/lib/sradix-tree.c b/lib/sradix-tree.c ---- a/lib/sradix-tree.c 1970-01-01 01:00:00.000000000 +0100 -+++ b/lib/sradix-tree.c 2019-07-07 09:32:50.451840235 +0100 -@@ -0,0 +1,476 @@ -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+ -+static inline int sradix_node_full(struct sradix_tree_root *root, struct sradix_tree_node *node) -+{ -+ return node->fulls == root->stores_size || -+ (node->height == 1 && node->count == root->stores_size); -+} -+ -+/* -+ * Extend a sradix tree so it can store key @index. -+ */ -+static int sradix_tree_extend(struct sradix_tree_root *root, unsigned long index) -+{ -+ struct sradix_tree_node *node; -+ unsigned int height; -+ -+ if (unlikely(root->rnode == NULL)) { -+ if (!(node = root->alloc())) -+ return -ENOMEM; -+ -+ node->height = 1; -+ root->rnode = node; -+ root->height = 1; -+ } -+ -+ /* Figure out what the height should be. */ -+ height = root->height; -+ index >>= root->shift * height; -+ -+ while (index) { -+ index >>= root->shift; -+ height++; -+ } -+ -+ while (height > root->height) { -+ unsigned int newheight; -+ -+ if (!(node = root->alloc())) -+ return -ENOMEM; -+ -+ /* Increase the height. */ -+ node->stores[0] = root->rnode; -+ root->rnode->parent = node; -+ if (root->extend) -+ root->extend(node, root->rnode); -+ -+ newheight = root->height + 1; -+ node->height = newheight; -+ node->count = 1; -+ if (sradix_node_full(root, root->rnode)) -+ node->fulls = 1; -+ -+ root->rnode = node; -+ root->height = newheight; -+ } -+ -+ return 0; -+} -+ -+/* -+ * Search the next item from the current node, that is not NULL -+ * and can satify root->iter(). -+ */ -+void *sradix_tree_next(struct sradix_tree_root *root, -+ struct sradix_tree_node *node, unsigned long index, -+ int (*iter)(void *item, unsigned long height)) -+{ -+ unsigned long offset; -+ void *item; -+ -+ if (unlikely(node == NULL)) { -+ node = root->rnode; -+ for (offset = 0; offset < root->stores_size; offset++) { -+ item = node->stores[offset]; -+ if (item && (!iter || iter(item, node->height))) -+ break; -+ } -+ -+ if (unlikely(offset >= root->stores_size)) -+ return NULL; -+ -+ if (node->height == 1) -+ return item; -+ else -+ goto go_down; -+ } -+ -+ while (node) { -+ offset = (index & root->mask) + 1; -+ for (; offset < root->stores_size; offset++) { -+ item = node->stores[offset]; -+ if (item && (!iter || iter(item, node->height))) -+ break; -+ } -+ -+ if (offset < root->stores_size) -+ break; -+ -+ node = node->parent; -+ index >>= root->shift; -+ } -+ -+ if (!node) -+ return NULL; -+ -+ while (node->height > 1) { -+go_down: -+ node = item; -+ for (offset = 0; offset < root->stores_size; offset++) { -+ item = node->stores[offset]; -+ if (item && (!iter || iter(item, node->height))) -+ break; -+ } -+ -+ if (unlikely(offset >= root->stores_size)) -+ return NULL; -+ } -+ -+ BUG_ON(offset > root->stores_size); -+ -+ return item; -+} -+ -+/* -+ * Blindly insert the item to the tree. Typically, we reuse the -+ * first empty store item. -+ */ -+int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num) -+{ -+ unsigned long index; -+ unsigned int height; -+ struct sradix_tree_node *node, *tmp = NULL; -+ int offset, offset_saved; -+ void **store = NULL; -+ int error, i, j, shift; -+ -+go_on: -+ index = root->min; -+ -+ if (root->enter_node && !sradix_node_full(root, root->enter_node)) { -+ node = root->enter_node; -+ BUG_ON((index >> (root->shift * root->height))); -+ } else { -+ node = root->rnode; -+ if (node == NULL || (index >> (root->shift * root->height)) -+ || sradix_node_full(root, node)) { -+ error = sradix_tree_extend(root, index); -+ if (error) -+ return error; -+ -+ node = root->rnode; -+ } -+ } -+ -+ -+ height = node->height; -+ shift = (height - 1) * root->shift; -+ offset = (index >> shift) & root->mask; -+ while (shift > 0) { -+ offset_saved = offset; -+ for (; offset < root->stores_size; offset++) { -+ store = &node->stores[offset]; -+ tmp = *store; -+ -+ if (!tmp || !sradix_node_full(root, tmp)) -+ break; -+ } -+ BUG_ON(offset >= root->stores_size); -+ -+ if (offset != offset_saved) { -+ index += (offset - offset_saved) << shift; -+ index &= ~((1UL << shift) - 1); -+ } -+ -+ if (!tmp) { -+ if (!(tmp = root->alloc())) -+ return -ENOMEM; -+ -+ tmp->height = shift / root->shift; -+ *store = tmp; -+ tmp->parent = node; -+ node->count++; -+// if (root->extend) -+// root->extend(node, tmp); -+ } -+ -+ node = tmp; -+ shift -= root->shift; -+ offset = (index >> shift) & root->mask; -+ } -+ -+ BUG_ON(node->height != 1); -+ -+ -+ store = &node->stores[offset]; -+ for (i = 0, j = 0; -+ j < root->stores_size - node->count && -+ i < root->stores_size - offset && j < num; i++) { -+ if (!store[i]) { -+ store[i] = item[j]; -+ if (root->assign) -+ root->assign(node, index + i, item[j]); -+ j++; -+ } -+ } -+ -+ node->count += j; -+ root->num += j; -+ num -= j; -+ -+ while (sradix_node_full(root, node)) { -+ node = node->parent; -+ if (!node) -+ break; -+ -+ node->fulls++; -+ } -+ -+ if (unlikely(!node)) { -+ /* All nodes are full */ -+ root->min = 1 << (root->height * root->shift); -+ root->enter_node = NULL; -+ } else { -+ root->min = index + i - 1; -+ root->min |= (1UL << (node->height - 1)) - 1; -+ root->min++; -+ root->enter_node = node; -+ } -+ -+ if (num) { -+ item += j; -+ goto go_on; -+ } -+ -+ return 0; -+} -+ -+ -+/** -+ * sradix_tree_shrink - shrink height of a sradix tree to minimal -+ * @root sradix tree root -+ * -+ */ -+static inline void sradix_tree_shrink(struct sradix_tree_root *root) -+{ -+ /* try to shrink tree height */ -+ while (root->height > 1) { -+ struct sradix_tree_node *to_free = root->rnode; -+ -+ /* -+ * The candidate node has more than one child, or its child -+ * is not at the leftmost store, we cannot shrink. -+ */ -+ if (to_free->count != 1 || !to_free->stores[0]) -+ break; -+ -+ root->rnode = to_free->stores[0]; -+ root->rnode->parent = NULL; -+ root->height--; -+ if (unlikely(root->enter_node == to_free)) -+ root->enter_node = NULL; -+ root->free(to_free); -+ } -+} -+ -+/* -+ * Del the item on the known leaf node and index -+ */ -+void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, -+ struct sradix_tree_node *node, unsigned long index) -+{ -+ unsigned int offset; -+ struct sradix_tree_node *start, *end; -+ -+ BUG_ON(node->height != 1); -+ -+ start = node; -+ while (node && !(--node->count)) -+ node = node->parent; -+ -+ end = node; -+ if (!node) { -+ root->rnode = NULL; -+ root->height = 0; -+ root->min = 0; -+ root->num = 0; -+ root->enter_node = NULL; -+ } else { -+ offset = (index >> (root->shift * (node->height - 1))) & root->mask; -+ if (root->rm) -+ root->rm(node, offset); -+ node->stores[offset] = NULL; -+ root->num--; -+ if (root->min > index) { -+ root->min = index; -+ root->enter_node = node; -+ } -+ } -+ -+ if (start != end) { -+ do { -+ node = start; -+ start = start->parent; -+ if (unlikely(root->enter_node == node)) -+ root->enter_node = end; -+ root->free(node); -+ } while (start != end); -+ -+ /* -+ * Note that shrink may free "end", so enter_node still need to -+ * be checked inside. -+ */ -+ sradix_tree_shrink(root); -+ } else if (node->count == root->stores_size - 1) { -+ /* It WAS a full leaf node. Update the ancestors */ -+ node = node->parent; -+ while (node) { -+ node->fulls--; -+ if (node->fulls != root->stores_size - 1) -+ break; -+ -+ node = node->parent; -+ } -+ } -+} -+ -+void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index) -+{ -+ unsigned int height, offset; -+ struct sradix_tree_node *node; -+ int shift; -+ -+ node = root->rnode; -+ if (node == NULL || (index >> (root->shift * root->height))) -+ return NULL; -+ -+ height = root->height; -+ shift = (height - 1) * root->shift; -+ -+ do { -+ offset = (index >> shift) & root->mask; -+ node = node->stores[offset]; -+ if (!node) -+ return NULL; -+ -+ shift -= root->shift; -+ } while (shift >= 0); -+ -+ return node; -+} -+ -+/* -+ * Return the item if it exists, otherwise create it in place -+ * and return the created item. -+ */ -+void *sradix_tree_lookup_create(struct sradix_tree_root *root, -+ unsigned long index, void *(*item_alloc)(void)) -+{ -+ unsigned int height, offset; -+ struct sradix_tree_node *node, *tmp; -+ void *item; -+ int shift, error; -+ -+ if (root->rnode == NULL || (index >> (root->shift * root->height))) { -+ if (item_alloc) { -+ error = sradix_tree_extend(root, index); -+ if (error) -+ return NULL; -+ } else { -+ return NULL; -+ } -+ } -+ -+ node = root->rnode; -+ height = root->height; -+ shift = (height - 1) * root->shift; -+ -+ do { -+ offset = (index >> shift) & root->mask; -+ if (!node->stores[offset]) { -+ if (!(tmp = root->alloc())) -+ return NULL; -+ -+ tmp->height = shift / root->shift; -+ node->stores[offset] = tmp; -+ tmp->parent = node; -+ node->count++; -+ node = tmp; -+ } else { -+ node = node->stores[offset]; -+ } -+ -+ shift -= root->shift; -+ } while (shift > 0); -+ -+ BUG_ON(node->height != 1); -+ offset = index & root->mask; -+ if (node->stores[offset]) { -+ return node->stores[offset]; -+ } else if (item_alloc) { -+ if (!(item = item_alloc())) -+ return NULL; -+ -+ node->stores[offset] = item; -+ -+ /* -+ * NOTE: we do NOT call root->assign here, since this item is -+ * newly created by us having no meaning. Caller can call this -+ * if it's necessary to do so. -+ */ -+ -+ node->count++; -+ root->num++; -+ -+ while (sradix_node_full(root, node)) { -+ node = node->parent; -+ if (!node) -+ break; -+ -+ node->fulls++; -+ } -+ -+ if (unlikely(!node)) { -+ /* All nodes are full */ -+ root->min = 1 << (root->height * root->shift); -+ } else { -+ if (root->min == index) { -+ root->min |= (1UL << (node->height - 1)) - 1; -+ root->min++; -+ root->enter_node = node; -+ } -+ } -+ -+ return item; -+ } else { -+ return NULL; -+ } -+ -+} -+ -+int sradix_tree_delete(struct sradix_tree_root *root, unsigned long index) -+{ -+ unsigned int height, offset; -+ struct sradix_tree_node *node; -+ int shift; -+ -+ node = root->rnode; -+ if (node == NULL || (index >> (root->shift * root->height))) -+ return -ENOENT; -+ -+ height = root->height; -+ shift = (height - 1) * root->shift; -+ -+ do { -+ offset = (index >> shift) & root->mask; -+ node = node->stores[offset]; -+ if (!node) -+ return -ENOENT; -+ -+ shift -= root->shift; -+ } while (shift > 0); -+ -+ offset = index & root->mask; -+ if (!node->stores[offset]) -+ return -ENOENT; -+ -+ sradix_tree_delete_from_leaf(root, node, index); -+ -+ return 0; -+} -diff -Nur a/mm/Kconfig b/mm/Kconfig ---- a/mm/Kconfig 2019-07-07 09:08:19.162348955 +0100 -+++ b/mm/Kconfig 2019-07-07 09:32:50.451840235 +0100 -@@ -302,6 +302,32 @@ - See Documentation/vm/ksm.rst for more information: KSM is inactive - until a program has madvised that an area is MADV_MERGEABLE, and - root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set). -+choice -+ prompt "Choose UKSM/KSM strategy" -+ default UKSM -+ depends on KSM -+ help -+ This option allows to select a UKSM/KSM stragety. -+ -+config UKSM -+ bool "Ultra-KSM for page merging" -+ depends on KSM -+ help -+ UKSM is inspired by the Linux kernel project \u2014 KSM(Kernel Same -+ page Merging), but with a fundamentally rewritten core algorithm. With -+ an advanced algorithm, UKSM now can transparently scans all anonymously -+ mapped user space applications with an significantly improved scan speed -+ and CPU efficiency. Since KVM is friendly to KSM, KVM can also benefit from -+ UKSM. Now UKSM has its first stable release and first real world enterprise user. -+ For more information, please goto its project page. -+ (www.kerneldedup.org) -+ -+config KSM_LEGACY -+ bool "Legacy KSM implementation" -+ depends on KSM -+ help -+ The legacy KSM implementation from Red Hat. -+endchoice - - config DEFAULT_MMAP_MIN_ADDR - int "Low address space to protect from user allocation" -diff -Nur a/mm/ksm.c b/mm/ksm.c ---- a/mm/ksm.c 2019-06-25 04:34:56.000000000 +0100 -+++ b/mm/ksm.c 2019-07-07 09:32:50.461840572 +0100 -@@ -858,17 +858,6 @@ - return err; - } - --static inline struct stable_node *page_stable_node(struct page *page) --{ -- return PageKsm(page) ? page_rmapping(page) : NULL; --} -- --static inline void set_page_stable_node(struct page *page, -- struct stable_node *stable_node) --{ -- page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); --} -- - #ifdef CONFIG_SYSFS - /* - * Only called through the sysfs control interface: -diff -Nur a/mm/Makefile b/mm/Makefile ---- a/mm/Makefile 2019-06-25 04:34:56.000000000 +0100 -+++ b/mm/Makefile 2019-07-07 09:32:50.451840235 +0100 -@@ -58,7 +58,8 @@ - obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o - obj-$(CONFIG_SLOB) += slob.o - obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o --obj-$(CONFIG_KSM) += ksm.o -+obj-$(CONFIG_KSM_LEGACY) += ksm.o -+obj-$(CONFIG_UKSM) += uksm.o - obj-$(CONFIG_PAGE_POISONING) += page_poison.o - obj-$(CONFIG_SLAB) += slab.o - obj-$(CONFIG_SLUB) += slub.o -diff -Nur a/mm/memory.c b/mm/memory.c ---- a/mm/memory.c 2019-06-25 04:34:56.000000000 +0100 -+++ b/mm/memory.c 2019-07-07 09:32:50.461840572 +0100 -@@ -129,6 +129,25 @@ - - unsigned long highest_memmap_pfn __read_mostly; - -+#ifdef CONFIG_UKSM -+unsigned long uksm_zero_pfn __read_mostly; -+EXPORT_SYMBOL_GPL(uksm_zero_pfn); -+struct page *empty_uksm_zero_page; -+ -+static int __init setup_uksm_zero_page(void) -+{ -+ empty_uksm_zero_page = alloc_pages(__GFP_ZERO & ~__GFP_MOVABLE, 0); -+ if (!empty_uksm_zero_page) -+ panic("Oh boy, that early out of memory?"); -+ -+ SetPageReserved(empty_uksm_zero_page); -+ uksm_zero_pfn = page_to_pfn(empty_uksm_zero_page); -+ -+ return 0; -+} -+core_initcall(setup_uksm_zero_page); -+#endif -+ - /* - * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() - */ -@@ -140,6 +159,7 @@ - core_initcall(init_zero_pfn); - - -+ - #if defined(SPLIT_RSS_COUNTING) - - void sync_mm_rss(struct mm_struct *mm) -@@ -794,6 +814,9 @@ - get_page(page); - page_dup_rmap(page, false); - rss[mm_counter(page)]++; -+ -+ /* Should return NULL in vm_normal_page() */ -+ uksm_bugon_zeropage(pte); - } else if (pte_devmap(pte)) { - page = pte_page(pte); - -@@ -807,6 +830,8 @@ - page_dup_rmap(page, false); - rss[mm_counter(page)]++; - } -+ } else { -+ uksm_map_zero_page(pte); - } - - out_set_pte: -@@ -1075,8 +1100,10 @@ - ptent = ptep_get_and_clear_full(mm, addr, pte, - tlb->fullmm); - tlb_remove_tlb_entry(tlb, pte, addr); -- if (unlikely(!page)) -+ if (unlikely(!page)) { -+ uksm_unmap_zero_page(ptent); - continue; -+ } - - if (!PageAnon(page)) { - if (pte_dirty(ptent)) { -@@ -2117,8 +2144,10 @@ - clear_page(kaddr); - kunmap_atomic(kaddr); - flush_dcache_page(dst); -- } else -+ } else { - copy_user_highpage(dst, src, va, vma); -+ uksm_cow_page(vma, src); -+ } - } - - static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) -@@ -2266,6 +2295,7 @@ - vmf->address); - if (!new_page) - goto oom; -+ uksm_cow_pte(vma, vmf->orig_pte); - } else { - new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, - vmf->address); -@@ -2294,7 +2324,9 @@ - mm_counter_file(old_page)); - inc_mm_counter_fast(mm, MM_ANONPAGES); - } -+ uksm_bugon_zeropage(vmf->orig_pte); - } else { -+ uksm_unmap_zero_page(vmf->orig_pte); - inc_mm_counter_fast(mm, MM_ANONPAGES); - } - flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); -diff -Nur a/mm/mmap.c b/mm/mmap.c ---- a/mm/mmap.c 2019-07-07 09:08:19.162348955 +0100 -+++ b/mm/mmap.c 2019-07-07 09:34:22.544947675 +0100 -@@ -46,6 +46,7 @@ - #include - #include - #include -+#include - - #include - #include -@@ -183,6 +184,7 @@ - if (vma->vm_file) - fput(vma->vm_file); - mpol_put(vma_policy(vma)); -+ uksm_remove_vma(vma); - vm_area_free(vma); - return next; - } -@@ -733,9 +735,16 @@ - long adjust_next = 0; - int remove_next = 0; - -+/* -+ * to avoid deadlock, ksm_remove_vma must be done before any spin_lock is -+ * acquired -+ */ -+ uksm_remove_vma(vma); -+ - if (next && !insert) { - struct vm_area_struct *exporter = NULL, *importer = NULL; - -+ uksm_remove_vma(next); - if (end >= next->vm_end) { - /* - * vma expands, overlapping all the next, and -@@ -868,6 +877,7 @@ - end_changed = true; - } - vma->vm_pgoff = pgoff; -+ - if (adjust_next) { - next->vm_start += adjust_next << PAGE_SHIFT; - next->vm_pgoff += adjust_next; -@@ -973,6 +983,7 @@ - if (remove_next == 2) { - remove_next = 1; - end = next->vm_end; -+ uksm_remove_vma(next); - goto again; - } - else if (next) -@@ -999,10 +1010,14 @@ - */ - VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma)); - } -+ } else { -+ if (next && !insert) -+ uksm_vma_add_new(next); - } - if (insert && file) - uprobe_mmap(insert); - -+ uksm_vma_add_new(vma); - validate_mm(mm); - - return 0; -@@ -1459,6 +1474,9 @@ - vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | - mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; - -+ /* If uksm is enabled, we add VM_MERGEABLE to new VMAs. */ -+ uksm_vm_flags_mod(&vm_flags); -+ - if (flags & MAP_LOCKED) - if (!can_do_mlock()) - return -EPERM; -@@ -1823,6 +1841,7 @@ - allow_write_access(file); - } - file = vma->vm_file; -+ uksm_vma_add_new(vma); - out: - perf_event_mmap(vma); - -@@ -1865,6 +1884,7 @@ - if (vm_flags & VM_DENYWRITE) - allow_write_access(file); - free_vma: -+ uksm_remove_vma(vma); - vm_area_free(vma); - unacct_error: - if (charged) -@@ -2697,6 +2717,8 @@ - else - err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); - -+ uksm_vma_add_new(new); -+ - /* Success. */ - if (!err) - return 0; -@@ -3001,6 +3023,7 @@ - if ((flags & (~VM_EXEC)) != 0) - return -EINVAL; - flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; -+ uksm_vm_flags_mod(&flags); - - error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); - if (offset_in_page(error)) -@@ -3051,6 +3074,7 @@ - vma->vm_flags = flags; - vma->vm_page_prot = vm_get_page_prot(flags); - vma_link(mm, vma, prev, rb_link, rb_parent); -+ uksm_vma_add_new(vma); - out: - perf_event_mmap(vma); - mm->total_vm += len >> PAGE_SHIFT; -@@ -3128,6 +3152,12 @@ - up_write(&mm->mmap_sem); - } - -+ /* -+ * Taking write lock on mmap_sem does not harm others, -+ * but it's crucial for uksm to avoid races. -+ */ -+ down_write(&mm->mmap_sem); -+ - if (mm->locked_vm) { - vma = mm->mmap; - while (vma) { -@@ -3162,6 +3192,11 @@ - vma = remove_vma(vma); - } - vm_unacct_memory(nr_accounted); -+ -+ mm->mmap = NULL; -+ mm->mm_rb = RB_ROOT; -+ vmacache_invalidate(mm); -+ up_write(&mm->mmap_sem); - } - - /* Insert vm structure into process list sorted by address -@@ -3269,6 +3304,7 @@ - new_vma->vm_ops->open(new_vma); - vma_link(mm, new_vma, prev, rb_link, rb_parent); - *need_rmap_locks = false; -+ uksm_vma_add_new(new_vma); - } - return new_vma; - -@@ -3419,6 +3455,7 @@ - vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); - - perf_event_mmap(vma); -+ uksm_vma_add_new(vma); - - return vma; - -diff -Nur a/mm/uksm.c b/mm/uksm.c ---- a/mm/uksm.c 1970-01-01 01:00:00.000000000 +0100 -+++ b/mm/uksm.c 2019-07-07 09:32:50.461840572 +0100 -@@ -0,0 +1,5580 @@ -+/* -+ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia -+ * -+ * This is an improvement upon KSM. Some basic data structures and routines -+ * are borrowed from ksm.c . -+ * -+ * Its new features: -+ * 1. Full system scan: -+ * It automatically scans all user processes' anonymous VMAs. Kernel-user -+ * interaction to submit a memory area to KSM is no longer needed. -+ * -+ * 2. Rich area detection: -+ * It automatically detects rich areas containing abundant duplicated -+ * pages based. Rich areas are given a full scan speed. Poor areas are -+ * sampled at a reasonable speed with very low CPU consumption. -+ * -+ * 3. Ultra Per-page scan speed improvement: -+ * A new hash algorithm is proposed. As a result, on a machine with -+ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it -+ * can scan memory areas that does not contain duplicated pages at speed of -+ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of -+ * 477MB/sec ~ 923MB/sec. -+ * -+ * 4. Thrashing area avoidance: -+ * Thrashing area(an VMA that has frequent Ksm page break-out) can be -+ * filtered out. My benchmark shows it's more efficient than KSM's per-page -+ * hash value based volatile page detection. -+ * -+ * -+ * 5. Misc changes upon KSM: -+ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page -+ * comparison. It's much faster than default C version on x86. -+ * * rmap_item now has an struct *page member to loosely cache a -+ * address-->page mapping, which reduces too much time-costly -+ * follow_page(). -+ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. -+ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ -+ * ksm is needed for this case. -+ * -+ * 6. Full Zero Page consideration(contributed by Figo Zhang) -+ * Now uksmd consider full zero pages as special pages and merge them to an -+ * special unswappable uksm zero page. -+ */ -+ -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+#include -+ -+#include -+#include "internal.h" -+ -+#ifdef CONFIG_X86 -+#undef memcmp -+ -+#ifdef CONFIG_X86_32 -+#define memcmp memcmpx86_32 -+/* -+ * Compare 4-byte-aligned address s1 and s2, with length n -+ */ -+int memcmpx86_32(void *s1, void *s2, size_t n) -+{ -+ size_t num = n / 4; -+ register int res; -+ -+ __asm__ __volatile__ -+ ( -+ "testl %3,%3\n\t" -+ "repe; cmpsd\n\t" -+ "je 1f\n\t" -+ "sbbl %0,%0\n\t" -+ "orl $1,%0\n" -+ "1:" -+ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) -+ : "0" (0) -+ : "cc"); -+ -+ return res; -+} -+ -+/* -+ * Check the page is all zero ? -+ */ -+static int is_full_zero(const void *s1, size_t len) -+{ -+ unsigned char same; -+ -+ len /= 4; -+ -+ __asm__ __volatile__ -+ ("repe; scasl;" -+ "sete %0" -+ : "=qm" (same), "+D" (s1), "+c" (len) -+ : "a" (0) -+ : "cc"); -+ -+ return same; -+} -+ -+ -+#elif defined(CONFIG_X86_64) -+#define memcmp memcmpx86_64 -+/* -+ * Compare 8-byte-aligned address s1 and s2, with length n -+ */ -+int memcmpx86_64(void *s1, void *s2, size_t n) -+{ -+ size_t num = n / 8; -+ register int res; -+ -+ __asm__ __volatile__ -+ ( -+ "testq %q3,%q3\n\t" -+ "repe; cmpsq\n\t" -+ "je 1f\n\t" -+ "sbbq %q0,%q0\n\t" -+ "orq $1,%q0\n" -+ "1:" -+ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) -+ : "0" (0) -+ : "cc"); -+ -+ return res; -+} -+ -+static int is_full_zero(const void *s1, size_t len) -+{ -+ unsigned char same; -+ -+ len /= 8; -+ -+ __asm__ __volatile__ -+ ("repe; scasq;" -+ "sete %0" -+ : "=qm" (same), "+D" (s1), "+c" (len) -+ : "a" (0) -+ : "cc"); -+ -+ return same; -+} -+ -+#endif -+#else -+static int is_full_zero(const void *s1, size_t len) -+{ -+ unsigned long *src = s1; -+ int i; -+ -+ len /= sizeof(*src); -+ -+ for (i = 0; i < len; i++) { -+ if (src[i]) -+ return 0; -+ } -+ -+ return 1; -+} -+#endif -+ -+#define UKSM_RUNG_ROUND_FINISHED (1 << 0) -+#define TIME_RATIO_SCALE 10000 -+ -+#define SLOT_TREE_NODE_SHIFT 8 -+#define SLOT_TREE_NODE_STORE_SIZE (1UL << SLOT_TREE_NODE_SHIFT) -+struct slot_tree_node { -+ unsigned long size; -+ struct sradix_tree_node snode; -+ void *stores[SLOT_TREE_NODE_STORE_SIZE]; -+}; -+ -+static struct kmem_cache *slot_tree_node_cachep; -+ -+static struct sradix_tree_node *slot_tree_node_alloc(void) -+{ -+ struct slot_tree_node *p; -+ -+ p = kmem_cache_zalloc(slot_tree_node_cachep, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (!p) -+ return NULL; -+ -+ return &p->snode; -+} -+ -+static void slot_tree_node_free(struct sradix_tree_node *node) -+{ -+ struct slot_tree_node *p; -+ -+ p = container_of(node, struct slot_tree_node, snode); -+ kmem_cache_free(slot_tree_node_cachep, p); -+} -+ -+static void slot_tree_node_extend(struct sradix_tree_node *parent, -+ struct sradix_tree_node *child) -+{ -+ struct slot_tree_node *p, *c; -+ -+ p = container_of(parent, struct slot_tree_node, snode); -+ c = container_of(child, struct slot_tree_node, snode); -+ -+ p->size += c->size; -+} -+ -+void slot_tree_node_assign(struct sradix_tree_node *node, -+ unsigned int index, void *item) -+{ -+ struct vma_slot *slot = item; -+ struct slot_tree_node *cur; -+ -+ slot->snode = node; -+ slot->sindex = index; -+ -+ while (node) { -+ cur = container_of(node, struct slot_tree_node, snode); -+ cur->size += slot->pages; -+ node = node->parent; -+ } -+} -+ -+void slot_tree_node_rm(struct sradix_tree_node *node, unsigned int offset) -+{ -+ struct vma_slot *slot; -+ struct slot_tree_node *cur; -+ unsigned long pages; -+ -+ if (node->height == 1) { -+ slot = node->stores[offset]; -+ pages = slot->pages; -+ } else { -+ cur = container_of(node->stores[offset], -+ struct slot_tree_node, snode); -+ pages = cur->size; -+ } -+ -+ while (node) { -+ cur = container_of(node, struct slot_tree_node, snode); -+ cur->size -= pages; -+ node = node->parent; -+ } -+} -+ -+unsigned long slot_iter_index; -+int slot_iter(void *item, unsigned long height) -+{ -+ struct slot_tree_node *node; -+ struct vma_slot *slot; -+ -+ if (height == 1) { -+ slot = item; -+ if (slot_iter_index < slot->pages) { -+ /*in this one*/ -+ return 1; -+ } else { -+ slot_iter_index -= slot->pages; -+ return 0; -+ } -+ -+ } else { -+ node = container_of(item, struct slot_tree_node, snode); -+ if (slot_iter_index < node->size) { -+ /*in this one*/ -+ return 1; -+ } else { -+ slot_iter_index -= node->size; -+ return 0; -+ } -+ } -+} -+ -+ -+static inline void slot_tree_init_root(struct sradix_tree_root *root) -+{ -+ init_sradix_tree_root(root, SLOT_TREE_NODE_SHIFT); -+ root->alloc = slot_tree_node_alloc; -+ root->free = slot_tree_node_free; -+ root->extend = slot_tree_node_extend; -+ root->assign = slot_tree_node_assign; -+ root->rm = slot_tree_node_rm; -+} -+ -+void slot_tree_init(void) -+{ -+ slot_tree_node_cachep = kmem_cache_create("slot_tree_node", -+ sizeof(struct slot_tree_node), 0, -+ SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, -+ NULL); -+} -+ -+ -+/* Each rung of this ladder is a list of VMAs having a same scan ratio */ -+struct scan_rung { -+ //struct list_head scanned_list; -+ struct sradix_tree_root vma_root; -+ struct sradix_tree_root vma_root2; -+ -+ struct vma_slot *current_scan; -+ unsigned long current_offset; -+ -+ /* -+ * The initial value for current_offset, it should loop over -+ * [0~ step - 1] to let all slot have its chance to be scanned. -+ */ -+ unsigned long offset_init; -+ unsigned long step; /* dynamic step for current_offset */ -+ unsigned int flags; -+ unsigned long pages_to_scan; -+ //unsigned long fully_scanned_slots; -+ /* -+ * a little bit tricky - if cpu_time_ratio > 0, then the value is the -+ * the cpu time ratio it can spend in rung_i for every scan -+ * period. if < 0, then it is the cpu time ratio relative to the -+ * max cpu percentage user specified. Both in unit of -+ * 1/TIME_RATIO_SCALE -+ */ -+ int cpu_ratio; -+ -+ /* -+ * How long it will take for all slots in this rung to be fully -+ * scanned? If it's zero, we don't care about the cover time: -+ * it's fully scanned. -+ */ -+ unsigned int cover_msecs; -+ //unsigned long vma_num; -+ //unsigned long pages; /* Sum of all slot's pages in rung */ -+}; -+ -+/** -+ * node of either the stable or unstale rbtree -+ * -+ */ -+struct tree_node { -+ struct rb_node node; /* link in the main (un)stable rbtree */ -+ struct rb_root sub_root; /* rb_root for sublevel collision rbtree */ -+ u32 hash; -+ unsigned long count; /* TODO: merged with sub_root */ -+ struct list_head all_list; /* all tree nodes in stable/unstable tree */ -+}; -+ -+/** -+ * struct stable_node - node of the stable rbtree -+ * @node: rb node of this ksm page in the stable tree -+ * @hlist: hlist head of rmap_items using this ksm page -+ * @kpfn: page frame number of this ksm page -+ */ -+struct stable_node { -+ struct rb_node node; /* link in sub-rbtree */ -+ struct tree_node *tree_node; /* it's tree node root in stable tree, NULL if it's in hell list */ -+ struct hlist_head hlist; -+ unsigned long kpfn; -+ u32 hash_max; /* if ==0 then it's not been calculated yet */ -+ struct list_head all_list; /* in a list for all stable nodes */ -+}; -+ -+/** -+ * struct node_vma - group rmap_items linked in a same stable -+ * node together. -+ */ -+struct node_vma { -+ union { -+ struct vma_slot *slot; -+ unsigned long key; /* slot is used as key sorted on hlist */ -+ }; -+ struct hlist_node hlist; -+ struct hlist_head rmap_hlist; -+ struct stable_node *head; -+}; -+ -+/** -+ * struct rmap_item - reverse mapping item for virtual addresses -+ * @rmap_list: next rmap_item in mm_slot's singly-linked rmap_list -+ * @anon_vma: pointer to anon_vma for this mm,address, when in stable tree -+ * @mm: the memory structure this rmap_item is pointing into -+ * @address: the virtual address this rmap_item tracks (+ flags in low bits) -+ * @node: rb node of this rmap_item in the unstable tree -+ * @head: pointer to stable_node heading this list in the stable tree -+ * @hlist: link into hlist of rmap_items hanging off that stable_node -+ */ -+struct rmap_item { -+ struct vma_slot *slot; -+ struct page *page; -+ unsigned long address; /* + low bits used for flags below */ -+ unsigned long hash_round; -+ unsigned long entry_index; -+ union { -+ struct {/* when in unstable tree */ -+ struct rb_node node; -+ struct tree_node *tree_node; -+ u32 hash_max; -+ }; -+ struct { /* when in stable tree */ -+ struct node_vma *head; -+ struct hlist_node hlist; -+ struct anon_vma *anon_vma; -+ }; -+ }; -+} __aligned(4); -+ -+struct rmap_list_entry { -+ union { -+ struct rmap_item *item; -+ unsigned long addr; -+ }; -+ /* lowest bit is used for is_addr tag */ -+} __aligned(4); /* 4 aligned to fit in to pages*/ -+ -+ -+/* Basic data structure definition ends */ -+ -+ -+/* -+ * Flags for rmap_item to judge if it's listed in the stable/unstable tree. -+ * The flags use the low bits of rmap_item.address -+ */ -+#define UNSTABLE_FLAG 0x1 -+#define STABLE_FLAG 0x2 -+#define get_rmap_addr(x) ((x)->address & PAGE_MASK) -+ -+/* -+ * rmap_list_entry helpers -+ */ -+#define IS_ADDR_FLAG 1 -+#define is_addr(ptr) ((unsigned long)(ptr) & IS_ADDR_FLAG) -+#define set_is_addr(ptr) ((ptr) |= IS_ADDR_FLAG) -+#define get_clean_addr(ptr) (((ptr) & ~(__typeof__(ptr))IS_ADDR_FLAG)) -+ -+ -+/* -+ * High speed caches for frequently allocated and freed structs -+ */ -+static struct kmem_cache *rmap_item_cache; -+static struct kmem_cache *stable_node_cache; -+static struct kmem_cache *node_vma_cache; -+static struct kmem_cache *vma_slot_cache; -+static struct kmem_cache *tree_node_cache; -+#define UKSM_KMEM_CACHE(__struct, __flags) kmem_cache_create("uksm_"#__struct,\ -+ sizeof(struct __struct), __alignof__(struct __struct),\ -+ (__flags), NULL) -+ -+/* Array of all scan_rung, uksm_scan_ladder[0] having the minimum scan ratio */ -+#define SCAN_LADDER_SIZE 4 -+static struct scan_rung uksm_scan_ladder[SCAN_LADDER_SIZE]; -+ -+/* The evaluation rounds uksmd has finished */ -+static unsigned long long uksm_eval_round = 1; -+ -+/* -+ * we add 1 to this var when we consider we should rebuild the whole -+ * unstable tree. -+ */ -+static unsigned long uksm_hash_round = 1; -+ -+/* -+ * How many times the whole memory is scanned. -+ */ -+static unsigned long long fully_scanned_round = 1; -+ -+/* The total number of virtual pages of all vma slots */ -+static u64 uksm_pages_total; -+ -+/* The number of pages has been scanned since the start up */ -+static u64 uksm_pages_scanned; -+ -+static u64 scanned_virtual_pages; -+ -+/* The number of pages has been scanned since last encode_benefit call */ -+static u64 uksm_pages_scanned_last; -+ -+/* If the scanned number is tooo large, we encode it here */ -+static u64 pages_scanned_stored; -+ -+static unsigned long pages_scanned_base; -+ -+/* The number of nodes in the stable tree */ -+static unsigned long uksm_pages_shared; -+ -+/* The number of page slots additionally sharing those nodes */ -+static unsigned long uksm_pages_sharing; -+ -+/* The number of nodes in the unstable tree */ -+static unsigned long uksm_pages_unshared; -+ -+/* -+ * Milliseconds ksmd should sleep between scans, -+ * >= 100ms to be consistent with -+ * scan_time_to_sleep_msec() -+ */ -+static unsigned int uksm_sleep_jiffies; -+ -+/* The real value for the uksmd next sleep */ -+static unsigned int uksm_sleep_real; -+ -+/* Saved value for user input uksm_sleep_jiffies when it's enlarged */ -+static unsigned int uksm_sleep_saved; -+ -+/* Max percentage of cpu utilization ksmd can take to scan in one batch */ -+static unsigned int uksm_max_cpu_percentage; -+ -+static int uksm_cpu_governor; -+ -+static char *uksm_cpu_governor_str[4] = { "full", "medium", "low", "quiet" }; -+ -+struct uksm_cpu_preset_s { -+ int cpu_ratio[SCAN_LADDER_SIZE]; -+ unsigned int cover_msecs[SCAN_LADDER_SIZE]; -+ unsigned int max_cpu; /* percentage */ -+}; -+ -+struct uksm_cpu_preset_s uksm_cpu_preset[4] = { -+ { {20, 40, -2500, -10000}, {1000, 500, 200, 50}, 95}, -+ { {20, 30, -2500, -10000}, {1000, 500, 400, 100}, 50}, -+ { {10, 20, -5000, -10000}, {1500, 1000, 1000, 250}, 20}, -+ { {10, 20, 40, 75}, {2000, 1000, 1000, 1000}, 1}, -+}; -+ -+/* The default value for uksm_ema_page_time if it's not initialized */ -+#define UKSM_PAGE_TIME_DEFAULT 500 -+ -+/*cost to scan one page by expotional moving average in nsecs */ -+static unsigned long uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; -+ -+/* The expotional moving average alpha weight, in percentage. */ -+#define EMA_ALPHA 20 -+ -+/* -+ * The threshold used to filter out thrashing areas, -+ * If it == 0, filtering is disabled, otherwise it's the percentage up-bound -+ * of the thrashing ratio of all areas. Any area with a bigger thrashing ratio -+ * will be considered as having a zero duplication ratio. -+ */ -+static unsigned int uksm_thrash_threshold = 50; -+ -+/* How much dedup ratio is considered to be abundant*/ -+static unsigned int uksm_abundant_threshold = 10; -+ -+/* All slots having merged pages in this eval round. */ -+struct list_head vma_slot_dedup = LIST_HEAD_INIT(vma_slot_dedup); -+ -+/* How many times the ksmd has slept since startup */ -+static unsigned long long uksm_sleep_times; -+ -+#define UKSM_RUN_STOP 0 -+#define UKSM_RUN_MERGE 1 -+static unsigned int uksm_run = 1; -+ -+static DECLARE_WAIT_QUEUE_HEAD(uksm_thread_wait); -+static DEFINE_MUTEX(uksm_thread_mutex); -+ -+/* -+ * List vma_slot_new is for newly created vma_slot waiting to be added by -+ * ksmd. If one cannot be added(e.g. due to it's too small), it's moved to -+ * vma_slot_noadd. vma_slot_del is the list for vma_slot whose corresponding -+ * VMA has been removed/freed. -+ */ -+struct list_head vma_slot_new = LIST_HEAD_INIT(vma_slot_new); -+struct list_head vma_slot_noadd = LIST_HEAD_INIT(vma_slot_noadd); -+struct list_head vma_slot_del = LIST_HEAD_INIT(vma_slot_del); -+static DEFINE_SPINLOCK(vma_slot_list_lock); -+ -+/* The unstable tree heads */ -+static struct rb_root root_unstable_tree = RB_ROOT; -+ -+/* -+ * All tree_nodes are in a list to be freed at once when unstable tree is -+ * freed after each scan round. -+ */ -+static struct list_head unstable_tree_node_list = -+ LIST_HEAD_INIT(unstable_tree_node_list); -+ -+/* List contains all stable nodes */ -+static struct list_head stable_node_list = LIST_HEAD_INIT(stable_node_list); -+ -+/* -+ * When the hash strength is changed, the stable tree must be delta_hashed and -+ * re-structured. We use two set of below structs to speed up the -+ * re-structuring of stable tree. -+ */ -+static struct list_head -+stable_tree_node_list[2] = {LIST_HEAD_INIT(stable_tree_node_list[0]), -+ LIST_HEAD_INIT(stable_tree_node_list[1])}; -+ -+static struct list_head *stable_tree_node_listp = &stable_tree_node_list[0]; -+static struct rb_root root_stable_tree[2] = {RB_ROOT, RB_ROOT}; -+static struct rb_root *root_stable_treep = &root_stable_tree[0]; -+static unsigned long stable_tree_index; -+ -+/* The hash strength needed to hash a full page */ -+#define HASH_STRENGTH_FULL (PAGE_SIZE / sizeof(u32)) -+ -+/* The hash strength needed for loop-back hashing */ -+#define HASH_STRENGTH_MAX (HASH_STRENGTH_FULL + 10) -+ -+/* The random offsets in a page */ -+static u32 *random_nums; -+ -+/* The hash strength */ -+static unsigned long hash_strength = HASH_STRENGTH_FULL >> 4; -+ -+/* The delta value each time the hash strength increases or decreases */ -+static unsigned long hash_strength_delta; -+#define HASH_STRENGTH_DELTA_MAX 5 -+ -+/* The time we have saved due to random_sample_hash */ -+static u64 rshash_pos; -+ -+/* The time we have wasted due to hash collision */ -+static u64 rshash_neg; -+ -+struct uksm_benefit { -+ u64 pos; -+ u64 neg; -+ u64 scanned; -+ unsigned long base; -+} benefit; -+ -+/* -+ * The relative cost of memcmp, compared to 1 time unit of random sample -+ * hash, this value is tested when ksm module is initialized -+ */ -+static unsigned long memcmp_cost; -+ -+static unsigned long rshash_neg_cont_zero; -+static unsigned long rshash_cont_obscure; -+ -+/* The possible states of hash strength adjustment heuristic */ -+enum rshash_states { -+ RSHASH_STILL, -+ RSHASH_TRYUP, -+ RSHASH_TRYDOWN, -+ RSHASH_NEW, -+ RSHASH_PRE_STILL, -+}; -+ -+/* The possible direction we are about to adjust hash strength */ -+enum rshash_direct { -+ GO_UP, -+ GO_DOWN, -+ OBSCURE, -+ STILL, -+}; -+ -+/* random sampling hash state machine */ -+static struct { -+ enum rshash_states state; -+ enum rshash_direct pre_direct; -+ u8 below_count; -+ /* Keep a lookup window of size 5, iff above_count/below_count > 3 -+ * in this window we stop trying. -+ */ -+ u8 lookup_window_index; -+ u64 stable_benefit; -+ unsigned long turn_point_down; -+ unsigned long turn_benefit_down; -+ unsigned long turn_point_up; -+ unsigned long turn_benefit_up; -+ unsigned long stable_point; -+} rshash_state; -+ -+/*zero page hash table, hash_strength [0 ~ HASH_STRENGTH_MAX]*/ -+static u32 *zero_hash_table; -+ -+static inline struct node_vma *alloc_node_vma(void) -+{ -+ struct node_vma *node_vma; -+ -+ node_vma = kmem_cache_zalloc(node_vma_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (node_vma) { -+ INIT_HLIST_HEAD(&node_vma->rmap_hlist); -+ INIT_HLIST_NODE(&node_vma->hlist); -+ } -+ return node_vma; -+} -+ -+static inline void free_node_vma(struct node_vma *node_vma) -+{ -+ kmem_cache_free(node_vma_cache, node_vma); -+} -+ -+ -+static inline struct vma_slot *alloc_vma_slot(void) -+{ -+ struct vma_slot *slot; -+ -+ /* -+ * In case ksm is not initialized by now. -+ * Oops, we need to consider the call site of uksm_init() in the future. -+ */ -+ if (!vma_slot_cache) -+ return NULL; -+ -+ slot = kmem_cache_zalloc(vma_slot_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (slot) { -+ INIT_LIST_HEAD(&slot->slot_list); -+ INIT_LIST_HEAD(&slot->dedup_list); -+ slot->flags |= UKSM_SLOT_NEED_RERAND; -+ } -+ return slot; -+} -+ -+static inline void free_vma_slot(struct vma_slot *vma_slot) -+{ -+ kmem_cache_free(vma_slot_cache, vma_slot); -+} -+ -+ -+ -+static inline struct rmap_item *alloc_rmap_item(void) -+{ -+ struct rmap_item *rmap_item; -+ -+ rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (rmap_item) { -+ /* bug on lowest bit is not clear for flag use */ -+ BUG_ON(is_addr(rmap_item)); -+ } -+ return rmap_item; -+} -+ -+static inline void free_rmap_item(struct rmap_item *rmap_item) -+{ -+ rmap_item->slot = NULL; /* debug safety */ -+ kmem_cache_free(rmap_item_cache, rmap_item); -+} -+ -+static inline struct stable_node *alloc_stable_node(void) -+{ -+ struct stable_node *node; -+ -+ node = kmem_cache_alloc(stable_node_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (!node) -+ return NULL; -+ -+ INIT_HLIST_HEAD(&node->hlist); -+ list_add(&node->all_list, &stable_node_list); -+ return node; -+} -+ -+static inline void free_stable_node(struct stable_node *stable_node) -+{ -+ list_del(&stable_node->all_list); -+ kmem_cache_free(stable_node_cache, stable_node); -+} -+ -+static inline struct tree_node *alloc_tree_node(struct list_head *list) -+{ -+ struct tree_node *node; -+ -+ node = kmem_cache_zalloc(tree_node_cache, GFP_KERNEL | -+ __GFP_NORETRY | __GFP_NOWARN); -+ if (!node) -+ return NULL; -+ -+ list_add(&node->all_list, list); -+ return node; -+} -+ -+static inline void free_tree_node(struct tree_node *node) -+{ -+ list_del(&node->all_list); -+ kmem_cache_free(tree_node_cache, node); -+} -+ -+static void uksm_drop_anon_vma(struct rmap_item *rmap_item) -+{ -+ struct anon_vma *anon_vma = rmap_item->anon_vma; -+ -+ put_anon_vma(anon_vma); -+} -+ -+ -+/** -+ * Remove a stable node from stable_tree, may unlink from its tree_node and -+ * may remove its parent tree_node if no other stable node is pending. -+ * -+ * @stable_node The node need to be removed -+ * @unlink_rb Will this node be unlinked from the rbtree? -+ * @remove_tree_ node Will its tree_node be removed if empty? -+ */ -+static void remove_node_from_stable_tree(struct stable_node *stable_node, -+ int unlink_rb, int remove_tree_node) -+{ -+ struct node_vma *node_vma; -+ struct rmap_item *rmap_item; -+ struct hlist_node *n; -+ -+ if (!hlist_empty(&stable_node->hlist)) { -+ hlist_for_each_entry_safe(node_vma, n, -+ &stable_node->hlist, hlist) { -+ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { -+ uksm_pages_sharing--; -+ -+ uksm_drop_anon_vma(rmap_item); -+ rmap_item->address &= PAGE_MASK; -+ } -+ free_node_vma(node_vma); -+ cond_resched(); -+ } -+ -+ /* the last one is counted as shared */ -+ uksm_pages_shared--; -+ uksm_pages_sharing++; -+ } -+ -+ if (stable_node->tree_node && unlink_rb) { -+ rb_erase(&stable_node->node, -+ &stable_node->tree_node->sub_root); -+ -+ if (RB_EMPTY_ROOT(&stable_node->tree_node->sub_root) && -+ remove_tree_node) { -+ rb_erase(&stable_node->tree_node->node, -+ root_stable_treep); -+ free_tree_node(stable_node->tree_node); -+ } else { -+ stable_node->tree_node->count--; -+ } -+ } -+ -+ free_stable_node(stable_node); -+} -+ -+ -+/* -+ * get_uksm_page: checks if the page indicated by the stable node -+ * is still its ksm page, despite having held no reference to it. -+ * In which case we can trust the content of the page, and it -+ * returns the gotten page; but if the page has now been zapped, -+ * remove the stale node from the stable tree and return NULL. -+ * -+ * You would expect the stable_node to hold a reference to the ksm page. -+ * But if it increments the page's count, swapping out has to wait for -+ * ksmd to come around again before it can free the page, which may take -+ * seconds or even minutes: much too unresponsive. So instead we use a -+ * "keyhole reference": access to the ksm page from the stable node peeps -+ * out through its keyhole to see if that page still holds the right key, -+ * pointing back to this stable node. This relies on freeing a PageAnon -+ * page to reset its page->mapping to NULL, and relies on no other use of -+ * a page to put something that might look like our key in page->mapping. -+ * -+ * include/linux/pagemap.h page_cache_get_speculative() is a good reference, -+ * but this is different - made simpler by uksm_thread_mutex being held, but -+ * interesting for assuming that no other use of the struct page could ever -+ * put our expected_mapping into page->mapping (or a field of the union which -+ * coincides with page->mapping). The RCU calls are not for KSM at all, but -+ * to keep the page_count protocol described with page_cache_get_speculative. -+ * -+ * Note: it is possible that get_uksm_page() will return NULL one moment, -+ * then page the next, if the page is in between page_freeze_refs() and -+ * page_unfreeze_refs(): this shouldn't be a problem anywhere, the page -+ * is on its way to being freed; but it is an anomaly to bear in mind. -+ * -+ * @unlink_rb: if the removal of this node will firstly unlink from -+ * its rbtree. stable_node_reinsert will prevent this when restructuring the -+ * node from its old tree. -+ * -+ * @remove_tree_node: if this is the last one of its tree_node, will the -+ * tree_node be freed ? If we are inserting stable node, this tree_node may -+ * be reused, so don't free it. -+ */ -+static struct page *get_uksm_page(struct stable_node *stable_node, -+ int unlink_rb, int remove_tree_node) -+{ -+ struct page *page; -+ void *expected_mapping; -+ unsigned long kpfn; -+ -+ expected_mapping = (void *)((unsigned long)stable_node | -+ PAGE_MAPPING_KSM); -+again: -+ kpfn = READ_ONCE(stable_node->kpfn); -+ page = pfn_to_page(kpfn); -+ -+ /* -+ * page is computed from kpfn, so on most architectures reading -+ * page->mapping is naturally ordered after reading node->kpfn, -+ * but on Alpha we need to be more careful. -+ */ -+ smp_read_barrier_depends(); -+ -+ if (READ_ONCE(page->mapping) != expected_mapping) -+ goto stale; -+ -+ /* -+ * We cannot do anything with the page while its refcount is 0. -+ * Usually 0 means free, or tail of a higher-order page: in which -+ * case this node is no longer referenced, and should be freed; -+ * however, it might mean that the page is under page_freeze_refs(). -+ * The __remove_mapping() case is easy, again the node is now stale; -+ * but if page is swapcache in migrate_page_move_mapping(), it might -+ * still be our page, in which case it's essential to keep the node. -+ */ -+ while (!get_page_unless_zero(page)) { -+ /* -+ * Another check for page->mapping != expected_mapping would -+ * work here too. We have chosen the !PageSwapCache test to -+ * optimize the common case, when the page is or is about to -+ * be freed: PageSwapCache is cleared (under spin_lock_irq) -+ * in the freeze_refs section of __remove_mapping(); but Anon -+ * page->mapping reset to NULL later, in free_pages_prepare(). -+ */ -+ if (!PageSwapCache(page)) -+ goto stale; -+ cpu_relax(); -+ } -+ -+ if (READ_ONCE(page->mapping) != expected_mapping) { -+ put_page(page); -+ goto stale; -+ } -+ -+ lock_page(page); -+ if (READ_ONCE(page->mapping) != expected_mapping) { -+ unlock_page(page); -+ put_page(page); -+ goto stale; -+ } -+ unlock_page(page); -+ return page; -+stale: -+ /* -+ * We come here from above when page->mapping or !PageSwapCache -+ * suggests that the node is stale; but it might be under migration. -+ * We need smp_rmb(), matching the smp_wmb() in ksm_migrate_page(), -+ * before checking whether node->kpfn has been changed. -+ */ -+ smp_rmb(); -+ if (stable_node->kpfn != kpfn) -+ goto again; -+ -+ remove_node_from_stable_tree(stable_node, unlink_rb, remove_tree_node); -+ -+ return NULL; -+} -+ -+/* -+ * Removing rmap_item from stable or unstable tree. -+ * This function will clean the information from the stable/unstable tree. -+ */ -+static inline void remove_rmap_item_from_tree(struct rmap_item *rmap_item) -+{ -+ if (rmap_item->address & STABLE_FLAG) { -+ struct stable_node *stable_node; -+ struct node_vma *node_vma; -+ struct page *page; -+ -+ node_vma = rmap_item->head; -+ stable_node = node_vma->head; -+ page = get_uksm_page(stable_node, 1, 1); -+ if (!page) -+ goto out; -+ -+ /* -+ * page lock is needed because it's racing with -+ * try_to_unmap_ksm(), etc. -+ */ -+ lock_page(page); -+ hlist_del(&rmap_item->hlist); -+ -+ if (hlist_empty(&node_vma->rmap_hlist)) { -+ hlist_del(&node_vma->hlist); -+ free_node_vma(node_vma); -+ } -+ unlock_page(page); -+ -+ put_page(page); -+ if (hlist_empty(&stable_node->hlist)) { -+ /* do NOT call remove_node_from_stable_tree() here, -+ * it's possible for a forked rmap_item not in -+ * stable tree while the in-tree rmap_items were -+ * deleted. -+ */ -+ uksm_pages_shared--; -+ } else -+ uksm_pages_sharing--; -+ -+ -+ uksm_drop_anon_vma(rmap_item); -+ } else if (rmap_item->address & UNSTABLE_FLAG) { -+ if (rmap_item->hash_round == uksm_hash_round) { -+ -+ rb_erase(&rmap_item->node, -+ &rmap_item->tree_node->sub_root); -+ if (RB_EMPTY_ROOT(&rmap_item->tree_node->sub_root)) { -+ rb_erase(&rmap_item->tree_node->node, -+ &root_unstable_tree); -+ -+ free_tree_node(rmap_item->tree_node); -+ } else -+ rmap_item->tree_node->count--; -+ } -+ uksm_pages_unshared--; -+ } -+ -+ rmap_item->address &= PAGE_MASK; -+ rmap_item->hash_max = 0; -+ -+out: -+ cond_resched(); /* we're called from many long loops */ -+} -+ -+static inline int slot_in_uksm(struct vma_slot *slot) -+{ -+ return list_empty(&slot->slot_list); -+} -+ -+/* -+ * Test if the mm is exiting -+ */ -+static inline bool uksm_test_exit(struct mm_struct *mm) -+{ -+ return atomic_read(&mm->mm_users) == 0; -+} -+ -+static inline unsigned long vma_pool_size(struct vma_slot *slot) -+{ -+ return round_up(sizeof(struct rmap_list_entry) * slot->pages, -+ PAGE_SIZE) >> PAGE_SHIFT; -+} -+ -+#define CAN_OVERFLOW_U64(x, delta) (U64_MAX - (x) < (delta)) -+ -+/* must be done with sem locked */ -+static int slot_pool_alloc(struct vma_slot *slot) -+{ -+ unsigned long pool_size; -+ -+ if (slot->rmap_list_pool) -+ return 0; -+ -+ pool_size = vma_pool_size(slot); -+ slot->rmap_list_pool = kcalloc(pool_size, sizeof(struct page *), -+ GFP_KERNEL); -+ if (!slot->rmap_list_pool) -+ return -ENOMEM; -+ -+ slot->pool_counts = kcalloc(pool_size, sizeof(unsigned int), -+ GFP_KERNEL); -+ if (!slot->pool_counts) { -+ kfree(slot->rmap_list_pool); -+ return -ENOMEM; -+ } -+ -+ slot->pool_size = pool_size; -+ BUG_ON(CAN_OVERFLOW_U64(uksm_pages_total, slot->pages)); -+ slot->flags |= UKSM_SLOT_IN_UKSM; -+ uksm_pages_total += slot->pages; -+ -+ return 0; -+} -+ -+/* -+ * Called after vma is unlinked from its mm -+ */ -+void uksm_remove_vma(struct vm_area_struct *vma) -+{ -+ struct vma_slot *slot; -+ -+ if (!vma->uksm_vma_slot) -+ return; -+ -+ spin_lock(&vma_slot_list_lock); -+ slot = vma->uksm_vma_slot; -+ if (!slot) -+ goto out; -+ -+ if (slot_in_uksm(slot)) { -+ /** -+ * This slot has been added by ksmd, so move to the del list -+ * waiting ksmd to free it. -+ */ -+ list_add_tail(&slot->slot_list, &vma_slot_del); -+ } else { -+ /** -+ * It's still on new list. It's ok to free slot directly. -+ */ -+ list_del(&slot->slot_list); -+ free_vma_slot(slot); -+ } -+out: -+ vma->uksm_vma_slot = NULL; -+ spin_unlock(&vma_slot_list_lock); -+} -+ -+/** -+ * Need to do two things: -+ * 1. check if slot was moved to del list -+ * 2. make sure the mmap_sem is manipulated under valid vma. -+ * -+ * My concern here is that in some cases, this may make -+ * vma_slot_list_lock() waiters to serialized further by some -+ * sem->wait_lock, can this really be expensive? -+ * -+ * -+ * @return -+ * 0: if successfully locked mmap_sem -+ * -ENOENT: this slot was moved to del list -+ * -EBUSY: vma lock failed -+ */ -+static int try_down_read_slot_mmap_sem(struct vma_slot *slot) -+{ -+ struct vm_area_struct *vma; -+ struct mm_struct *mm; -+ struct rw_semaphore *sem; -+ -+ spin_lock(&vma_slot_list_lock); -+ -+ /* the slot_list was removed and inited from new list, when it enters -+ * uksm_list. If now it's not empty, then it must be moved to del list -+ */ -+ if (!slot_in_uksm(slot)) { -+ spin_unlock(&vma_slot_list_lock); -+ return -ENOENT; -+ } -+ -+ BUG_ON(slot->pages != vma_pages(slot->vma)); -+ /* Ok, vma still valid */ -+ vma = slot->vma; -+ mm = vma->vm_mm; -+ sem = &mm->mmap_sem; -+ -+ if (uksm_test_exit(mm)) { -+ spin_unlock(&vma_slot_list_lock); -+ return -ENOENT; -+ } -+ -+ if (down_read_trylock(sem)) { -+ spin_unlock(&vma_slot_list_lock); -+ if (slot_pool_alloc(slot)) { -+ uksm_remove_vma(vma); -+ up_read(sem); -+ return -ENOENT; -+ } -+ return 0; -+ } -+ -+ spin_unlock(&vma_slot_list_lock); -+ return -EBUSY; -+} -+ -+static inline unsigned long -+vma_page_address(struct page *page, struct vm_area_struct *vma) -+{ -+ pgoff_t pgoff = page->index; -+ unsigned long address; -+ -+ address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); -+ if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { -+ /* page should be within @vma mapping range */ -+ return -EFAULT; -+ } -+ return address; -+} -+ -+ -+/* return 0 on success with the item's mmap_sem locked */ -+static inline int get_mergeable_page_lock_mmap(struct rmap_item *item) -+{ -+ struct mm_struct *mm; -+ struct vma_slot *slot = item->slot; -+ int err = -EINVAL; -+ -+ struct page *page; -+ -+ /* -+ * try_down_read_slot_mmap_sem() returns non-zero if the slot -+ * has been removed by uksm_remove_vma(). -+ */ -+ if (try_down_read_slot_mmap_sem(slot)) -+ return -EBUSY; -+ -+ mm = slot->vma->vm_mm; -+ -+ if (uksm_test_exit(mm)) -+ goto failout_up; -+ -+ page = item->page; -+ rcu_read_lock(); -+ if (!get_page_unless_zero(page)) { -+ rcu_read_unlock(); -+ goto failout_up; -+ } -+ -+ /* No need to consider huge page here. */ -+ if (item->slot->vma->anon_vma != page_anon_vma(page) || -+ vma_page_address(page, item->slot->vma) != get_rmap_addr(item)) { -+ /* -+ * TODO: -+ * should we release this item becase of its stale page -+ * mapping? -+ */ -+ put_page(page); -+ rcu_read_unlock(); -+ goto failout_up; -+ } -+ rcu_read_unlock(); -+ return 0; -+ -+failout_up: -+ up_read(&mm->mmap_sem); -+ return err; -+} -+ -+/* -+ * What kind of VMA is considered ? -+ */ -+static inline int vma_can_enter(struct vm_area_struct *vma) -+{ -+ return uksm_flags_can_scan(vma->vm_flags); -+} -+ -+/* -+ * Called whenever a fresh new vma is created A new vma_slot. -+ * is created and inserted into a global list Must be called. -+ * after vma is inserted to its mm. -+ */ -+void uksm_vma_add_new(struct vm_area_struct *vma) -+{ -+ struct vma_slot *slot; -+ -+ if (!vma_can_enter(vma)) { -+ vma->uksm_vma_slot = NULL; -+ return; -+ } -+ -+ slot = alloc_vma_slot(); -+ if (!slot) { -+ vma->uksm_vma_slot = NULL; -+ return; -+ } -+ -+ vma->uksm_vma_slot = slot; -+ vma->vm_flags |= VM_MERGEABLE; -+ slot->vma = vma; -+ slot->mm = vma->vm_mm; -+ slot->ctime_j = jiffies; -+ slot->pages = vma_pages(vma); -+ spin_lock(&vma_slot_list_lock); -+ list_add_tail(&slot->slot_list, &vma_slot_new); -+ spin_unlock(&vma_slot_list_lock); -+} -+ -+/* 32/3 < they < 32/2 */ -+#define shiftl 8 -+#define shiftr 12 -+ -+#define HASH_FROM_TO(from, to) \ -+for (index = from; index < to; index++) { \ -+ pos = random_nums[index]; \ -+ hash += key[pos]; \ -+ hash += (hash << shiftl); \ -+ hash ^= (hash >> shiftr); \ -+} -+ -+ -+#define HASH_FROM_DOWN_TO(from, to) \ -+for (index = from - 1; index >= to; index--) { \ -+ hash ^= (hash >> shiftr); \ -+ hash ^= (hash >> (shiftr*2)); \ -+ hash -= (hash << shiftl); \ -+ hash += (hash << (shiftl*2)); \ -+ pos = random_nums[index]; \ -+ hash -= key[pos]; \ -+} -+ -+/* -+ * The main random sample hash function. -+ */ -+static u32 random_sample_hash(void *addr, u32 hash_strength) -+{ -+ u32 hash = 0xdeadbeef; -+ int index, pos, loop = hash_strength; -+ u32 *key = (u32 *)addr; -+ -+ if (loop > HASH_STRENGTH_FULL) -+ loop = HASH_STRENGTH_FULL; -+ -+ HASH_FROM_TO(0, loop); -+ -+ if (hash_strength > HASH_STRENGTH_FULL) { -+ loop = hash_strength - HASH_STRENGTH_FULL; -+ HASH_FROM_TO(0, loop); -+ } -+ -+ return hash; -+} -+ -+ -+/** -+ * It's used when hash strength is adjusted -+ * -+ * @addr The page's virtual address -+ * @from The original hash strength -+ * @to The hash strength changed to -+ * @hash The hash value generated with "from" hash value -+ * -+ * return the hash value -+ */ -+static u32 delta_hash(void *addr, int from, int to, u32 hash) -+{ -+ u32 *key = (u32 *)addr; -+ int index, pos; /* make sure they are int type */ -+ -+ if (to > from) { -+ if (from >= HASH_STRENGTH_FULL) { -+ from -= HASH_STRENGTH_FULL; -+ to -= HASH_STRENGTH_FULL; -+ HASH_FROM_TO(from, to); -+ } else if (to <= HASH_STRENGTH_FULL) { -+ HASH_FROM_TO(from, to); -+ } else { -+ HASH_FROM_TO(from, HASH_STRENGTH_FULL); -+ HASH_FROM_TO(0, to - HASH_STRENGTH_FULL); -+ } -+ } else { -+ if (from <= HASH_STRENGTH_FULL) { -+ HASH_FROM_DOWN_TO(from, to); -+ } else if (to >= HASH_STRENGTH_FULL) { -+ from -= HASH_STRENGTH_FULL; -+ to -= HASH_STRENGTH_FULL; -+ HASH_FROM_DOWN_TO(from, to); -+ } else { -+ HASH_FROM_DOWN_TO(from - HASH_STRENGTH_FULL, 0); -+ HASH_FROM_DOWN_TO(HASH_STRENGTH_FULL, to); -+ } -+ } -+ -+ return hash; -+} -+ -+/** -+ * -+ * Called when: rshash_pos or rshash_neg is about to overflow or a scan round -+ * has finished. -+ * -+ * return 0 if no page has been scanned since last call, 1 otherwise. -+ */ -+static inline int encode_benefit(void) -+{ -+ u64 scanned_delta, pos_delta, neg_delta; -+ unsigned long base = benefit.base; -+ -+ scanned_delta = uksm_pages_scanned - uksm_pages_scanned_last; -+ -+ if (!scanned_delta) -+ return 0; -+ -+ scanned_delta >>= base; -+ pos_delta = rshash_pos >> base; -+ neg_delta = rshash_neg >> base; -+ -+ if (CAN_OVERFLOW_U64(benefit.pos, pos_delta) || -+ CAN_OVERFLOW_U64(benefit.neg, neg_delta) || -+ CAN_OVERFLOW_U64(benefit.scanned, scanned_delta)) { -+ benefit.scanned >>= 1; -+ benefit.neg >>= 1; -+ benefit.pos >>= 1; -+ benefit.base++; -+ scanned_delta >>= 1; -+ pos_delta >>= 1; -+ neg_delta >>= 1; -+ } -+ -+ benefit.pos += pos_delta; -+ benefit.neg += neg_delta; -+ benefit.scanned += scanned_delta; -+ -+ BUG_ON(!benefit.scanned); -+ -+ rshash_pos = rshash_neg = 0; -+ uksm_pages_scanned_last = uksm_pages_scanned; -+ -+ return 1; -+} -+ -+static inline void reset_benefit(void) -+{ -+ benefit.pos = 0; -+ benefit.neg = 0; -+ benefit.base = 0; -+ benefit.scanned = 0; -+} -+ -+static inline void inc_rshash_pos(unsigned long delta) -+{ -+ if (CAN_OVERFLOW_U64(rshash_pos, delta)) -+ encode_benefit(); -+ -+ rshash_pos += delta; -+} -+ -+static inline void inc_rshash_neg(unsigned long delta) -+{ -+ if (CAN_OVERFLOW_U64(rshash_neg, delta)) -+ encode_benefit(); -+ -+ rshash_neg += delta; -+} -+ -+ -+static inline u32 page_hash(struct page *page, unsigned long hash_strength, -+ int cost_accounting) -+{ -+ u32 val; -+ unsigned long delta; -+ -+ void *addr = kmap_atomic(page); -+ -+ val = random_sample_hash(addr, hash_strength); -+ kunmap_atomic(addr); -+ -+ if (cost_accounting) { -+ if (hash_strength < HASH_STRENGTH_FULL) -+ delta = HASH_STRENGTH_FULL - hash_strength; -+ else -+ delta = 0; -+ -+ inc_rshash_pos(delta); -+ } -+ -+ return val; -+} -+ -+static int memcmp_pages(struct page *page1, struct page *page2, -+ int cost_accounting) -+{ -+ char *addr1, *addr2; -+ int ret; -+ -+ addr1 = kmap_atomic(page1); -+ addr2 = kmap_atomic(page2); -+ ret = memcmp(addr1, addr2, PAGE_SIZE); -+ kunmap_atomic(addr2); -+ kunmap_atomic(addr1); -+ -+ if (cost_accounting) -+ inc_rshash_neg(memcmp_cost); -+ -+ return ret; -+} -+ -+static inline int pages_identical(struct page *page1, struct page *page2) -+{ -+ return !memcmp_pages(page1, page2, 0); -+} -+ -+static inline int is_page_full_zero(struct page *page) -+{ -+ char *addr; -+ int ret; -+ -+ addr = kmap_atomic(page); -+ ret = is_full_zero(addr, PAGE_SIZE); -+ kunmap_atomic(addr); -+ -+ return ret; -+} -+ -+static int write_protect_page(struct vm_area_struct *vma, struct page *page, -+ pte_t *orig_pte, pte_t *old_pte) -+{ -+ struct mm_struct *mm = vma->vm_mm; -+ struct page_vma_mapped_walk pvmw = { -+ .page = page, -+ .vma = vma, -+ }; -+ struct mmu_notifier_range range; -+ int swapped; -+ int err = -EFAULT; -+ -+ pvmw.address = page_address_in_vma(page, vma); -+ if (pvmw.address == -EFAULT) -+ goto out; -+ -+ BUG_ON(PageTransCompound(page)); -+ -+ mmu_notifier_range_init(&range, mm, pvmw.address, pvmw.address + PAGE_SIZE); -+ mmu_notifier_invalidate_range_start(&range); -+ -+ if (!page_vma_mapped_walk(&pvmw)) -+ goto out_mn; -+ if (WARN_ONCE(!pvmw.pte, "Unexpected PMD mapping?")) -+ goto out_unlock; -+ -+ if (old_pte) -+ *old_pte = *pvmw.pte; -+ -+ if (pte_write(*pvmw.pte) || pte_dirty(*pvmw.pte) || -+ (pte_protnone(*pvmw.pte) && pte_savedwrite(*pvmw.pte)) || mm_tlb_flush_pending(mm)) { -+ pte_t entry; -+ -+ swapped = PageSwapCache(page); -+ flush_cache_page(vma, pvmw.address, page_to_pfn(page)); -+ /* -+ * Ok this is tricky, when get_user_pages_fast() run it doesn't -+ * take any lock, therefore the check that we are going to make -+ * with the pagecount against the mapcount is racey and -+ * O_DIRECT can happen right after the check. -+ * So we clear the pte and flush the tlb before the check -+ * this assure us that no O_DIRECT can happen after the check -+ * or in the middle of the check. -+ */ -+ entry = ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte); -+ /* -+ * Check that no O_DIRECT or similar I/O is in progress on the -+ * page -+ */ -+ if (page_mapcount(page) + 1 + swapped != page_count(page)) { -+ set_pte_at(mm, pvmw.address, pvmw.pte, entry); -+ goto out_unlock; -+ } -+ if (pte_dirty(entry)) -+ set_page_dirty(page); -+ -+ if (pte_protnone(entry)) -+ entry = pte_mkclean(pte_clear_savedwrite(entry)); -+ else -+ entry = pte_mkclean(pte_wrprotect(entry)); -+ -+ set_pte_at_notify(mm, pvmw.address, pvmw.pte, entry); -+ } -+ *orig_pte = *pvmw.pte; -+ err = 0; -+ -+out_unlock: -+ page_vma_mapped_walk_done(&pvmw); -+out_mn: -+ mmu_notifier_invalidate_range_end(&range); -+out: -+ return err; -+} -+ -+#define MERGE_ERR_PGERR 1 /* the page is invalid cannot continue */ -+#define MERGE_ERR_COLLI 2 /* there is a collision */ -+#define MERGE_ERR_COLLI_MAX 3 /* collision at the max hash strength */ -+#define MERGE_ERR_CHANGED 4 /* the page has changed since last hash */ -+ -+ -+/** -+ * replace_page - replace page in vma by new ksm page -+ * @vma: vma that holds the pte pointing to page -+ * @page: the page we are replacing by kpage -+ * @kpage: the ksm page we replace page by -+ * @orig_pte: the original value of the pte -+ * -+ * Returns 0 on success, MERGE_ERR_PGERR on failure. -+ */ -+static int replace_page(struct vm_area_struct *vma, struct page *page, -+ struct page *kpage, pte_t orig_pte) -+{ -+ struct mm_struct *mm = vma->vm_mm; -+ struct mmu_notifier_range range; -+ pgd_t *pgd; -+ p4d_t *p4d; -+ pud_t *pud; -+ pmd_t *pmd; -+ pte_t *ptep; -+ spinlock_t *ptl; -+ pte_t entry; -+ -+ unsigned long addr; -+ int err = MERGE_ERR_PGERR; -+ -+ addr = page_address_in_vma(page, vma); -+ if (addr == -EFAULT) -+ goto out; -+ -+ pgd = pgd_offset(mm, addr); -+ if (!pgd_present(*pgd)) -+ goto out; -+ -+ p4d = p4d_offset(pgd, addr); -+ pud = pud_offset(p4d, addr); -+ if (!pud_present(*pud)) -+ goto out; -+ -+ pmd = pmd_offset(pud, addr); -+ BUG_ON(pmd_trans_huge(*pmd)); -+ if (!pmd_present(*pmd)) -+ goto out; -+ -+ mmu_notifier_range_init(&range, mm, addr, addr + PAGE_SIZE); -+ mmu_notifier_invalidate_range_start(&range); -+ -+ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); -+ if (!pte_same(*ptep, orig_pte)) { -+ pte_unmap_unlock(ptep, ptl); -+ goto out_mn; -+ } -+ -+ flush_cache_page(vma, addr, pte_pfn(*ptep)); -+ ptep_clear_flush_notify(vma, addr, ptep); -+ entry = mk_pte(kpage, vma->vm_page_prot); -+ -+ /* special treatment is needed for zero_page */ -+ if ((page_to_pfn(kpage) == uksm_zero_pfn) || -+ (page_to_pfn(kpage) == zero_pfn)) { -+ entry = pte_mkspecial(entry); -+ dec_mm_counter(mm, MM_ANONPAGES); -+ inc_zone_page_state(page, NR_UKSM_ZERO_PAGES); -+ } else { -+ get_page(kpage); -+ page_add_anon_rmap(kpage, vma, addr, false); -+ } -+ -+ set_pte_at_notify(mm, addr, ptep, entry); -+ -+ page_remove_rmap(page, false); -+ if (!page_mapped(page)) -+ try_to_free_swap(page); -+ put_page(page); -+ -+ pte_unmap_unlock(ptep, ptl); -+ err = 0; -+out_mn: -+ mmu_notifier_invalidate_range_end(&range); -+out: -+ return err; -+} -+ -+ -+/** -+ * Fully hash a page with HASH_STRENGTH_MAX return a non-zero hash value. The -+ * zero hash value at HASH_STRENGTH_MAX is used to indicated that its -+ * hash_max member has not been calculated. -+ * -+ * @page The page needs to be hashed -+ * @hash_old The hash value calculated with current hash strength -+ * -+ * return the new hash value calculated at HASH_STRENGTH_MAX -+ */ -+static inline u32 page_hash_max(struct page *page, u32 hash_old) -+{ -+ u32 hash_max = 0; -+ void *addr; -+ -+ addr = kmap_atomic(page); -+ hash_max = delta_hash(addr, hash_strength, -+ HASH_STRENGTH_MAX, hash_old); -+ -+ kunmap_atomic(addr); -+ -+ if (!hash_max) -+ hash_max = 1; -+ -+ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); -+ return hash_max; -+} -+ -+/* -+ * We compare the hash again, to ensure that it is really a hash collision -+ * instead of being caused by page write. -+ */ -+static inline int check_collision(struct rmap_item *rmap_item, -+ u32 hash) -+{ -+ int err; -+ struct page *page = rmap_item->page; -+ -+ /* if this rmap_item has already been hash_maxed, then the collision -+ * must appears in the second-level rbtree search. In this case we check -+ * if its hash_max value has been changed. Otherwise, the collision -+ * happens in the first-level rbtree search, so we check against it's -+ * current hash value. -+ */ -+ if (rmap_item->hash_max) { -+ inc_rshash_neg(memcmp_cost); -+ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); -+ -+ if (rmap_item->hash_max == page_hash_max(page, hash)) -+ err = MERGE_ERR_COLLI; -+ else -+ err = MERGE_ERR_CHANGED; -+ } else { -+ inc_rshash_neg(memcmp_cost + hash_strength); -+ -+ if (page_hash(page, hash_strength, 0) == hash) -+ err = MERGE_ERR_COLLI; -+ else -+ err = MERGE_ERR_CHANGED; -+ } -+ -+ return err; -+} -+ -+/** -+ * Try to merge a rmap_item.page with a kpage in stable node. kpage must -+ * already be a ksm page. -+ * -+ * @return 0 if the pages were merged, -EFAULT otherwise. -+ */ -+static int try_to_merge_with_uksm_page(struct rmap_item *rmap_item, -+ struct page *kpage, u32 hash) -+{ -+ struct vm_area_struct *vma = rmap_item->slot->vma; -+ struct mm_struct *mm = vma->vm_mm; -+ pte_t orig_pte = __pte(0); -+ int err = MERGE_ERR_PGERR; -+ struct page *page; -+ -+ if (uksm_test_exit(mm)) -+ goto out; -+ -+ page = rmap_item->page; -+ -+ if (page == kpage) { /* ksm page forked */ -+ err = 0; -+ goto out; -+ } -+ -+ /* -+ * We need the page lock to read a stable PageSwapCache in -+ * write_protect_page(). We use trylock_page() instead of -+ * lock_page() because we don't want to wait here - we -+ * prefer to continue scanning and merging different pages, -+ * then come back to this page when it is unlocked. -+ */ -+ if (!trylock_page(page)) -+ goto out; -+ -+ if (!PageAnon(page) || !PageKsm(kpage)) -+ goto out_unlock; -+ -+ if (PageTransCompound(page)) { -+ err = split_huge_page(page); -+ if (err) -+ goto out_unlock; -+ } -+ -+ /* -+ * If this anonymous page is mapped only here, its pte may need -+ * to be write-protected. If it's mapped elsewhere, all of its -+ * ptes are necessarily already write-protected. But in either -+ * case, we need to lock and check page_count is not raised. -+ */ -+ if (write_protect_page(vma, page, &orig_pte, NULL) == 0) { -+ if (pages_identical(page, kpage)) -+ err = replace_page(vma, page, kpage, orig_pte); -+ else -+ err = check_collision(rmap_item, hash); -+ } -+ -+ if ((vma->vm_flags & VM_LOCKED) && kpage && !err) { -+ munlock_vma_page(page); -+ if (!PageMlocked(kpage)) { -+ unlock_page(page); -+ lock_page(kpage); -+ mlock_vma_page(kpage); -+ page = kpage; /* for final unlock */ -+ } -+ } -+ -+out_unlock: -+ unlock_page(page); -+out: -+ return err; -+} -+ -+ -+ -+/** -+ * If two pages fail to merge in try_to_merge_two_pages, then we have a chance -+ * to restore a page mapping that has been changed in try_to_merge_two_pages. -+ * -+ * @return 0 on success. -+ */ -+static int restore_uksm_page_pte(struct vm_area_struct *vma, unsigned long addr, -+ pte_t orig_pte, pte_t wprt_pte) -+{ -+ struct mm_struct *mm = vma->vm_mm; -+ pgd_t *pgd; -+ p4d_t *p4d; -+ pud_t *pud; -+ pmd_t *pmd; -+ pte_t *ptep; -+ spinlock_t *ptl; -+ -+ int err = -EFAULT; -+ -+ pgd = pgd_offset(mm, addr); -+ if (!pgd_present(*pgd)) -+ goto out; -+ -+ p4d = p4d_offset(pgd, addr); -+ pud = pud_offset(p4d, addr); -+ if (!pud_present(*pud)) -+ goto out; -+ -+ pmd = pmd_offset(pud, addr); -+ if (!pmd_present(*pmd)) -+ goto out; -+ -+ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); -+ if (!pte_same(*ptep, wprt_pte)) { -+ /* already copied, let it be */ -+ pte_unmap_unlock(ptep, ptl); -+ goto out; -+ } -+ -+ /* -+ * Good boy, still here. When we still get the ksm page, it does not -+ * return to the free page pool, there is no way that a pte was changed -+ * to other page and gets back to this page. And remind that ksm page -+ * do not reuse in do_wp_page(). So it's safe to restore the original -+ * pte. -+ */ -+ flush_cache_page(vma, addr, pte_pfn(*ptep)); -+ ptep_clear_flush_notify(vma, addr, ptep); -+ set_pte_at_notify(mm, addr, ptep, orig_pte); -+ -+ pte_unmap_unlock(ptep, ptl); -+ err = 0; -+out: -+ return err; -+} -+ -+/** -+ * try_to_merge_two_pages() - take two identical pages and prepare -+ * them to be merged into one page(rmap_item->page) -+ * -+ * @return 0 if we successfully merged two identical pages into -+ * one ksm page. MERGE_ERR_COLLI if it's only a hash collision -+ * search in rbtree. MERGE_ERR_CHANGED if rmap_item has been -+ * changed since it's hashed. MERGE_ERR_PGERR otherwise. -+ * -+ */ -+static int try_to_merge_two_pages(struct rmap_item *rmap_item, -+ struct rmap_item *tree_rmap_item, -+ u32 hash) -+{ -+ pte_t orig_pte1 = __pte(0), orig_pte2 = __pte(0); -+ pte_t wprt_pte1 = __pte(0), wprt_pte2 = __pte(0); -+ struct vm_area_struct *vma1 = rmap_item->slot->vma; -+ struct vm_area_struct *vma2 = tree_rmap_item->slot->vma; -+ struct page *page = rmap_item->page; -+ struct page *tree_page = tree_rmap_item->page; -+ int err = MERGE_ERR_PGERR; -+ struct address_space *saved_mapping; -+ -+ -+ if (rmap_item->page == tree_rmap_item->page) -+ goto out; -+ -+ if (!trylock_page(page)) -+ goto out; -+ -+ if (!PageAnon(page)) -+ goto out_unlock; -+ -+ if (PageTransCompound(page)) { -+ err = split_huge_page(page); -+ if (err) -+ goto out_unlock; -+ } -+ -+ if (write_protect_page(vma1, page, &wprt_pte1, &orig_pte1) != 0) { -+ unlock_page(page); -+ goto out; -+ } -+ -+ /* -+ * While we hold page lock, upgrade page from -+ * PageAnon+anon_vma to PageKsm+NULL stable_node: -+ * stable_tree_insert() will update stable_node. -+ */ -+ saved_mapping = page->mapping; -+ set_page_stable_node(page, NULL); -+ mark_page_accessed(page); -+ if (!PageDirty(page)) -+ SetPageDirty(page); -+ -+ unlock_page(page); -+ -+ if (!trylock_page(tree_page)) -+ goto restore_out; -+ -+ if (!PageAnon(tree_page)) { -+ unlock_page(tree_page); -+ goto restore_out; -+ } -+ -+ if (PageTransCompound(tree_page)) { -+ err = split_huge_page(tree_page); -+ if (err) { -+ unlock_page(tree_page); -+ goto restore_out; -+ } -+ } -+ -+ if (write_protect_page(vma2, tree_page, &wprt_pte2, &orig_pte2) != 0) { -+ unlock_page(tree_page); -+ goto restore_out; -+ } -+ -+ if (pages_identical(page, tree_page)) { -+ err = replace_page(vma2, tree_page, page, wprt_pte2); -+ if (err) { -+ unlock_page(tree_page); -+ goto restore_out; -+ } -+ -+ if ((vma2->vm_flags & VM_LOCKED)) { -+ munlock_vma_page(tree_page); -+ if (!PageMlocked(page)) { -+ unlock_page(tree_page); -+ lock_page(page); -+ mlock_vma_page(page); -+ tree_page = page; /* for final unlock */ -+ } -+ } -+ -+ unlock_page(tree_page); -+ -+ goto out; /* success */ -+ -+ } else { -+ if (tree_rmap_item->hash_max && -+ tree_rmap_item->hash_max == rmap_item->hash_max) { -+ err = MERGE_ERR_COLLI_MAX; -+ } else if (page_hash(page, hash_strength, 0) == -+ page_hash(tree_page, hash_strength, 0)) { -+ inc_rshash_neg(memcmp_cost + hash_strength * 2); -+ err = MERGE_ERR_COLLI; -+ } else { -+ err = MERGE_ERR_CHANGED; -+ } -+ -+ unlock_page(tree_page); -+ } -+ -+restore_out: -+ lock_page(page); -+ if (!restore_uksm_page_pte(vma1, get_rmap_addr(rmap_item), -+ orig_pte1, wprt_pte1)) -+ page->mapping = saved_mapping; -+ -+out_unlock: -+ unlock_page(page); -+out: -+ return err; -+} -+ -+static inline int hash_cmp(u32 new_val, u32 node_val) -+{ -+ if (new_val > node_val) -+ return 1; -+ else if (new_val < node_val) -+ return -1; -+ else -+ return 0; -+} -+ -+static inline u32 rmap_item_hash_max(struct rmap_item *item, u32 hash) -+{ -+ u32 hash_max = item->hash_max; -+ -+ if (!hash_max) { -+ hash_max = page_hash_max(item->page, hash); -+ -+ item->hash_max = hash_max; -+ } -+ -+ return hash_max; -+} -+ -+ -+ -+/** -+ * stable_tree_search() - search the stable tree for a page -+ * -+ * @item: the rmap_item we are comparing with -+ * @hash: the hash value of this item->page already calculated -+ * -+ * @return the page we have found, NULL otherwise. The page returned has -+ * been gotten. -+ */ -+static struct page *stable_tree_search(struct rmap_item *item, u32 hash) -+{ -+ struct rb_node *node = root_stable_treep->rb_node; -+ struct tree_node *tree_node; -+ unsigned long hash_max; -+ struct page *page = item->page; -+ struct stable_node *stable_node; -+ -+ stable_node = page_stable_node(page); -+ if (stable_node) { -+ /* ksm page forked, that is -+ * if (PageKsm(page) && !in_stable_tree(rmap_item)) -+ * it's actually gotten once outside. -+ */ -+ get_page(page); -+ return page; -+ } -+ -+ while (node) { -+ int cmp; -+ -+ tree_node = rb_entry(node, struct tree_node, node); -+ -+ cmp = hash_cmp(hash, tree_node->hash); -+ -+ if (cmp < 0) -+ node = node->rb_left; -+ else if (cmp > 0) -+ node = node->rb_right; -+ else -+ break; -+ } -+ -+ if (!node) -+ return NULL; -+ -+ if (tree_node->count == 1) { -+ stable_node = rb_entry(tree_node->sub_root.rb_node, -+ struct stable_node, node); -+ BUG_ON(!stable_node); -+ -+ goto get_page_out; -+ } -+ -+ /* -+ * ok, we have to search the second -+ * level subtree, hash the page to a -+ * full strength. -+ */ -+ node = tree_node->sub_root.rb_node; -+ BUG_ON(!node); -+ hash_max = rmap_item_hash_max(item, hash); -+ -+ while (node) { -+ int cmp; -+ -+ stable_node = rb_entry(node, struct stable_node, node); -+ -+ cmp = hash_cmp(hash_max, stable_node->hash_max); -+ -+ if (cmp < 0) -+ node = node->rb_left; -+ else if (cmp > 0) -+ node = node->rb_right; -+ else -+ goto get_page_out; -+ } -+ -+ return NULL; -+ -+get_page_out: -+ page = get_uksm_page(stable_node, 1, 1); -+ return page; -+} -+ -+static int try_merge_rmap_item(struct rmap_item *item, -+ struct page *kpage, -+ struct page *tree_page) -+{ -+ struct vm_area_struct *vma = item->slot->vma; -+ struct page_vma_mapped_walk pvmw = { -+ .page = kpage, -+ .vma = vma, -+ }; -+ -+ pvmw.address = get_rmap_addr(item); -+ if (!page_vma_mapped_walk(&pvmw)) -+ return 0; -+ -+ if (pte_write(*pvmw.pte)) { -+ /* has changed, abort! */ -+ page_vma_mapped_walk_done(&pvmw); -+ return 0; -+ } -+ -+ get_page(tree_page); -+ page_add_anon_rmap(tree_page, vma, pvmw.address, false); -+ -+ flush_cache_page(vma, pvmw.address, page_to_pfn(kpage)); -+ ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte); -+ set_pte_at_notify(vma->vm_mm, pvmw.address, pvmw.pte, -+ mk_pte(tree_page, vma->vm_page_prot)); -+ -+ page_remove_rmap(kpage, false); -+ put_page(kpage); -+ -+ page_vma_mapped_walk_done(&pvmw); -+ -+ return 1; -+} -+ -+/** -+ * try_to_merge_with_stable_page() - when two rmap_items need to be inserted -+ * into stable tree, the page was found to be identical to a stable ksm page, -+ * this is the last chance we can merge them into one. -+ * -+ * @item1: the rmap_item holding the page which we wanted to insert -+ * into stable tree. -+ * @item2: the other rmap_item we found when unstable tree search -+ * @oldpage: the page currently mapped by the two rmap_items -+ * @tree_page: the page we found identical in stable tree node -+ * @success1: return if item1 is successfully merged -+ * @success2: return if item2 is successfully merged -+ */ -+static void try_merge_with_stable(struct rmap_item *item1, -+ struct rmap_item *item2, -+ struct page **kpage, -+ struct page *tree_page, -+ int *success1, int *success2) -+{ -+ struct vm_area_struct *vma1 = item1->slot->vma; -+ struct vm_area_struct *vma2 = item2->slot->vma; -+ *success1 = 0; -+ *success2 = 0; -+ -+ if (unlikely(*kpage == tree_page)) { -+ /* I don't think this can really happen */ -+ pr_warn("UKSM: unexpected condition detected in " -+ "%s -- *kpage == tree_page !\n", __func__); -+ *success1 = 1; -+ *success2 = 1; -+ return; -+ } -+ -+ if (!PageAnon(*kpage) || !PageKsm(*kpage)) -+ goto failed; -+ -+ if (!trylock_page(tree_page)) -+ goto failed; -+ -+ /* If the oldpage is still ksm and still pointed -+ * to in the right place, and still write protected, -+ * we are confident it's not changed, no need to -+ * memcmp anymore. -+ * be ware, we cannot take nested pte locks, -+ * deadlock risk. -+ */ -+ if (!try_merge_rmap_item(item1, *kpage, tree_page)) -+ goto unlock_failed; -+ -+ /* ok, then vma2, remind that pte1 already set */ -+ if (!try_merge_rmap_item(item2, *kpage, tree_page)) -+ goto success_1; -+ -+ *success2 = 1; -+success_1: -+ *success1 = 1; -+ -+ -+ if ((*success1 && vma1->vm_flags & VM_LOCKED) || -+ (*success2 && vma2->vm_flags & VM_LOCKED)) { -+ munlock_vma_page(*kpage); -+ if (!PageMlocked(tree_page)) -+ mlock_vma_page(tree_page); -+ } -+ -+ /* -+ * We do not need oldpage any more in the caller, so can break the lock -+ * now. -+ */ -+ unlock_page(*kpage); -+ *kpage = tree_page; /* Get unlocked outside. */ -+ return; -+ -+unlock_failed: -+ unlock_page(tree_page); -+failed: -+ return; -+} -+ -+static inline void stable_node_hash_max(struct stable_node *node, -+ struct page *page, u32 hash) -+{ -+ u32 hash_max = node->hash_max; -+ -+ if (!hash_max) { -+ hash_max = page_hash_max(page, hash); -+ node->hash_max = hash_max; -+ } -+} -+ -+static inline -+struct stable_node *new_stable_node(struct tree_node *tree_node, -+ struct page *kpage, u32 hash_max) -+{ -+ struct stable_node *new_stable_node; -+ -+ new_stable_node = alloc_stable_node(); -+ if (!new_stable_node) -+ return NULL; -+ -+ new_stable_node->kpfn = page_to_pfn(kpage); -+ new_stable_node->hash_max = hash_max; -+ new_stable_node->tree_node = tree_node; -+ set_page_stable_node(kpage, new_stable_node); -+ -+ return new_stable_node; -+} -+ -+static inline -+struct stable_node *first_level_insert(struct tree_node *tree_node, -+ struct rmap_item *rmap_item, -+ struct rmap_item *tree_rmap_item, -+ struct page **kpage, u32 hash, -+ int *success1, int *success2) -+{ -+ int cmp; -+ struct page *tree_page; -+ u32 hash_max = 0; -+ struct stable_node *stable_node, *new_snode; -+ struct rb_node *parent = NULL, **new; -+ -+ /* this tree node contains no sub-tree yet */ -+ stable_node = rb_entry(tree_node->sub_root.rb_node, -+ struct stable_node, node); -+ -+ tree_page = get_uksm_page(stable_node, 1, 0); -+ if (tree_page) { -+ cmp = memcmp_pages(*kpage, tree_page, 1); -+ if (!cmp) { -+ try_merge_with_stable(rmap_item, tree_rmap_item, kpage, -+ tree_page, success1, success2); -+ put_page(tree_page); -+ if (!*success1 && !*success2) -+ goto failed; -+ -+ return stable_node; -+ -+ } else { -+ /* -+ * collision in first level try to create a subtree. -+ * A new node need to be created. -+ */ -+ put_page(tree_page); -+ -+ stable_node_hash_max(stable_node, tree_page, -+ tree_node->hash); -+ hash_max = rmap_item_hash_max(rmap_item, hash); -+ cmp = hash_cmp(hash_max, stable_node->hash_max); -+ -+ parent = &stable_node->node; -+ if (cmp < 0) -+ new = &parent->rb_left; -+ else if (cmp > 0) -+ new = &parent->rb_right; -+ else -+ goto failed; -+ } -+ -+ } else { -+ /* the only stable_node deleted, we reuse its tree_node. -+ */ -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ } -+ -+ new_snode = new_stable_node(tree_node, *kpage, hash_max); -+ if (!new_snode) -+ goto failed; -+ -+ rb_link_node(&new_snode->node, parent, new); -+ rb_insert_color(&new_snode->node, &tree_node->sub_root); -+ tree_node->count++; -+ *success1 = *success2 = 1; -+ -+ return new_snode; -+ -+failed: -+ return NULL; -+} -+ -+static inline -+struct stable_node *stable_subtree_insert(struct tree_node *tree_node, -+ struct rmap_item *rmap_item, -+ struct rmap_item *tree_rmap_item, -+ struct page **kpage, u32 hash, -+ int *success1, int *success2) -+{ -+ struct page *tree_page; -+ u32 hash_max; -+ struct stable_node *stable_node, *new_snode; -+ struct rb_node *parent, **new; -+ -+research: -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ BUG_ON(!*new); -+ hash_max = rmap_item_hash_max(rmap_item, hash); -+ while (*new) { -+ int cmp; -+ -+ stable_node = rb_entry(*new, struct stable_node, node); -+ -+ cmp = hash_cmp(hash_max, stable_node->hash_max); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else { -+ tree_page = get_uksm_page(stable_node, 1, 0); -+ if (tree_page) { -+ cmp = memcmp_pages(*kpage, tree_page, 1); -+ if (!cmp) { -+ try_merge_with_stable(rmap_item, -+ tree_rmap_item, kpage, -+ tree_page, success1, success2); -+ -+ put_page(tree_page); -+ if (!*success1 && !*success2) -+ goto failed; -+ /* -+ * successfully merged with a stable -+ * node -+ */ -+ return stable_node; -+ } else { -+ put_page(tree_page); -+ goto failed; -+ } -+ } else { -+ /* -+ * stable node may be deleted, -+ * and subtree maybe -+ * restructed, cannot -+ * continue, research it. -+ */ -+ if (tree_node->count) { -+ goto research; -+ } else { -+ /* reuse the tree node*/ -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ } -+ } -+ } -+ } -+ -+ new_snode = new_stable_node(tree_node, *kpage, hash_max); -+ if (!new_snode) -+ goto failed; -+ -+ rb_link_node(&new_snode->node, parent, new); -+ rb_insert_color(&new_snode->node, &tree_node->sub_root); -+ tree_node->count++; -+ *success1 = *success2 = 1; -+ -+ return new_snode; -+ -+failed: -+ return NULL; -+} -+ -+ -+/** -+ * stable_tree_insert() - try to insert a merged page in unstable tree to -+ * the stable tree -+ * -+ * @kpage: the page need to be inserted -+ * @hash: the current hash of this page -+ * @rmap_item: the rmap_item being scanned -+ * @tree_rmap_item: the rmap_item found on unstable tree -+ * @success1: return if rmap_item is merged -+ * @success2: return if tree_rmap_item is merged -+ * -+ * @return the stable_node on stable tree if at least one -+ * rmap_item is inserted into stable tree, NULL -+ * otherwise. -+ */ -+static struct stable_node * -+stable_tree_insert(struct page **kpage, u32 hash, -+ struct rmap_item *rmap_item, -+ struct rmap_item *tree_rmap_item, -+ int *success1, int *success2) -+{ -+ struct rb_node **new = &root_stable_treep->rb_node; -+ struct rb_node *parent = NULL; -+ struct stable_node *stable_node; -+ struct tree_node *tree_node; -+ u32 hash_max = 0; -+ -+ *success1 = *success2 = 0; -+ -+ while (*new) { -+ int cmp; -+ -+ tree_node = rb_entry(*new, struct tree_node, node); -+ -+ cmp = hash_cmp(hash, tree_node->hash); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else -+ break; -+ } -+ -+ if (*new) { -+ if (tree_node->count == 1) { -+ stable_node = first_level_insert(tree_node, rmap_item, -+ tree_rmap_item, kpage, -+ hash, success1, success2); -+ } else { -+ stable_node = stable_subtree_insert(tree_node, -+ rmap_item, tree_rmap_item, kpage, -+ hash, success1, success2); -+ } -+ } else { -+ -+ /* no tree node found */ -+ tree_node = alloc_tree_node(stable_tree_node_listp); -+ if (!tree_node) { -+ stable_node = NULL; -+ goto out; -+ } -+ -+ stable_node = new_stable_node(tree_node, *kpage, hash_max); -+ if (!stable_node) { -+ free_tree_node(tree_node); -+ goto out; -+ } -+ -+ tree_node->hash = hash; -+ rb_link_node(&tree_node->node, parent, new); -+ rb_insert_color(&tree_node->node, root_stable_treep); -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ -+ rb_link_node(&stable_node->node, parent, new); -+ rb_insert_color(&stable_node->node, &tree_node->sub_root); -+ tree_node->count++; -+ *success1 = *success2 = 1; -+ } -+ -+out: -+ return stable_node; -+} -+ -+ -+/** -+ * get_tree_rmap_item_page() - try to get the page and lock the mmap_sem -+ * -+ * @return 0 on success, -EBUSY if unable to lock the mmap_sem, -+ * -EINVAL if the page mapping has been changed. -+ */ -+static inline int get_tree_rmap_item_page(struct rmap_item *tree_rmap_item) -+{ -+ int err; -+ -+ err = get_mergeable_page_lock_mmap(tree_rmap_item); -+ -+ if (err == -EINVAL) { -+ /* its page map has been changed, remove it */ -+ remove_rmap_item_from_tree(tree_rmap_item); -+ } -+ -+ /* The page is gotten and mmap_sem is locked now. */ -+ return err; -+} -+ -+ -+/** -+ * unstable_tree_search_insert() - search an unstable tree rmap_item with the -+ * same hash value. Get its page and trylock the mmap_sem -+ */ -+static inline -+struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, -+ u32 hash) -+ -+{ -+ struct rb_node **new = &root_unstable_tree.rb_node; -+ struct rb_node *parent = NULL; -+ struct tree_node *tree_node; -+ u32 hash_max; -+ struct rmap_item *tree_rmap_item; -+ -+ while (*new) { -+ int cmp; -+ -+ tree_node = rb_entry(*new, struct tree_node, node); -+ -+ cmp = hash_cmp(hash, tree_node->hash); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else -+ break; -+ } -+ -+ if (*new) { -+ /* got the tree_node */ -+ if (tree_node->count == 1) { -+ tree_rmap_item = rb_entry(tree_node->sub_root.rb_node, -+ struct rmap_item, node); -+ BUG_ON(!tree_rmap_item); -+ -+ goto get_page_out; -+ } -+ -+ /* well, search the collision subtree */ -+ new = &tree_node->sub_root.rb_node; -+ BUG_ON(!*new); -+ hash_max = rmap_item_hash_max(rmap_item, hash); -+ -+ while (*new) { -+ int cmp; -+ -+ tree_rmap_item = rb_entry(*new, struct rmap_item, -+ node); -+ -+ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); -+ parent = *new; -+ if (cmp < 0) -+ new = &parent->rb_left; -+ else if (cmp > 0) -+ new = &parent->rb_right; -+ else -+ goto get_page_out; -+ } -+ } else { -+ /* alloc a new tree_node */ -+ tree_node = alloc_tree_node(&unstable_tree_node_list); -+ if (!tree_node) -+ return NULL; -+ -+ tree_node->hash = hash; -+ rb_link_node(&tree_node->node, parent, new); -+ rb_insert_color(&tree_node->node, &root_unstable_tree); -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ } -+ -+ /* did not found even in sub-tree */ -+ rmap_item->tree_node = tree_node; -+ rmap_item->address |= UNSTABLE_FLAG; -+ rmap_item->hash_round = uksm_hash_round; -+ rb_link_node(&rmap_item->node, parent, new); -+ rb_insert_color(&rmap_item->node, &tree_node->sub_root); -+ -+ uksm_pages_unshared++; -+ return NULL; -+ -+get_page_out: -+ if (tree_rmap_item->page == rmap_item->page) -+ return NULL; -+ -+ if (get_tree_rmap_item_page(tree_rmap_item)) -+ return NULL; -+ -+ return tree_rmap_item; -+} -+ -+static void hold_anon_vma(struct rmap_item *rmap_item, -+ struct anon_vma *anon_vma) -+{ -+ rmap_item->anon_vma = anon_vma; -+ get_anon_vma(anon_vma); -+} -+ -+ -+/** -+ * stable_tree_append() - append a rmap_item to a stable node. Deduplication -+ * ratio statistics is done in this function. -+ * -+ */ -+static void stable_tree_append(struct rmap_item *rmap_item, -+ struct stable_node *stable_node, int logdedup) -+{ -+ struct node_vma *node_vma = NULL, *new_node_vma, *node_vma_cont = NULL; -+ unsigned long key = (unsigned long)rmap_item->slot; -+ unsigned long factor = rmap_item->slot->rung->step; -+ -+ BUG_ON(!stable_node); -+ rmap_item->address |= STABLE_FLAG; -+ -+ if (hlist_empty(&stable_node->hlist)) { -+ uksm_pages_shared++; -+ goto node_vma_new; -+ } else { -+ uksm_pages_sharing++; -+ } -+ -+ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { -+ if (node_vma->key >= key) -+ break; -+ -+ if (logdedup) { -+ node_vma->slot->pages_bemerged += factor; -+ if (list_empty(&node_vma->slot->dedup_list)) -+ list_add(&node_vma->slot->dedup_list, -+ &vma_slot_dedup); -+ } -+ } -+ -+ if (node_vma) { -+ if (node_vma->key == key) { -+ node_vma_cont = hlist_entry_safe(node_vma->hlist.next, struct node_vma, hlist); -+ goto node_vma_ok; -+ } else if (node_vma->key > key) { -+ node_vma_cont = node_vma; -+ } -+ } -+ -+node_vma_new: -+ /* no same vma already in node, alloc a new node_vma */ -+ new_node_vma = alloc_node_vma(); -+ BUG_ON(!new_node_vma); -+ new_node_vma->head = stable_node; -+ new_node_vma->slot = rmap_item->slot; -+ -+ if (!node_vma) { -+ hlist_add_head(&new_node_vma->hlist, &stable_node->hlist); -+ } else if (node_vma->key != key) { -+ if (node_vma->key < key) -+ hlist_add_behind(&new_node_vma->hlist, &node_vma->hlist); -+ else { -+ hlist_add_before(&new_node_vma->hlist, -+ &node_vma->hlist); -+ } -+ -+ } -+ node_vma = new_node_vma; -+ -+node_vma_ok: /* ok, ready to add to the list */ -+ rmap_item->head = node_vma; -+ hlist_add_head(&rmap_item->hlist, &node_vma->rmap_hlist); -+ hold_anon_vma(rmap_item, rmap_item->slot->vma->anon_vma); -+ if (logdedup) { -+ rmap_item->slot->pages_merged++; -+ if (node_vma_cont) { -+ node_vma = node_vma_cont; -+ hlist_for_each_entry_continue(node_vma, hlist) { -+ node_vma->slot->pages_bemerged += factor; -+ if (list_empty(&node_vma->slot->dedup_list)) -+ list_add(&node_vma->slot->dedup_list, -+ &vma_slot_dedup); -+ } -+ } -+ } -+} -+ -+/* -+ * We use break_ksm to break COW on a ksm page: it's a stripped down -+ * -+ * if (get_user_pages(addr, 1, 1, 1, &page, NULL) == 1) -+ * put_page(page); -+ * -+ * but taking great care only to touch a ksm page, in a VM_MERGEABLE vma, -+ * in case the application has unmapped and remapped mm,addr meanwhile. -+ * Could a ksm page appear anywhere else? Actually yes, in a VM_PFNMAP -+ * mmap of /dev/mem or /dev/kmem, where we would not want to touch it. -+ */ -+static int break_ksm(struct vm_area_struct *vma, unsigned long addr) -+{ -+ struct page *page; -+ int ret = 0; -+ -+ do { -+ cond_resched(); -+ page = follow_page(vma, addr, FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); -+ if (IS_ERR_OR_NULL(page)) -+ break; -+ if (PageKsm(page)) { -+ ret = handle_mm_fault(vma, addr, -+ FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE); -+ } else -+ ret = VM_FAULT_WRITE; -+ put_page(page); -+ } while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | VM_FAULT_OOM))); -+ /* -+ * We must loop because handle_mm_fault() may back out if there's -+ * any difficulty e.g. if pte accessed bit gets updated concurrently. -+ * -+ * VM_FAULT_WRITE is what we have been hoping for: it indicates that -+ * COW has been broken, even if the vma does not permit VM_WRITE; -+ * but note that a concurrent fault might break PageKsm for us. -+ * -+ * VM_FAULT_SIGBUS could occur if we race with truncation of the -+ * backing file, which also invalidates anonymous pages: that's -+ * okay, that truncation will have unmapped the PageKsm for us. -+ * -+ * VM_FAULT_OOM: at the time of writing (late July 2009), setting -+ * aside mem_cgroup limits, VM_FAULT_OOM would only be set if the -+ * current task has TIF_MEMDIE set, and will be OOM killed on return -+ * to user; and ksmd, having no mm, would never be chosen for that. -+ * -+ * But if the mm is in a limited mem_cgroup, then the fault may fail -+ * with VM_FAULT_OOM even if the current task is not TIF_MEMDIE; and -+ * even ksmd can fail in this way - though it's usually breaking ksm -+ * just to undo a merge it made a moment before, so unlikely to oom. -+ * -+ * That's a pity: we might therefore have more kernel pages allocated -+ * than we're counting as nodes in the stable tree; but uksm_do_scan -+ * will retry to break_cow on each pass, so should recover the page -+ * in due course. The important thing is to not let VM_MERGEABLE -+ * be cleared while any such pages might remain in the area. -+ */ -+ return (ret & VM_FAULT_OOM) ? -ENOMEM : 0; -+} -+ -+static void break_cow(struct rmap_item *rmap_item) -+{ -+ struct vm_area_struct *vma = rmap_item->slot->vma; -+ struct mm_struct *mm = vma->vm_mm; -+ unsigned long addr = get_rmap_addr(rmap_item); -+ -+ if (uksm_test_exit(mm)) -+ goto out; -+ -+ break_ksm(vma, addr); -+out: -+ return; -+} -+ -+/* -+ * Though it's very tempting to unmerge in_stable_tree(rmap_item)s rather -+ * than check every pte of a given vma, the locking doesn't quite work for -+ * that - an rmap_item is assigned to the stable tree after inserting ksm -+ * page and upping mmap_sem. Nor does it fit with the way we skip dup'ing -+ * rmap_items from parent to child at fork time (so as not to waste time -+ * if exit comes before the next scan reaches it). -+ * -+ * Similarly, although we'd like to remove rmap_items (so updating counts -+ * and freeing memory) when unmerging an area, it's easier to leave that -+ * to the next pass of ksmd - consider, for example, how ksmd might be -+ * in cmp_and_merge_page on one of the rmap_items we would be removing. -+ */ -+inline int unmerge_uksm_pages(struct vm_area_struct *vma, -+ unsigned long start, unsigned long end) -+{ -+ unsigned long addr; -+ int err = 0; -+ -+ for (addr = start; addr < end && !err; addr += PAGE_SIZE) { -+ if (uksm_test_exit(vma->vm_mm)) -+ break; -+ if (signal_pending(current)) -+ err = -ERESTARTSYS; -+ else -+ err = break_ksm(vma, addr); -+ } -+ return err; -+} -+ -+static inline void inc_uksm_pages_scanned(void) -+{ -+ u64 delta; -+ -+ -+ if (uksm_pages_scanned == U64_MAX) { -+ encode_benefit(); -+ -+ delta = uksm_pages_scanned >> pages_scanned_base; -+ -+ if (CAN_OVERFLOW_U64(pages_scanned_stored, delta)) { -+ pages_scanned_stored >>= 1; -+ delta >>= 1; -+ pages_scanned_base++; -+ } -+ -+ pages_scanned_stored += delta; -+ -+ uksm_pages_scanned = uksm_pages_scanned_last = 0; -+ } -+ -+ uksm_pages_scanned++; -+} -+ -+static inline int find_zero_page_hash(int strength, u32 hash) -+{ -+ return (zero_hash_table[strength] == hash); -+} -+ -+static -+int cmp_and_merge_zero_page(struct vm_area_struct *vma, struct page *page) -+{ -+ struct page *zero_page = empty_uksm_zero_page; -+ struct mm_struct *mm = vma->vm_mm; -+ pte_t orig_pte = __pte(0); -+ int err = -EFAULT; -+ -+ if (uksm_test_exit(mm)) -+ goto out; -+ -+ if (!trylock_page(page)) -+ goto out; -+ -+ if (!PageAnon(page)) -+ goto out_unlock; -+ -+ if (PageTransCompound(page)) { -+ err = split_huge_page(page); -+ if (err) -+ goto out_unlock; -+ } -+ -+ if (write_protect_page(vma, page, &orig_pte, 0) == 0) { -+ if (is_page_full_zero(page)) -+ err = replace_page(vma, page, zero_page, orig_pte); -+ } -+ -+out_unlock: -+ unlock_page(page); -+out: -+ return err; -+} -+ -+/* -+ * cmp_and_merge_page() - first see if page can be merged into the stable -+ * tree; if not, compare hash to previous and if it's the same, see if page -+ * can be inserted into the unstable tree, or merged with a page already there -+ * and both transferred to the stable tree. -+ * -+ * @page: the page that we are searching identical page to. -+ * @rmap_item: the reverse mapping into the virtual address of this page -+ */ -+static void cmp_and_merge_page(struct rmap_item *rmap_item, u32 hash) -+{ -+ struct rmap_item *tree_rmap_item; -+ struct page *page; -+ struct page *kpage = NULL; -+ u32 hash_max; -+ int err; -+ unsigned int success1, success2; -+ struct stable_node *snode; -+ int cmp; -+ struct rb_node *parent = NULL, **new; -+ -+ remove_rmap_item_from_tree(rmap_item); -+ page = rmap_item->page; -+ -+ /* We first start with searching the page inside the stable tree */ -+ kpage = stable_tree_search(rmap_item, hash); -+ if (kpage) { -+ err = try_to_merge_with_uksm_page(rmap_item, kpage, -+ hash); -+ if (!err) { -+ /* -+ * The page was successfully merged, add -+ * its rmap_item to the stable tree. -+ * page lock is needed because it's -+ * racing with try_to_unmap_ksm(), etc. -+ */ -+ lock_page(kpage); -+ snode = page_stable_node(kpage); -+ stable_tree_append(rmap_item, snode, 1); -+ unlock_page(kpage); -+ put_page(kpage); -+ return; /* success */ -+ } -+ put_page(kpage); -+ -+ /* -+ * if it's a collision and it has been search in sub-rbtree -+ * (hash_max != 0), we want to abort, because if it is -+ * successfully merged in unstable tree, the collision trends to -+ * happen again. -+ */ -+ if (err == MERGE_ERR_COLLI && rmap_item->hash_max) -+ return; -+ } -+ -+ tree_rmap_item = -+ unstable_tree_search_insert(rmap_item, hash); -+ if (tree_rmap_item) { -+ err = try_to_merge_two_pages(rmap_item, tree_rmap_item, hash); -+ /* -+ * As soon as we merge this page, we want to remove the -+ * rmap_item of the page we have merged with from the unstable -+ * tree, and insert it instead as new node in the stable tree. -+ */ -+ if (!err) { -+ kpage = page; -+ remove_rmap_item_from_tree(tree_rmap_item); -+ lock_page(kpage); -+ snode = stable_tree_insert(&kpage, hash, -+ rmap_item, tree_rmap_item, -+ &success1, &success2); -+ -+ /* -+ * Do not log dedup for tree item, it's not counted as -+ * scanned in this round. -+ */ -+ if (success2) -+ stable_tree_append(tree_rmap_item, snode, 0); -+ -+ /* -+ * The order of these two stable append is important: -+ * we are scanning rmap_item. -+ */ -+ if (success1) -+ stable_tree_append(rmap_item, snode, 1); -+ -+ /* -+ * The original kpage may be unlocked inside -+ * stable_tree_insert() already. This page -+ * should be unlocked before doing -+ * break_cow(). -+ */ -+ unlock_page(kpage); -+ -+ if (!success1) -+ break_cow(rmap_item); -+ -+ if (!success2) -+ break_cow(tree_rmap_item); -+ -+ } else if (err == MERGE_ERR_COLLI) { -+ BUG_ON(tree_rmap_item->tree_node->count > 1); -+ -+ rmap_item_hash_max(tree_rmap_item, -+ tree_rmap_item->tree_node->hash); -+ -+ hash_max = rmap_item_hash_max(rmap_item, hash); -+ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); -+ parent = &tree_rmap_item->node; -+ if (cmp < 0) -+ new = &parent->rb_left; -+ else if (cmp > 0) -+ new = &parent->rb_right; -+ else -+ goto put_up_out; -+ -+ rmap_item->tree_node = tree_rmap_item->tree_node; -+ rmap_item->address |= UNSTABLE_FLAG; -+ rmap_item->hash_round = uksm_hash_round; -+ rb_link_node(&rmap_item->node, parent, new); -+ rb_insert_color(&rmap_item->node, -+ &tree_rmap_item->tree_node->sub_root); -+ rmap_item->tree_node->count++; -+ } else { -+ /* -+ * either one of the page has changed or they collide -+ * at the max hash, we consider them as ill items. -+ */ -+ remove_rmap_item_from_tree(tree_rmap_item); -+ } -+put_up_out: -+ put_page(tree_rmap_item->page); -+ up_read(&tree_rmap_item->slot->vma->vm_mm->mmap_sem); -+ } -+} -+ -+ -+ -+ -+static inline unsigned long get_pool_index(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = (sizeof(struct rmap_list_entry *) * index) >> PAGE_SHIFT; -+ if (pool_index >= slot->pool_size) -+ BUG(); -+ return pool_index; -+} -+ -+static inline unsigned long index_page_offset(unsigned long index) -+{ -+ return offset_in_page(sizeof(struct rmap_list_entry *) * index); -+} -+ -+static inline -+struct rmap_list_entry *get_rmap_list_entry(struct vma_slot *slot, -+ unsigned long index, int need_alloc) -+{ -+ unsigned long pool_index; -+ struct page *page; -+ void *addr; -+ -+ -+ pool_index = get_pool_index(slot, index); -+ if (!slot->rmap_list_pool[pool_index]) { -+ if (!need_alloc) -+ return NULL; -+ -+ page = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN); -+ if (!page) -+ return NULL; -+ -+ slot->rmap_list_pool[pool_index] = page; -+ } -+ -+ addr = kmap(slot->rmap_list_pool[pool_index]); -+ addr += index_page_offset(index); -+ -+ return addr; -+} -+ -+static inline void put_rmap_list_entry(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = get_pool_index(slot, index); -+ BUG_ON(!slot->rmap_list_pool[pool_index]); -+ kunmap(slot->rmap_list_pool[pool_index]); -+} -+ -+static inline int entry_is_new(struct rmap_list_entry *entry) -+{ -+ return !entry->item; -+} -+ -+static inline unsigned long get_index_orig_addr(struct vma_slot *slot, -+ unsigned long index) -+{ -+ return slot->vma->vm_start + (index << PAGE_SHIFT); -+} -+ -+static inline unsigned long get_entry_address(struct rmap_list_entry *entry) -+{ -+ unsigned long addr; -+ -+ if (is_addr(entry->addr)) -+ addr = get_clean_addr(entry->addr); -+ else if (entry->item) -+ addr = get_rmap_addr(entry->item); -+ else -+ BUG(); -+ -+ return addr; -+} -+ -+static inline struct rmap_item *get_entry_item(struct rmap_list_entry *entry) -+{ -+ if (is_addr(entry->addr)) -+ return NULL; -+ -+ return entry->item; -+} -+ -+static inline void inc_rmap_list_pool_count(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = get_pool_index(slot, index); -+ BUG_ON(!slot->rmap_list_pool[pool_index]); -+ slot->pool_counts[pool_index]++; -+} -+ -+static inline void dec_rmap_list_pool_count(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = get_pool_index(slot, index); -+ BUG_ON(!slot->rmap_list_pool[pool_index]); -+ BUG_ON(!slot->pool_counts[pool_index]); -+ slot->pool_counts[pool_index]--; -+} -+ -+static inline int entry_has_rmap(struct rmap_list_entry *entry) -+{ -+ return !is_addr(entry->addr) && entry->item; -+} -+ -+static inline void swap_entries(struct rmap_list_entry *entry1, -+ unsigned long index1, -+ struct rmap_list_entry *entry2, -+ unsigned long index2) -+{ -+ struct rmap_list_entry tmp; -+ -+ /* swapping two new entries is meaningless */ -+ BUG_ON(entry_is_new(entry1) && entry_is_new(entry2)); -+ -+ tmp = *entry1; -+ *entry1 = *entry2; -+ *entry2 = tmp; -+ -+ if (entry_has_rmap(entry1)) -+ entry1->item->entry_index = index1; -+ -+ if (entry_has_rmap(entry2)) -+ entry2->item->entry_index = index2; -+ -+ if (entry_has_rmap(entry1) && !entry_has_rmap(entry2)) { -+ inc_rmap_list_pool_count(entry1->item->slot, index1); -+ dec_rmap_list_pool_count(entry1->item->slot, index2); -+ } else if (!entry_has_rmap(entry1) && entry_has_rmap(entry2)) { -+ inc_rmap_list_pool_count(entry2->item->slot, index2); -+ dec_rmap_list_pool_count(entry2->item->slot, index1); -+ } -+} -+ -+static inline void free_entry_item(struct rmap_list_entry *entry) -+{ -+ unsigned long index; -+ struct rmap_item *item; -+ -+ if (!is_addr(entry->addr)) { -+ BUG_ON(!entry->item); -+ item = entry->item; -+ entry->addr = get_rmap_addr(item); -+ set_is_addr(entry->addr); -+ index = item->entry_index; -+ remove_rmap_item_from_tree(item); -+ dec_rmap_list_pool_count(item->slot, index); -+ free_rmap_item(item); -+ } -+} -+ -+static inline int pool_entry_boundary(unsigned long index) -+{ -+ unsigned long linear_addr; -+ -+ linear_addr = sizeof(struct rmap_list_entry *) * index; -+ return index && !offset_in_page(linear_addr); -+} -+ -+static inline void try_free_last_pool(struct vma_slot *slot, -+ unsigned long index) -+{ -+ unsigned long pool_index; -+ -+ pool_index = get_pool_index(slot, index); -+ if (slot->rmap_list_pool[pool_index] && -+ !slot->pool_counts[pool_index]) { -+ __free_page(slot->rmap_list_pool[pool_index]); -+ slot->rmap_list_pool[pool_index] = NULL; -+ slot->flags |= UKSM_SLOT_NEED_SORT; -+ } -+ -+} -+ -+static inline unsigned long vma_item_index(struct vm_area_struct *vma, -+ struct rmap_item *item) -+{ -+ return (get_rmap_addr(item) - vma->vm_start) >> PAGE_SHIFT; -+} -+ -+static int within_same_pool(struct vma_slot *slot, -+ unsigned long i, unsigned long j) -+{ -+ unsigned long pool_i, pool_j; -+ -+ pool_i = get_pool_index(slot, i); -+ pool_j = get_pool_index(slot, j); -+ -+ return (pool_i == pool_j); -+} -+ -+static void sort_rmap_entry_list(struct vma_slot *slot) -+{ -+ unsigned long i, j; -+ struct rmap_list_entry *entry, *swap_entry; -+ -+ entry = get_rmap_list_entry(slot, 0, 0); -+ for (i = 0; i < slot->pages; ) { -+ -+ if (!entry) -+ goto skip_whole_pool; -+ -+ if (entry_is_new(entry)) -+ goto next_entry; -+ -+ if (is_addr(entry->addr)) { -+ entry->addr = 0; -+ goto next_entry; -+ } -+ -+ j = vma_item_index(slot->vma, entry->item); -+ if (j == i) -+ goto next_entry; -+ -+ if (within_same_pool(slot, i, j)) -+ swap_entry = entry + j - i; -+ else -+ swap_entry = get_rmap_list_entry(slot, j, 1); -+ -+ swap_entries(entry, i, swap_entry, j); -+ if (!within_same_pool(slot, i, j)) -+ put_rmap_list_entry(slot, j); -+ continue; -+ -+skip_whole_pool: -+ i += PAGE_SIZE / sizeof(*entry); -+ if (i < slot->pages) -+ entry = get_rmap_list_entry(slot, i, 0); -+ continue; -+ -+next_entry: -+ if (i >= slot->pages - 1 || -+ !within_same_pool(slot, i, i + 1)) { -+ put_rmap_list_entry(slot, i); -+ if (i + 1 < slot->pages) -+ entry = get_rmap_list_entry(slot, i + 1, 0); -+ } else -+ entry++; -+ i++; -+ continue; -+ } -+ -+ /* free empty pool entries which contain no rmap_item */ -+ /* CAN be simplied to based on only pool_counts when bug freed !!!!! */ -+ for (i = 0; i < slot->pool_size; i++) { -+ unsigned char has_rmap; -+ void *addr; -+ -+ if (!slot->rmap_list_pool[i]) -+ continue; -+ -+ has_rmap = 0; -+ addr = kmap(slot->rmap_list_pool[i]); -+ BUG_ON(!addr); -+ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { -+ entry = (struct rmap_list_entry *)addr + j; -+ if (is_addr(entry->addr)) -+ continue; -+ if (!entry->item) -+ continue; -+ has_rmap = 1; -+ } -+ kunmap(slot->rmap_list_pool[i]); -+ if (!has_rmap) { -+ BUG_ON(slot->pool_counts[i]); -+ __free_page(slot->rmap_list_pool[i]); -+ slot->rmap_list_pool[i] = NULL; -+ } -+ } -+ -+ slot->flags &= ~UKSM_SLOT_NEED_SORT; -+} -+ -+/* -+ * vma_fully_scanned() - if all the pages in this slot have been scanned. -+ */ -+static inline int vma_fully_scanned(struct vma_slot *slot) -+{ -+ return slot->pages_scanned == slot->pages; -+} -+ -+/** -+ * get_next_rmap_item() - Get the next rmap_item in a vma_slot according to -+ * its random permutation. This function is embedded with the random -+ * permutation index management code. -+ */ -+static struct rmap_item *get_next_rmap_item(struct vma_slot *slot, u32 *hash) -+{ -+ unsigned long rand_range, addr, swap_index, scan_index; -+ struct rmap_item *item = NULL; -+ struct rmap_list_entry *scan_entry, *swap_entry = NULL; -+ struct page *page; -+ -+ scan_index = swap_index = slot->pages_scanned % slot->pages; -+ -+ if (pool_entry_boundary(scan_index)) -+ try_free_last_pool(slot, scan_index - 1); -+ -+ if (vma_fully_scanned(slot)) { -+ if (slot->flags & UKSM_SLOT_NEED_SORT) -+ slot->flags |= UKSM_SLOT_NEED_RERAND; -+ else -+ slot->flags &= ~UKSM_SLOT_NEED_RERAND; -+ if (slot->flags & UKSM_SLOT_NEED_SORT) -+ sort_rmap_entry_list(slot); -+ } -+ -+ scan_entry = get_rmap_list_entry(slot, scan_index, 1); -+ if (!scan_entry) -+ return NULL; -+ -+ if (entry_is_new(scan_entry)) { -+ scan_entry->addr = get_index_orig_addr(slot, scan_index); -+ set_is_addr(scan_entry->addr); -+ } -+ -+ if (slot->flags & UKSM_SLOT_NEED_RERAND) { -+ rand_range = slot->pages - scan_index; -+ BUG_ON(!rand_range); -+ swap_index = scan_index + (prandom_u32() % rand_range); -+ } -+ -+ if (swap_index != scan_index) { -+ swap_entry = get_rmap_list_entry(slot, swap_index, 1); -+ if (entry_is_new(swap_entry)) { -+ swap_entry->addr = get_index_orig_addr(slot, -+ swap_index); -+ set_is_addr(swap_entry->addr); -+ } -+ swap_entries(scan_entry, scan_index, swap_entry, swap_index); -+ } -+ -+ addr = get_entry_address(scan_entry); -+ item = get_entry_item(scan_entry); -+ BUG_ON(addr > slot->vma->vm_end || addr < slot->vma->vm_start); -+ -+ page = follow_page(slot->vma, addr, FOLL_GET); -+ if (IS_ERR_OR_NULL(page)) -+ goto nopage; -+ -+ if (!PageAnon(page)) -+ goto putpage; -+ -+ /*check is zero_page pfn or uksm_zero_page*/ -+ if ((page_to_pfn(page) == zero_pfn) -+ || (page_to_pfn(page) == uksm_zero_pfn)) -+ goto putpage; -+ -+ flush_anon_page(slot->vma, page, addr); -+ flush_dcache_page(page); -+ -+ -+ *hash = page_hash(page, hash_strength, 1); -+ inc_uksm_pages_scanned(); -+ /*if the page content all zero, re-map to zero-page*/ -+ if (find_zero_page_hash(hash_strength, *hash)) { -+ if (!cmp_and_merge_zero_page(slot->vma, page)) { -+ slot->pages_merged++; -+ -+ /* For full-zero pages, no need to create rmap item */ -+ goto putpage; -+ } else { -+ inc_rshash_neg(memcmp_cost / 2); -+ } -+ } -+ -+ if (!item) { -+ item = alloc_rmap_item(); -+ if (item) { -+ /* It has already been zeroed */ -+ item->slot = slot; -+ item->address = addr; -+ item->entry_index = scan_index; -+ scan_entry->item = item; -+ inc_rmap_list_pool_count(slot, scan_index); -+ } else -+ goto putpage; -+ } -+ -+ BUG_ON(item->slot != slot); -+ /* the page may have changed */ -+ item->page = page; -+ put_rmap_list_entry(slot, scan_index); -+ if (swap_entry) -+ put_rmap_list_entry(slot, swap_index); -+ return item; -+ -+putpage: -+ put_page(page); -+ page = NULL; -+nopage: -+ /* no page, store addr back and free rmap_item if possible */ -+ free_entry_item(scan_entry); -+ put_rmap_list_entry(slot, scan_index); -+ if (swap_entry) -+ put_rmap_list_entry(slot, swap_index); -+ return NULL; -+} -+ -+static inline int in_stable_tree(struct rmap_item *rmap_item) -+{ -+ return rmap_item->address & STABLE_FLAG; -+} -+ -+/** -+ * scan_vma_one_page() - scan the next page in a vma_slot. Called with -+ * mmap_sem locked. -+ */ -+static noinline void scan_vma_one_page(struct vma_slot *slot) -+{ -+ u32 hash; -+ struct mm_struct *mm; -+ struct rmap_item *rmap_item = NULL; -+ struct vm_area_struct *vma = slot->vma; -+ -+ mm = vma->vm_mm; -+ BUG_ON(!mm); -+ BUG_ON(!slot); -+ -+ rmap_item = get_next_rmap_item(slot, &hash); -+ if (!rmap_item) -+ goto out1; -+ -+ if (PageKsm(rmap_item->page) && in_stable_tree(rmap_item)) -+ goto out2; -+ -+ cmp_and_merge_page(rmap_item, hash); -+out2: -+ put_page(rmap_item->page); -+out1: -+ slot->pages_scanned++; -+ slot->this_sampled++; -+ if (slot->fully_scanned_round != fully_scanned_round) -+ scanned_virtual_pages++; -+ -+ if (vma_fully_scanned(slot)) -+ slot->fully_scanned_round = fully_scanned_round; -+} -+ -+static inline unsigned long rung_get_pages(struct scan_rung *rung) -+{ -+ struct slot_tree_node *node; -+ -+ if (!rung->vma_root.rnode) -+ return 0; -+ -+ node = container_of(rung->vma_root.rnode, struct slot_tree_node, snode); -+ -+ return node->size; -+} -+ -+#define RUNG_SAMPLED_MIN 3 -+ -+static inline -+void uksm_calc_rung_step(struct scan_rung *rung, -+ unsigned long page_time, unsigned long ratio) -+{ -+ unsigned long sampled, pages; -+ -+ /* will be fully scanned ? */ -+ if (!rung->cover_msecs) { -+ rung->step = 1; -+ return; -+ } -+ -+ sampled = rung->cover_msecs * (NSEC_PER_MSEC / TIME_RATIO_SCALE) -+ * ratio / page_time; -+ -+ /* -+ * Before we finsish a scan round and expensive per-round jobs, -+ * we need to have a chance to estimate the per page time. So -+ * the sampled number can not be too small. -+ */ -+ if (sampled < RUNG_SAMPLED_MIN) -+ sampled = RUNG_SAMPLED_MIN; -+ -+ pages = rung_get_pages(rung); -+ if (likely(pages > sampled)) -+ rung->step = pages / sampled; -+ else -+ rung->step = 1; -+} -+ -+static inline int step_need_recalc(struct scan_rung *rung) -+{ -+ unsigned long pages, stepmax; -+ -+ pages = rung_get_pages(rung); -+ stepmax = pages / RUNG_SAMPLED_MIN; -+ -+ return pages && (rung->step > pages || -+ (stepmax && rung->step > stepmax)); -+} -+ -+static inline -+void reset_current_scan(struct scan_rung *rung, int finished, int step_recalc) -+{ -+ struct vma_slot *slot; -+ -+ if (finished) -+ rung->flags |= UKSM_RUNG_ROUND_FINISHED; -+ -+ if (step_recalc || step_need_recalc(rung)) { -+ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); -+ BUG_ON(step_need_recalc(rung)); -+ } -+ -+ slot_iter_index = prandom_u32() % rung->step; -+ BUG_ON(!rung->vma_root.rnode); -+ slot = sradix_tree_next(&rung->vma_root, NULL, 0, slot_iter); -+ BUG_ON(!slot); -+ -+ rung->current_scan = slot; -+ rung->current_offset = slot_iter_index; -+} -+ -+static inline struct sradix_tree_root *slot_get_root(struct vma_slot *slot) -+{ -+ return &slot->rung->vma_root; -+} -+ -+/* -+ * return if resetted. -+ */ -+static int advance_current_scan(struct scan_rung *rung) -+{ -+ unsigned short n; -+ struct vma_slot *slot, *next = NULL; -+ -+ BUG_ON(!rung->vma_root.num); -+ -+ slot = rung->current_scan; -+ n = (slot->pages - rung->current_offset) % rung->step; -+ slot_iter_index = rung->step - n; -+ next = sradix_tree_next(&rung->vma_root, slot->snode, -+ slot->sindex, slot_iter); -+ -+ if (next) { -+ rung->current_offset = slot_iter_index; -+ rung->current_scan = next; -+ return 0; -+ } else { -+ reset_current_scan(rung, 1, 0); -+ return 1; -+ } -+} -+ -+static inline void rung_rm_slot(struct vma_slot *slot) -+{ -+ struct scan_rung *rung = slot->rung; -+ struct sradix_tree_root *root; -+ -+ if (rung->current_scan == slot) -+ advance_current_scan(rung); -+ -+ root = slot_get_root(slot); -+ sradix_tree_delete_from_leaf(root, slot->snode, slot->sindex); -+ slot->snode = NULL; -+ if (step_need_recalc(rung)) { -+ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); -+ BUG_ON(step_need_recalc(rung)); -+ } -+ -+ /* In case advance_current_scan loop back to this slot again */ -+ if (rung->vma_root.num && rung->current_scan == slot) -+ reset_current_scan(slot->rung, 1, 0); -+} -+ -+static inline void rung_add_new_slots(struct scan_rung *rung, -+ struct vma_slot **slots, unsigned long num) -+{ -+ int err; -+ struct vma_slot *slot; -+ unsigned long i; -+ struct sradix_tree_root *root = &rung->vma_root; -+ -+ err = sradix_tree_enter(root, (void **)slots, num); -+ BUG_ON(err); -+ -+ for (i = 0; i < num; i++) { -+ slot = slots[i]; -+ slot->rung = rung; -+ BUG_ON(vma_fully_scanned(slot)); -+ } -+ -+ if (rung->vma_root.num == num) -+ reset_current_scan(rung, 0, 1); -+} -+ -+static inline int rung_add_one_slot(struct scan_rung *rung, -+ struct vma_slot *slot) -+{ -+ int err; -+ -+ err = sradix_tree_enter(&rung->vma_root, (void **)&slot, 1); -+ if (err) -+ return err; -+ -+ slot->rung = rung; -+ if (rung->vma_root.num == 1) -+ reset_current_scan(rung, 0, 1); -+ -+ return 0; -+} -+ -+/* -+ * Return true if the slot is deleted from its rung. -+ */ -+static inline int vma_rung_enter(struct vma_slot *slot, struct scan_rung *rung) -+{ -+ struct scan_rung *old_rung = slot->rung; -+ int err; -+ -+ if (old_rung == rung) -+ return 0; -+ -+ rung_rm_slot(slot); -+ err = rung_add_one_slot(rung, slot); -+ if (err) { -+ err = rung_add_one_slot(old_rung, slot); -+ WARN_ON(err); /* OOPS, badly OOM, we lost this slot */ -+ } -+ -+ return 1; -+} -+ -+static inline int vma_rung_up(struct vma_slot *slot) -+{ -+ struct scan_rung *rung; -+ -+ rung = slot->rung; -+ if (slot->rung != &uksm_scan_ladder[SCAN_LADDER_SIZE-1]) -+ rung++; -+ -+ return vma_rung_enter(slot, rung); -+} -+ -+static inline int vma_rung_down(struct vma_slot *slot) -+{ -+ struct scan_rung *rung; -+ -+ rung = slot->rung; -+ if (slot->rung != &uksm_scan_ladder[0]) -+ rung--; -+ -+ return vma_rung_enter(slot, rung); -+} -+ -+/** -+ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. -+ */ -+static unsigned long cal_dedup_ratio(struct vma_slot *slot) -+{ -+ unsigned long ret; -+ unsigned long pages; -+ -+ pages = slot->this_sampled; -+ if (!pages) -+ return 0; -+ -+ BUG_ON(slot->pages_scanned == slot->last_scanned); -+ -+ ret = slot->pages_merged; -+ -+ /* Thrashing area filtering */ -+ if (ret && uksm_thrash_threshold) { -+ if (slot->pages_cowed * 100 / slot->pages_merged -+ > uksm_thrash_threshold) { -+ ret = 0; -+ } else { -+ ret = slot->pages_merged - slot->pages_cowed; -+ } -+ } -+ -+ return ret * 100 / pages; -+} -+ -+/** -+ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. -+ */ -+static unsigned long cal_dedup_ratio_old(struct vma_slot *slot) -+{ -+ unsigned long ret; -+ unsigned long pages; -+ -+ pages = slot->pages; -+ if (!pages) -+ return 0; -+ -+ ret = slot->pages_bemerged; -+ -+ /* Thrashing area filtering */ -+ if (ret && uksm_thrash_threshold) { -+ if (slot->pages_cowed * 100 / slot->pages_bemerged -+ > uksm_thrash_threshold) { -+ ret = 0; -+ } else { -+ ret = slot->pages_bemerged - slot->pages_cowed; -+ } -+ } -+ -+ return ret * 100 / pages; -+} -+ -+/** -+ * stable_node_reinsert() - When the hash_strength has been adjusted, the -+ * stable tree need to be restructured, this is the function re-inserting the -+ * stable node. -+ */ -+static inline void stable_node_reinsert(struct stable_node *new_node, -+ struct page *page, -+ struct rb_root *root_treep, -+ struct list_head *tree_node_listp, -+ u32 hash) -+{ -+ struct rb_node **new = &root_treep->rb_node; -+ struct rb_node *parent = NULL; -+ struct stable_node *stable_node; -+ struct tree_node *tree_node; -+ struct page *tree_page; -+ int cmp; -+ -+ while (*new) { -+ int cmp; -+ -+ tree_node = rb_entry(*new, struct tree_node, node); -+ -+ cmp = hash_cmp(hash, tree_node->hash); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else -+ break; -+ } -+ -+ if (*new) { -+ /* find a stable tree node with same first level hash value */ -+ stable_node_hash_max(new_node, page, hash); -+ if (tree_node->count == 1) { -+ stable_node = rb_entry(tree_node->sub_root.rb_node, -+ struct stable_node, node); -+ tree_page = get_uksm_page(stable_node, 1, 0); -+ if (tree_page) { -+ stable_node_hash_max(stable_node, -+ tree_page, hash); -+ put_page(tree_page); -+ -+ /* prepare for stable node insertion */ -+ -+ cmp = hash_cmp(new_node->hash_max, -+ stable_node->hash_max); -+ parent = &stable_node->node; -+ if (cmp < 0) -+ new = &parent->rb_left; -+ else if (cmp > 0) -+ new = &parent->rb_right; -+ else -+ goto failed; -+ -+ goto add_node; -+ } else { -+ /* the only stable_node deleted, the tree node -+ * was not deleted. -+ */ -+ goto tree_node_reuse; -+ } -+ } -+ -+ /* well, search the collision subtree */ -+ new = &tree_node->sub_root.rb_node; -+ parent = NULL; -+ BUG_ON(!*new); -+ while (*new) { -+ int cmp; -+ -+ stable_node = rb_entry(*new, struct stable_node, node); -+ -+ cmp = hash_cmp(new_node->hash_max, -+ stable_node->hash_max); -+ -+ if (cmp < 0) { -+ parent = *new; -+ new = &parent->rb_left; -+ } else if (cmp > 0) { -+ parent = *new; -+ new = &parent->rb_right; -+ } else { -+ /* oh, no, still a collision */ -+ goto failed; -+ } -+ } -+ -+ goto add_node; -+ } -+ -+ /* no tree node found */ -+ tree_node = alloc_tree_node(tree_node_listp); -+ if (!tree_node) { -+ pr_err("UKSM: memory allocation error!\n"); -+ goto failed; -+ } else { -+ tree_node->hash = hash; -+ rb_link_node(&tree_node->node, parent, new); -+ rb_insert_color(&tree_node->node, root_treep); -+ -+tree_node_reuse: -+ /* prepare for stable node insertion */ -+ parent = NULL; -+ new = &tree_node->sub_root.rb_node; -+ } -+ -+add_node: -+ rb_link_node(&new_node->node, parent, new); -+ rb_insert_color(&new_node->node, &tree_node->sub_root); -+ new_node->tree_node = tree_node; -+ tree_node->count++; -+ return; -+ -+failed: -+ /* This can only happen when two nodes have collided -+ * in two levels. -+ */ -+ new_node->tree_node = NULL; -+ return; -+} -+ -+static inline void free_all_tree_nodes(struct list_head *list) -+{ -+ struct tree_node *node, *tmp; -+ -+ list_for_each_entry_safe(node, tmp, list, all_list) { -+ free_tree_node(node); -+ } -+} -+ -+/** -+ * stable_tree_delta_hash() - Delta hash the stable tree from previous hash -+ * strength to the current hash_strength. It re-structures the hole tree. -+ */ -+static inline void stable_tree_delta_hash(u32 prev_hash_strength) -+{ -+ struct stable_node *node, *tmp; -+ struct rb_root *root_new_treep; -+ struct list_head *new_tree_node_listp; -+ -+ stable_tree_index = (stable_tree_index + 1) % 2; -+ root_new_treep = &root_stable_tree[stable_tree_index]; -+ new_tree_node_listp = &stable_tree_node_list[stable_tree_index]; -+ *root_new_treep = RB_ROOT; -+ BUG_ON(!list_empty(new_tree_node_listp)); -+ -+ /* -+ * we need to be safe, the node could be removed by get_uksm_page() -+ */ -+ list_for_each_entry_safe(node, tmp, &stable_node_list, all_list) { -+ void *addr; -+ struct page *node_page; -+ u32 hash; -+ -+ /* -+ * We are completely re-structuring the stable nodes to a new -+ * stable tree. We don't want to touch the old tree unlinks and -+ * old tree_nodes. The old tree_nodes will be freed at once. -+ */ -+ node_page = get_uksm_page(node, 0, 0); -+ if (!node_page) -+ continue; -+ -+ if (node->tree_node) { -+ hash = node->tree_node->hash; -+ -+ addr = kmap_atomic(node_page); -+ -+ hash = delta_hash(addr, prev_hash_strength, -+ hash_strength, hash); -+ kunmap_atomic(addr); -+ } else { -+ /* -+ *it was not inserted to rbtree due to collision in last -+ *round scan. -+ */ -+ hash = page_hash(node_page, hash_strength, 0); -+ } -+ -+ stable_node_reinsert(node, node_page, root_new_treep, -+ new_tree_node_listp, hash); -+ put_page(node_page); -+ } -+ -+ root_stable_treep = root_new_treep; -+ free_all_tree_nodes(stable_tree_node_listp); -+ BUG_ON(!list_empty(stable_tree_node_listp)); -+ stable_tree_node_listp = new_tree_node_listp; -+} -+ -+static inline void inc_hash_strength(unsigned long delta) -+{ -+ hash_strength += 1 << delta; -+ if (hash_strength > HASH_STRENGTH_MAX) -+ hash_strength = HASH_STRENGTH_MAX; -+} -+ -+static inline void dec_hash_strength(unsigned long delta) -+{ -+ unsigned long change = 1 << delta; -+ -+ if (hash_strength <= change + 1) -+ hash_strength = 1; -+ else -+ hash_strength -= change; -+} -+ -+static inline void inc_hash_strength_delta(void) -+{ -+ hash_strength_delta++; -+ if (hash_strength_delta > HASH_STRENGTH_DELTA_MAX) -+ hash_strength_delta = HASH_STRENGTH_DELTA_MAX; -+} -+ -+static inline unsigned long get_current_neg_ratio(void) -+{ -+ u64 pos = benefit.pos; -+ u64 neg = benefit.neg; -+ -+ if (!neg) -+ return 0; -+ -+ if (!pos || neg > pos) -+ return 100; -+ -+ if (neg > div64_u64(U64_MAX, 100)) -+ pos = div64_u64(pos, 100); -+ else -+ neg *= 100; -+ -+ return div64_u64(neg, pos); -+} -+ -+static inline unsigned long get_current_benefit(void) -+{ -+ u64 pos = benefit.pos; -+ u64 neg = benefit.neg; -+ u64 scanned = benefit.scanned; -+ -+ if (neg > pos) -+ return 0; -+ -+ return div64_u64((pos - neg), scanned); -+} -+ -+static inline int judge_rshash_direction(void) -+{ -+ u64 current_neg_ratio, stable_benefit; -+ u64 current_benefit, delta = 0; -+ int ret = STILL; -+ -+ /* -+ * Try to probe a value after the boot, and in case the system -+ * are still for a long time. -+ */ -+ if ((fully_scanned_round & 0xFFULL) == 10) { -+ ret = OBSCURE; -+ goto out; -+ } -+ -+ current_neg_ratio = get_current_neg_ratio(); -+ -+ if (current_neg_ratio == 0) { -+ rshash_neg_cont_zero++; -+ if (rshash_neg_cont_zero > 2) -+ return GO_DOWN; -+ else -+ return STILL; -+ } -+ rshash_neg_cont_zero = 0; -+ -+ if (current_neg_ratio > 90) { -+ ret = GO_UP; -+ goto out; -+ } -+ -+ current_benefit = get_current_benefit(); -+ stable_benefit = rshash_state.stable_benefit; -+ -+ if (!stable_benefit) { -+ ret = OBSCURE; -+ goto out; -+ } -+ -+ if (current_benefit > stable_benefit) -+ delta = current_benefit - stable_benefit; -+ else if (current_benefit < stable_benefit) -+ delta = stable_benefit - current_benefit; -+ -+ delta = div64_u64(100 * delta, stable_benefit); -+ -+ if (delta > 50) { -+ rshash_cont_obscure++; -+ if (rshash_cont_obscure > 2) -+ return OBSCURE; -+ else -+ return STILL; -+ } -+ -+out: -+ rshash_cont_obscure = 0; -+ return ret; -+} -+ -+/** -+ * rshash_adjust() - The main function to control the random sampling state -+ * machine for hash strength adapting. -+ * -+ * return true if hash_strength has changed. -+ */ -+static inline int rshash_adjust(void) -+{ -+ unsigned long prev_hash_strength = hash_strength; -+ -+ if (!encode_benefit()) -+ return 0; -+ -+ switch (rshash_state.state) { -+ case RSHASH_STILL: -+ switch (judge_rshash_direction()) { -+ case GO_UP: -+ if (rshash_state.pre_direct == GO_DOWN) -+ hash_strength_delta = 0; -+ -+ inc_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ rshash_state.stable_benefit = get_current_benefit(); -+ rshash_state.pre_direct = GO_UP; -+ break; -+ -+ case GO_DOWN: -+ if (rshash_state.pre_direct == GO_UP) -+ hash_strength_delta = 0; -+ -+ dec_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ rshash_state.stable_benefit = get_current_benefit(); -+ rshash_state.pre_direct = GO_DOWN; -+ break; -+ -+ case OBSCURE: -+ rshash_state.stable_point = hash_strength; -+ rshash_state.turn_point_down = hash_strength; -+ rshash_state.turn_point_up = hash_strength; -+ rshash_state.turn_benefit_down = get_current_benefit(); -+ rshash_state.turn_benefit_up = get_current_benefit(); -+ rshash_state.lookup_window_index = 0; -+ rshash_state.state = RSHASH_TRYDOWN; -+ dec_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ break; -+ -+ case STILL: -+ break; -+ default: -+ BUG(); -+ } -+ break; -+ -+ case RSHASH_TRYDOWN: -+ if (rshash_state.lookup_window_index++ % 5 == 0) -+ rshash_state.below_count = 0; -+ -+ if (get_current_benefit() < rshash_state.stable_benefit) -+ rshash_state.below_count++; -+ else if (get_current_benefit() > -+ rshash_state.turn_benefit_down) { -+ rshash_state.turn_point_down = hash_strength; -+ rshash_state.turn_benefit_down = get_current_benefit(); -+ } -+ -+ if (rshash_state.below_count >= 3 || -+ judge_rshash_direction() == GO_UP || -+ hash_strength == 1) { -+ hash_strength = rshash_state.stable_point; -+ hash_strength_delta = 0; -+ inc_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ rshash_state.lookup_window_index = 0; -+ rshash_state.state = RSHASH_TRYUP; -+ hash_strength_delta = 0; -+ } else { -+ dec_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ } -+ break; -+ -+ case RSHASH_TRYUP: -+ if (rshash_state.lookup_window_index++ % 5 == 0) -+ rshash_state.below_count = 0; -+ -+ if (get_current_benefit() < rshash_state.turn_benefit_down) -+ rshash_state.below_count++; -+ else if (get_current_benefit() > rshash_state.turn_benefit_up) { -+ rshash_state.turn_point_up = hash_strength; -+ rshash_state.turn_benefit_up = get_current_benefit(); -+ } -+ -+ if (rshash_state.below_count >= 3 || -+ judge_rshash_direction() == GO_DOWN || -+ hash_strength == HASH_STRENGTH_MAX) { -+ hash_strength = rshash_state.turn_benefit_up > -+ rshash_state.turn_benefit_down ? -+ rshash_state.turn_point_up : -+ rshash_state.turn_point_down; -+ -+ rshash_state.state = RSHASH_PRE_STILL; -+ } else { -+ inc_hash_strength(hash_strength_delta); -+ inc_hash_strength_delta(); -+ } -+ -+ break; -+ -+ case RSHASH_NEW: -+ case RSHASH_PRE_STILL: -+ rshash_state.stable_benefit = get_current_benefit(); -+ rshash_state.state = RSHASH_STILL; -+ hash_strength_delta = 0; -+ break; -+ default: -+ BUG(); -+ } -+ -+ /* rshash_neg = rshash_pos = 0; */ -+ reset_benefit(); -+ -+ if (prev_hash_strength != hash_strength) -+ stable_tree_delta_hash(prev_hash_strength); -+ -+ return prev_hash_strength != hash_strength; -+} -+ -+/** -+ * round_update_ladder() - The main function to do update of all the -+ * adjustments whenever a scan round is finished. -+ */ -+static noinline void round_update_ladder(void) -+{ -+ int i; -+ unsigned long dedup; -+ struct vma_slot *slot, *tmp_slot; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) -+ uksm_scan_ladder[i].flags &= ~UKSM_RUNG_ROUND_FINISHED; -+ -+ list_for_each_entry_safe(slot, tmp_slot, &vma_slot_dedup, dedup_list) { -+ -+ /* slot may be rung_rm_slot() when mm exits */ -+ if (slot->snode) { -+ dedup = cal_dedup_ratio_old(slot); -+ if (dedup && dedup >= uksm_abundant_threshold) -+ vma_rung_up(slot); -+ } -+ -+ slot->pages_bemerged = 0; -+ slot->pages_cowed = 0; -+ -+ list_del_init(&slot->dedup_list); -+ } -+} -+ -+static void uksm_del_vma_slot(struct vma_slot *slot) -+{ -+ int i, j; -+ struct rmap_list_entry *entry; -+ -+ if (slot->snode) { -+ /* -+ * In case it just failed when entering the rung, it's not -+ * necessary. -+ */ -+ rung_rm_slot(slot); -+ } -+ -+ if (!list_empty(&slot->dedup_list)) -+ list_del(&slot->dedup_list); -+ -+ if (!slot->rmap_list_pool || !slot->pool_counts) { -+ /* In case it OOMed in uksm_vma_enter() */ -+ goto out; -+ } -+ -+ for (i = 0; i < slot->pool_size; i++) { -+ void *addr; -+ -+ if (!slot->rmap_list_pool[i]) -+ continue; -+ -+ addr = kmap(slot->rmap_list_pool[i]); -+ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { -+ entry = (struct rmap_list_entry *)addr + j; -+ if (is_addr(entry->addr)) -+ continue; -+ if (!entry->item) -+ continue; -+ -+ remove_rmap_item_from_tree(entry->item); -+ free_rmap_item(entry->item); -+ slot->pool_counts[i]--; -+ } -+ BUG_ON(slot->pool_counts[i]); -+ kunmap(slot->rmap_list_pool[i]); -+ __free_page(slot->rmap_list_pool[i]); -+ } -+ kfree(slot->rmap_list_pool); -+ kfree(slot->pool_counts); -+ -+out: -+ slot->rung = NULL; -+ if (slot->flags & UKSM_SLOT_IN_UKSM) { -+ BUG_ON(uksm_pages_total < slot->pages); -+ uksm_pages_total -= slot->pages; -+ } -+ -+ if (slot->fully_scanned_round == fully_scanned_round) -+ scanned_virtual_pages -= slot->pages; -+ else -+ scanned_virtual_pages -= slot->pages_scanned; -+ free_vma_slot(slot); -+} -+ -+ -+#define SPIN_LOCK_PERIOD 32 -+static struct vma_slot *cleanup_slots[SPIN_LOCK_PERIOD]; -+static inline void cleanup_vma_slots(void) -+{ -+ struct vma_slot *slot; -+ int i; -+ -+ i = 0; -+ spin_lock(&vma_slot_list_lock); -+ while (!list_empty(&vma_slot_del)) { -+ slot = list_entry(vma_slot_del.next, -+ struct vma_slot, slot_list); -+ list_del(&slot->slot_list); -+ cleanup_slots[i++] = slot; -+ if (i == SPIN_LOCK_PERIOD) { -+ spin_unlock(&vma_slot_list_lock); -+ while (--i >= 0) -+ uksm_del_vma_slot(cleanup_slots[i]); -+ i = 0; -+ spin_lock(&vma_slot_list_lock); -+ } -+ } -+ spin_unlock(&vma_slot_list_lock); -+ -+ while (--i >= 0) -+ uksm_del_vma_slot(cleanup_slots[i]); -+} -+ -+/* -+ * Expotional moving average formula -+ */ -+static inline unsigned long ema(unsigned long curr, unsigned long last_ema) -+{ -+ /* -+ * For a very high burst, even the ema cannot work well, a false very -+ * high per-page time estimation can result in feedback in very high -+ * overhead of context switch and rung update -- this will then lead -+ * to higher per-paper time, this may not converge. -+ * -+ * Instead, we try to approach this value in a binary manner. -+ */ -+ if (curr > last_ema * 10) -+ return last_ema * 2; -+ -+ return (EMA_ALPHA * curr + (100 - EMA_ALPHA) * last_ema) / 100; -+} -+ -+/* -+ * convert cpu ratio in 1/TIME_RATIO_SCALE configured by user to -+ * nanoseconds based on current uksm_sleep_jiffies. -+ */ -+static inline unsigned long cpu_ratio_to_nsec(unsigned int ratio) -+{ -+ return NSEC_PER_USEC * jiffies_to_usecs(uksm_sleep_jiffies) / -+ (TIME_RATIO_SCALE - ratio) * ratio; -+} -+ -+ -+static inline unsigned long rung_real_ratio(int cpu_time_ratio) -+{ -+ unsigned long ret; -+ -+ BUG_ON(!cpu_time_ratio); -+ -+ if (cpu_time_ratio > 0) -+ ret = cpu_time_ratio; -+ else -+ ret = (unsigned long)(-cpu_time_ratio) * -+ uksm_max_cpu_percentage / 100UL; -+ -+ return ret ? ret : 1; -+} -+ -+static noinline void uksm_calc_scan_pages(void) -+{ -+ struct scan_rung *ladder = uksm_scan_ladder; -+ unsigned long sleep_usecs, nsecs; -+ unsigned long ratio; -+ int i; -+ unsigned long per_page; -+ -+ if (uksm_ema_page_time > 100000 || -+ (((unsigned long) uksm_eval_round & (256UL - 1)) == 0UL)) -+ uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; -+ -+ per_page = uksm_ema_page_time; -+ BUG_ON(!per_page); -+ -+ /* -+ * For every 8 eval round, we try to probe a uksm_sleep_jiffies value -+ * based on saved user input. -+ */ -+ if (((unsigned long) uksm_eval_round & (8UL - 1)) == 0UL) -+ uksm_sleep_jiffies = uksm_sleep_saved; -+ -+ /* We require a rung scan at least 1 page in a period. */ -+ nsecs = per_page; -+ ratio = rung_real_ratio(ladder[0].cpu_ratio); -+ if (cpu_ratio_to_nsec(ratio) < nsecs) { -+ sleep_usecs = nsecs * (TIME_RATIO_SCALE - ratio) / ratio -+ / NSEC_PER_USEC; -+ uksm_sleep_jiffies = usecs_to_jiffies(sleep_usecs) + 1; -+ } -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ ratio = rung_real_ratio(ladder[i].cpu_ratio); -+ ladder[i].pages_to_scan = cpu_ratio_to_nsec(ratio) / -+ per_page; -+ BUG_ON(!ladder[i].pages_to_scan); -+ uksm_calc_rung_step(&ladder[i], per_page, ratio); -+ } -+} -+ -+/* -+ * From the scan time of this round (ns) to next expected min sleep time -+ * (ms), be careful of the possible overflows. ratio is taken from -+ * rung_real_ratio() -+ */ -+static inline -+unsigned int scan_time_to_sleep(unsigned long long scan_time, unsigned long ratio) -+{ -+ scan_time >>= 20; /* to msec level now */ -+ BUG_ON(scan_time > (ULONG_MAX / TIME_RATIO_SCALE)); -+ -+ return (unsigned int) ((unsigned long) scan_time * -+ (TIME_RATIO_SCALE - ratio) / ratio); -+} -+ -+#define __round_mask(x, y) ((__typeof__(x))((y)-1)) -+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) -+ -+static void uksm_vma_enter(struct vma_slot **slots, unsigned long num) -+{ -+ struct scan_rung *rung; -+ -+ rung = &uksm_scan_ladder[0]; -+ rung_add_new_slots(rung, slots, num); -+} -+ -+static struct vma_slot *batch_slots[SLOT_TREE_NODE_STORE_SIZE]; -+ -+static void uksm_enter_all_slots(void) -+{ -+ struct vma_slot *slot; -+ unsigned long index; -+ struct list_head empty_vma_list; -+ int i; -+ -+ i = 0; -+ index = 0; -+ INIT_LIST_HEAD(&empty_vma_list); -+ -+ spin_lock(&vma_slot_list_lock); -+ while (!list_empty(&vma_slot_new)) { -+ slot = list_entry(vma_slot_new.next, -+ struct vma_slot, slot_list); -+ -+ if (!slot->vma->anon_vma) { -+ list_move(&slot->slot_list, &empty_vma_list); -+ } else if (vma_can_enter(slot->vma)) { -+ batch_slots[index++] = slot; -+ list_del_init(&slot->slot_list); -+ } else { -+ list_move(&slot->slot_list, &vma_slot_noadd); -+ } -+ -+ if (++i == SPIN_LOCK_PERIOD || -+ (index && !(index % SLOT_TREE_NODE_STORE_SIZE))) { -+ spin_unlock(&vma_slot_list_lock); -+ -+ if (index && !(index % SLOT_TREE_NODE_STORE_SIZE)) { -+ uksm_vma_enter(batch_slots, index); -+ index = 0; -+ } -+ i = 0; -+ cond_resched(); -+ spin_lock(&vma_slot_list_lock); -+ } -+ } -+ -+ list_splice(&empty_vma_list, &vma_slot_new); -+ -+ spin_unlock(&vma_slot_list_lock); -+ -+ if (index) -+ uksm_vma_enter(batch_slots, index); -+ -+} -+ -+static inline int rung_round_finished(struct scan_rung *rung) -+{ -+ return rung->flags & UKSM_RUNG_ROUND_FINISHED; -+} -+ -+static inline void judge_slot(struct vma_slot *slot) -+{ -+ struct scan_rung *rung = slot->rung; -+ unsigned long dedup; -+ int deleted; -+ -+ dedup = cal_dedup_ratio(slot); -+ if (vma_fully_scanned(slot) && uksm_thrash_threshold) -+ deleted = vma_rung_enter(slot, &uksm_scan_ladder[0]); -+ else if (dedup && dedup >= uksm_abundant_threshold) -+ deleted = vma_rung_up(slot); -+ else -+ deleted = vma_rung_down(slot); -+ -+ slot->pages_merged = 0; -+ slot->pages_cowed = 0; -+ slot->this_sampled = 0; -+ -+ if (vma_fully_scanned(slot)) -+ slot->pages_scanned = 0; -+ -+ slot->last_scanned = slot->pages_scanned; -+ -+ /* If its deleted in above, then rung was already advanced. */ -+ if (!deleted) -+ advance_current_scan(rung); -+} -+ -+ -+static inline int hash_round_finished(void) -+{ -+ if (scanned_virtual_pages > (uksm_pages_total >> 2)) { -+ scanned_virtual_pages = 0; -+ if (uksm_pages_scanned) -+ fully_scanned_round++; -+ -+ return 1; -+ } else { -+ return 0; -+ } -+} -+ -+#define UKSM_MMSEM_BATCH 5 -+#define BUSY_RETRY 100 -+ -+/** -+ * uksm_do_scan() - the main worker function. -+ */ -+static noinline void uksm_do_scan(void) -+{ -+ struct vma_slot *slot, *iter; -+ struct mm_struct *busy_mm; -+ unsigned char round_finished, all_rungs_emtpy; -+ int i, err, mmsem_batch; -+ unsigned long pcost; -+ long long delta_exec; -+ unsigned long vpages, max_cpu_ratio; -+ unsigned long long start_time, end_time, scan_time; -+ unsigned int expected_jiffies; -+ -+ might_sleep(); -+ -+ vpages = 0; -+ -+ start_time = task_sched_runtime(current); -+ max_cpu_ratio = 0; -+ mmsem_batch = 0; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE;) { -+ struct scan_rung *rung = &uksm_scan_ladder[i]; -+ unsigned long ratio; -+ int busy_retry; -+ -+ if (!rung->pages_to_scan) { -+ i++; -+ continue; -+ } -+ -+ if (!rung->vma_root.num) { -+ rung->pages_to_scan = 0; -+ i++; -+ continue; -+ } -+ -+ ratio = rung_real_ratio(rung->cpu_ratio); -+ if (ratio > max_cpu_ratio) -+ max_cpu_ratio = ratio; -+ -+ busy_retry = BUSY_RETRY; -+ /* -+ * Do not consider rung_round_finished() here, just used up the -+ * rung->pages_to_scan quota. -+ */ -+ while (rung->pages_to_scan && rung->vma_root.num && -+ likely(!freezing(current))) { -+ int reset = 0; -+ -+ slot = rung->current_scan; -+ -+ BUG_ON(vma_fully_scanned(slot)); -+ -+ if (mmsem_batch) -+ err = 0; -+ else -+ err = try_down_read_slot_mmap_sem(slot); -+ -+ if (err == -ENOENT) { -+rm_slot: -+ rung_rm_slot(slot); -+ continue; -+ } -+ -+ busy_mm = slot->mm; -+ -+ if (err == -EBUSY) { -+ /* skip other vmas on the same mm */ -+ do { -+ reset = advance_current_scan(rung); -+ iter = rung->current_scan; -+ busy_retry--; -+ if (iter->vma->vm_mm != busy_mm || -+ !busy_retry || reset) -+ break; -+ } while (1); -+ -+ if (iter->vma->vm_mm != busy_mm) { -+ continue; -+ } else { -+ /* scan round finsished */ -+ break; -+ } -+ } -+ -+ BUG_ON(!vma_can_enter(slot->vma)); -+ if (uksm_test_exit(slot->vma->vm_mm)) { -+ mmsem_batch = 0; -+ up_read(&slot->vma->vm_mm->mmap_sem); -+ goto rm_slot; -+ } -+ -+ if (mmsem_batch) -+ mmsem_batch--; -+ else -+ mmsem_batch = UKSM_MMSEM_BATCH; -+ -+ /* Ok, we have take the mmap_sem, ready to scan */ -+ scan_vma_one_page(slot); -+ rung->pages_to_scan--; -+ vpages++; -+ -+ if (rung->current_offset + rung->step > slot->pages - 1 -+ || vma_fully_scanned(slot)) { -+ up_read(&slot->vma->vm_mm->mmap_sem); -+ judge_slot(slot); -+ mmsem_batch = 0; -+ } else { -+ rung->current_offset += rung->step; -+ if (!mmsem_batch) -+ up_read(&slot->vma->vm_mm->mmap_sem); -+ } -+ -+ busy_retry = BUSY_RETRY; -+ cond_resched(); -+ } -+ -+ if (mmsem_batch) { -+ up_read(&slot->vma->vm_mm->mmap_sem); -+ mmsem_batch = 0; -+ } -+ -+ if (freezing(current)) -+ break; -+ -+ cond_resched(); -+ } -+ end_time = task_sched_runtime(current); -+ delta_exec = end_time - start_time; -+ -+ if (freezing(current)) -+ return; -+ -+ cleanup_vma_slots(); -+ uksm_enter_all_slots(); -+ -+ round_finished = 1; -+ all_rungs_emtpy = 1; -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ struct scan_rung *rung = &uksm_scan_ladder[i]; -+ -+ if (rung->vma_root.num) { -+ all_rungs_emtpy = 0; -+ if (!rung_round_finished(rung)) -+ round_finished = 0; -+ } -+ } -+ -+ if (all_rungs_emtpy) -+ round_finished = 0; -+ -+ if (round_finished) { -+ round_update_ladder(); -+ uksm_eval_round++; -+ -+ if (hash_round_finished() && rshash_adjust()) { -+ /* Reset the unstable root iff hash strength changed */ -+ uksm_hash_round++; -+ root_unstable_tree = RB_ROOT; -+ free_all_tree_nodes(&unstable_tree_node_list); -+ } -+ -+ /* -+ * A number of pages can hang around indefinitely on per-cpu -+ * pagevecs, raised page count preventing write_protect_page -+ * from merging them. Though it doesn't really matter much, -+ * it is puzzling to see some stuck in pages_volatile until -+ * other activity jostles them out, and they also prevented -+ * LTP's KSM test from succeeding deterministically; so drain -+ * them here (here rather than on entry to uksm_do_scan(), -+ * so we don't IPI too often when pages_to_scan is set low). -+ */ -+ lru_add_drain_all(); -+ } -+ -+ -+ if (vpages && delta_exec > 0) { -+ pcost = (unsigned long) delta_exec / vpages; -+ if (likely(uksm_ema_page_time)) -+ uksm_ema_page_time = ema(pcost, uksm_ema_page_time); -+ else -+ uksm_ema_page_time = pcost; -+ } -+ -+ uksm_calc_scan_pages(); -+ uksm_sleep_real = uksm_sleep_jiffies; -+ /* in case of radical cpu bursts, apply the upper bound */ -+ end_time = task_sched_runtime(current); -+ if (max_cpu_ratio && end_time > start_time) { -+ scan_time = end_time - start_time; -+ expected_jiffies = msecs_to_jiffies( -+ scan_time_to_sleep(scan_time, max_cpu_ratio)); -+ -+ if (expected_jiffies > uksm_sleep_real) -+ uksm_sleep_real = expected_jiffies; -+ -+ /* We have a 1 second up bound for responsiveness. */ -+ if (jiffies_to_msecs(uksm_sleep_real) > MSEC_PER_SEC) -+ uksm_sleep_real = msecs_to_jiffies(1000); -+ } -+ -+ return; -+} -+ -+static int ksmd_should_run(void) -+{ -+ return uksm_run & UKSM_RUN_MERGE; -+} -+ -+static int uksm_scan_thread(void *nothing) -+{ -+ set_freezable(); -+ set_user_nice(current, 5); -+ -+ while (!kthread_should_stop()) { -+ mutex_lock(&uksm_thread_mutex); -+ if (ksmd_should_run()) -+ uksm_do_scan(); -+ mutex_unlock(&uksm_thread_mutex); -+ -+ try_to_freeze(); -+ -+ if (ksmd_should_run()) { -+ schedule_timeout_interruptible(uksm_sleep_real); -+ uksm_sleep_times++; -+ } else { -+ wait_event_freezable(uksm_thread_wait, -+ ksmd_should_run() || kthread_should_stop()); -+ } -+ } -+ return 0; -+} -+ -+void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) -+{ -+ struct stable_node *stable_node; -+ struct node_vma *node_vma; -+ struct rmap_item *rmap_item; -+ int search_new_forks = 0; -+ unsigned long address; -+ -+ VM_BUG_ON_PAGE(!PageKsm(page), page); -+ VM_BUG_ON_PAGE(!PageLocked(page), page); -+ -+ stable_node = page_stable_node(page); -+ if (!stable_node) -+ return; -+again: -+ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { -+ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { -+ struct anon_vma *anon_vma = rmap_item->anon_vma; -+ struct anon_vma_chain *vmac; -+ struct vm_area_struct *vma; -+ -+ cond_resched(); -+ anon_vma_lock_read(anon_vma); -+ anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, -+ 0, ULONG_MAX) { -+ cond_resched(); -+ vma = vmac->vma; -+ address = get_rmap_addr(rmap_item); -+ -+ if (address < vma->vm_start || -+ address >= vma->vm_end) -+ continue; -+ -+ if ((rmap_item->slot->vma == vma) == -+ search_new_forks) -+ continue; -+ -+ if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg)) -+ continue; -+ -+ if (!rwc->rmap_one(page, vma, address, rwc->arg)) { -+ anon_vma_unlock_read(anon_vma); -+ return; -+ } -+ -+ if (rwc->done && rwc->done(page)) { -+ anon_vma_unlock_read(anon_vma); -+ return; -+ } -+ } -+ anon_vma_unlock_read(anon_vma); -+ } -+ } -+ if (!search_new_forks++) -+ goto again; -+} -+ -+#ifdef CONFIG_MIGRATION -+/* Common ksm interface but may be specific to uksm */ -+void ksm_migrate_page(struct page *newpage, struct page *oldpage) -+{ -+ struct stable_node *stable_node; -+ -+ VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage); -+ VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); -+ VM_BUG_ON(newpage->mapping != oldpage->mapping); -+ -+ stable_node = page_stable_node(newpage); -+ if (stable_node) { -+ VM_BUG_ON(stable_node->kpfn != page_to_pfn(oldpage)); -+ stable_node->kpfn = page_to_pfn(newpage); -+ /* -+ * newpage->mapping was set in advance; now we need smp_wmb() -+ * to make sure that the new stable_node->kpfn is visible -+ * to get_ksm_page() before it can see that oldpage->mapping -+ * has gone stale (or that PageSwapCache has been cleared). -+ */ -+ smp_wmb(); -+ set_page_stable_node(oldpage, NULL); -+ } -+} -+#endif /* CONFIG_MIGRATION */ -+ -+#ifdef CONFIG_MEMORY_HOTREMOVE -+static struct stable_node *uksm_check_stable_tree(unsigned long start_pfn, -+ unsigned long end_pfn) -+{ -+ struct rb_node *node; -+ -+ for (node = rb_first(root_stable_treep); node; node = rb_next(node)) { -+ struct stable_node *stable_node; -+ -+ stable_node = rb_entry(node, struct stable_node, node); -+ if (stable_node->kpfn >= start_pfn && -+ stable_node->kpfn < end_pfn) -+ return stable_node; -+ } -+ return NULL; -+} -+ -+static int uksm_memory_callback(struct notifier_block *self, -+ unsigned long action, void *arg) -+{ -+ struct memory_notify *mn = arg; -+ struct stable_node *stable_node; -+ -+ switch (action) { -+ case MEM_GOING_OFFLINE: -+ /* -+ * Keep it very simple for now: just lock out ksmd and -+ * MADV_UNMERGEABLE while any memory is going offline. -+ * mutex_lock_nested() is necessary because lockdep was alarmed -+ * that here we take uksm_thread_mutex inside notifier chain -+ * mutex, and later take notifier chain mutex inside -+ * uksm_thread_mutex to unlock it. But that's safe because both -+ * are inside mem_hotplug_mutex. -+ */ -+ mutex_lock_nested(&uksm_thread_mutex, SINGLE_DEPTH_NESTING); -+ break; -+ -+ case MEM_OFFLINE: -+ /* -+ * Most of the work is done by page migration; but there might -+ * be a few stable_nodes left over, still pointing to struct -+ * pages which have been offlined: prune those from the tree. -+ */ -+ while ((stable_node = uksm_check_stable_tree(mn->start_pfn, -+ mn->start_pfn + mn->nr_pages)) != NULL) -+ remove_node_from_stable_tree(stable_node, 1, 1); -+ /* fallthrough */ -+ -+ case MEM_CANCEL_OFFLINE: -+ mutex_unlock(&uksm_thread_mutex); -+ break; -+ } -+ return NOTIFY_OK; -+} -+#endif /* CONFIG_MEMORY_HOTREMOVE */ -+ -+#ifdef CONFIG_SYSFS -+/* -+ * This all compiles without CONFIG_SYSFS, but is a waste of space. -+ */ -+ -+#define UKSM_ATTR_RO(_name) \ -+ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) -+#define UKSM_ATTR(_name) \ -+ static struct kobj_attribute _name##_attr = \ -+ __ATTR(_name, 0644, _name##_show, _name##_store) -+ -+static ssize_t max_cpu_percentage_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%u\n", uksm_max_cpu_percentage); -+} -+ -+static ssize_t max_cpu_percentage_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ unsigned long max_cpu_percentage; -+ int err; -+ -+ err = kstrtoul(buf, 10, &max_cpu_percentage); -+ if (err || max_cpu_percentage > 100) -+ return -EINVAL; -+ -+ if (max_cpu_percentage == 100) -+ max_cpu_percentage = 99; -+ else if (max_cpu_percentage < 10) -+ max_cpu_percentage = 10; -+ -+ uksm_max_cpu_percentage = max_cpu_percentage; -+ -+ return count; -+} -+UKSM_ATTR(max_cpu_percentage); -+ -+static ssize_t sleep_millisecs_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%u\n", jiffies_to_msecs(uksm_sleep_jiffies)); -+} -+ -+static ssize_t sleep_millisecs_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ unsigned long msecs; -+ int err; -+ -+ err = kstrtoul(buf, 10, &msecs); -+ if (err || msecs > MSEC_PER_SEC) -+ return -EINVAL; -+ -+ uksm_sleep_jiffies = msecs_to_jiffies(msecs); -+ uksm_sleep_saved = uksm_sleep_jiffies; -+ -+ return count; -+} -+UKSM_ATTR(sleep_millisecs); -+ -+ -+static ssize_t cpu_governor_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); -+ int i; -+ -+ buf[0] = '\0'; -+ for (i = 0; i < n ; i++) { -+ if (uksm_cpu_governor == i) -+ strcat(buf, "["); -+ -+ strcat(buf, uksm_cpu_governor_str[i]); -+ -+ if (uksm_cpu_governor == i) -+ strcat(buf, "]"); -+ -+ strcat(buf, " "); -+ } -+ strcat(buf, "\n"); -+ -+ return strlen(buf); -+} -+ -+static inline void init_performance_values(void) -+{ -+ int i; -+ struct scan_rung *rung; -+ struct uksm_cpu_preset_s *preset = uksm_cpu_preset + uksm_cpu_governor; -+ -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = uksm_scan_ladder + i; -+ rung->cpu_ratio = preset->cpu_ratio[i]; -+ rung->cover_msecs = preset->cover_msecs[i]; -+ } -+ -+ uksm_max_cpu_percentage = preset->max_cpu; -+} -+ -+static ssize_t cpu_governor_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); -+ -+ for (n--; n >= 0 ; n--) { -+ if (!strncmp(buf, uksm_cpu_governor_str[n], -+ strlen(uksm_cpu_governor_str[n]))) -+ break; -+ } -+ -+ if (n < 0) -+ return -EINVAL; -+ else -+ uksm_cpu_governor = n; -+ -+ init_performance_values(); -+ -+ return count; -+} -+UKSM_ATTR(cpu_governor); -+ -+static ssize_t run_show(struct kobject *kobj, struct kobj_attribute *attr, -+ char *buf) -+{ -+ return sprintf(buf, "%u\n", uksm_run); -+} -+ -+static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int err; -+ unsigned long flags; -+ -+ err = kstrtoul(buf, 10, &flags); -+ if (err || flags > UINT_MAX) -+ return -EINVAL; -+ if (flags > UKSM_RUN_MERGE) -+ return -EINVAL; -+ -+ mutex_lock(&uksm_thread_mutex); -+ if (uksm_run != flags) -+ uksm_run = flags; -+ mutex_unlock(&uksm_thread_mutex); -+ -+ if (flags & UKSM_RUN_MERGE) -+ wake_up_interruptible(&uksm_thread_wait); -+ -+ return count; -+} -+UKSM_ATTR(run); -+ -+static ssize_t abundant_threshold_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%u\n", uksm_abundant_threshold); -+} -+ -+static ssize_t abundant_threshold_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int err; -+ unsigned long flags; -+ -+ err = kstrtoul(buf, 10, &flags); -+ if (err || flags > 99) -+ return -EINVAL; -+ -+ uksm_abundant_threshold = flags; -+ -+ return count; -+} -+UKSM_ATTR(abundant_threshold); -+ -+static ssize_t thrash_threshold_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%u\n", uksm_thrash_threshold); -+} -+ -+static ssize_t thrash_threshold_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int err; -+ unsigned long flags; -+ -+ err = kstrtoul(buf, 10, &flags); -+ if (err || flags > 99) -+ return -EINVAL; -+ -+ uksm_thrash_threshold = flags; -+ -+ return count; -+} -+UKSM_ATTR(thrash_threshold); -+ -+static ssize_t cpu_ratios_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ int i, size; -+ struct scan_rung *rung; -+ char *p = buf; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = &uksm_scan_ladder[i]; -+ -+ if (rung->cpu_ratio > 0) -+ size = sprintf(p, "%d ", rung->cpu_ratio); -+ else -+ size = sprintf(p, "MAX/%d ", -+ TIME_RATIO_SCALE / -rung->cpu_ratio); -+ -+ p += size; -+ } -+ -+ *p++ = '\n'; -+ *p = '\0'; -+ -+ return p - buf; -+} -+ -+static ssize_t cpu_ratios_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int i, cpuratios[SCAN_LADDER_SIZE], err; -+ unsigned long value; -+ struct scan_rung *rung; -+ char *p, *end = NULL; -+ -+ p = kzalloc(count, GFP_KERNEL); -+ if (!p) -+ return -ENOMEM; -+ -+ memcpy(p, buf, count); -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ if (i != SCAN_LADDER_SIZE - 1) { -+ end = strchr(p, ' '); -+ if (!end) -+ return -EINVAL; -+ -+ *end = '\0'; -+ } -+ -+ if (strstr(p, "MAX/")) { -+ p = strchr(p, '/') + 1; -+ err = kstrtoul(p, 10, &value); -+ if (err || value > TIME_RATIO_SCALE || !value) -+ return -EINVAL; -+ -+ cpuratios[i] = -(int) (TIME_RATIO_SCALE / value); -+ } else { -+ err = kstrtoul(p, 10, &value); -+ if (err || value > TIME_RATIO_SCALE || !value) -+ return -EINVAL; -+ -+ cpuratios[i] = value; -+ } -+ -+ p = end + 1; -+ } -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = &uksm_scan_ladder[i]; -+ -+ rung->cpu_ratio = cpuratios[i]; -+ } -+ -+ return count; -+} -+UKSM_ATTR(cpu_ratios); -+ -+static ssize_t eval_intervals_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ int i, size; -+ struct scan_rung *rung; -+ char *p = buf; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = &uksm_scan_ladder[i]; -+ size = sprintf(p, "%u ", rung->cover_msecs); -+ p += size; -+ } -+ -+ *p++ = '\n'; -+ *p = '\0'; -+ -+ return p - buf; -+} -+ -+static ssize_t eval_intervals_store(struct kobject *kobj, -+ struct kobj_attribute *attr, -+ const char *buf, size_t count) -+{ -+ int i, err; -+ unsigned long values[SCAN_LADDER_SIZE]; -+ struct scan_rung *rung; -+ char *p, *end = NULL; -+ ssize_t ret = count; -+ -+ p = kzalloc(count + 2, GFP_KERNEL); -+ if (!p) -+ return -ENOMEM; -+ -+ memcpy(p, buf, count); -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ if (i != SCAN_LADDER_SIZE - 1) { -+ end = strchr(p, ' '); -+ if (!end) { -+ ret = -EINVAL; -+ goto out; -+ } -+ -+ *end = '\0'; -+ } -+ -+ err = kstrtoul(p, 10, &values[i]); -+ if (err) { -+ ret = -EINVAL; -+ goto out; -+ } -+ -+ p = end + 1; -+ } -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = &uksm_scan_ladder[i]; -+ -+ rung->cover_msecs = values[i]; -+ } -+ -+out: -+ kfree(p); -+ return ret; -+} -+UKSM_ATTR(eval_intervals); -+ -+static ssize_t ema_per_page_time_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", uksm_ema_page_time); -+} -+UKSM_ATTR_RO(ema_per_page_time); -+ -+static ssize_t pages_shared_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", uksm_pages_shared); -+} -+UKSM_ATTR_RO(pages_shared); -+ -+static ssize_t pages_sharing_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", uksm_pages_sharing); -+} -+UKSM_ATTR_RO(pages_sharing); -+ -+static ssize_t pages_unshared_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", uksm_pages_unshared); -+} -+UKSM_ATTR_RO(pages_unshared); -+ -+static ssize_t full_scans_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%llu\n", fully_scanned_round); -+} -+UKSM_ATTR_RO(full_scans); -+ -+static ssize_t pages_scanned_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ unsigned long base = 0; -+ u64 delta, ret; -+ -+ if (pages_scanned_stored) { -+ base = pages_scanned_base; -+ ret = pages_scanned_stored; -+ delta = uksm_pages_scanned >> base; -+ if (CAN_OVERFLOW_U64(ret, delta)) { -+ ret >>= 1; -+ delta >>= 1; -+ base++; -+ ret += delta; -+ } -+ } else { -+ ret = uksm_pages_scanned; -+ } -+ -+ while (ret > ULONG_MAX) { -+ ret >>= 1; -+ base++; -+ } -+ -+ if (base) -+ return sprintf(buf, "%lu * 2^%lu\n", (unsigned long)ret, base); -+ else -+ return sprintf(buf, "%lu\n", (unsigned long)ret); -+} -+UKSM_ATTR_RO(pages_scanned); -+ -+static ssize_t hash_strength_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%lu\n", hash_strength); -+} -+UKSM_ATTR_RO(hash_strength); -+ -+static ssize_t sleep_times_show(struct kobject *kobj, -+ struct kobj_attribute *attr, char *buf) -+{ -+ return sprintf(buf, "%llu\n", uksm_sleep_times); -+} -+UKSM_ATTR_RO(sleep_times); -+ -+ -+static struct attribute *uksm_attrs[] = { -+ &max_cpu_percentage_attr.attr, -+ &sleep_millisecs_attr.attr, -+ &cpu_governor_attr.attr, -+ &run_attr.attr, -+ &ema_per_page_time_attr.attr, -+ &pages_shared_attr.attr, -+ &pages_sharing_attr.attr, -+ &pages_unshared_attr.attr, -+ &full_scans_attr.attr, -+ &pages_scanned_attr.attr, -+ &hash_strength_attr.attr, -+ &sleep_times_attr.attr, -+ &thrash_threshold_attr.attr, -+ &abundant_threshold_attr.attr, -+ &cpu_ratios_attr.attr, -+ &eval_intervals_attr.attr, -+ NULL, -+}; -+ -+static struct attribute_group uksm_attr_group = { -+ .attrs = uksm_attrs, -+ .name = "uksm", -+}; -+#endif /* CONFIG_SYSFS */ -+ -+static inline void init_scan_ladder(void) -+{ -+ int i; -+ struct scan_rung *rung; -+ -+ for (i = 0; i < SCAN_LADDER_SIZE; i++) { -+ rung = uksm_scan_ladder + i; -+ slot_tree_init_root(&rung->vma_root); -+ } -+ -+ init_performance_values(); -+ uksm_calc_scan_pages(); -+} -+ -+static inline int cal_positive_negative_costs(void) -+{ -+ struct page *p1, *p2; -+ unsigned char *addr1, *addr2; -+ unsigned long i, time_start, hash_cost; -+ unsigned long loopnum = 0; -+ -+ /*IMPORTANT: volatile is needed to prevent over-optimization by gcc. */ -+ volatile u32 hash; -+ volatile int ret; -+ -+ p1 = alloc_page(GFP_KERNEL); -+ if (!p1) -+ return -ENOMEM; -+ -+ p2 = alloc_page(GFP_KERNEL); -+ if (!p2) -+ return -ENOMEM; -+ -+ addr1 = kmap_atomic(p1); -+ addr2 = kmap_atomic(p2); -+ memset(addr1, prandom_u32(), PAGE_SIZE); -+ memcpy(addr2, addr1, PAGE_SIZE); -+ -+ /* make sure that the two pages differ in last byte */ -+ addr2[PAGE_SIZE-1] = ~addr2[PAGE_SIZE-1]; -+ kunmap_atomic(addr2); -+ kunmap_atomic(addr1); -+ -+ time_start = jiffies; -+ while (jiffies - time_start < 100) { -+ for (i = 0; i < 100; i++) -+ hash = page_hash(p1, HASH_STRENGTH_FULL, 0); -+ loopnum += 100; -+ } -+ hash_cost = (jiffies - time_start); -+ -+ time_start = jiffies; -+ for (i = 0; i < loopnum; i++) -+ ret = pages_identical(p1, p2); -+ memcmp_cost = HASH_STRENGTH_FULL * (jiffies - time_start); -+ memcmp_cost /= hash_cost; -+ pr_info("UKSM: relative memcmp_cost = %lu " -+ "hash=%u cmp_ret=%d.\n", -+ memcmp_cost, hash, ret); -+ -+ __free_page(p1); -+ __free_page(p2); -+ return 0; -+} -+ -+static int init_zeropage_hash_table(void) -+{ -+ struct page *page; -+ char *addr; -+ int i; -+ -+ page = alloc_page(GFP_KERNEL); -+ if (!page) -+ return -ENOMEM; -+ -+ addr = kmap_atomic(page); -+ memset(addr, 0, PAGE_SIZE); -+ kunmap_atomic(addr); -+ -+ zero_hash_table = kmalloc_array(HASH_STRENGTH_MAX, sizeof(u32), -+ GFP_KERNEL); -+ if (!zero_hash_table) -+ return -ENOMEM; -+ -+ for (i = 0; i < HASH_STRENGTH_MAX; i++) -+ zero_hash_table[i] = page_hash(page, i, 0); -+ -+ __free_page(page); -+ -+ return 0; -+} -+ -+static inline int init_random_sampling(void) -+{ -+ unsigned long i; -+ -+ random_nums = kmalloc(PAGE_SIZE, GFP_KERNEL); -+ if (!random_nums) -+ return -ENOMEM; -+ -+ for (i = 0; i < HASH_STRENGTH_FULL; i++) -+ random_nums[i] = i; -+ -+ for (i = 0; i < HASH_STRENGTH_FULL; i++) { -+ unsigned long rand_range, swap_index, tmp; -+ -+ rand_range = HASH_STRENGTH_FULL - i; -+ swap_index = i + prandom_u32() % rand_range; -+ tmp = random_nums[i]; -+ random_nums[i] = random_nums[swap_index]; -+ random_nums[swap_index] = tmp; -+ } -+ -+ rshash_state.state = RSHASH_NEW; -+ rshash_state.below_count = 0; -+ rshash_state.lookup_window_index = 0; -+ -+ return cal_positive_negative_costs(); -+} -+ -+static int __init uksm_slab_init(void) -+{ -+ rmap_item_cache = UKSM_KMEM_CACHE(rmap_item, 0); -+ if (!rmap_item_cache) -+ goto out; -+ -+ stable_node_cache = UKSM_KMEM_CACHE(stable_node, 0); -+ if (!stable_node_cache) -+ goto out_free1; -+ -+ node_vma_cache = UKSM_KMEM_CACHE(node_vma, 0); -+ if (!node_vma_cache) -+ goto out_free2; -+ -+ vma_slot_cache = UKSM_KMEM_CACHE(vma_slot, 0); -+ if (!vma_slot_cache) -+ goto out_free3; -+ -+ tree_node_cache = UKSM_KMEM_CACHE(tree_node, 0); -+ if (!tree_node_cache) -+ goto out_free4; -+ -+ return 0; -+ -+out_free4: -+ kmem_cache_destroy(vma_slot_cache); -+out_free3: -+ kmem_cache_destroy(node_vma_cache); -+out_free2: -+ kmem_cache_destroy(stable_node_cache); -+out_free1: -+ kmem_cache_destroy(rmap_item_cache); -+out: -+ return -ENOMEM; -+} -+ -+static void __init uksm_slab_free(void) -+{ -+ kmem_cache_destroy(stable_node_cache); -+ kmem_cache_destroy(rmap_item_cache); -+ kmem_cache_destroy(node_vma_cache); -+ kmem_cache_destroy(vma_slot_cache); -+ kmem_cache_destroy(tree_node_cache); -+} -+ -+/* Common interface to ksm, different to it. */ -+int ksm_madvise(struct vm_area_struct *vma, unsigned long start, -+ unsigned long end, int advice, unsigned long *vm_flags) -+{ -+ int err; -+ -+ switch (advice) { -+ case MADV_MERGEABLE: -+ return 0; /* just ignore the advice */ -+ -+ case MADV_UNMERGEABLE: -+ if (!(*vm_flags & VM_MERGEABLE) || !uksm_flags_can_scan(*vm_flags)) -+ return 0; /* just ignore the advice */ -+ -+ if (vma->anon_vma) { -+ err = unmerge_uksm_pages(vma, start, end); -+ if (err) -+ return err; -+ } -+ -+ uksm_remove_vma(vma); -+ *vm_flags &= ~VM_MERGEABLE; -+ break; -+ } -+ -+ return 0; -+} -+ -+/* Common interface to ksm, actually the same. */ -+struct page *ksm_might_need_to_copy(struct page *page, -+ struct vm_area_struct *vma, unsigned long address) -+{ -+ struct anon_vma *anon_vma = page_anon_vma(page); -+ struct page *new_page; -+ -+ if (PageKsm(page)) { -+ if (page_stable_node(page)) -+ return page; /* no need to copy it */ -+ } else if (!anon_vma) { -+ return page; /* no need to copy it */ -+ } else if (anon_vma->root == vma->anon_vma->root && -+ page->index == linear_page_index(vma, address)) { -+ return page; /* still no need to copy it */ -+ } -+ if (!PageUptodate(page)) -+ return page; /* let do_swap_page report the error */ -+ -+ new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); -+ if (new_page) { -+ copy_user_highpage(new_page, page, address, vma); -+ -+ SetPageDirty(new_page); -+ __SetPageUptodate(new_page); -+ __SetPageLocked(new_page); -+ } -+ -+ return new_page; -+} -+ -+static int __init uksm_init(void) -+{ -+ struct task_struct *uksm_thread; -+ int err; -+ -+ uksm_sleep_jiffies = msecs_to_jiffies(100); -+ uksm_sleep_saved = uksm_sleep_jiffies; -+ -+ slot_tree_init(); -+ init_scan_ladder(); -+ -+ -+ err = init_random_sampling(); -+ if (err) -+ goto out_free2; -+ -+ err = uksm_slab_init(); -+ if (err) -+ goto out_free1; -+ -+ err = init_zeropage_hash_table(); -+ if (err) -+ goto out_free0; -+ -+ uksm_thread = kthread_run(uksm_scan_thread, NULL, "uksmd"); -+ if (IS_ERR(uksm_thread)) { -+ pr_err("uksm: creating kthread failed\n"); -+ err = PTR_ERR(uksm_thread); -+ goto out_free; -+ } -+ -+#ifdef CONFIG_SYSFS -+ err = sysfs_create_group(mm_kobj, &uksm_attr_group); -+ if (err) { -+ pr_err("uksm: register sysfs failed\n"); -+ kthread_stop(uksm_thread); -+ goto out_free; -+ } -+#else -+ uksm_run = UKSM_RUN_MERGE; /* no way for user to start it */ -+ -+#endif /* CONFIG_SYSFS */ -+ -+#ifdef CONFIG_MEMORY_HOTREMOVE -+ /* -+ * Choose a high priority since the callback takes uksm_thread_mutex: -+ * later callbacks could only be taking locks which nest within that. -+ */ -+ hotplug_memory_notifier(uksm_memory_callback, 100); -+#endif -+ return 0; -+ -+out_free: -+ kfree(zero_hash_table); -+out_free0: -+ uksm_slab_free(); -+out_free1: -+ kfree(random_nums); -+out_free2: -+ kfree(uksm_scan_ladder); -+ return err; -+} -+ -+#ifdef MODULE -+subsys_initcall(ksm_init); -+#else -+late_initcall(uksm_init); -+#endif -+ -diff -Nur a/mm/vmstat.c b/mm/vmstat.c ---- a/mm/vmstat.c 2019-06-25 04:34:56.000000000 +0100 -+++ b/mm/vmstat.c 2019-07-07 09:32:50.461840572 +0100 -@@ -1165,6 +1165,9 @@ - "nr_written", - "nr_kernel_misc_reclaimable", - -+#ifdef CONFIG_UKSM -+ "nr_uksm_zero_pages", -+#endif - /* enum writeback_stat_item counters */ - "nr_dirty_threshold", - "nr_dirty_background_threshold", diff --git a/sys-kernel/linux-sources-redcore/linux-sources-redcore-5.1.15.ebuild b/sys-kernel/linux-sources-redcore/linux-sources-redcore-5.1.15.ebuild index 585459a0..3d644b85 100644 --- a/sys-kernel/linux-sources-redcore/linux-sources-redcore-5.1.15.ebuild +++ b/sys-kernel/linux-sources-redcore/linux-sources-redcore-5.1.15.ebuild @@ -36,7 +36,8 @@ PATCHES=( "${FILESDIR}"/"${KV_MAJOR}"-fix-acpi_dbg_level.patch "${FILESDIR}"/"${KV_MAJOR}"-radeon_dp_aux_transfer_native-no-ratelimited_debug.patch "${FILESDIR}"/"${KV_MAJOR}"-Unknow-SSD-HFM128GDHTNG-8310B-QUIRK_NO_APST.patch - "${FILESDIR}"/"${KV_MAJOR}"-linux-hardened.patch + "${FILESDIR}"/"${KV_MAJOR}"-0001-uksm-initial-submission-linux-hardened.patch + "${FILESDIR}"/"${KV_MAJOR}"-0001-uksm-apply-52d1e606ee733.patch "${FILESDIR}"/"${KV_MAJOR}"-uksm-linux-hardened.patch "${FILESDIR}"/"${KV_MAJOR}"-0001-MultiQueue-Skiplist-Scheduler-version-0.192-linux-hardened.patch "${FILESDIR}"/"${KV_MAJOR}"-0002-Fix-Werror-build-failure-in-tools.patch -- cgit v1.2.3