Commit | Line | Data |
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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
f8af4da3 HD |
2 | #ifndef __LINUX_KSM_H |
3 | #define __LINUX_KSM_H | |
4 | /* | |
5 | * Memory merging support. | |
6 | * | |
7 | * This code enables dynamic sharing of identical pages found in different | |
8 | * memory areas, even if they are not shared by fork(). | |
9 | */ | |
10 | ||
11 | #include <linux/bitops.h> | |
12 | #include <linux/mm.h> | |
5ad64688 HD |
13 | #include <linux/pagemap.h> |
14 | #include <linux/rmap.h> | |
f8af4da3 | 15 | #include <linux/sched.h> |
f7ccbae4 | 16 | #include <linux/sched/coredump.h> |
f8af4da3 HD |
17 | |
18 | #ifdef CONFIG_KSM | |
19 | int ksm_madvise(struct vm_area_struct *vma, unsigned long start, | |
20 | unsigned long end, int advice, unsigned long *vm_flags); | |
d7597f59 SR |
21 | |
22 | void ksm_add_vma(struct vm_area_struct *vma); | |
23 | int ksm_enable_merge_any(struct mm_struct *mm); | |
24139c07 | 24 | int ksm_disable_merge_any(struct mm_struct *mm); |
2c281f54 | 25 | int ksm_disable(struct mm_struct *mm); |
d7597f59 | 26 | |
f8af4da3 | 27 | int __ksm_enter(struct mm_struct *mm); |
1c2fb7a4 | 28 | void __ksm_exit(struct mm_struct *mm); |
79271476 | 29 | /* |
30 | * To identify zeropages that were mapped by KSM, we reuse the dirty bit | |
31 | * in the PTE. If the PTE is dirty, the zeropage was mapped by KSM when | |
32 | * deduplicating memory. | |
33 | */ | |
34 | #define is_ksm_zero_pte(pte) (is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte)) | |
f8af4da3 | 35 | |
c2dc78b8 CZ |
36 | extern atomic_long_t ksm_zero_pages; |
37 | ||
38 | static inline void ksm_map_zero_page(struct mm_struct *mm) | |
39 | { | |
40 | atomic_long_inc(&ksm_zero_pages); | |
41 | atomic_long_inc(&mm->ksm_zero_pages); | |
42 | } | |
e2942062 | 43 | |
6080d19f | 44 | static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte) |
e2942062 | 45 | { |
6080d19f | 46 | if (is_ksm_zero_pte(pte)) { |
c2dc78b8 CZ |
47 | atomic_long_dec(&ksm_zero_pages); |
48 | atomic_long_dec(&mm->ksm_zero_pages); | |
6080d19f | 49 | } |
e2942062 | 50 | } |
51 | ||
c2dc78b8 CZ |
52 | static inline long mm_ksm_zero_pages(struct mm_struct *mm) |
53 | { | |
54 | return atomic_long_read(&mm->ksm_zero_pages); | |
55 | } | |
56 | ||
f8af4da3 HD |
57 | static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) |
58 | { | |
7edea4c6 JT |
59 | if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) |
60 | return __ksm_enter(mm); | |
d7597f59 | 61 | |
f8af4da3 HD |
62 | return 0; |
63 | } | |
64 | ||
3a9e567c JT |
65 | static inline int ksm_execve(struct mm_struct *mm) |
66 | { | |
67 | if (test_bit(MMF_VM_MERGE_ANY, &mm->flags)) | |
68 | return __ksm_enter(mm); | |
69 | ||
70 | return 0; | |
71 | } | |
72 | ||
1c2fb7a4 | 73 | static inline void ksm_exit(struct mm_struct *mm) |
f8af4da3 HD |
74 | { |
75 | if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) | |
1c2fb7a4 | 76 | __ksm_exit(mm); |
f8af4da3 | 77 | } |
9a840895 | 78 | |
5ad64688 HD |
79 | /* |
80 | * When do_swap_page() first faults in from swap what used to be a KSM page, | |
81 | * no problem, it will be assigned to this vma's anon_vma; but thereafter, | |
82 | * it might be faulted into a different anon_vma (or perhaps to a different | |
83 | * offset in the same anon_vma). do_swap_page() cannot do all the locking | |
84 | * needed to reconstitute a cross-anon_vma KSM page: for now it has to make | |
85 | * a copy, and leave remerging the pages to a later pass of ksmd. | |
86 | * | |
87 | * We'd like to make this conditional on vma->vm_flags & VM_MERGEABLE, | |
88 | * but what if the vma was unmerged while the page was swapped out? | |
89 | */ | |
96db66d9 | 90 | struct folio *ksm_might_need_to_copy(struct folio *folio, |
1486fb50 | 91 | struct vm_area_struct *vma, unsigned long addr); |
5ad64688 | 92 | |
6d4675e6 | 93 | void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc); |
19138349 | 94 | void folio_migrate_ksm(struct folio *newfolio, struct folio *folio); |
b650e1d2 MWO |
95 | void collect_procs_ksm(struct folio *folio, struct page *page, |
96 | struct list_head *to_kill, int force_early); | |
d21077fb | 97 | long ksm_process_profit(struct mm_struct *); |
d21077fb | 98 | |
f8af4da3 HD |
99 | #else /* !CONFIG_KSM */ |
100 | ||
d7597f59 SR |
101 | static inline void ksm_add_vma(struct vm_area_struct *vma) |
102 | { | |
103 | } | |
104 | ||
2c281f54 DH |
105 | static inline int ksm_disable(struct mm_struct *mm) |
106 | { | |
107 | return 0; | |
108 | } | |
109 | ||
f8af4da3 HD |
110 | static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) |
111 | { | |
112 | return 0; | |
113 | } | |
114 | ||
3a9e567c JT |
115 | static inline int ksm_execve(struct mm_struct *mm) |
116 | { | |
117 | return 0; | |
118 | } | |
119 | ||
1c2fb7a4 | 120 | static inline void ksm_exit(struct mm_struct *mm) |
f8af4da3 HD |
121 | { |
122 | } | |
9a840895 | 123 | |
6080d19f | 124 | static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte) |
e2942062 | 125 | { |
126 | } | |
127 | ||
b650e1d2 | 128 | static inline void collect_procs_ksm(struct folio *folio, struct page *page, |
4248d008 LX |
129 | struct list_head *to_kill, int force_early) |
130 | { | |
131 | } | |
4248d008 | 132 | |
f42647ac HD |
133 | #ifdef CONFIG_MMU |
134 | static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start, | |
135 | unsigned long end, int advice, unsigned long *vm_flags) | |
136 | { | |
137 | return 0; | |
138 | } | |
139 | ||
96db66d9 | 140 | static inline struct folio *ksm_might_need_to_copy(struct folio *folio, |
1486fb50 | 141 | struct vm_area_struct *vma, unsigned long addr) |
5ad64688 | 142 | { |
96db66d9 | 143 | return folio; |
5ad64688 HD |
144 | } |
145 | ||
2f031c6f | 146 | static inline void rmap_walk_ksm(struct folio *folio, |
6d4675e6 | 147 | struct rmap_walk_control *rwc) |
e9995ef9 | 148 | { |
e9995ef9 HD |
149 | } |
150 | ||
19138349 | 151 | static inline void folio_migrate_ksm(struct folio *newfolio, struct folio *old) |
e9995ef9 HD |
152 | { |
153 | } | |
f42647ac | 154 | #endif /* CONFIG_MMU */ |
f8af4da3 HD |
155 | #endif /* !CONFIG_KSM */ |
156 | ||
5ad64688 | 157 | #endif /* __LINUX_KSM_H */ |