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); | |
24 | ||
f8af4da3 | 25 | int __ksm_enter(struct mm_struct *mm); |
1c2fb7a4 | 26 | void __ksm_exit(struct mm_struct *mm); |
f8af4da3 HD |
27 | |
28 | static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) | |
29 | { | |
d7597f59 SR |
30 | int ret; |
31 | ||
32 | if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) { | |
33 | ret = __ksm_enter(mm); | |
34 | if (ret) | |
35 | return ret; | |
36 | } | |
37 | ||
38 | if (test_bit(MMF_VM_MERGE_ANY, &oldmm->flags)) | |
39 | set_bit(MMF_VM_MERGE_ANY, &mm->flags); | |
40 | ||
f8af4da3 HD |
41 | return 0; |
42 | } | |
43 | ||
1c2fb7a4 | 44 | static inline void ksm_exit(struct mm_struct *mm) |
f8af4da3 HD |
45 | { |
46 | if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) | |
1c2fb7a4 | 47 | __ksm_exit(mm); |
f8af4da3 | 48 | } |
9a840895 | 49 | |
5ad64688 HD |
50 | /* |
51 | * When do_swap_page() first faults in from swap what used to be a KSM page, | |
52 | * no problem, it will be assigned to this vma's anon_vma; but thereafter, | |
53 | * it might be faulted into a different anon_vma (or perhaps to a different | |
54 | * offset in the same anon_vma). do_swap_page() cannot do all the locking | |
55 | * needed to reconstitute a cross-anon_vma KSM page: for now it has to make | |
56 | * a copy, and leave remerging the pages to a later pass of ksmd. | |
57 | * | |
58 | * We'd like to make this conditional on vma->vm_flags & VM_MERGEABLE, | |
59 | * but what if the vma was unmerged while the page was swapped out? | |
60 | */ | |
cbf86cfe HD |
61 | struct page *ksm_might_need_to_copy(struct page *page, |
62 | struct vm_area_struct *vma, unsigned long address); | |
5ad64688 | 63 | |
6d4675e6 | 64 | void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc); |
19138349 | 65 | void folio_migrate_ksm(struct folio *newfolio, struct folio *folio); |
5ad64688 | 66 | |
4248d008 LX |
67 | #ifdef CONFIG_MEMORY_FAILURE |
68 | void collect_procs_ksm(struct page *page, struct list_head *to_kill, | |
69 | int force_early); | |
70 | #endif | |
d21077fb SR |
71 | |
72 | #ifdef CONFIG_PROC_FS | |
73 | long ksm_process_profit(struct mm_struct *); | |
74 | #endif /* CONFIG_PROC_FS */ | |
75 | ||
f8af4da3 HD |
76 | #else /* !CONFIG_KSM */ |
77 | ||
d7597f59 SR |
78 | static inline void ksm_add_vma(struct vm_area_struct *vma) |
79 | { | |
80 | } | |
81 | ||
f8af4da3 HD |
82 | static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) |
83 | { | |
84 | return 0; | |
85 | } | |
86 | ||
1c2fb7a4 | 87 | static inline void ksm_exit(struct mm_struct *mm) |
f8af4da3 HD |
88 | { |
89 | } | |
9a840895 | 90 | |
4248d008 LX |
91 | #ifdef CONFIG_MEMORY_FAILURE |
92 | static inline void collect_procs_ksm(struct page *page, | |
93 | struct list_head *to_kill, int force_early) | |
94 | { | |
95 | } | |
96 | #endif | |
97 | ||
f42647ac HD |
98 | #ifdef CONFIG_MMU |
99 | static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start, | |
100 | unsigned long end, int advice, unsigned long *vm_flags) | |
101 | { | |
102 | return 0; | |
103 | } | |
104 | ||
cbf86cfe | 105 | static inline struct page *ksm_might_need_to_copy(struct page *page, |
5ad64688 HD |
106 | struct vm_area_struct *vma, unsigned long address) |
107 | { | |
cbf86cfe | 108 | return page; |
5ad64688 HD |
109 | } |
110 | ||
2f031c6f | 111 | static inline void rmap_walk_ksm(struct folio *folio, |
6d4675e6 | 112 | struct rmap_walk_control *rwc) |
e9995ef9 | 113 | { |
e9995ef9 HD |
114 | } |
115 | ||
19138349 | 116 | static inline void folio_migrate_ksm(struct folio *newfolio, struct folio *old) |
e9995ef9 HD |
117 | { |
118 | } | |
f42647ac | 119 | #endif /* CONFIG_MMU */ |
f8af4da3 HD |
120 | #endif /* !CONFIG_KSM */ |
121 | ||
5ad64688 | 122 | #endif /* __LINUX_KSM_H */ |