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1da177e4 LT |
1 | #ifndef _LINUX_RMAP_H |
2 | #define _LINUX_RMAP_H | |
3 | /* | |
4 | * Declarations for Reverse Mapping functions in mm/rmap.c | |
5 | */ | |
6 | ||
1da177e4 LT |
7 | #include <linux/list.h> |
8 | #include <linux/slab.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/spinlock.h> | |
bed7161a | 11 | #include <linux/memcontrol.h> |
1da177e4 LT |
12 | |
13 | /* | |
14 | * The anon_vma heads a list of private "related" vmas, to scan if | |
15 | * an anonymous page pointing to this anon_vma needs to be unmapped: | |
16 | * the vmas on the list will be related by forking, or by splitting. | |
17 | * | |
18 | * Since vmas come and go as they are split and merged (particularly | |
19 | * in mprotect), the mapping field of an anonymous page cannot point | |
20 | * directly to a vma: instead it points to an anon_vma, on whose list | |
21 | * the related vmas can be easily linked or unlinked. | |
22 | * | |
23 | * After unlinking the last vma on the list, we must garbage collect | |
24 | * the anon_vma object itself: we're guaranteed no page can be | |
25 | * pointing to this anon_vma once its vma list is empty. | |
26 | */ | |
27 | struct anon_vma { | |
28 | spinlock_t lock; /* Serialize access to vma list */ | |
db114b83 HD |
29 | #ifdef CONFIG_KSM |
30 | atomic_t ksm_refcount; | |
31 | #endif | |
7906d00c AA |
32 | /* |
33 | * NOTE: the LSB of the head.next is set by | |
34 | * mm_take_all_locks() _after_ taking the above lock. So the | |
35 | * head must only be read/written after taking the above lock | |
36 | * to be sure to see a valid next pointer. The LSB bit itself | |
37 | * is serialized by a system wide lock only visible to | |
38 | * mm_take_all_locks() (mm_all_locks_mutex). | |
39 | */ | |
5beb4930 RR |
40 | struct list_head head; /* Chain of private "related" vmas */ |
41 | }; | |
42 | ||
43 | /* | |
44 | * The copy-on-write semantics of fork mean that an anon_vma | |
45 | * can become associated with multiple processes. Furthermore, | |
46 | * each child process will have its own anon_vma, where new | |
47 | * pages for that process are instantiated. | |
48 | * | |
49 | * This structure allows us to find the anon_vmas associated | |
50 | * with a VMA, or the VMAs associated with an anon_vma. | |
51 | * The "same_vma" list contains the anon_vma_chains linking | |
52 | * all the anon_vmas associated with this VMA. | |
53 | * The "same_anon_vma" list contains the anon_vma_chains | |
54 | * which link all the VMAs associated with this anon_vma. | |
55 | */ | |
56 | struct anon_vma_chain { | |
57 | struct vm_area_struct *vma; | |
58 | struct anon_vma *anon_vma; | |
59 | struct list_head same_vma; /* locked by mmap_sem & page_table_lock */ | |
60 | struct list_head same_anon_vma; /* locked by anon_vma->lock */ | |
1da177e4 LT |
61 | }; |
62 | ||
63 | #ifdef CONFIG_MMU | |
db114b83 HD |
64 | #ifdef CONFIG_KSM |
65 | static inline void ksm_refcount_init(struct anon_vma *anon_vma) | |
66 | { | |
67 | atomic_set(&anon_vma->ksm_refcount, 0); | |
68 | } | |
69 | ||
70 | static inline int ksm_refcount(struct anon_vma *anon_vma) | |
71 | { | |
72 | return atomic_read(&anon_vma->ksm_refcount); | |
73 | } | |
74 | #else | |
75 | static inline void ksm_refcount_init(struct anon_vma *anon_vma) | |
76 | { | |
77 | } | |
78 | ||
79 | static inline int ksm_refcount(struct anon_vma *anon_vma) | |
80 | { | |
81 | return 0; | |
82 | } | |
83 | #endif /* CONFIG_KSM */ | |
1da177e4 | 84 | |
3ca7b3c5 HD |
85 | static inline struct anon_vma *page_anon_vma(struct page *page) |
86 | { | |
87 | if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != | |
88 | PAGE_MAPPING_ANON) | |
89 | return NULL; | |
90 | return page_rmapping(page); | |
91 | } | |
92 | ||
1da177e4 LT |
93 | static inline void anon_vma_lock(struct vm_area_struct *vma) |
94 | { | |
95 | struct anon_vma *anon_vma = vma->anon_vma; | |
96 | if (anon_vma) | |
97 | spin_lock(&anon_vma->lock); | |
98 | } | |
99 | ||
100 | static inline void anon_vma_unlock(struct vm_area_struct *vma) | |
101 | { | |
102 | struct anon_vma *anon_vma = vma->anon_vma; | |
103 | if (anon_vma) | |
104 | spin_unlock(&anon_vma->lock); | |
105 | } | |
106 | ||
107 | /* | |
108 | * anon_vma helper functions. | |
109 | */ | |
110 | void anon_vma_init(void); /* create anon_vma_cachep */ | |
111 | int anon_vma_prepare(struct vm_area_struct *); | |
5beb4930 RR |
112 | void unlink_anon_vmas(struct vm_area_struct *); |
113 | int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *); | |
114 | int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *); | |
1da177e4 | 115 | void __anon_vma_link(struct vm_area_struct *); |
db114b83 | 116 | void anon_vma_free(struct anon_vma *); |
1da177e4 | 117 | |
5beb4930 RR |
118 | static inline void anon_vma_merge(struct vm_area_struct *vma, |
119 | struct vm_area_struct *next) | |
120 | { | |
121 | VM_BUG_ON(vma->anon_vma != next->anon_vma); | |
122 | unlink_anon_vmas(next); | |
123 | } | |
124 | ||
1da177e4 LT |
125 | /* |
126 | * rmap interfaces called when adding or removing pte of page | |
127 | */ | |
c44b6743 | 128 | void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
1da177e4 | 129 | void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
9617d95e | 130 | void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
1da177e4 | 131 | void page_add_file_rmap(struct page *); |
edc315fd | 132 | void page_remove_rmap(struct page *); |
1da177e4 | 133 | |
21333b2b | 134 | static inline void page_dup_rmap(struct page *page) |
1da177e4 LT |
135 | { |
136 | atomic_inc(&page->_mapcount); | |
137 | } | |
138 | ||
139 | /* | |
140 | * Called from mm/vmscan.c to handle paging out | |
141 | */ | |
6fe6b7e3 WF |
142 | int page_referenced(struct page *, int is_locked, |
143 | struct mem_cgroup *cnt, unsigned long *vm_flags); | |
5ad64688 HD |
144 | int page_referenced_one(struct page *, struct vm_area_struct *, |
145 | unsigned long address, unsigned int *mapcount, unsigned long *vm_flags); | |
146 | ||
14fa31b8 AK |
147 | enum ttu_flags { |
148 | TTU_UNMAP = 0, /* unmap mode */ | |
149 | TTU_MIGRATION = 1, /* migration mode */ | |
150 | TTU_MUNLOCK = 2, /* munlock mode */ | |
151 | TTU_ACTION_MASK = 0xff, | |
152 | ||
153 | TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */ | |
154 | TTU_IGNORE_ACCESS = (1 << 9), /* don't age */ | |
888b9f7c | 155 | TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */ |
14fa31b8 AK |
156 | }; |
157 | #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK) | |
158 | ||
159 | int try_to_unmap(struct page *, enum ttu_flags flags); | |
5ad64688 HD |
160 | int try_to_unmap_one(struct page *, struct vm_area_struct *, |
161 | unsigned long address, enum ttu_flags flags); | |
1da177e4 | 162 | |
ceffc078 CO |
163 | /* |
164 | * Called from mm/filemap_xip.c to unmap empty zero page | |
165 | */ | |
c0718806 | 166 | pte_t *page_check_address(struct page *, struct mm_struct *, |
479db0bf | 167 | unsigned long, spinlock_t **, int); |
ceffc078 | 168 | |
1da177e4 LT |
169 | /* |
170 | * Used by swapoff to help locate where page is expected in vma. | |
171 | */ | |
172 | unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); | |
173 | ||
d08b3851 PZ |
174 | /* |
175 | * Cleans the PTEs of shared mappings. | |
176 | * (and since clean PTEs should also be readonly, write protects them too) | |
177 | * | |
178 | * returns the number of cleaned PTEs. | |
179 | */ | |
180 | int page_mkclean(struct page *); | |
181 | ||
b291f000 NP |
182 | /* |
183 | * called in munlock()/munmap() path to check for other vmas holding | |
184 | * the page mlocked. | |
185 | */ | |
186 | int try_to_munlock(struct page *); | |
b291f000 | 187 | |
10be22df AK |
188 | /* |
189 | * Called by memory-failure.c to kill processes. | |
190 | */ | |
191 | struct anon_vma *page_lock_anon_vma(struct page *page); | |
192 | void page_unlock_anon_vma(struct anon_vma *anon_vma); | |
6a46079c | 193 | int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma); |
10be22df | 194 | |
e9995ef9 HD |
195 | /* |
196 | * Called by migrate.c to remove migration ptes, but might be used more later. | |
197 | */ | |
198 | int rmap_walk(struct page *page, int (*rmap_one)(struct page *, | |
199 | struct vm_area_struct *, unsigned long, void *), void *arg); | |
200 | ||
1da177e4 LT |
201 | #else /* !CONFIG_MMU */ |
202 | ||
203 | #define anon_vma_init() do {} while (0) | |
204 | #define anon_vma_prepare(vma) (0) | |
205 | #define anon_vma_link(vma) do {} while (0) | |
206 | ||
01ff53f4 MF |
207 | static inline int page_referenced(struct page *page, int is_locked, |
208 | struct mem_cgroup *cnt, | |
209 | unsigned long *vm_flags) | |
210 | { | |
211 | *vm_flags = 0; | |
64574746 | 212 | return 0; |
01ff53f4 MF |
213 | } |
214 | ||
a48d07af | 215 | #define try_to_unmap(page, refs) SWAP_FAIL |
1da177e4 | 216 | |
d08b3851 PZ |
217 | static inline int page_mkclean(struct page *page) |
218 | { | |
219 | return 0; | |
220 | } | |
221 | ||
222 | ||
1da177e4 LT |
223 | #endif /* CONFIG_MMU */ |
224 | ||
225 | /* | |
226 | * Return values of try_to_unmap | |
227 | */ | |
228 | #define SWAP_SUCCESS 0 | |
229 | #define SWAP_AGAIN 1 | |
230 | #define SWAP_FAIL 2 | |
b291f000 | 231 | #define SWAP_MLOCK 3 |
1da177e4 LT |
232 | |
233 | #endif /* _LINUX_RMAP_H */ |