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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> | |
5a505085 | 10 | #include <linux/rwsem.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 { | |
5a505085 IM |
28 | struct anon_vma *root; /* Root of this anon_vma tree */ |
29 | struct rw_semaphore rwsem; /* W: modification, R: walking the list */ | |
7f60c214 | 30 | /* |
83813267 | 31 | * The refcount is taken on an anon_vma when there is no |
7f60c214 MG |
32 | * guarantee that the vma of page tables will exist for |
33 | * the duration of the operation. A caller that takes | |
34 | * the reference is responsible for clearing up the | |
35 | * anon_vma if they are the last user on release | |
36 | */ | |
83813267 PZ |
37 | atomic_t refcount; |
38 | ||
7906d00c | 39 | /* |
bf181b9f | 40 | * NOTE: the LSB of the rb_root.rb_node is set by |
7906d00c | 41 | * mm_take_all_locks() _after_ taking the above lock. So the |
bf181b9f | 42 | * rb_root must only be read/written after taking the above lock |
7906d00c AA |
43 | * to be sure to see a valid next pointer. The LSB bit itself |
44 | * is serialized by a system wide lock only visible to | |
45 | * mm_take_all_locks() (mm_all_locks_mutex). | |
46 | */ | |
bf181b9f | 47 | struct rb_root rb_root; /* Interval tree of private "related" vmas */ |
5beb4930 RR |
48 | }; |
49 | ||
50 | /* | |
51 | * The copy-on-write semantics of fork mean that an anon_vma | |
52 | * can become associated with multiple processes. Furthermore, | |
53 | * each child process will have its own anon_vma, where new | |
54 | * pages for that process are instantiated. | |
55 | * | |
56 | * This structure allows us to find the anon_vmas associated | |
57 | * with a VMA, or the VMAs associated with an anon_vma. | |
58 | * The "same_vma" list contains the anon_vma_chains linking | |
59 | * all the anon_vmas associated with this VMA. | |
bf181b9f | 60 | * The "rb" field indexes on an interval tree the anon_vma_chains |
5beb4930 RR |
61 | * which link all the VMAs associated with this anon_vma. |
62 | */ | |
63 | struct anon_vma_chain { | |
64 | struct vm_area_struct *vma; | |
65 | struct anon_vma *anon_vma; | |
66 | struct list_head same_vma; /* locked by mmap_sem & page_table_lock */ | |
5a505085 | 67 | struct rb_node rb; /* locked by anon_vma->rwsem */ |
bf181b9f | 68 | unsigned long rb_subtree_last; |
ed8ea815 ML |
69 | #ifdef CONFIG_DEBUG_VM_RB |
70 | unsigned long cached_vma_start, cached_vma_last; | |
71 | #endif | |
1da177e4 LT |
72 | }; |
73 | ||
02c6de8d MK |
74 | enum ttu_flags { |
75 | TTU_UNMAP = 0, /* unmap mode */ | |
76 | TTU_MIGRATION = 1, /* migration mode */ | |
77 | TTU_MUNLOCK = 2, /* munlock mode */ | |
78 | TTU_ACTION_MASK = 0xff, | |
79 | ||
80 | TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */ | |
81 | TTU_IGNORE_ACCESS = (1 << 9), /* don't age */ | |
82 | TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */ | |
83 | }; | |
84 | ||
1da177e4 | 85 | #ifdef CONFIG_MMU |
76545066 RR |
86 | static inline void get_anon_vma(struct anon_vma *anon_vma) |
87 | { | |
83813267 | 88 | atomic_inc(&anon_vma->refcount); |
76545066 RR |
89 | } |
90 | ||
01d8b20d PZ |
91 | void __put_anon_vma(struct anon_vma *anon_vma); |
92 | ||
93 | static inline void put_anon_vma(struct anon_vma *anon_vma) | |
94 | { | |
95 | if (atomic_dec_and_test(&anon_vma->refcount)) | |
96 | __put_anon_vma(anon_vma); | |
97 | } | |
1da177e4 | 98 | |
3ca7b3c5 HD |
99 | static inline struct anon_vma *page_anon_vma(struct page *page) |
100 | { | |
101 | if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != | |
102 | PAGE_MAPPING_ANON) | |
103 | return NULL; | |
104 | return page_rmapping(page); | |
105 | } | |
106 | ||
bb4a340e | 107 | static inline void vma_lock_anon_vma(struct vm_area_struct *vma) |
1da177e4 LT |
108 | { |
109 | struct anon_vma *anon_vma = vma->anon_vma; | |
110 | if (anon_vma) | |
5a505085 | 111 | down_write(&anon_vma->root->rwsem); |
1da177e4 LT |
112 | } |
113 | ||
bb4a340e | 114 | static inline void vma_unlock_anon_vma(struct vm_area_struct *vma) |
1da177e4 LT |
115 | { |
116 | struct anon_vma *anon_vma = vma->anon_vma; | |
117 | if (anon_vma) | |
5a505085 | 118 | up_write(&anon_vma->root->rwsem); |
1da177e4 LT |
119 | } |
120 | ||
4fc3f1d6 | 121 | static inline void anon_vma_lock_write(struct anon_vma *anon_vma) |
cba48b98 | 122 | { |
5a505085 | 123 | down_write(&anon_vma->root->rwsem); |
cba48b98 RR |
124 | } |
125 | ||
08b52706 | 126 | static inline void anon_vma_unlock_write(struct anon_vma *anon_vma) |
cba48b98 | 127 | { |
5a505085 | 128 | up_write(&anon_vma->root->rwsem); |
cba48b98 RR |
129 | } |
130 | ||
4fc3f1d6 IM |
131 | static inline void anon_vma_lock_read(struct anon_vma *anon_vma) |
132 | { | |
133 | down_read(&anon_vma->root->rwsem); | |
134 | } | |
135 | ||
136 | static inline void anon_vma_unlock_read(struct anon_vma *anon_vma) | |
137 | { | |
138 | up_read(&anon_vma->root->rwsem); | |
139 | } | |
140 | ||
141 | ||
1da177e4 LT |
142 | /* |
143 | * anon_vma helper functions. | |
144 | */ | |
145 | void anon_vma_init(void); /* create anon_vma_cachep */ | |
146 | int anon_vma_prepare(struct vm_area_struct *); | |
5beb4930 RR |
147 | void unlink_anon_vmas(struct vm_area_struct *); |
148 | int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *); | |
149 | int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *); | |
1da177e4 | 150 | |
5beb4930 RR |
151 | static inline void anon_vma_merge(struct vm_area_struct *vma, |
152 | struct vm_area_struct *next) | |
153 | { | |
154 | VM_BUG_ON(vma->anon_vma != next->anon_vma); | |
155 | unlink_anon_vmas(next); | |
156 | } | |
157 | ||
01d8b20d PZ |
158 | struct anon_vma *page_get_anon_vma(struct page *page); |
159 | ||
1da177e4 LT |
160 | /* |
161 | * rmap interfaces called when adding or removing pte of page | |
162 | */ | |
c44b6743 | 163 | void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
1da177e4 | 164 | void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
ad8c2ee8 RR |
165 | void do_page_add_anon_rmap(struct page *, struct vm_area_struct *, |
166 | unsigned long, int); | |
9617d95e | 167 | void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
1da177e4 | 168 | void page_add_file_rmap(struct page *); |
edc315fd | 169 | void page_remove_rmap(struct page *); |
1da177e4 | 170 | |
0fe6e20b NH |
171 | void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, |
172 | unsigned long); | |
173 | void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *, | |
174 | unsigned long); | |
175 | ||
21333b2b | 176 | static inline void page_dup_rmap(struct page *page) |
1da177e4 LT |
177 | { |
178 | atomic_inc(&page->_mapcount); | |
179 | } | |
180 | ||
181 | /* | |
182 | * Called from mm/vmscan.c to handle paging out | |
183 | */ | |
6fe6b7e3 | 184 | int page_referenced(struct page *, int is_locked, |
72835c86 | 185 | struct mem_cgroup *memcg, unsigned long *vm_flags); |
5ad64688 | 186 | int page_referenced_one(struct page *, struct vm_area_struct *, |
9f32624b | 187 | unsigned long address, void *arg); |
5ad64688 | 188 | |
14fa31b8 AK |
189 | #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK) |
190 | ||
191 | int try_to_unmap(struct page *, enum ttu_flags flags); | |
5ad64688 | 192 | int try_to_unmap_one(struct page *, struct vm_area_struct *, |
52629506 | 193 | unsigned long address, void *arg); |
1da177e4 | 194 | |
ceffc078 CO |
195 | /* |
196 | * Called from mm/filemap_xip.c to unmap empty zero page | |
197 | */ | |
e9a81a82 | 198 | pte_t *__page_check_address(struct page *, struct mm_struct *, |
479db0bf | 199 | unsigned long, spinlock_t **, int); |
ceffc078 | 200 | |
e9a81a82 NK |
201 | static inline pte_t *page_check_address(struct page *page, struct mm_struct *mm, |
202 | unsigned long address, | |
203 | spinlock_t **ptlp, int sync) | |
204 | { | |
205 | pte_t *ptep; | |
206 | ||
207 | __cond_lock(*ptlp, ptep = __page_check_address(page, mm, address, | |
208 | ptlp, sync)); | |
209 | return ptep; | |
210 | } | |
211 | ||
1da177e4 LT |
212 | /* |
213 | * Used by swapoff to help locate where page is expected in vma. | |
214 | */ | |
215 | unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); | |
216 | ||
d08b3851 PZ |
217 | /* |
218 | * Cleans the PTEs of shared mappings. | |
219 | * (and since clean PTEs should also be readonly, write protects them too) | |
220 | * | |
221 | * returns the number of cleaned PTEs. | |
222 | */ | |
223 | int page_mkclean(struct page *); | |
224 | ||
b291f000 NP |
225 | /* |
226 | * called in munlock()/munmap() path to check for other vmas holding | |
227 | * the page mlocked. | |
228 | */ | |
229 | int try_to_munlock(struct page *); | |
b291f000 | 230 | |
10be22df AK |
231 | /* |
232 | * Called by memory-failure.c to kill processes. | |
233 | */ | |
4fc3f1d6 IM |
234 | struct anon_vma *page_lock_anon_vma_read(struct page *page); |
235 | void page_unlock_anon_vma_read(struct anon_vma *anon_vma); | |
6a46079c | 236 | int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma); |
10be22df | 237 | |
0dd1c7bb JK |
238 | /* |
239 | * rmap_walk_control: To control rmap traversing for specific needs | |
240 | * | |
241 | * arg: passed to rmap_one() and invalid_vma() | |
242 | * rmap_one: executed on each vma where page is mapped | |
243 | * done: for checking traversing termination condition | |
244 | * file_nonlinear: for handling file nonlinear mapping | |
245 | * anon_lock: for getting anon_lock by optimized way rather than default | |
246 | * invalid_vma: for skipping uninterested vma | |
247 | */ | |
051ac83a JK |
248 | struct rmap_walk_control { |
249 | void *arg; | |
250 | int (*rmap_one)(struct page *page, struct vm_area_struct *vma, | |
251 | unsigned long addr, void *arg); | |
0dd1c7bb JK |
252 | int (*done)(struct page *page); |
253 | int (*file_nonlinear)(struct page *, struct address_space *, | |
254 | struct vm_area_struct *vma); | |
255 | struct anon_vma *(*anon_lock)(struct page *page); | |
256 | bool (*invalid_vma)(struct vm_area_struct *vma, void *arg); | |
051ac83a JK |
257 | }; |
258 | ||
051ac83a | 259 | int rmap_walk(struct page *page, struct rmap_walk_control *rwc); |
e9995ef9 | 260 | |
1da177e4 LT |
261 | #else /* !CONFIG_MMU */ |
262 | ||
263 | #define anon_vma_init() do {} while (0) | |
264 | #define anon_vma_prepare(vma) (0) | |
265 | #define anon_vma_link(vma) do {} while (0) | |
266 | ||
01ff53f4 | 267 | static inline int page_referenced(struct page *page, int is_locked, |
72835c86 | 268 | struct mem_cgroup *memcg, |
01ff53f4 MF |
269 | unsigned long *vm_flags) |
270 | { | |
271 | *vm_flags = 0; | |
64574746 | 272 | return 0; |
01ff53f4 MF |
273 | } |
274 | ||
a48d07af | 275 | #define try_to_unmap(page, refs) SWAP_FAIL |
1da177e4 | 276 | |
d08b3851 PZ |
277 | static inline int page_mkclean(struct page *page) |
278 | { | |
279 | return 0; | |
280 | } | |
281 | ||
282 | ||
1da177e4 LT |
283 | #endif /* CONFIG_MMU */ |
284 | ||
285 | /* | |
286 | * Return values of try_to_unmap | |
287 | */ | |
288 | #define SWAP_SUCCESS 0 | |
289 | #define SWAP_AGAIN 1 | |
290 | #define SWAP_FAIL 2 | |
b291f000 | 291 | #define SWAP_MLOCK 3 |
1da177e4 LT |
292 | |
293 | #endif /* _LINUX_RMAP_H */ |