Commit | Line | Data |
---|---|---|
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 */ | |
7f60c214 MG |
29 | #if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION) |
30 | ||
31 | /* | |
32 | * The external_refcount is taken by either KSM or page migration | |
33 | * to take a reference to an anon_vma when there is no | |
34 | * guarantee that the vma of page tables will exist for | |
35 | * the duration of the operation. A caller that takes | |
36 | * the reference is responsible for clearing up the | |
37 | * anon_vma if they are the last user on release | |
38 | */ | |
39 | atomic_t external_refcount; | |
db114b83 | 40 | #endif |
7906d00c AA |
41 | /* |
42 | * NOTE: the LSB of the head.next is set by | |
43 | * mm_take_all_locks() _after_ taking the above lock. So the | |
44 | * head must only be read/written after taking the above lock | |
45 | * to be sure to see a valid next pointer. The LSB bit itself | |
46 | * is serialized by a system wide lock only visible to | |
47 | * mm_take_all_locks() (mm_all_locks_mutex). | |
48 | */ | |
5beb4930 RR |
49 | struct list_head head; /* Chain of private "related" vmas */ |
50 | }; | |
51 | ||
52 | /* | |
53 | * The copy-on-write semantics of fork mean that an anon_vma | |
54 | * can become associated with multiple processes. Furthermore, | |
55 | * each child process will have its own anon_vma, where new | |
56 | * pages for that process are instantiated. | |
57 | * | |
58 | * This structure allows us to find the anon_vmas associated | |
59 | * with a VMA, or the VMAs associated with an anon_vma. | |
60 | * The "same_vma" list contains the anon_vma_chains linking | |
61 | * all the anon_vmas associated with this VMA. | |
62 | * The "same_anon_vma" list contains the anon_vma_chains | |
63 | * which link all the VMAs associated with this anon_vma. | |
64 | */ | |
65 | struct anon_vma_chain { | |
66 | struct vm_area_struct *vma; | |
67 | struct anon_vma *anon_vma; | |
68 | struct list_head same_vma; /* locked by mmap_sem & page_table_lock */ | |
69 | struct list_head same_anon_vma; /* locked by anon_vma->lock */ | |
1da177e4 LT |
70 | }; |
71 | ||
72 | #ifdef CONFIG_MMU | |
7f60c214 MG |
73 | #if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION) |
74 | static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma) | |
db114b83 | 75 | { |
7f60c214 | 76 | atomic_set(&anon_vma->external_refcount, 0); |
db114b83 HD |
77 | } |
78 | ||
7f60c214 | 79 | static inline int anonvma_external_refcount(struct anon_vma *anon_vma) |
db114b83 | 80 | { |
7f60c214 | 81 | return atomic_read(&anon_vma->external_refcount); |
db114b83 HD |
82 | } |
83 | #else | |
7f60c214 | 84 | static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma) |
db114b83 HD |
85 | { |
86 | } | |
87 | ||
7f60c214 | 88 | static inline int anonvma_external_refcount(struct anon_vma *anon_vma) |
db114b83 HD |
89 | { |
90 | return 0; | |
91 | } | |
92 | #endif /* CONFIG_KSM */ | |
1da177e4 | 93 | |
3ca7b3c5 HD |
94 | static inline struct anon_vma *page_anon_vma(struct page *page) |
95 | { | |
96 | if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != | |
97 | PAGE_MAPPING_ANON) | |
98 | return NULL; | |
99 | return page_rmapping(page); | |
100 | } | |
101 | ||
bb4a340e | 102 | static inline void vma_lock_anon_vma(struct vm_area_struct *vma) |
1da177e4 LT |
103 | { |
104 | struct anon_vma *anon_vma = vma->anon_vma; | |
105 | if (anon_vma) | |
106 | spin_lock(&anon_vma->lock); | |
107 | } | |
108 | ||
bb4a340e | 109 | static inline void vma_unlock_anon_vma(struct vm_area_struct *vma) |
1da177e4 LT |
110 | { |
111 | struct anon_vma *anon_vma = vma->anon_vma; | |
112 | if (anon_vma) | |
113 | spin_unlock(&anon_vma->lock); | |
114 | } | |
115 | ||
cba48b98 RR |
116 | static inline void anon_vma_lock(struct anon_vma *anon_vma) |
117 | { | |
118 | spin_lock(&anon_vma->lock); | |
119 | } | |
120 | ||
121 | static inline void anon_vma_unlock(struct anon_vma *anon_vma) | |
122 | { | |
123 | spin_unlock(&anon_vma->lock); | |
124 | } | |
125 | ||
1da177e4 LT |
126 | /* |
127 | * anon_vma helper functions. | |
128 | */ | |
129 | void anon_vma_init(void); /* create anon_vma_cachep */ | |
130 | int anon_vma_prepare(struct vm_area_struct *); | |
5beb4930 RR |
131 | void unlink_anon_vmas(struct vm_area_struct *); |
132 | int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *); | |
133 | int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *); | |
1da177e4 | 134 | void __anon_vma_link(struct vm_area_struct *); |
db114b83 | 135 | void anon_vma_free(struct anon_vma *); |
1da177e4 | 136 | |
5beb4930 RR |
137 | static inline void anon_vma_merge(struct vm_area_struct *vma, |
138 | struct vm_area_struct *next) | |
139 | { | |
140 | VM_BUG_ON(vma->anon_vma != next->anon_vma); | |
141 | unlink_anon_vmas(next); | |
142 | } | |
143 | ||
1da177e4 LT |
144 | /* |
145 | * rmap interfaces called when adding or removing pte of page | |
146 | */ | |
c44b6743 | 147 | void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
1da177e4 | 148 | void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
9617d95e | 149 | void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
1da177e4 | 150 | void page_add_file_rmap(struct page *); |
edc315fd | 151 | void page_remove_rmap(struct page *); |
1da177e4 | 152 | |
21333b2b | 153 | static inline void page_dup_rmap(struct page *page) |
1da177e4 LT |
154 | { |
155 | atomic_inc(&page->_mapcount); | |
156 | } | |
157 | ||
158 | /* | |
159 | * Called from mm/vmscan.c to handle paging out | |
160 | */ | |
6fe6b7e3 WF |
161 | int page_referenced(struct page *, int is_locked, |
162 | struct mem_cgroup *cnt, unsigned long *vm_flags); | |
5ad64688 HD |
163 | int page_referenced_one(struct page *, struct vm_area_struct *, |
164 | unsigned long address, unsigned int *mapcount, unsigned long *vm_flags); | |
165 | ||
14fa31b8 AK |
166 | enum ttu_flags { |
167 | TTU_UNMAP = 0, /* unmap mode */ | |
168 | TTU_MIGRATION = 1, /* migration mode */ | |
169 | TTU_MUNLOCK = 2, /* munlock mode */ | |
170 | TTU_ACTION_MASK = 0xff, | |
171 | ||
172 | TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */ | |
173 | TTU_IGNORE_ACCESS = (1 << 9), /* don't age */ | |
888b9f7c | 174 | TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */ |
14fa31b8 AK |
175 | }; |
176 | #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK) | |
177 | ||
178 | int try_to_unmap(struct page *, enum ttu_flags flags); | |
5ad64688 HD |
179 | int try_to_unmap_one(struct page *, struct vm_area_struct *, |
180 | unsigned long address, enum ttu_flags flags); | |
1da177e4 | 181 | |
ceffc078 CO |
182 | /* |
183 | * Called from mm/filemap_xip.c to unmap empty zero page | |
184 | */ | |
c0718806 | 185 | pte_t *page_check_address(struct page *, struct mm_struct *, |
479db0bf | 186 | unsigned long, spinlock_t **, int); |
ceffc078 | 187 | |
1da177e4 LT |
188 | /* |
189 | * Used by swapoff to help locate where page is expected in vma. | |
190 | */ | |
191 | unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); | |
192 | ||
d08b3851 PZ |
193 | /* |
194 | * Cleans the PTEs of shared mappings. | |
195 | * (and since clean PTEs should also be readonly, write protects them too) | |
196 | * | |
197 | * returns the number of cleaned PTEs. | |
198 | */ | |
199 | int page_mkclean(struct page *); | |
200 | ||
b291f000 NP |
201 | /* |
202 | * called in munlock()/munmap() path to check for other vmas holding | |
203 | * the page mlocked. | |
204 | */ | |
205 | int try_to_munlock(struct page *); | |
b291f000 | 206 | |
10be22df AK |
207 | /* |
208 | * Called by memory-failure.c to kill processes. | |
209 | */ | |
210 | struct anon_vma *page_lock_anon_vma(struct page *page); | |
211 | void page_unlock_anon_vma(struct anon_vma *anon_vma); | |
6a46079c | 212 | int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma); |
10be22df | 213 | |
e9995ef9 HD |
214 | /* |
215 | * Called by migrate.c to remove migration ptes, but might be used more later. | |
216 | */ | |
217 | int rmap_walk(struct page *page, int (*rmap_one)(struct page *, | |
218 | struct vm_area_struct *, unsigned long, void *), void *arg); | |
219 | ||
1da177e4 LT |
220 | #else /* !CONFIG_MMU */ |
221 | ||
222 | #define anon_vma_init() do {} while (0) | |
223 | #define anon_vma_prepare(vma) (0) | |
224 | #define anon_vma_link(vma) do {} while (0) | |
225 | ||
01ff53f4 MF |
226 | static inline int page_referenced(struct page *page, int is_locked, |
227 | struct mem_cgroup *cnt, | |
228 | unsigned long *vm_flags) | |
229 | { | |
230 | *vm_flags = 0; | |
64574746 | 231 | return 0; |
01ff53f4 MF |
232 | } |
233 | ||
a48d07af | 234 | #define try_to_unmap(page, refs) SWAP_FAIL |
1da177e4 | 235 | |
d08b3851 PZ |
236 | static inline int page_mkclean(struct page *page) |
237 | { | |
238 | return 0; | |
239 | } | |
240 | ||
241 | ||
1da177e4 LT |
242 | #endif /* CONFIG_MMU */ |
243 | ||
244 | /* | |
245 | * Return values of try_to_unmap | |
246 | */ | |
247 | #define SWAP_SUCCESS 0 | |
248 | #define SWAP_AGAIN 1 | |
249 | #define SWAP_FAIL 2 | |
b291f000 | 250 | #define SWAP_MLOCK 3 |
1da177e4 LT |
251 | |
252 | #endif /* _LINUX_RMAP_H */ |