4 * Declarations for Reverse Mapping functions in mm/rmap.c
7 #include <linux/list.h>
8 #include <linux/slab.h>
10 #include <linux/mutex.h>
11 #include <linux/memcontrol.h>
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.
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.
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.
28 struct anon_vma *root; /* Root of this anon_vma tree */
29 struct mutex mutex; /* Serialize access to vma list */
31 * The refcount is taken on an anon_vma when there is no
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
40 * Count of child anon_vmas and VMAs which points to this anon_vma.
42 * This counter is used for making decision about reusing anon_vma
43 * instead of forking new one. See comments in function anon_vma_clone.
47 struct anon_vma *parent; /* Parent of this anon_vma */
50 * NOTE: the LSB of the head.next is set by
51 * mm_take_all_locks() _after_ taking the above lock. So the
52 * head must only be read/written after taking the above lock
53 * to be sure to see a valid next pointer. The LSB bit itself
54 * is serialized by a system wide lock only visible to
55 * mm_take_all_locks() (mm_all_locks_mutex).
57 struct list_head head; /* Chain of private "related" vmas */
61 * The copy-on-write semantics of fork mean that an anon_vma
62 * can become associated with multiple processes. Furthermore,
63 * each child process will have its own anon_vma, where new
64 * pages for that process are instantiated.
66 * This structure allows us to find the anon_vmas associated
67 * with a VMA, or the VMAs associated with an anon_vma.
68 * The "same_vma" list contains the anon_vma_chains linking
69 * all the anon_vmas associated with this VMA.
70 * The "same_anon_vma" list contains the anon_vma_chains
71 * which link all the VMAs associated with this anon_vma.
73 struct anon_vma_chain {
74 struct vm_area_struct *vma;
75 struct anon_vma *anon_vma;
76 struct list_head same_vma; /* locked by mmap_sem & page_table_lock */
77 struct list_head same_anon_vma; /* locked by anon_vma->mutex */
81 static inline void get_anon_vma(struct anon_vma *anon_vma)
83 atomic_inc(&anon_vma->refcount);
86 void __put_anon_vma(struct anon_vma *anon_vma);
88 static inline void put_anon_vma(struct anon_vma *anon_vma)
90 if (atomic_dec_and_test(&anon_vma->refcount))
91 __put_anon_vma(anon_vma);
94 static inline struct anon_vma *page_anon_vma(struct page *page)
96 if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) !=
99 return page_rmapping(page);
102 static inline void vma_lock_anon_vma(struct vm_area_struct *vma)
104 struct anon_vma *anon_vma = vma->anon_vma;
106 mutex_lock(&anon_vma->root->mutex);
109 static inline void vma_unlock_anon_vma(struct vm_area_struct *vma)
111 struct anon_vma *anon_vma = vma->anon_vma;
113 mutex_unlock(&anon_vma->root->mutex);
116 static inline void anon_vma_lock(struct anon_vma *anon_vma)
118 mutex_lock(&anon_vma->root->mutex);
121 static inline void anon_vma_unlock(struct anon_vma *anon_vma)
123 mutex_unlock(&anon_vma->root->mutex);
127 * anon_vma helper functions.
129 void anon_vma_init(void); /* create anon_vma_cachep */
130 int anon_vma_prepare(struct vm_area_struct *);
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 *);
134 void __anon_vma_link(struct vm_area_struct *);
136 static inline void anon_vma_merge(struct vm_area_struct *vma,
137 struct vm_area_struct *next)
139 VM_BUG_ON(vma->anon_vma != next->anon_vma);
140 unlink_anon_vmas(next);
143 struct anon_vma *page_get_anon_vma(struct page *page);
146 * rmap interfaces called when adding or removing pte of page
148 void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
149 void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
150 void do_page_add_anon_rmap(struct page *, struct vm_area_struct *,
152 void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
153 void page_add_file_rmap(struct page *);
154 void page_remove_rmap(struct page *);
156 void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *,
158 void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *,
161 static inline void page_dup_rmap(struct page *page)
163 atomic_inc(&page->_mapcount);
167 * Called from mm/vmscan.c to handle paging out
169 int page_referenced(struct page *, int is_locked,
170 struct mem_cgroup *cnt, unsigned long *vm_flags);
171 int page_referenced_one(struct page *, struct vm_area_struct *,
172 unsigned long address, unsigned int *mapcount, unsigned long *vm_flags);
175 TTU_UNMAP = 0, /* unmap mode */
176 TTU_MIGRATION = 1, /* migration mode */
177 TTU_MUNLOCK = 2, /* munlock mode */
178 TTU_ACTION_MASK = 0xff,
180 TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
181 TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
182 TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
184 #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
186 bool is_vma_temporary_stack(struct vm_area_struct *vma);
188 int try_to_unmap(struct page *, enum ttu_flags flags);
189 int try_to_unmap_one(struct page *, struct vm_area_struct *,
190 unsigned long address, enum ttu_flags flags);
193 * Called from mm/filemap_xip.c to unmap empty zero page
195 pte_t *__page_check_address(struct page *, struct mm_struct *,
196 unsigned long, spinlock_t **, int);
198 static inline pte_t *page_check_address(struct page *page, struct mm_struct *mm,
199 unsigned long address,
200 spinlock_t **ptlp, int sync)
204 __cond_lock(*ptlp, ptep = __page_check_address(page, mm, address,
210 * Used by swapoff to help locate where page is expected in vma.
212 unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
215 * Cleans the PTEs of shared mappings.
216 * (and since clean PTEs should also be readonly, write protects them too)
218 * returns the number of cleaned PTEs.
220 int page_mkclean(struct page *);
223 * called in munlock()/munmap() path to check for other vmas holding
226 int try_to_munlock(struct page *);
229 * Called by memory-failure.c to kill processes.
231 struct anon_vma *page_lock_anon_vma(struct page *page);
232 void page_unlock_anon_vma(struct anon_vma *anon_vma);
233 int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
236 * Called by migrate.c to remove migration ptes, but might be used more later.
238 int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
239 struct vm_area_struct *, unsigned long, void *), void *arg);
241 #else /* !CONFIG_MMU */
243 #define anon_vma_init() do {} while (0)
244 #define anon_vma_prepare(vma) (0)
245 #define anon_vma_link(vma) do {} while (0)
247 static inline int page_referenced(struct page *page, int is_locked,
248 struct mem_cgroup *cnt,
249 unsigned long *vm_flags)
255 #define try_to_unmap(page, refs) SWAP_FAIL
257 static inline int page_mkclean(struct page *page)
263 #endif /* CONFIG_MMU */
266 * Return values of try_to_unmap
268 #define SWAP_SUCCESS 0
273 #endif /* _LINUX_RMAP_H */