4 * Declarations for Reverse Mapping functions in mm/rmap.c
7 #include <linux/list.h>
8 #include <linux/slab.h>
10 #include <linux/rwsem.h>
11 #include <linux/memcontrol.h>
13 extern int isolate_lru_page(struct page *page);
14 extern void putback_lru_page(struct page *page);
15 extern unsigned long reclaim_pages_from_list(struct list_head *page_list,
16 struct vm_area_struct *vma);
19 * The anon_vma heads a list of private "related" vmas, to scan if
20 * an anonymous page pointing to this anon_vma needs to be unmapped:
21 * the vmas on the list will be related by forking, or by splitting.
23 * Since vmas come and go as they are split and merged (particularly
24 * in mprotect), the mapping field of an anonymous page cannot point
25 * directly to a vma: instead it points to an anon_vma, on whose list
26 * the related vmas can be easily linked or unlinked.
28 * After unlinking the last vma on the list, we must garbage collect
29 * the anon_vma object itself: we're guaranteed no page can be
30 * pointing to this anon_vma once its vma list is empty.
33 struct anon_vma *root; /* Root of this anon_vma tree */
34 struct rw_semaphore rwsem; /* W: modification, R: walking the list */
36 * The refcount is taken on an anon_vma when there is no
37 * guarantee that the vma of page tables will exist for
38 * the duration of the operation. A caller that takes
39 * the reference is responsible for clearing up the
40 * anon_vma if they are the last user on release
45 * Count of child anon_vmas and VMAs which points to this anon_vma.
47 * This counter is used for making decision about reusing anon_vma
48 * instead of forking new one. See comments in function anon_vma_clone.
52 struct anon_vma *parent; /* Parent of this anon_vma */
55 * NOTE: the LSB of the rb_root.rb_node is set by
56 * mm_take_all_locks() _after_ taking the above lock. So the
57 * rb_root must only be read/written after taking the above lock
58 * to be sure to see a valid next pointer. The LSB bit itself
59 * is serialized by a system wide lock only visible to
60 * mm_take_all_locks() (mm_all_locks_mutex).
62 struct rb_root rb_root; /* Interval tree of private "related" vmas */
66 * The copy-on-write semantics of fork mean that an anon_vma
67 * can become associated with multiple processes. Furthermore,
68 * each child process will have its own anon_vma, where new
69 * pages for that process are instantiated.
71 * This structure allows us to find the anon_vmas associated
72 * with a VMA, or the VMAs associated with an anon_vma.
73 * The "same_vma" list contains the anon_vma_chains linking
74 * all the anon_vmas associated with this VMA.
75 * The "rb" field indexes on an interval tree the anon_vma_chains
76 * which link all the VMAs associated with this anon_vma.
78 struct anon_vma_chain {
79 struct vm_area_struct *vma;
80 struct anon_vma *anon_vma;
81 struct list_head same_vma; /* locked by mmap_sem & page_table_lock */
82 struct rb_node rb; /* locked by anon_vma->rwsem */
83 unsigned long rb_subtree_last;
84 #ifdef CONFIG_DEBUG_VM_RB
85 unsigned long cached_vma_start, cached_vma_last;
90 TTU_UNMAP = 1, /* unmap mode */
91 TTU_MIGRATION = 2, /* migration mode */
92 TTU_MUNLOCK = 4, /* munlock mode */
94 TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
95 TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
96 TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
97 TTU_BATCH_FLUSH = (1 << 11), /* Batch TLB flushes where possible
98 * and caller guarantees they will
99 * do a final flush if necessary */
103 static inline void get_anon_vma(struct anon_vma *anon_vma)
105 atomic_inc(&anon_vma->refcount);
108 void __put_anon_vma(struct anon_vma *anon_vma);
110 static inline void put_anon_vma(struct anon_vma *anon_vma)
112 if (atomic_dec_and_test(&anon_vma->refcount))
113 __put_anon_vma(anon_vma);
116 static inline void anon_vma_lock_write(struct anon_vma *anon_vma)
118 down_write(&anon_vma->root->rwsem);
121 static inline void anon_vma_unlock_write(struct anon_vma *anon_vma)
123 up_write(&anon_vma->root->rwsem);
126 static inline void anon_vma_lock_read(struct anon_vma *anon_vma)
128 down_read(&anon_vma->root->rwsem);
131 static inline void anon_vma_unlock_read(struct anon_vma *anon_vma)
133 up_read(&anon_vma->root->rwsem);
138 * anon_vma helper functions.
140 void anon_vma_init(void); /* create anon_vma_cachep */
141 int anon_vma_prepare(struct vm_area_struct *);
142 void unlink_anon_vmas(struct vm_area_struct *);
143 int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *);
144 int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *);
146 static inline void anon_vma_merge(struct vm_area_struct *vma,
147 struct vm_area_struct *next)
149 VM_BUG_ON_VMA(vma->anon_vma != next->anon_vma, vma);
150 unlink_anon_vmas(next);
153 struct anon_vma *page_get_anon_vma(struct page *page);
156 * rmap interfaces called when adding or removing pte of page
158 void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
159 void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
160 void do_page_add_anon_rmap(struct page *, struct vm_area_struct *,
162 void __page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
163 static inline void page_add_new_anon_rmap(struct page *page,
164 struct vm_area_struct *vma, unsigned long address)
166 VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
167 __page_add_new_anon_rmap(page, vma, address);
170 void page_add_file_rmap(struct page *);
171 void page_remove_rmap(struct page *);
173 void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *,
175 void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *,
178 static inline void page_dup_rmap(struct page *page)
180 atomic_inc(&page->_mapcount);
184 * Called from mm/vmscan.c to handle paging out
186 int page_referenced(struct page *, int is_locked,
187 struct mem_cgroup *memcg, unsigned long *vm_flags);
189 #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
191 int try_to_unmap(struct page *, enum ttu_flags flags,
192 struct vm_area_struct *vma);
195 * Used by uprobes to replace a userspace page safely
197 pte_t *__page_check_address(struct page *, struct mm_struct *,
198 unsigned long, spinlock_t **, int);
200 static inline pte_t *page_check_address(struct page *page, struct mm_struct *mm,
201 unsigned long address,
202 spinlock_t **ptlp, int sync)
206 __cond_lock(*ptlp, ptep = __page_check_address(page, mm, address,
212 * Used by swapoff to help locate where page is expected in vma.
214 unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
217 * Cleans the PTEs of shared mappings.
218 * (and since clean PTEs should also be readonly, write protects them too)
220 * returns the number of cleaned PTEs.
222 int page_mkclean(struct page *);
225 * called in munlock()/munmap() path to check for other vmas holding
228 int try_to_munlock(struct page *);
231 * Called by memory-failure.c to kill processes.
233 struct anon_vma *page_lock_anon_vma_read(struct page *page);
234 void page_unlock_anon_vma_read(struct anon_vma *anon_vma);
235 int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
238 * rmap_walk_control: To control rmap traversing for specific needs
240 * arg: passed to rmap_one() and invalid_vma()
241 * rmap_one: executed on each vma where page is mapped
242 * done: for checking traversing termination condition
243 * anon_lock: for getting anon_lock by optimized way rather than default
244 * invalid_vma: for skipping uninterested vma
246 struct rmap_walk_control {
248 struct vm_area_struct *target_vma;
249 int (*rmap_one)(struct page *page, struct vm_area_struct *vma,
250 unsigned long addr, void *arg);
251 int (*done)(struct page *page);
252 struct anon_vma *(*anon_lock)(struct page *page);
253 bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);
256 int rmap_walk(struct page *page, struct rmap_walk_control *rwc);
258 #else /* !CONFIG_MMU */
260 #define anon_vma_init() do {} while (0)
261 #define anon_vma_prepare(vma) (0)
262 #define anon_vma_link(vma) do {} while (0)
264 static inline int page_referenced(struct page *page, int is_locked,
265 struct mem_cgroup *memcg,
266 unsigned long *vm_flags)
272 #define try_to_unmap(page, refs, vma) SWAP_FAIL
274 static inline int page_mkclean(struct page *page)
280 #endif /* CONFIG_MMU */
283 * Return values of try_to_unmap
285 #define SWAP_SUCCESS 0
290 #endif /* _LINUX_RMAP_H */