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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_RMAP_H
2#define _LINUX_RMAP_H
3/*
4 * Declarations for Reverse Mapping functions in mm/rmap.c
5 */
6
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <linux/list.h>
8#include <linux/slab.h>
9#include <linux/mm.h>
10#include <linux/spinlock.h>
Balbir Singhbed71612008-02-07 00:14:01 -080011#include <linux/memcontrol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012
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 */
27struct anon_vma {
28 spinlock_t lock; /* Serialize access to vma list */
Rik van Riel5c341ee12010-08-09 17:18:39 -070029 struct anon_vma *root; /* Root of this anon_vma tree */
Mel Gorman7f60c212010-05-24 14:32:18 -070030#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
31
32 /*
33 * The external_refcount is taken by either KSM or page migration
34 * to take a reference to an anon_vma when there is no
35 * guarantee that the vma of page tables will exist for
36 * the duration of the operation. A caller that takes
37 * the reference is responsible for clearing up the
38 * anon_vma if they are the last user on release
39 */
40 atomic_t external_refcount;
Mel Gorman3f6c8272010-05-24 14:32:17 -070041#endif
Andrea Arcangeli7906d002008-07-28 15:46:26 -070042 /*
43 * NOTE: the LSB of the head.next is set by
44 * mm_take_all_locks() _after_ taking the above lock. So the
45 * head must only be read/written after taking the above lock
46 * to be sure to see a valid next pointer. The LSB bit itself
47 * is serialized by a system wide lock only visible to
48 * mm_take_all_locks() (mm_all_locks_mutex).
49 */
Rik van Riel5beb4932010-03-05 13:42:07 -080050 struct list_head head; /* Chain of private "related" vmas */
51};
52
53/*
54 * The copy-on-write semantics of fork mean that an anon_vma
55 * can become associated with multiple processes. Furthermore,
56 * each child process will have its own anon_vma, where new
57 * pages for that process are instantiated.
58 *
59 * This structure allows us to find the anon_vmas associated
60 * with a VMA, or the VMAs associated with an anon_vma.
61 * The "same_vma" list contains the anon_vma_chains linking
62 * all the anon_vmas associated with this VMA.
63 * The "same_anon_vma" list contains the anon_vma_chains
64 * which link all the VMAs associated with this anon_vma.
65 */
66struct anon_vma_chain {
67 struct vm_area_struct *vma;
68 struct anon_vma *anon_vma;
69 struct list_head same_vma; /* locked by mmap_sem & page_table_lock */
70 struct list_head same_anon_vma; /* locked by anon_vma->lock */
Linus Torvalds1da177e2005-04-16 15:20:36 -070071};
72
73#ifdef CONFIG_MMU
Mel Gorman7f60c212010-05-24 14:32:18 -070074#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
75static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma)
Hugh Dickinsdb114b82009-12-14 17:59:25 -080076{
Mel Gorman7f60c212010-05-24 14:32:18 -070077 atomic_set(&anon_vma->external_refcount, 0);
Hugh Dickinsdb114b82009-12-14 17:59:25 -080078}
79
Mel Gorman7f60c212010-05-24 14:32:18 -070080static inline int anonvma_external_refcount(struct anon_vma *anon_vma)
Hugh Dickinsdb114b82009-12-14 17:59:25 -080081{
Mel Gorman7f60c212010-05-24 14:32:18 -070082 return atomic_read(&anon_vma->external_refcount);
Hugh Dickinsdb114b82009-12-14 17:59:25 -080083}
Rik van Riel76545062010-08-09 17:18:41 -070084
85static inline void get_anon_vma(struct anon_vma *anon_vma)
86{
87 atomic_inc(&anon_vma->external_refcount);
88}
89
90void drop_anon_vma(struct anon_vma *);
Hugh Dickinsdb114b82009-12-14 17:59:25 -080091#else
Mel Gorman7f60c212010-05-24 14:32:18 -070092static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma)
Hugh Dickinsdb114b82009-12-14 17:59:25 -080093{
94}
95
Mel Gorman7f60c212010-05-24 14:32:18 -070096static inline int anonvma_external_refcount(struct anon_vma *anon_vma)
Hugh Dickinsdb114b82009-12-14 17:59:25 -080097{
98 return 0;
99}
Rik van Riel76545062010-08-09 17:18:41 -0700100
101static inline void get_anon_vma(struct anon_vma *anon_vma)
102{
103}
104
105static inline void drop_anon_vma(struct anon_vma *anon_vma)
106{
107}
Hugh Dickinsdb114b82009-12-14 17:59:25 -0800108#endif /* CONFIG_KSM */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109
Hugh Dickins3ca7b3c2009-12-14 17:58:57 -0800110static inline struct anon_vma *page_anon_vma(struct page *page)
111{
112 if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) !=
113 PAGE_MAPPING_ANON)
114 return NULL;
115 return page_rmapping(page);
116}
117
Rik van Rielbb4a3402010-08-09 17:18:37 -0700118static inline void vma_lock_anon_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119{
120 struct anon_vma *anon_vma = vma->anon_vma;
121 if (anon_vma)
Rik van Riel012f18002010-08-09 17:18:40 -0700122 spin_lock(&anon_vma->root->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123}
124
Rik van Rielbb4a3402010-08-09 17:18:37 -0700125static inline void vma_unlock_anon_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126{
127 struct anon_vma *anon_vma = vma->anon_vma;
128 if (anon_vma)
Rik van Riel012f18002010-08-09 17:18:40 -0700129 spin_unlock(&anon_vma->root->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130}
131
Rik van Rielcba48b92010-08-09 17:18:38 -0700132static inline void anon_vma_lock(struct anon_vma *anon_vma)
133{
Rik van Riel012f18002010-08-09 17:18:40 -0700134 spin_lock(&anon_vma->root->lock);
Rik van Rielcba48b92010-08-09 17:18:38 -0700135}
136
137static inline void anon_vma_unlock(struct anon_vma *anon_vma)
138{
Rik van Riel012f18002010-08-09 17:18:40 -0700139 spin_unlock(&anon_vma->root->lock);
Rik van Rielcba48b92010-08-09 17:18:38 -0700140}
141
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142/*
143 * anon_vma helper functions.
144 */
145void anon_vma_init(void); /* create anon_vma_cachep */
146int anon_vma_prepare(struct vm_area_struct *);
Rik van Riel5beb4932010-03-05 13:42:07 -0800147void unlink_anon_vmas(struct vm_area_struct *);
148int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *);
149int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150void __anon_vma_link(struct vm_area_struct *);
Hugh Dickinsdb114b82009-12-14 17:59:25 -0800151void anon_vma_free(struct anon_vma *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
Rik van Riel5beb4932010-03-05 13:42:07 -0800153static inline void anon_vma_merge(struct vm_area_struct *vma,
154 struct vm_area_struct *next)
155{
156 VM_BUG_ON(vma->anon_vma != next->anon_vma);
157 unlink_anon_vmas(next);
158}
159
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160/*
161 * rmap interfaces called when adding or removing pte of page
162 */
Rik van Rielc44b6742010-03-05 13:42:09 -0800163void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
Rik van Rielad8c2ee2010-08-09 17:19:48 -0700165void do_page_add_anon_rmap(struct page *, struct vm_area_struct *,
166 unsigned long, int);
Nick Piggin9617d952006-01-06 00:11:12 -0800167void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168void page_add_file_rmap(struct page *);
Hugh Dickinsedc315f2009-01-06 14:40:11 -0800169void page_remove_rmap(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170
Naoya Horiguchi0fe6e202010-05-28 09:29:16 +0900171void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *,
172 unsigned long);
173void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *,
174 unsigned long);
175
Hugh Dickins21333b22009-09-21 17:01:59 -0700176static inline void page_dup_rmap(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177{
178 atomic_inc(&page->_mapcount);
179}
180
181/*
182 * Called from mm/vmscan.c to handle paging out
183 */
Wu Fengguang6fe6b7e2009-06-16 15:33:05 -0700184int page_referenced(struct page *, int is_locked,
185 struct mem_cgroup *cnt, unsigned long *vm_flags);
Hugh Dickins5ad64682009-12-14 17:59:24 -0800186int page_referenced_one(struct page *, struct vm_area_struct *,
187 unsigned long address, unsigned int *mapcount, unsigned long *vm_flags);
188
Andi Kleen14fa31b2009-09-16 11:50:10 +0200189enum ttu_flags {
190 TTU_UNMAP = 0, /* unmap mode */
191 TTU_MIGRATION = 1, /* migration mode */
192 TTU_MUNLOCK = 2, /* munlock mode */
193 TTU_ACTION_MASK = 0xff,
194
195 TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
196 TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
Andi Kleen888b9f72009-09-16 11:50:11 +0200197 TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
Andi Kleen14fa31b2009-09-16 11:50:10 +0200198};
199#define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
200
201int try_to_unmap(struct page *, enum ttu_flags flags);
Hugh Dickins5ad64682009-12-14 17:59:24 -0800202int try_to_unmap_one(struct page *, struct vm_area_struct *,
203 unsigned long address, enum ttu_flags flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
205/*
Carsten Otteceffc072005-06-23 22:05:25 -0700206 * Called from mm/filemap_xip.c to unmap empty zero page
207 */
Hugh Dickinsc0718802005-10-29 18:16:31 -0700208pte_t *page_check_address(struct page *, struct mm_struct *,
Nick Piggin479db0b2008-08-20 14:09:18 -0700209 unsigned long, spinlock_t **, int);
Carsten Otteceffc072005-06-23 22:05:25 -0700210
211/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 * Used by swapoff to help locate where page is expected in vma.
213 */
214unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
215
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700216/*
217 * Cleans the PTEs of shared mappings.
218 * (and since clean PTEs should also be readonly, write protects them too)
219 *
220 * returns the number of cleaned PTEs.
221 */
222int page_mkclean(struct page *);
223
Nick Pigginb291f002008-10-18 20:26:44 -0700224/*
225 * called in munlock()/munmap() path to check for other vmas holding
226 * the page mlocked.
227 */
228int try_to_munlock(struct page *);
Nick Pigginb291f002008-10-18 20:26:44 -0700229
Andi Kleen10be22d2009-09-16 11:50:04 +0200230/*
231 * Called by memory-failure.c to kill processes.
232 */
233struct anon_vma *page_lock_anon_vma(struct page *page);
234void page_unlock_anon_vma(struct anon_vma *anon_vma);
Andi Kleen6a460792009-09-16 11:50:15 +0200235int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
Andi Kleen10be22d2009-09-16 11:50:04 +0200236
Hugh Dickinse9995ef2009-12-14 17:59:31 -0800237/*
238 * Called by migrate.c to remove migration ptes, but might be used more later.
239 */
240int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
241 struct vm_area_struct *, unsigned long, void *), void *arg);
242
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243#else /* !CONFIG_MMU */
244
245#define anon_vma_init() do {} while (0)
246#define anon_vma_prepare(vma) (0)
247#define anon_vma_link(vma) do {} while (0)
248
Mike Frysinger01ff53f2009-06-23 12:37:01 -0700249static inline int page_referenced(struct page *page, int is_locked,
250 struct mem_cgroup *cnt,
251 unsigned long *vm_flags)
252{
253 *vm_flags = 0;
Johannes Weiner645747462010-03-05 13:42:22 -0800254 return 0;
Mike Frysinger01ff53f2009-06-23 12:37:01 -0700255}
256
Christoph Lametera48d07a2006-02-01 03:05:38 -0800257#define try_to_unmap(page, refs) SWAP_FAIL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700259static inline int page_mkclean(struct page *page)
260{
261 return 0;
262}
263
264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265#endif /* CONFIG_MMU */
266
267/*
268 * Return values of try_to_unmap
269 */
270#define SWAP_SUCCESS 0
271#define SWAP_AGAIN 1
272#define SWAP_FAIL 2
Nick Pigginb291f002008-10-18 20:26:44 -0700273#define SWAP_MLOCK 3
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275#endif /* _LINUX_RMAP_H */