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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 */
Hugh Dickinsdb114b82009-12-14 17:59:25 -080029#ifdef CONFIG_KSM
30 atomic_t ksm_refcount;
31#endif
Andrea Arcangeli7906d002008-07-28 15:46:26 -070032 /*
33 * NOTE: the LSB of the head.next is set by
34 * mm_take_all_locks() _after_ taking the above lock. So the
35 * head must only be read/written after taking the above lock
36 * to be sure to see a valid next pointer. The LSB bit itself
37 * is serialized by a system wide lock only visible to
38 * mm_take_all_locks() (mm_all_locks_mutex).
39 */
Rik van Riel5beb4932010-03-05 13:42:07 -080040 struct list_head head; /* Chain of private "related" vmas */
41};
42
43/*
44 * The copy-on-write semantics of fork mean that an anon_vma
45 * can become associated with multiple processes. Furthermore,
46 * each child process will have its own anon_vma, where new
47 * pages for that process are instantiated.
48 *
49 * This structure allows us to find the anon_vmas associated
50 * with a VMA, or the VMAs associated with an anon_vma.
51 * The "same_vma" list contains the anon_vma_chains linking
52 * all the anon_vmas associated with this VMA.
53 * The "same_anon_vma" list contains the anon_vma_chains
54 * which link all the VMAs associated with this anon_vma.
55 */
56struct anon_vma_chain {
57 struct vm_area_struct *vma;
58 struct anon_vma *anon_vma;
59 struct list_head same_vma; /* locked by mmap_sem & page_table_lock */
60 struct list_head same_anon_vma; /* locked by anon_vma->lock */
Linus Torvalds1da177e2005-04-16 15:20:36 -070061};
62
63#ifdef CONFIG_MMU
Hugh Dickinsdb114b82009-12-14 17:59:25 -080064#ifdef CONFIG_KSM
65static inline void ksm_refcount_init(struct anon_vma *anon_vma)
66{
67 atomic_set(&anon_vma->ksm_refcount, 0);
68}
69
70static inline int ksm_refcount(struct anon_vma *anon_vma)
71{
72 return atomic_read(&anon_vma->ksm_refcount);
73}
74#else
75static inline void ksm_refcount_init(struct anon_vma *anon_vma)
76{
77}
78
79static inline int ksm_refcount(struct anon_vma *anon_vma)
80{
81 return 0;
82}
83#endif /* CONFIG_KSM */
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
Hugh Dickins3ca7b3c2009-12-14 17:58:57 -080085static inline struct anon_vma *page_anon_vma(struct page *page)
86{
87 if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) !=
88 PAGE_MAPPING_ANON)
89 return NULL;
90 return page_rmapping(page);
91}
92
Linus Torvalds1da177e2005-04-16 15:20:36 -070093static inline void anon_vma_lock(struct vm_area_struct *vma)
94{
95 struct anon_vma *anon_vma = vma->anon_vma;
96 if (anon_vma)
97 spin_lock(&anon_vma->lock);
98}
99
100static inline void anon_vma_unlock(struct vm_area_struct *vma)
101{
102 struct anon_vma *anon_vma = vma->anon_vma;
103 if (anon_vma)
104 spin_unlock(&anon_vma->lock);
105}
106
107/*
108 * anon_vma helper functions.
109 */
110void anon_vma_init(void); /* create anon_vma_cachep */
111int anon_vma_prepare(struct vm_area_struct *);
Rik van Riel5beb4932010-03-05 13:42:07 -0800112void unlink_anon_vmas(struct vm_area_struct *);
113int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *);
114int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115void __anon_vma_link(struct vm_area_struct *);
Hugh Dickinsdb114b82009-12-14 17:59:25 -0800116void anon_vma_free(struct anon_vma *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
Rik van Riel5beb4932010-03-05 13:42:07 -0800118static inline void anon_vma_merge(struct vm_area_struct *vma,
119 struct vm_area_struct *next)
120{
121 VM_BUG_ON(vma->anon_vma != next->anon_vma);
122 unlink_anon_vmas(next);
123}
124
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125/*
126 * rmap interfaces called when adding or removing pte of page
127 */
Rik van Rielc44b6742010-03-05 13:42:09 -0800128void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
Nick Piggin9617d952006-01-06 00:11:12 -0800130void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131void page_add_file_rmap(struct page *);
Hugh Dickinsedc315f2009-01-06 14:40:11 -0800132void page_remove_rmap(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
Hugh Dickins21333b22009-09-21 17:01:59 -0700134static inline void page_dup_rmap(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135{
136 atomic_inc(&page->_mapcount);
137}
138
139/*
140 * Called from mm/vmscan.c to handle paging out
141 */
Wu Fengguang6fe6b7e2009-06-16 15:33:05 -0700142int page_referenced(struct page *, int is_locked,
143 struct mem_cgroup *cnt, unsigned long *vm_flags);
Hugh Dickins5ad64682009-12-14 17:59:24 -0800144int page_referenced_one(struct page *, struct vm_area_struct *,
145 unsigned long address, unsigned int *mapcount, unsigned long *vm_flags);
146
Andi Kleen14fa31b2009-09-16 11:50:10 +0200147enum ttu_flags {
148 TTU_UNMAP = 0, /* unmap mode */
149 TTU_MIGRATION = 1, /* migration mode */
150 TTU_MUNLOCK = 2, /* munlock mode */
151 TTU_ACTION_MASK = 0xff,
152
153 TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
154 TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
Andi Kleen888b9f72009-09-16 11:50:11 +0200155 TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
Andi Kleen14fa31b2009-09-16 11:50:10 +0200156};
157#define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
158
159int try_to_unmap(struct page *, enum ttu_flags flags);
Hugh Dickins5ad64682009-12-14 17:59:24 -0800160int try_to_unmap_one(struct page *, struct vm_area_struct *,
161 unsigned long address, enum ttu_flags flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
163/*
Carsten Otteceffc072005-06-23 22:05:25 -0700164 * Called from mm/filemap_xip.c to unmap empty zero page
165 */
Hugh Dickinsc0718802005-10-29 18:16:31 -0700166pte_t *page_check_address(struct page *, struct mm_struct *,
Nick Piggin479db0b2008-08-20 14:09:18 -0700167 unsigned long, spinlock_t **, int);
Carsten Otteceffc072005-06-23 22:05:25 -0700168
169/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 * Used by swapoff to help locate where page is expected in vma.
171 */
172unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
173
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700174/*
175 * Cleans the PTEs of shared mappings.
176 * (and since clean PTEs should also be readonly, write protects them too)
177 *
178 * returns the number of cleaned PTEs.
179 */
180int page_mkclean(struct page *);
181
Nick Pigginb291f002008-10-18 20:26:44 -0700182/*
183 * called in munlock()/munmap() path to check for other vmas holding
184 * the page mlocked.
185 */
186int try_to_munlock(struct page *);
Nick Pigginb291f002008-10-18 20:26:44 -0700187
Andi Kleen10be22d2009-09-16 11:50:04 +0200188/*
189 * Called by memory-failure.c to kill processes.
190 */
191struct anon_vma *page_lock_anon_vma(struct page *page);
192void page_unlock_anon_vma(struct anon_vma *anon_vma);
Andi Kleen6a460792009-09-16 11:50:15 +0200193int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
Andi Kleen10be22d2009-09-16 11:50:04 +0200194
Hugh Dickinse9995ef2009-12-14 17:59:31 -0800195/*
196 * Called by migrate.c to remove migration ptes, but might be used more later.
197 */
198int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
199 struct vm_area_struct *, unsigned long, void *), void *arg);
200
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201#else /* !CONFIG_MMU */
202
203#define anon_vma_init() do {} while (0)
204#define anon_vma_prepare(vma) (0)
205#define anon_vma_link(vma) do {} while (0)
206
Mike Frysinger01ff53f2009-06-23 12:37:01 -0700207static inline int page_referenced(struct page *page, int is_locked,
208 struct mem_cgroup *cnt,
209 unsigned long *vm_flags)
210{
211 *vm_flags = 0;
Johannes Weiner645747462010-03-05 13:42:22 -0800212 return 0;
Mike Frysinger01ff53f2009-06-23 12:37:01 -0700213}
214
Christoph Lametera48d07a2006-02-01 03:05:38 -0800215#define try_to_unmap(page, refs) SWAP_FAIL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700217static inline int page_mkclean(struct page *page)
218{
219 return 0;
220}
221
222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223#endif /* CONFIG_MMU */
224
225/*
226 * Return values of try_to_unmap
227 */
228#define SWAP_SUCCESS 0
229#define SWAP_AGAIN 1
230#define SWAP_FAIL 2
Nick Pigginb291f002008-10-18 20:26:44 -0700231#define SWAP_MLOCK 3
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
233#endif /* _LINUX_RMAP_H */