Linux kernel mirror (for testing)
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1#ifndef _LINUX_RMAP_H
2#define _LINUX_RMAP_H
3/*
4 * Declarations for Reverse Mapping functions in mm/rmap.c
5 */
6
7#include <linux/list.h>
8#include <linux/slab.h>
9#include <linux/mm.h>
10#include <linux/spinlock.h>
11#include <linux/memcontrol.h>
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 */
27struct anon_vma {
28 spinlock_t lock; /* Serialize access to vma list */
29 /*
30 * NOTE: the LSB of the head.next is set by
31 * mm_take_all_locks() _after_ taking the above lock. So the
32 * head must only be read/written after taking the above lock
33 * to be sure to see a valid next pointer. The LSB bit itself
34 * is serialized by a system wide lock only visible to
35 * mm_take_all_locks() (mm_all_locks_mutex).
36 */
37 struct list_head head; /* List of private "related" vmas */
38};
39
40#ifdef CONFIG_MMU
41
42static inline void anon_vma_lock(struct vm_area_struct *vma)
43{
44 struct anon_vma *anon_vma = vma->anon_vma;
45 if (anon_vma)
46 spin_lock(&anon_vma->lock);
47}
48
49static inline void anon_vma_unlock(struct vm_area_struct *vma)
50{
51 struct anon_vma *anon_vma = vma->anon_vma;
52 if (anon_vma)
53 spin_unlock(&anon_vma->lock);
54}
55
56/*
57 * anon_vma helper functions.
58 */
59void anon_vma_init(void); /* create anon_vma_cachep */
60int anon_vma_prepare(struct vm_area_struct *);
61void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *);
62void anon_vma_unlink(struct vm_area_struct *);
63void anon_vma_link(struct vm_area_struct *);
64void __anon_vma_link(struct vm_area_struct *);
65
66extern struct anon_vma *page_lock_anon_vma(struct page *page);
67extern void page_unlock_anon_vma(struct anon_vma *anon_vma);
68
69/*
70 * rmap interfaces called when adding or removing pte of page
71 */
72void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
73void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
74void page_add_file_rmap(struct page *);
75void page_remove_rmap(struct page *, struct vm_area_struct *);
76
77#ifdef CONFIG_DEBUG_VM
78void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address);
79#else
80static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address)
81{
82 atomic_inc(&page->_mapcount);
83}
84#endif
85
86/*
87 * Called from mm/vmscan.c to handle paging out
88 */
89int page_referenced(struct page *, int is_locked, struct mem_cgroup *cnt);
90int try_to_unmap(struct page *, int ignore_refs);
91
92/*
93 * Called from mm/filemap_xip.c to unmap empty zero page
94 */
95pte_t *page_check_address(struct page *, struct mm_struct *,
96 unsigned long, spinlock_t **, int);
97
98/*
99 * Used by swapoff to help locate where page is expected in vma.
100 */
101unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
102
103/*
104 * Cleans the PTEs of shared mappings.
105 * (and since clean PTEs should also be readonly, write protects them too)
106 *
107 * returns the number of cleaned PTEs.
108 */
109int page_mkclean(struct page *);
110
111#ifdef CONFIG_UNEVICTABLE_LRU
112/*
113 * called in munlock()/munmap() path to check for other vmas holding
114 * the page mlocked.
115 */
116int try_to_munlock(struct page *);
117#else
118static inline int try_to_munlock(struct page *page)
119{
120 return 0; /* a.k.a. SWAP_SUCCESS */
121}
122#endif
123
124#else /* !CONFIG_MMU */
125
126#define anon_vma_init() do {} while (0)
127#define anon_vma_prepare(vma) (0)
128#define anon_vma_link(vma) do {} while (0)
129
130#define page_referenced(page,l,cnt) TestClearPageReferenced(page)
131#define try_to_unmap(page, refs) SWAP_FAIL
132
133static inline int page_mkclean(struct page *page)
134{
135 return 0;
136}
137
138
139#endif /* CONFIG_MMU */
140
141/*
142 * Return values of try_to_unmap
143 */
144#define SWAP_SUCCESS 0
145#define SWAP_AGAIN 1
146#define SWAP_FAIL 2
147#define SWAP_MLOCK 3
148
149#endif /* _LINUX_RMAP_H */