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/config.h>
8#include <linux/list.h>
9#include <linux/slab.h>
10#include <linux/mm.h>
11#include <linux/spinlock.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 struct list_head head; /* List of private "related" vmas */
30};
31
32#ifdef CONFIG_MMU
33
34extern kmem_cache_t *anon_vma_cachep;
35
36static inline struct anon_vma *anon_vma_alloc(void)
37{
38 return kmem_cache_alloc(anon_vma_cachep, SLAB_KERNEL);
39}
40
41static inline void anon_vma_free(struct anon_vma *anon_vma)
42{
43 kmem_cache_free(anon_vma_cachep, anon_vma);
44}
45
46static inline void anon_vma_lock(struct vm_area_struct *vma)
47{
48 struct anon_vma *anon_vma = vma->anon_vma;
49 if (anon_vma)
50 spin_lock(&anon_vma->lock);
51}
52
53static inline void anon_vma_unlock(struct vm_area_struct *vma)
54{
55 struct anon_vma *anon_vma = vma->anon_vma;
56 if (anon_vma)
57 spin_unlock(&anon_vma->lock);
58}
59
60/*
61 * anon_vma helper functions.
62 */
63void anon_vma_init(void); /* create anon_vma_cachep */
64int anon_vma_prepare(struct vm_area_struct *);
65void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *);
66void anon_vma_unlink(struct vm_area_struct *);
67void anon_vma_link(struct vm_area_struct *);
68void __anon_vma_link(struct vm_area_struct *);
69
70/*
71 * rmap interfaces called when adding or removing pte of page
72 */
73void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
74void page_add_file_rmap(struct page *);
75void page_remove_rmap(struct page *);
76
77/**
78 * page_dup_rmap - duplicate pte mapping to a page
79 * @page: the page to add the mapping to
80 *
81 * For copy_page_range only: minimal extract from page_add_rmap,
82 * avoiding unnecessary tests (already checked) so it's quicker.
83 */
84static inline void page_dup_rmap(struct page *page)
85{
86 atomic_inc(&page->_mapcount);
87}
88
89/*
90 * Called from mm/vmscan.c to handle paging out
91 */
92int page_referenced(struct page *, int is_locked, int ignore_token);
93int try_to_unmap(struct page *);
94
95/*
96 * Used by swapoff to help locate where page is expected in vma.
97 */
98unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
99
100#else /* !CONFIG_MMU */
101
102#define anon_vma_init() do {} while (0)
103#define anon_vma_prepare(vma) (0)
104#define anon_vma_link(vma) do {} while (0)
105
106#define page_referenced(page,l,i) TestClearPageReferenced(page)
107#define try_to_unmap(page) SWAP_FAIL
108
109#endif /* CONFIG_MMU */
110
111/*
112 * Return values of try_to_unmap
113 */
114#define SWAP_SUCCESS 0
115#define SWAP_AGAIN 1
116#define SWAP_FAIL 2
117
118#endif /* _LINUX_RMAP_H */