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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - include/linux/rmap.h
4 * Declarations for Reverse Mapping functions in mm/rmap.c
7 #include <linux/config.h>
8 #include <linux/list.h>
9 #include <linux/slab.h>
11 #include <linux/spinlock.h>
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.
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.
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.
28 spinlock_t lock
; /* Serialize access to vma list */
29 struct list_head head
; /* List of private "related" vmas */
34 extern kmem_cache_t
*anon_vma_cachep
;
36 static inline struct anon_vma
*anon_vma_alloc(void)
38 return kmem_cache_alloc(anon_vma_cachep
, SLAB_KERNEL
);
41 static inline void anon_vma_free(struct anon_vma
*anon_vma
)
43 kmem_cache_free(anon_vma_cachep
, anon_vma
);
46 static inline void anon_vma_lock(struct vm_area_struct
*vma
)
48 struct anon_vma
*anon_vma
= vma
->anon_vma
;
50 spin_lock(&anon_vma
->lock
);
53 static inline void anon_vma_unlock(struct vm_area_struct
*vma
)
55 struct anon_vma
*anon_vma
= vma
->anon_vma
;
57 spin_unlock(&anon_vma
->lock
);
61 * anon_vma helper functions.
63 void anon_vma_init(void); /* create anon_vma_cachep */
64 int anon_vma_prepare(struct vm_area_struct
*);
65 void __anon_vma_merge(struct vm_area_struct
*, struct vm_area_struct
*);
66 void anon_vma_unlink(struct vm_area_struct
*);
67 void anon_vma_link(struct vm_area_struct
*);
68 void __anon_vma_link(struct vm_area_struct
*);
71 * rmap interfaces called when adding or removing pte of page
73 void page_add_anon_rmap(struct page
*, struct vm_area_struct
*, unsigned long);
74 void page_add_file_rmap(struct page
*);
75 void page_remove_rmap(struct page
*);
78 * page_dup_rmap - duplicate pte mapping to a page
79 * @page: the page to add the mapping to
81 * For copy_page_range only: minimal extract from page_add_rmap,
82 * avoiding unnecessary tests (already checked) so it's quicker.
84 static inline void page_dup_rmap(struct page
*page
)
86 atomic_inc(&page
->_mapcount
);
90 * Called from mm/vmscan.c to handle paging out
92 int page_referenced(struct page
*, int is_locked
, int ignore_token
);
93 int try_to_unmap(struct page
*);
96 * Called from mm/filemap_xip.c to unmap empty zero page
98 pte_t
*page_check_address(struct page
*, struct mm_struct
*, unsigned long);
102 * Used by swapoff to help locate where page is expected in vma.
104 unsigned long page_address_in_vma(struct page
*, struct vm_area_struct
*);
106 #else /* !CONFIG_MMU */
108 #define anon_vma_init() do {} while (0)
109 #define anon_vma_prepare(vma) (0)
110 #define anon_vma_link(vma) do {} while (0)
112 #define page_referenced(page,l,i) TestClearPageReferenced(page)
113 #define try_to_unmap(page) SWAP_FAIL
115 #endif /* CONFIG_MMU */
118 * Return values of try_to_unmap
120 #define SWAP_SUCCESS 0
124 #endif /* _LINUX_RMAP_H */