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>
10 #include <linux/spinlock.h>
12 #define page_map_lock(page) \
13 bit_spin_lock(PG_maplock, (unsigned long *)&(page)->flags)
14 #define page_map_unlock(page) \
15 bit_spin_unlock(PG_maplock, (unsigned long *)&(page)->flags)
18 * The anon_vma heads a list of private "related" vmas, to scan if
19 * an anonymous page pointing to this anon_vma needs to be unmapped:
20 * the vmas on the list will be related by forking, or by splitting.
22 * Since vmas come and go as they are split and merged (particularly
23 * in mprotect), the mapping field of an anonymous page cannot point
24 * directly to a vma: instead it points to an anon_vma, on whose list
25 * the related vmas can be easily linked or unlinked.
27 * After unlinking the last vma on the list, we must garbage collect
28 * the anon_vma object itself: we're guaranteed no page can be
29 * pointing to this anon_vma once its vma list is empty.
32 spinlock_t lock; /* Serialize access to vma list */
33 struct list_head head; /* List of private "related" vmas */
38 extern kmem_cache_t *anon_vma_cachep;
40 static inline struct anon_vma *anon_vma_alloc(void)
42 return kmem_cache_alloc(anon_vma_cachep, SLAB_KERNEL);
45 static inline void anon_vma_free(struct anon_vma *anon_vma)
47 kmem_cache_free(anon_vma_cachep, anon_vma);
50 static inline void anon_vma_lock(struct vm_area_struct *vma)
52 struct anon_vma *anon_vma = vma->anon_vma;
54 spin_lock(&anon_vma->lock);
57 static inline void anon_vma_unlock(struct vm_area_struct *vma)
59 struct anon_vma *anon_vma = vma->anon_vma;
61 spin_unlock(&anon_vma->lock);
65 * anon_vma helper functions.
67 void anon_vma_init(void); /* create anon_vma_cachep */
68 int anon_vma_prepare(struct vm_area_struct *);
69 void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *);
70 void anon_vma_unlink(struct vm_area_struct *);
71 void anon_vma_link(struct vm_area_struct *);
72 void __anon_vma_link(struct vm_area_struct *);
75 * rmap interfaces called when adding or removing pte of page
77 void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
78 void page_add_file_rmap(struct page *);
79 void page_remove_rmap(struct page *);
82 * page_dup_rmap - duplicate pte mapping to a page
83 * @page: the page to add the mapping to
85 * For copy_page_range only: minimal extract from page_add_rmap,
86 * avoiding unnecessary tests (already checked) so it's quicker.
88 static inline void page_dup_rmap(struct page *page)
92 page_map_unlock(page);
96 * Called from mm/vmscan.c to handle paging out
98 int page_referenced(struct page *);
99 int try_to_unmap(struct page *);
101 #else /* !CONFIG_MMU */
103 #define anon_vma_init() do {} while (0)
104 #define anon_vma_prepare(vma) (0)
105 #define anon_vma_link(vma) do {} while (0)
107 #define page_referenced(page) TestClearPageReferenced(page)
108 #define try_to_unmap(page) SWAP_FAIL
110 #endif /* CONFIG_MMU */
113 * Return values of try_to_unmap
115 #define SWAP_SUCCESS 0
119 #endif /* _LINUX_RMAP_H */