4 * Declarations for Reverse Mapping functions in mm/rmap.c
7 #include <linux/list.h>
8 #include <linux/slab.h>
10 #include <linux/spinlock.h>
11 #include <linux/memcontrol.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 */
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).
37 struct list_head head
; /* List of private "related" vmas */
42 static inline void anon_vma_lock(struct vm_area_struct
*vma
)
44 struct anon_vma
*anon_vma
= vma
->anon_vma
;
46 spin_lock(&anon_vma
->lock
);
49 static inline void anon_vma_unlock(struct vm_area_struct
*vma
)
51 struct anon_vma
*anon_vma
= vma
->anon_vma
;
53 spin_unlock(&anon_vma
->lock
);
57 * anon_vma helper functions.
59 void anon_vma_init(void); /* create anon_vma_cachep */
60 int anon_vma_prepare(struct vm_area_struct
*);
61 void __anon_vma_merge(struct vm_area_struct
*, struct vm_area_struct
*);
62 void anon_vma_unlink(struct vm_area_struct
*);
63 void anon_vma_link(struct vm_area_struct
*);
64 void __anon_vma_link(struct vm_area_struct
*);
67 * rmap interfaces called when adding or removing pte of page
69 void page_add_anon_rmap(struct page
*, struct vm_area_struct
*, unsigned long);
70 void page_add_new_anon_rmap(struct page
*, struct vm_area_struct
*, unsigned long);
71 void page_add_file_rmap(struct page
*);
72 void page_remove_rmap(struct page
*);
74 #ifdef CONFIG_DEBUG_VM
75 void page_dup_rmap(struct page
*page
, struct vm_area_struct
*vma
, unsigned long address
);
77 static inline void page_dup_rmap(struct page
*page
, struct vm_area_struct
*vma
, unsigned long address
)
79 atomic_inc(&page
->_mapcount
);
84 * Called from mm/vmscan.c to handle paging out
86 int page_referenced(struct page
*, int is_locked
,
87 struct mem_cgroup
*cnt
, unsigned long *vm_flags
);
89 TTU_UNMAP
= 0, /* unmap mode */
90 TTU_MIGRATION
= 1, /* migration mode */
91 TTU_MUNLOCK
= 2, /* munlock mode */
92 TTU_ACTION_MASK
= 0xff,
94 TTU_IGNORE_MLOCK
= (1 << 8), /* ignore mlock */
95 TTU_IGNORE_ACCESS
= (1 << 9), /* don't age */
97 #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
99 int try_to_unmap(struct page
*, enum ttu_flags flags
);
102 * Called from mm/filemap_xip.c to unmap empty zero page
104 pte_t
*page_check_address(struct page
*, struct mm_struct
*,
105 unsigned long, spinlock_t
**, int);
108 * Used by swapoff to help locate where page is expected in vma.
110 unsigned long page_address_in_vma(struct page
*, struct vm_area_struct
*);
113 * Cleans the PTEs of shared mappings.
114 * (and since clean PTEs should also be readonly, write protects them too)
116 * returns the number of cleaned PTEs.
118 int page_mkclean(struct page
*);
121 * called in munlock()/munmap() path to check for other vmas holding
124 int try_to_munlock(struct page
*);
127 * Called by memory-failure.c to kill processes.
129 struct anon_vma
*page_lock_anon_vma(struct page
*page
);
130 void page_unlock_anon_vma(struct anon_vma
*anon_vma
);
132 #else /* !CONFIG_MMU */
134 #define anon_vma_init() do {} while (0)
135 #define anon_vma_prepare(vma) (0)
136 #define anon_vma_link(vma) do {} while (0)
138 static inline int page_referenced(struct page
*page
, int is_locked
,
139 struct mem_cgroup
*cnt
,
140 unsigned long *vm_flags
)
143 return TestClearPageReferenced(page
);
146 #define try_to_unmap(page, refs) SWAP_FAIL
148 static inline int page_mkclean(struct page
*page
)
154 #endif /* CONFIG_MMU */
157 * Return values of try_to_unmap
159 #define SWAP_SUCCESS 0
164 #endif /* _LINUX_RMAP_H */