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 extern struct kmem_cache
*anon_vma_cachep
;
44 static inline struct anon_vma
*anon_vma_alloc(void)
46 return kmem_cache_alloc(anon_vma_cachep
, GFP_KERNEL
);
49 static inline void anon_vma_free(struct anon_vma
*anon_vma
)
51 kmem_cache_free(anon_vma_cachep
, anon_vma
);
54 static inline void anon_vma_lock(struct vm_area_struct
*vma
)
56 struct anon_vma
*anon_vma
= vma
->anon_vma
;
58 spin_lock(&anon_vma
->lock
);
61 static inline void anon_vma_unlock(struct vm_area_struct
*vma
)
63 struct anon_vma
*anon_vma
= vma
->anon_vma
;
65 spin_unlock(&anon_vma
->lock
);
69 * anon_vma helper functions.
71 void anon_vma_init(void); /* create anon_vma_cachep */
72 int anon_vma_prepare(struct vm_area_struct
*);
73 void __anon_vma_merge(struct vm_area_struct
*, struct vm_area_struct
*);
74 void anon_vma_unlink(struct vm_area_struct
*);
75 void anon_vma_link(struct vm_area_struct
*);
76 void __anon_vma_link(struct vm_area_struct
*);
78 extern struct anon_vma
*page_lock_anon_vma(struct page
*page
);
79 extern void page_unlock_anon_vma(struct anon_vma
*anon_vma
);
82 * rmap interfaces called when adding or removing pte of page
84 void page_add_anon_rmap(struct page
*, struct vm_area_struct
*, unsigned long);
85 void page_add_new_anon_rmap(struct page
*, struct vm_area_struct
*, unsigned long);
86 void page_add_file_rmap(struct page
*);
87 void page_remove_rmap(struct page
*, struct vm_area_struct
*);
89 #ifdef CONFIG_DEBUG_VM
90 void page_dup_rmap(struct page
*page
, struct vm_area_struct
*vma
, unsigned long address
);
92 static inline void page_dup_rmap(struct page
*page
, struct vm_area_struct
*vma
, unsigned long address
)
94 atomic_inc(&page
->_mapcount
);
99 * Called from mm/vmscan.c to handle paging out
101 int page_referenced(struct page
*, int is_locked
, struct mem_cgroup
*cnt
);
102 int try_to_unmap(struct page
*, int ignore_refs
);
105 * Called from mm/filemap_xip.c to unmap empty zero page
107 pte_t
*page_check_address(struct page
*, struct mm_struct
*,
108 unsigned long, spinlock_t
**, int);
111 * Used by swapoff to help locate where page is expected in vma.
113 unsigned long page_address_in_vma(struct page
*, struct vm_area_struct
*);
116 * Cleans the PTEs of shared mappings.
117 * (and since clean PTEs should also be readonly, write protects them too)
119 * returns the number of cleaned PTEs.
121 int page_mkclean(struct page
*);
123 #ifdef CONFIG_UNEVICTABLE_LRU
125 * called in munlock()/munmap() path to check for other vmas holding
128 int try_to_munlock(struct page
*);
130 static inline int try_to_munlock(struct page
*page
)
132 return 0; /* a.k.a. SWAP_SUCCESS */
136 #else /* !CONFIG_MMU */
138 #define anon_vma_init() do {} while (0)
139 #define anon_vma_prepare(vma) (0)
140 #define anon_vma_link(vma) do {} while (0)
142 #define page_referenced(page,l,cnt) TestClearPageReferenced(page)
143 #define try_to_unmap(page, refs) SWAP_FAIL
145 static inline int page_mkclean(struct page
*page
)
151 #endif /* CONFIG_MMU */
154 * Return values of try_to_unmap
156 #define SWAP_SUCCESS 0
161 #endif /* _LINUX_RMAP_H */