Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 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 | */ |
| 27 | struct 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 | |
| 34 | extern kmem_cache_t *anon_vma_cachep; |
| 35 | |
| 36 | static inline struct anon_vma *anon_vma_alloc(void) |
| 37 | { |
| 38 | return kmem_cache_alloc(anon_vma_cachep, SLAB_KERNEL); |
| 39 | } |
| 40 | |
| 41 | static inline void anon_vma_free(struct anon_vma *anon_vma) |
| 42 | { |
| 43 | kmem_cache_free(anon_vma_cachep, anon_vma); |
| 44 | } |
| 45 | |
| 46 | static 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 | |
| 53 | static 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 | */ |
| 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 *); |
| 69 | |
| 70 | /* |
| 71 | * rmap interfaces called when adding or removing pte of page |
| 72 | */ |
| 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 *); |
| 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 | */ |
| 84 | static 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 | */ |
| 92 | int page_referenced(struct page *, int is_locked, int ignore_token); |
| 93 | int try_to_unmap(struct page *); |
| 94 | |
| 95 | /* |
| 96 | * Used by swapoff to help locate where page is expected in vma. |
| 97 | */ |
| 98 | unsigned 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 */ |