/include/linux/rmap.h

https://github.com/airy09/android_kernel_sony_apq8064 · C Header · 263 lines · 144 code · 40 blank · 79 comment · 7 complexity · 26559edc31de9f8d6460d48e51b0b74b MD5 · raw file

  1. #ifndef _LINUX_RMAP_H
  2. #define _LINUX_RMAP_H
  3. /*
  4. * Declarations for Reverse Mapping functions in mm/rmap.c
  5. */
  6. #include <linux/list.h>
  7. #include <linux/slab.h>
  8. #include <linux/mm.h>
  9. #include <linux/mutex.h>
  10. #include <linux/memcontrol.h>
  11. /*
  12. * The anon_vma heads a list of private "related" vmas, to scan if
  13. * an anonymous page pointing to this anon_vma needs to be unmapped:
  14. * the vmas on the list will be related by forking, or by splitting.
  15. *
  16. * Since vmas come and go as they are split and merged (particularly
  17. * in mprotect), the mapping field of an anonymous page cannot point
  18. * directly to a vma: instead it points to an anon_vma, on whose list
  19. * the related vmas can be easily linked or unlinked.
  20. *
  21. * After unlinking the last vma on the list, we must garbage collect
  22. * the anon_vma object itself: we're guaranteed no page can be
  23. * pointing to this anon_vma once its vma list is empty.
  24. */
  25. struct anon_vma {
  26. struct anon_vma *root; /* Root of this anon_vma tree */
  27. struct mutex mutex; /* Serialize access to vma list */
  28. /*
  29. * The refcount is taken on an anon_vma when there is no
  30. * guarantee that the vma of page tables will exist for
  31. * the duration of the operation. A caller that takes
  32. * the reference is responsible for clearing up the
  33. * anon_vma if they are the last user on release
  34. */
  35. atomic_t refcount;
  36. /*
  37. * NOTE: the LSB of the head.next is set by
  38. * mm_take_all_locks() _after_ taking the above lock. So the
  39. * head must only be read/written after taking the above lock
  40. * to be sure to see a valid next pointer. The LSB bit itself
  41. * is serialized by a system wide lock only visible to
  42. * mm_take_all_locks() (mm_all_locks_mutex).
  43. */
  44. struct list_head head; /* Chain of private "related" vmas */
  45. };
  46. /*
  47. * The copy-on-write semantics of fork mean that an anon_vma
  48. * can become associated with multiple processes. Furthermore,
  49. * each child process will have its own anon_vma, where new
  50. * pages for that process are instantiated.
  51. *
  52. * This structure allows us to find the anon_vmas associated
  53. * with a VMA, or the VMAs associated with an anon_vma.
  54. * The "same_vma" list contains the anon_vma_chains linking
  55. * all the anon_vmas associated with this VMA.
  56. * The "same_anon_vma" list contains the anon_vma_chains
  57. * which link all the VMAs associated with this anon_vma.
  58. */
  59. struct anon_vma_chain {
  60. struct vm_area_struct *vma;
  61. struct anon_vma *anon_vma;
  62. struct list_head same_vma; /* locked by mmap_sem & page_table_lock */
  63. struct list_head same_anon_vma; /* locked by anon_vma->mutex */
  64. };
  65. #ifdef CONFIG_MMU
  66. static inline void get_anon_vma(struct anon_vma *anon_vma)
  67. {
  68. atomic_inc(&anon_vma->refcount);
  69. }
  70. void __put_anon_vma(struct anon_vma *anon_vma);
  71. static inline void put_anon_vma(struct anon_vma *anon_vma)
  72. {
  73. if (atomic_dec_and_test(&anon_vma->refcount))
  74. __put_anon_vma(anon_vma);
  75. }
  76. static inline struct anon_vma *page_anon_vma(struct page *page)
  77. {
  78. if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) !=
  79. PAGE_MAPPING_ANON)
  80. return NULL;
  81. return page_rmapping(page);
  82. }
  83. static inline void vma_lock_anon_vma(struct vm_area_struct *vma)
  84. {
  85. struct anon_vma *anon_vma = vma->anon_vma;
  86. if (anon_vma)
  87. mutex_lock(&anon_vma->root->mutex);
  88. }
  89. static inline void vma_unlock_anon_vma(struct vm_area_struct *vma)
  90. {
  91. struct anon_vma *anon_vma = vma->anon_vma;
  92. if (anon_vma)
  93. mutex_unlock(&anon_vma->root->mutex);
  94. }
  95. static inline void anon_vma_lock(struct anon_vma *anon_vma)
  96. {
  97. mutex_lock(&anon_vma->root->mutex);
  98. }
  99. static inline void anon_vma_unlock(struct anon_vma *anon_vma)
  100. {
  101. mutex_unlock(&anon_vma->root->mutex);
  102. }
  103. /*
  104. * anon_vma helper functions.
  105. */
  106. void anon_vma_init(void); /* create anon_vma_cachep */
  107. int anon_vma_prepare(struct vm_area_struct *);
  108. void unlink_anon_vmas(struct vm_area_struct *);
  109. int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *);
  110. void anon_vma_moveto_tail(struct vm_area_struct *);
  111. int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *);
  112. static inline void anon_vma_merge(struct vm_area_struct *vma,
  113. struct vm_area_struct *next)
  114. {
  115. VM_BUG_ON(vma->anon_vma != next->anon_vma);
  116. unlink_anon_vmas(next);
  117. }
  118. struct anon_vma *page_get_anon_vma(struct page *page);
  119. /*
  120. * rmap interfaces called when adding or removing pte of page
  121. */
  122. void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
  123. void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
  124. void do_page_add_anon_rmap(struct page *, struct vm_area_struct *,
  125. unsigned long, int);
  126. void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
  127. void page_add_file_rmap(struct page *);
  128. void page_remove_rmap(struct page *);
  129. void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *,
  130. unsigned long);
  131. void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *,
  132. unsigned long);
  133. static inline void page_dup_rmap(struct page *page)
  134. {
  135. atomic_inc(&page->_mapcount);
  136. }
  137. /*
  138. * Called from mm/vmscan.c to handle paging out
  139. */
  140. int page_referenced(struct page *, int is_locked,
  141. struct mem_cgroup *memcg, unsigned long *vm_flags);
  142. int page_referenced_one(struct page *, struct vm_area_struct *,
  143. unsigned long address, unsigned int *mapcount, unsigned long *vm_flags);
  144. enum ttu_flags {
  145. TTU_UNMAP = 0, /* unmap mode */
  146. TTU_MIGRATION = 1, /* migration mode */
  147. TTU_MUNLOCK = 2, /* munlock mode */
  148. TTU_ACTION_MASK = 0xff,
  149. TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
  150. TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
  151. TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
  152. };
  153. #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
  154. bool is_vma_temporary_stack(struct vm_area_struct *vma);
  155. int try_to_unmap(struct page *, enum ttu_flags flags);
  156. int try_to_unmap_one(struct page *, struct vm_area_struct *,
  157. unsigned long address, enum ttu_flags flags);
  158. /*
  159. * Called from mm/filemap_xip.c to unmap empty zero page
  160. */
  161. pte_t *__page_check_address(struct page *, struct mm_struct *,
  162. unsigned long, spinlock_t **, int);
  163. static inline pte_t *page_check_address(struct page *page, struct mm_struct *mm,
  164. unsigned long address,
  165. spinlock_t **ptlp, int sync)
  166. {
  167. pte_t *ptep;
  168. __cond_lock(*ptlp, ptep = __page_check_address(page, mm, address,
  169. ptlp, sync));
  170. return ptep;
  171. }
  172. /*
  173. * Used by swapoff to help locate where page is expected in vma.
  174. */
  175. unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
  176. /*
  177. * Cleans the PTEs of shared mappings.
  178. * (and since clean PTEs should also be readonly, write protects them too)
  179. *
  180. * returns the number of cleaned PTEs.
  181. */
  182. int page_mkclean(struct page *);
  183. /*
  184. * called in munlock()/munmap() path to check for other vmas holding
  185. * the page mlocked.
  186. */
  187. int try_to_munlock(struct page *);
  188. /*
  189. * Called by memory-failure.c to kill processes.
  190. */
  191. struct anon_vma *page_lock_anon_vma(struct page *page);
  192. void page_unlock_anon_vma(struct anon_vma *anon_vma);
  193. int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
  194. /*
  195. * Called by migrate.c to remove migration ptes, but might be used more later.
  196. */
  197. int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
  198. struct vm_area_struct *, unsigned long, void *), void *arg);
  199. #else /* !CONFIG_MMU */
  200. #define anon_vma_init() do {} while (0)
  201. #define anon_vma_prepare(vma) (0)
  202. #define anon_vma_link(vma) do {} while (0)
  203. static inline int page_referenced(struct page *page, int is_locked,
  204. struct mem_cgroup *memcg,
  205. unsigned long *vm_flags)
  206. {
  207. *vm_flags = 0;
  208. return 0;
  209. }
  210. #define try_to_unmap(page, refs) SWAP_FAIL
  211. static inline int page_mkclean(struct page *page)
  212. {
  213. return 0;
  214. }
  215. #endif /* CONFIG_MMU */
  216. /*
  217. * Return values of try_to_unmap
  218. */
  219. #define SWAP_SUCCESS 0
  220. #define SWAP_AGAIN 1
  221. #define SWAP_FAIL 2
  222. #define SWAP_MLOCK 3
  223. #endif /* _LINUX_RMAP_H */