include/linux/migrate.h

   1 #ifndef _LINUX_MIGRATE_H
   2 #define _LINUX_MIGRATE_H
   3
   4 #include <linux/mm.h>
   5 #include <linux/mempolicy.h>
   6 #include <linux/migrate_mode.h>
   7
   8 typedef struct page *new_page_t(struct page *, unsigned long private, int **);
   9
  10 /*
  11  * Return values from addresss_space_operations.migratepage():
  12  * - negative errno on page migration failure;
  13  * - zero on page migration success;
  14  *
  15  * The balloon page migration introduces this special case where a 'distinct'
  16  * return code is used to flag a successful page migration to unmap_and_move().
  17  * This approach is necessary because page migration can race against balloon
  18  * deflation procedure, and for such case we could introduce a nasty page leak
  19  * if a successfully migrated balloon page gets released concurrently with
  20  * migration's unmap_and_move() wrap-up steps.
  21  */
  22 #define MIGRATEPAGE_SUCCESS             0
  23 #define MIGRATEPAGE_BALLOON_SUCCESS     1 /* special ret code for balloon page
  24                                            * sucessful migration case.
  25                                            */
  26 enum migrate_reason {
  27         MR_COMPACTION,
  28         MR_MEMORY_FAILURE,
  29         MR_MEMORY_HOTPLUG,
  30         MR_SYSCALL,             /* also applies to cpusets */
  31         MR_MEMPOLICY_MBIND,
  32         MR_NUMA_MISPLACED,
  33         MR_CMA
  34 };
  35
  36 #ifdef CONFIG_MIGRATION
  37
  38 extern void putback_lru_pages(struct list_head *l);
  39 extern void putback_movable_pages(struct list_head *l);
  40 extern int migrate_page(struct address_space *,
  41                         struct page *, struct page *, enum migrate_mode);
  42 extern int migrate_pages(struct list_head *l, new_page_t x,
  43                 unsigned long private, enum migrate_mode mode, int reason);
  44
  45 extern int fail_migrate_page(struct address_space *,
  46                         struct page *, struct page *);
  47
  48 extern int migrate_prep(void);
  49 extern int migrate_prep_local(void);
  50 extern int migrate_vmas(struct mm_struct *mm,
  51                 const nodemask_t *from, const nodemask_t *to,
  52                 unsigned long flags);
  53 extern void migrate_page_copy(struct page *newpage, struct page *page);
  54 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  55                                   struct page *newpage, struct page *page);
  56 extern int migrate_page_move_mapping(struct address_space *mapping,
  57                 struct page *newpage, struct page *page,
  58                 struct buffer_head *head, enum migrate_mode mode,
  59                 int extra_count);
  60 #else
  61
  62 static inline void putback_lru_pages(struct list_head *l) {}
  63 static inline void putback_movable_pages(struct list_head *l) {}
  64 static inline int migrate_pages(struct list_head *l, new_page_t x,
  65                 unsigned long private, enum migrate_mode mode, int reason)
  66         { return -ENOSYS; }
  67
  68 static inline int migrate_prep(void) { return -ENOSYS; }
  69 static inline int migrate_prep_local(void) { return -ENOSYS; }
  70
  71 static inline int migrate_vmas(struct mm_struct *mm,
  72                 const nodemask_t *from, const nodemask_t *to,
  73                 unsigned long flags)
  74 {
  75         return -ENOSYS;
  76 }
  77
  78 static inline void migrate_page_copy(struct page *newpage,
  79                                      struct page *page) {}
  80
  81 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
  82                                   struct page *newpage, struct page *page)
  83 {
  84         return -ENOSYS;
  85 }
  86
  87 /* Possible settings for the migrate_page() method in address_operations */
  88 #define migrate_page NULL
  89 #define fail_migrate_page NULL
  90
  91 #endif /* CONFIG_MIGRATION */
  92
  93 #ifdef CONFIG_NUMA_BALANCING
  94 extern bool pmd_trans_migrating(pmd_t pmd);
  95 extern void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd);
  96 extern int migrate_misplaced_page(struct page *page,
  97                                   struct vm_area_struct *vma, int node);
  98 extern bool migrate_ratelimited(int node);
  99 #else
 100 static inline bool pmd_trans_migrating(pmd_t pmd)
 101 {
 102         return false;
 103 }
 104 static inline void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd)
 105 {
 106 }
 107 static inline int migrate_misplaced_page(struct page *page,
 108                                          struct vm_area_struct *vma, int node)
 109 {
 110         return -EAGAIN; /* can't migrate now */
 111 }
 112 static inline bool migrate_ratelimited(int node)
 113 {
 114         return false;
 115 }
 116 #endif /* CONFIG_NUMA_BALANCING */
 117
 118 #if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 119 extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 120                         struct vm_area_struct *vma,
 121                         pmd_t *pmd, pmd_t entry,
 122                         unsigned long address,
 123                         struct page *page, int node);
 124 #else
 125 static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 126                         struct vm_area_struct *vma,
 127                         pmd_t *pmd, pmd_t entry,
 128                         unsigned long address,
 129                         struct page *page, int node)
 130 {
 131         return -EAGAIN;
 132 }
 133 #endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
 134
 135 #endif /* _LINUX_MIGRATE_H */