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