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_movable_pages(struct list_head *l);
  39 extern int migrate_page(struct address_space *,
  40                         struct page *, struct page *, enum migrate_mode);
  41 extern int migrate_pages(struct list_head *l, new_page_t x,
  42                 unsigned long private, enum migrate_mode mode, int reason);
  43
  44 extern int fail_migrate_page(struct address_space *,
  45                         struct page *, struct page *);
  46
  47 extern int migrate_prep(void);
  48 extern int migrate_prep_local(void);
  49 extern int migrate_vmas(struct mm_struct *mm,
  50                 const nodemask_t *from, const nodemask_t *to,
  51                 unsigned long flags);
  52 extern void migrate_page_copy(struct page *newpage, struct page *page);
  53 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  54                                   struct page *newpage, struct page *page);
  55 extern int migrate_page_move_mapping(struct address_space *mapping,
  56                 struct page *newpage, struct page *page,
  57                 struct buffer_head *head, enum migrate_mode mode,
  58                 int extra_count);
  59 #else
  60
  61 static inline void putback_movable_pages(struct list_head *l) {}
  62 static inline int migrate_pages(struct list_head *l, new_page_t x,
  63                 unsigned long private, enum migrate_mode mode, 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 #define fail_migrate_page NULL
  88
  89 #endif /* CONFIG_MIGRATION */
  90
  91 #ifdef CONFIG_NUMA_BALANCING
  92 extern bool pmd_trans_migrating(pmd_t pmd);
  93 extern void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd);
  94 extern int migrate_misplaced_page(struct page *page,
  95                                   struct vm_area_struct *vma, int node);
  96 extern bool migrate_ratelimited(int node);
  97 #else
  98 static inline bool pmd_trans_migrating(pmd_t pmd)
  99 {
 100         return false;
 101 }
 102 static inline void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd)
 103 {
 104 }
 105 static inline int migrate_misplaced_page(struct page *page,
 106                                          struct vm_area_struct *vma, int node)
 107 {
 108         return -EAGAIN; /* can't migrate now */
 109 }
 110 static inline bool migrate_ratelimited(int node)
 111 {
 112         return false;
 113 }
 114 #endif /* CONFIG_NUMA_BALANCING */
 115
 116 #if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 117 extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 118                         struct vm_area_struct *vma,
 119                         pmd_t *pmd, pmd_t entry,
 120                         unsigned long address,
 121                         struct page *page, int node);
 122 #else
 123 static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 124                         struct vm_area_struct *vma,
 125                         pmd_t *pmd, pmd_t entry,
 126                         unsigned long address,
 127                         struct page *page, int node)
 128 {
 129         return -EAGAIN;
 130 }
 131 #endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
 132
 133 #endif /* _LINUX_MIGRATE_H */