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 extern int migrate_huge_page(struct page *, new_page_t x,
  45                 unsigned long private, enum migrate_mode mode);
  46
  47 extern int fail_migrate_page(struct address_space *,
  48                         struct page *, struct page *);
  49
  50 extern int migrate_prep(void);
  51 extern int migrate_prep_local(void);
  52 extern int migrate_vmas(struct mm_struct *mm,
  53                 const nodemask_t *from, const nodemask_t *to,
  54                 unsigned long flags);
  55 extern void migrate_page_copy(struct page *newpage, struct page *page);
  56 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  57                                   struct page *newpage, struct page *page);
  58 #else
  59
  60 static inline void putback_lru_pages(struct list_head *l) {}
  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 static inline int migrate_huge_page(struct page *page, new_page_t x,
  66                 unsigned long private, enum migrate_mode mode)
  67         { return -ENOSYS; }
  68
  69 static inline int migrate_prep(void) { return -ENOSYS; }
  70 static inline int migrate_prep_local(void) { return -ENOSYS; }
  71
  72 static inline int migrate_vmas(struct mm_struct *mm,
  73                 const nodemask_t *from, const nodemask_t *to,
  74                 unsigned long flags)
  75 {
  76         return -ENOSYS;
  77 }
  78
  79 static inline void migrate_page_copy(struct page *newpage,
  80                                      struct page *page) {}
  81
  82 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
  83                                   struct page *newpage, struct page *page)
  84 {
  85         return -ENOSYS;
  86 }
  87
  88 /* Possible settings for the migrate_page() method in address_operations */
  89 #define migrate_page NULL
  90 #define fail_migrate_page NULL
  91
  92 #endif /* CONFIG_MIGRATION */
  93
  94 #ifdef CONFIG_NUMA_BALANCING
  95 extern int migrate_misplaced_page(struct page *page, int node);
  96 extern int migrate_misplaced_page(struct page *page, int node);
  97 extern bool migrate_ratelimited(int node);
  98 #else
  99 static inline int migrate_misplaced_page(struct page *page, int node)
 100 {
 101         return -EAGAIN; /* can't migrate now */
 102 }
 103 static inline bool migrate_ratelimited(int node)
 104 {
 105         return false;
 106 }
 107 #endif /* CONFIG_NUMA_BALANCING */
 108
 109 #if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 110 extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 111                         struct vm_area_struct *vma,
 112                         pmd_t *pmd, pmd_t entry,
 113                         unsigned long address,
 114                         struct page *page, int node);
 115 #else
 116 static inline 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 {
 122         return -EAGAIN;
 123 }
 124 #endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
 125
 126 #endif /* _LINUX_MIGRATE_H */