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, bool offlining,
  44                         enum migrate_mode mode, int reason);
  45 extern int migrate_huge_page(struct page *, new_page_t x,
  46                         unsigned long private, bool offlining,
  47                         enum migrate_mode mode);
  48
  49 extern int fail_migrate_page(struct address_space *,
  50                         struct page *, struct page *);
  51
  52 extern int migrate_prep(void);
  53 extern int migrate_prep_local(void);
  54 extern int migrate_vmas(struct mm_struct *mm,
  55                 const nodemask_t *from, const nodemask_t *to,
  56                 unsigned long flags);
  57 extern void migrate_page_copy(struct page *newpage, struct page *page);
  58 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  59                                   struct page *newpage, struct page *page);
  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, bool offlining,
  66                 enum migrate_mode mode, int reason) { return -ENOSYS; }
  67 static inline int migrate_huge_page(struct page *page, new_page_t x,
  68                 unsigned long private, bool offlining,
  69                 enum migrate_mode mode) { return -ENOSYS; }
  70
  71 static inline int migrate_prep(void) { return -ENOSYS; }
  72 static inline int migrate_prep_local(void) { return -ENOSYS; }
  73
  74 static inline int migrate_vmas(struct mm_struct *mm,
  75                 const nodemask_t *from, const nodemask_t *to,
  76                 unsigned long flags)
  77 {
  78         return -ENOSYS;
  79 }
  80
  81 static inline void migrate_page_copy(struct page *newpage,
  82                                      struct page *page) {}
  83
  84 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
  85                                   struct page *newpage, struct page *page)
  86 {
  87         return -ENOSYS;
  88 }
  89
  90 /* Possible settings for the migrate_page() method in address_operations */
  91 #define migrate_page NULL
  92 #define fail_migrate_page NULL
  93
  94 #endif /* CONFIG_MIGRATION */
  95
  96 #ifdef CONFIG_NUMA_BALANCING
  97 extern int migrate_misplaced_page(struct page *page, int node);
  98 extern int migrate_misplaced_page(struct page *page, int node);
  99 extern bool migrate_ratelimited(int node);
 100 #else
 101 static inline int migrate_misplaced_page(struct page *page, int node)
 102 {
 103         return -EAGAIN; /* can't migrate now */
 104 }
 105 static inline bool migrate_ratelimited(int node)
 106 {
 107         return false;
 108 }
 109 #endif /* CONFIG_NUMA_BALANCING */
 110
 111 #if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 112 extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 113                         struct vm_area_struct *vma,
 114                         pmd_t *pmd, pmd_t entry,
 115                         unsigned long address,
 116                         struct page *page, int node);
 117 #else
 118 static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 119                         struct vm_area_struct *vma,
 120                         pmd_t *pmd, pmd_t entry,
 121                         unsigned long address,
 122                         struct page *page, int node)
 123 {
 124         return -EAGAIN;
 125 }
 126 #endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
 127
 128 #endif /* _LINUX_MIGRATE_H */