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
  27 #ifdef CONFIG_MIGRATION
  28
  29 extern void putback_lru_pages(struct list_head *l);
  30 extern int migrate_page(struct address_space *,
  31                         struct page *, struct page *, enum migrate_mode);
  32 extern int migrate_pages(struct list_head *l, new_page_t x,
  33                         unsigned long private, bool offlining,
  34                         enum migrate_mode mode);
  35 extern int migrate_huge_page(struct page *, new_page_t x,
  36                         unsigned long private, bool offlining,
  37                         enum migrate_mode mode);
  38
  39 extern int fail_migrate_page(struct address_space *,
  40                         struct page *, struct page *);
  41
  42 extern int migrate_prep(void);
  43 extern int migrate_prep_local(void);
  44 extern int migrate_vmas(struct mm_struct *mm,
  45                 const nodemask_t *from, const nodemask_t *to,
  46                 unsigned long flags);
  47 extern void migrate_page_copy(struct page *newpage, struct page *page);
  48 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  49                                   struct page *newpage, struct page *page);
  50 #else
  51
  52 static inline void putback_lru_pages(struct list_head *l) {}
  53 static inline int migrate_pages(struct list_head *l, new_page_t x,
  54                 unsigned long private, bool offlining,
  55                 enum migrate_mode mode) { return -ENOSYS; }
  56 static inline int migrate_huge_page(struct page *page, new_page_t x,
  57                 unsigned long private, bool offlining,
  58                 enum migrate_mode mode) { return -ENOSYS; }
  59
  60 static inline int migrate_prep(void) { return -ENOSYS; }
  61 static inline int migrate_prep_local(void) { return -ENOSYS; }
  62
  63 static inline int migrate_vmas(struct mm_struct *mm,
  64                 const nodemask_t *from, const nodemask_t *to,
  65                 unsigned long flags)
  66 {
  67         return -ENOSYS;
  68 }
  69
  70 static inline void migrate_page_copy(struct page *newpage,
  71                                      struct page *page) {}
  72
  73 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
  74                                   struct page *newpage, struct page *page)
  75 {
  76         return -ENOSYS;
  77 }
  78
  79 /* Possible settings for the migrate_page() method in address_operations */
  80 #define migrate_page NULL
  81 #define fail_migrate_page NULL
  82
  83 #endif /* CONFIG_MIGRATION */
  84 #endif /* _LINUX_MIGRATE_H */