linux/include/linux/migrate.h
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   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
   8typedef 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                                           */
  26enum 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
  38extern void putback_lru_pages(struct list_head *l);
  39extern void putback_movable_pages(struct list_head *l);
  40extern int migrate_page(struct address_space *,
  41                        struct page *, struct page *, enum migrate_mode);
  42extern int migrate_pages(struct list_head *l, new_page_t x,
  43                        unsigned long private, bool offlining,
  44                        enum migrate_mode mode, int reason);
  45extern int migrate_huge_page(struct page *, new_page_t x,
  46                        unsigned long private, bool offlining,
  47                        enum migrate_mode mode);
  48
  49extern int fail_migrate_page(struct address_space *,
  50                        struct page *, struct page *);
  51
  52extern int migrate_prep(void);
  53extern int migrate_prep_local(void);
  54extern int migrate_vmas(struct mm_struct *mm,
  55                const nodemask_t *from, const nodemask_t *to,
  56                unsigned long flags);
  57extern void migrate_page_copy(struct page *newpage, struct page *page);
  58extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  59                                  struct page *newpage, struct page *page);
  60#else
  61
  62static inline void putback_lru_pages(struct list_head *l) {}
  63static inline void putback_movable_pages(struct list_head *l) {}
  64static 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; }
  67static 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
  71static inline int migrate_prep(void) { return -ENOSYS; }
  72static inline int migrate_prep_local(void) { return -ENOSYS; }
  73
  74static 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
  81static inline void migrate_page_copy(struct page *newpage,
  82                                     struct page *page) {}
  83
  84static 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
  97extern int migrate_misplaced_page(struct page *page, int node);
  98extern int migrate_misplaced_page(struct page *page, int node);
  99extern bool migrate_ratelimited(int node);
 100#else
 101static inline int migrate_misplaced_page(struct page *page, int node)
 102{
 103        return -EAGAIN; /* can't migrate now */
 104}
 105static 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)
 112extern 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
 118static 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 */
 129
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