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, enum migrate_mode mode, int reason);
  44extern int migrate_huge_page(struct page *, new_page_t x,
  45                unsigned long private, enum migrate_mode mode);
  46
  47extern int fail_migrate_page(struct address_space *,
  48                        struct page *, struct page *);
  49
  50extern int migrate_prep(void);
  51extern int migrate_prep_local(void);
  52extern int migrate_vmas(struct mm_struct *mm,
  53                const nodemask_t *from, const nodemask_t *to,
  54                unsigned long flags);
  55extern void migrate_page_copy(struct page *newpage, struct page *page);
  56extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  57                                  struct page *newpage, struct page *page);
  58#else
  59
  60static inline void putback_lru_pages(struct list_head *l) {}
  61static inline void putback_movable_pages(struct list_head *l) {}
  62static 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; }
  65static inline int migrate_huge_page(struct page *page, new_page_t x,
  66                unsigned long private, enum migrate_mode mode)
  67        { return -ENOSYS; }
  68
  69static inline int migrate_prep(void) { return -ENOSYS; }
  70static inline int migrate_prep_local(void) { return -ENOSYS; }
  71
  72static 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
  79static inline void migrate_page_copy(struct page *newpage,
  80                                     struct page *page) {}
  81
  82static 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
  95extern int migrate_misplaced_page(struct page *page, int node);
  96extern int migrate_misplaced_page(struct page *page, int node);
  97extern bool migrate_ratelimited(int node);
  98#else
  99static inline int migrate_misplaced_page(struct page *page, int node)
 100{
 101        return -EAGAIN; /* can't migrate now */
 102}
 103static 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)
 110extern 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
 116static 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 */
 127
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