LXR linux/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
   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_movable_pages(struct list_head *l);
  39extern int migrate_page(struct address_space *,
  40                        struct page *, struct page *, enum migrate_mode);
  41extern int migrate_pages(struct list_head *l, new_page_t x,
  42                unsigned long private, enum migrate_mode mode, int reason);
  43
  44extern int migrate_prep(void);
  45extern int migrate_prep_local(void);
  46extern int migrate_vmas(struct mm_struct *mm,
  47                const nodemask_t *from, const nodemask_t *to,
  48                unsigned long flags);
  49extern void migrate_page_copy(struct page *newpage, struct page *page);
  50extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  51                                  struct page *newpage, struct page *page);
  52extern int migrate_page_move_mapping(struct address_space *mapping,
  53                struct page *newpage, struct page *page,
  54                struct buffer_head *head, enum migrate_mode mode,
  55                int extra_count);
  56#else
  57
  58static inline void putback_movable_pages(struct list_head *l) {}
  59static inline int migrate_pages(struct list_head *l, new_page_t x,
  60                unsigned long private, enum migrate_mode mode, int reason)
  61        { return -ENOSYS; }
  62
  63static inline int migrate_prep(void) { return -ENOSYS; }
  64static inline int migrate_prep_local(void) { return -ENOSYS; }
  65
  66static inline int migrate_vmas(struct mm_struct *mm,
  67                const nodemask_t *from, const nodemask_t *to,
  68                unsigned long flags)
  69{
  70        return -ENOSYS;
  71}
  72
  73static inline void migrate_page_copy(struct page *newpage,
  74                                     struct page *page) {}
  75
  76static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
  77                                  struct page *newpage, struct page *page)
  78{
  79        return -ENOSYS;
  80}
  81
  82/* Possible settings for the migrate_page() method in address_operations */
  83#define migrate_page NULL
  84
  85#endif /* CONFIG_MIGRATION */
  86
  87#ifdef CONFIG_NUMA_BALANCING
  88extern bool pmd_trans_migrating(pmd_t pmd);
  89extern void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd);
  90extern int migrate_misplaced_page(struct page *page,
  91                                  struct vm_area_struct *vma, int node);
  92extern bool migrate_ratelimited(int node);
  93#else
  94static inline bool pmd_trans_migrating(pmd_t pmd)
  95{
  96        return false;
  97}
  98static inline void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd)
  99{
 100}
 101static inline int migrate_misplaced_page(struct page *page,
 102                                         struct vm_area_struct *vma, int node)
 103{
 104        return -EAGAIN; /* can't migrate now */
 105}
 106static inline bool migrate_ratelimited(int node)
 107{
 108        return false;
 109}
 110#endif /* CONFIG_NUMA_BALANCING */
 111
 112#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 113extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 114                        struct vm_area_struct *vma,
 115                        pmd_t *pmd, pmd_t entry,
 116                        unsigned long address,
 117                        struct page *page, int node);
 118#else
 119static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 120                        struct vm_area_struct *vma,
 121                        pmd_t *pmd, pmd_t entry,
 122                        unsigned long address,
 123                        struct page *page, int node)
 124{
 125        return -EAGAIN;
 126}
 127#endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
 128
 129#endif /* _LINUX_MIGRATE_H */
 130