LXR linux/include/linux/migrate.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_MIGRATE_H
   3#define _LINUX_MIGRATE_H
   4
   5#include <linux/mm.h>
   6#include <linux/mempolicy.h>
   7#include <linux/migrate_mode.h>
   8#include <linux/hugetlb.h>
   9
  10typedef struct page *new_page_t(struct page *page, unsigned long private);
  11typedef void free_page_t(struct page *page, unsigned long private);
  12
  13struct migration_target_control;
  14
  15/*
  16 * Return values from addresss_space_operations.migratepage():
  17 * - negative errno on page migration failure;
  18 * - zero on page migration success;
  19 */
  20#define MIGRATEPAGE_SUCCESS             0
  21
  22enum migrate_reason {
  23        MR_COMPACTION,
  24        MR_MEMORY_FAILURE,
  25        MR_MEMORY_HOTPLUG,
  26        MR_SYSCALL,             /* also applies to cpusets */
  27        MR_MEMPOLICY_MBIND,
  28        MR_NUMA_MISPLACED,
  29        MR_CONTIG_RANGE,
  30        MR_LONGTERM_PIN,
  31        MR_TYPES
  32};
  33
  34/* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
  35extern const char *migrate_reason_names[MR_TYPES];
  36
  37#ifdef CONFIG_MIGRATION
  38
  39extern void putback_movable_pages(struct list_head *l);
  40extern int migrate_page(struct address_space *mapping,
  41                        struct page *newpage, struct page *page,
  42                        enum migrate_mode mode);
  43extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
  44                unsigned long private, enum migrate_mode mode, int reason);
  45extern struct page *alloc_migration_target(struct page *page, unsigned long private);
  46extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
  47
  48extern void migrate_page_states(struct page *newpage, struct page *page);
  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, int extra_count);
  54#else
  55
  56static inline void putback_movable_pages(struct list_head *l) {}
  57static inline int migrate_pages(struct list_head *l, new_page_t new,
  58                free_page_t free, unsigned long private, enum migrate_mode mode,
  59                int reason)
  60        { return -ENOSYS; }
  61static inline struct page *alloc_migration_target(struct page *page,
  62                unsigned long private)
  63        { return NULL; }
  64static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
  65        { return -EBUSY; }
  66
  67static inline void migrate_page_states(struct page *newpage, struct page *page)
  68{
  69}
  70
  71static inline void migrate_page_copy(struct page *newpage,
  72                                     struct page *page) {}
  73
  74static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
  75                                  struct page *newpage, struct page *page)
  76{
  77        return -ENOSYS;
  78}
  79#endif /* CONFIG_MIGRATION */
  80
  81#ifdef CONFIG_COMPACTION
  82extern int PageMovable(struct page *page);
  83extern void __SetPageMovable(struct page *page, struct address_space *mapping);
  84extern void __ClearPageMovable(struct page *page);
  85#else
  86static inline int PageMovable(struct page *page) { return 0; }
  87static inline void __SetPageMovable(struct page *page,
  88                                struct address_space *mapping)
  89{
  90}
  91static inline void __ClearPageMovable(struct page *page)
  92{
  93}
  94#endif
  95
  96#ifdef CONFIG_NUMA_BALANCING
  97extern int migrate_misplaced_page(struct page *page,
  98                                  struct vm_area_struct *vma, int node);
  99#else
 100static inline int migrate_misplaced_page(struct page *page,
 101                                         struct vm_area_struct *vma, int node)
 102{
 103        return -EAGAIN; /* can't migrate now */
 104}
 105#endif /* CONFIG_NUMA_BALANCING */
 106
 107#ifdef CONFIG_MIGRATION
 108
 109/*
 110 * Watch out for PAE architecture, which has an unsigned long, and might not
 111 * have enough bits to store all physical address and flags. So far we have
 112 * enough room for all our flags.
 113 */
 114#define MIGRATE_PFN_VALID       (1UL << 0)
 115#define MIGRATE_PFN_MIGRATE     (1UL << 1)
 116#define MIGRATE_PFN_LOCKED      (1UL << 2)
 117#define MIGRATE_PFN_WRITE       (1UL << 3)
 118#define MIGRATE_PFN_SHIFT       6
 119
 120static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
 121{
 122        if (!(mpfn & MIGRATE_PFN_VALID))
 123                return NULL;
 124        return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
 125}
 126
 127static inline unsigned long migrate_pfn(unsigned long pfn)
 128{
 129        return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 130}
 131
 132enum migrate_vma_direction {
 133        MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 134        MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
 135};
 136
 137struct migrate_vma {
 138        struct vm_area_struct   *vma;
 139        /*
 140         * Both src and dst array must be big enough for
 141         * (end - start) >> PAGE_SHIFT entries.
 142         *
 143         * The src array must not be modified by the caller after
 144         * migrate_vma_setup(), and must not change the dst array after
 145         * migrate_vma_pages() returns.
 146         */
 147        unsigned long           *dst;
 148        unsigned long           *src;
 149        unsigned long           cpages;
 150        unsigned long           npages;
 151        unsigned long           start;
 152        unsigned long           end;
 153
 154        /*
 155         * Set to the owner value also stored in page->pgmap->owner for
 156         * migrating out of device private memory. The flags also need to
 157         * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
 158         * The caller should always set this field when using mmu notifier
 159         * callbacks to avoid device MMU invalidations for device private
 160         * pages that are not being migrated.
 161         */
 162        void                    *pgmap_owner;
 163        unsigned long           flags;
 164};
 165
 166int migrate_vma_setup(struct migrate_vma *args);
 167void migrate_vma_pages(struct migrate_vma *migrate);
 168void migrate_vma_finalize(struct migrate_vma *migrate);
 169
 170#endif /* CONFIG_MIGRATION */
 171
 172#endif /* _LINUX_MIGRATE_H */
 173