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
  80#endif /* CONFIG_MIGRATION */
  81
  82#ifdef CONFIG_COMPACTION
  83extern int PageMovable(struct page *page);
  84extern void __SetPageMovable(struct page *page, struct address_space *mapping);
  85extern void __ClearPageMovable(struct page *page);
  86#else
  87static inline int PageMovable(struct page *page) { return 0; }
  88static inline void __SetPageMovable(struct page *page,
  89                                struct address_space *mapping)
  90{
  91}
  92static inline void __ClearPageMovable(struct page *page)
  93{
  94}
  95#endif
  96
  97#ifdef CONFIG_NUMA_BALANCING
  98extern bool pmd_trans_migrating(pmd_t pmd);
  99extern int migrate_misplaced_page(struct page *page,
 100                                  struct vm_area_struct *vma, int node);
 101#else
 102static inline bool pmd_trans_migrating(pmd_t pmd)
 103{
 104        return false;
 105}
 106static inline int migrate_misplaced_page(struct page *page,
 107                                         struct vm_area_struct *vma, int node)
 108{
 109        return -EAGAIN; /* can't migrate now */
 110}
 111#endif /* CONFIG_NUMA_BALANCING */
 112
 113#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 114extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 115                        struct vm_area_struct *vma,
 116                        pmd_t *pmd, pmd_t entry,
 117                        unsigned long address,
 118                        struct page *page, int node);
 119#else
 120static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 121                        struct vm_area_struct *vma,
 122                        pmd_t *pmd, pmd_t entry,
 123                        unsigned long address,
 124                        struct page *page, int node)
 125{
 126        return -EAGAIN;
 127}
 128#endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
 129
 130
 131#ifdef CONFIG_MIGRATION
 132
 133/*
 134 * Watch out for PAE architecture, which has an unsigned long, and might not
 135 * have enough bits to store all physical address and flags. So far we have
 136 * enough room for all our flags.
 137 */
 138#define MIGRATE_PFN_VALID       (1UL << 0)
 139#define MIGRATE_PFN_MIGRATE     (1UL << 1)
 140#define MIGRATE_PFN_LOCKED      (1UL << 2)
 141#define MIGRATE_PFN_WRITE       (1UL << 3)
 142#define MIGRATE_PFN_SHIFT       6
 143
 144static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
 145{
 146        if (!(mpfn & MIGRATE_PFN_VALID))
 147                return NULL;
 148        return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
 149}
 150
 151static inline unsigned long migrate_pfn(unsigned long pfn)
 152{
 153        return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 154}
 155
 156enum migrate_vma_direction {
 157        MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 158        MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
 159};
 160
 161struct migrate_vma {
 162        struct vm_area_struct   *vma;
 163        /*
 164         * Both src and dst array must be big enough for
 165         * (end - start) >> PAGE_SHIFT entries.
 166         *
 167         * The src array must not be modified by the caller after
 168         * migrate_vma_setup(), and must not change the dst array after
 169         * migrate_vma_pages() returns.
 170         */
 171        unsigned long           *dst;
 172        unsigned long           *src;
 173        unsigned long           cpages;
 174        unsigned long           npages;
 175        unsigned long           start;
 176        unsigned long           end;
 177
 178        /*
 179         * Set to the owner value also stored in page->pgmap->owner for
 180         * migrating out of device private memory. The flags also need to
 181         * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
 182         * The caller should always set this field when using mmu notifier
 183         * callbacks to avoid device MMU invalidations for device private
 184         * pages that are not being migrated.
 185         */
 186        void                    *pgmap_owner;
 187        unsigned long           flags;
 188};
 189
 190int migrate_vma_setup(struct migrate_vma *args);
 191void migrate_vma_pages(struct migrate_vma *migrate);
 192void migrate_vma_finalize(struct migrate_vma *migrate);
 193
 194#endif /* CONFIG_MIGRATION */
 195
 196#endif /* _LINUX_MIGRATE_H */
 197