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_TYPES
  31};
  32
  33/* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
  34extern const char *migrate_reason_names[MR_TYPES];
  35
  36#ifdef CONFIG_MIGRATION
  37
  38extern void putback_movable_pages(struct list_head *l);
  39extern int migrate_page(struct address_space *mapping,
  40                        struct page *newpage, struct page *page,
  41                        enum migrate_mode mode);
  42extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
  43                unsigned long private, enum migrate_mode mode, int reason);
  44extern struct page *alloc_migration_target(struct page *page, unsigned long private);
  45extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
  46extern void putback_movable_page(struct page *page);
  47
  48extern int migrate_prep(void);
  49extern int migrate_prep_local(void);
  50extern void migrate_page_states(struct page *newpage, struct page *page);
  51extern void migrate_page_copy(struct page *newpage, struct page *page);
  52extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  53                                  struct page *newpage, struct page *page);
  54extern int migrate_page_move_mapping(struct address_space *mapping,
  55                struct page *newpage, struct page *page, 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 new,
  60                free_page_t free, unsigned long private, enum migrate_mode mode,
  61                int reason)
  62        { return -ENOSYS; }
  63static inline struct page *alloc_migration_target(struct page *page,
  64                unsigned long private)
  65        { return NULL; }
  66static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
  67        { return -EBUSY; }
  68
  69static inline int migrate_prep(void) { return -ENOSYS; }
  70static inline int migrate_prep_local(void) { return -ENOSYS; }
  71
  72static inline void migrate_page_states(struct page *newpage, struct page *page)
  73{
  74}
  75
  76static inline void migrate_page_copy(struct page *newpage,
  77                                     struct page *page) {}
  78
  79static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
  80                                  struct page *newpage, struct page *page)
  81{
  82        return -ENOSYS;
  83}
  84
  85#endif /* CONFIG_MIGRATION */
  86
  87#ifdef CONFIG_COMPACTION
  88extern int PageMovable(struct page *page);
  89extern void __SetPageMovable(struct page *page, struct address_space *mapping);
  90extern void __ClearPageMovable(struct page *page);
  91#else
  92static inline int PageMovable(struct page *page) { return 0; };
  93static inline void __SetPageMovable(struct page *page,
  94                                struct address_space *mapping)
  95{
  96}
  97static inline void __ClearPageMovable(struct page *page)
  98{
  99}
 100#endif
 101
 102#ifdef CONFIG_NUMA_BALANCING
 103extern bool pmd_trans_migrating(pmd_t pmd);
 104extern int migrate_misplaced_page(struct page *page,
 105                                  struct vm_area_struct *vma, int node);
 106#else
 107static inline bool pmd_trans_migrating(pmd_t pmd)
 108{
 109        return false;
 110}
 111static inline int migrate_misplaced_page(struct page *page,
 112                                         struct vm_area_struct *vma, int node)
 113{
 114        return -EAGAIN; /* can't migrate now */
 115}
 116#endif /* CONFIG_NUMA_BALANCING */
 117
 118#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 119extern 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#else
 125static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 126                        struct vm_area_struct *vma,
 127                        pmd_t *pmd, pmd_t entry,
 128                        unsigned long address,
 129                        struct page *page, int node)
 130{
 131        return -EAGAIN;
 132}
 133#endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
 134
 135
 136#ifdef CONFIG_MIGRATION
 137
 138/*
 139 * Watch out for PAE architecture, which has an unsigned long, and might not
 140 * have enough bits to store all physical address and flags. So far we have
 141 * enough room for all our flags.
 142 */
 143#define MIGRATE_PFN_VALID       (1UL << 0)
 144#define MIGRATE_PFN_MIGRATE     (1UL << 1)
 145#define MIGRATE_PFN_LOCKED      (1UL << 2)
 146#define MIGRATE_PFN_WRITE       (1UL << 3)
 147#define MIGRATE_PFN_SHIFT       6
 148
 149static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
 150{
 151        if (!(mpfn & MIGRATE_PFN_VALID))
 152                return NULL;
 153        return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
 154}
 155
 156static inline unsigned long migrate_pfn(unsigned long pfn)
 157{
 158        return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 159}
 160
 161enum migrate_vma_direction {
 162        MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 163        MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
 164};
 165
 166struct migrate_vma {
 167        struct vm_area_struct   *vma;
 168        /*
 169         * Both src and dst array must be big enough for
 170         * (end - start) >> PAGE_SHIFT entries.
 171         *
 172         * The src array must not be modified by the caller after
 173         * migrate_vma_setup(), and must not change the dst array after
 174         * migrate_vma_pages() returns.
 175         */
 176        unsigned long           *dst;
 177        unsigned long           *src;
 178        unsigned long           cpages;
 179        unsigned long           npages;
 180        unsigned long           start;
 181        unsigned long           end;
 182
 183        /*
 184         * Set to the owner value also stored in page->pgmap->owner for
 185         * migrating out of device private memory. The flags also need to
 186         * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
 187         * The caller should always set this field when using mmu notifier
 188         * callbacks to avoid device MMU invalidations for device private
 189         * pages that are not being migrated.
 190         */
 191        void                    *pgmap_owner;
 192        unsigned long           flags;
 193};
 194
 195int migrate_vma_setup(struct migrate_vma *args);
 196void migrate_vma_pages(struct migrate_vma *migrate);
 197void migrate_vma_finalize(struct migrate_vma *migrate);
 198
 199#endif /* CONFIG_MIGRATION */
 200
 201#endif /* _LINUX_MIGRATE_H */
 202