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
  10 typedef struct page *new_page_t(struct page *page, unsigned long private);
  11 typedef void free_page_t(struct page *page, unsigned long private);
  12
  13 struct 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
  22 enum 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 */
  34 extern const char *migrate_reason_names[MR_TYPES];
  35
  36 #ifdef CONFIG_MIGRATION
  37
  38 extern void putback_movable_pages(struct list_head *l);
  39 extern int migrate_page(struct address_space *mapping,
  40                         struct page *newpage, struct page *page,
  41                         enum migrate_mode mode);
  42 extern 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);
  44 extern struct page *alloc_migration_target(struct page *page, unsigned long private);
  45 extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
  46 extern void putback_movable_page(struct page *page);
  47
  48 extern void migrate_prep(void);
  49 extern void migrate_prep_local(void);
  50 extern void migrate_page_states(struct page *newpage, struct page *page);
  51 extern void migrate_page_copy(struct page *newpage, struct page *page);
  52 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  53                                   struct page *newpage, struct page *page);
  54 extern int migrate_page_move_mapping(struct address_space *mapping,
  55                 struct page *newpage, struct page *page, int extra_count);
  56 #else
  57
  58 static inline void putback_movable_pages(struct list_head *l) {}
  59 static 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; }
  63 static inline struct page *alloc_migration_target(struct page *page,
  64                 unsigned long private)
  65         { return NULL; }
  66 static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
  67         { return -EBUSY; }
  68
  69 static inline int migrate_prep(void) { return -ENOSYS; }
  70 static inline int migrate_prep_local(void) { return -ENOSYS; }
  71
  72 static inline void migrate_page_states(struct page *newpage, struct page *page)
  73 {
  74 }
  75
  76 static inline void migrate_page_copy(struct page *newpage,
  77                                      struct page *page) {}
  78
  79 static 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
  88 extern int PageMovable(struct page *page);
  89 extern void __SetPageMovable(struct page *page, struct address_space *mapping);
  90 extern void __ClearPageMovable(struct page *page);
  91 #else
  92 static inline int PageMovable(struct page *page) { return 0; };
  93 static inline void __SetPageMovable(struct page *page,
  94                                 struct address_space *mapping)
  95 {
  96 }
  97 static inline void __ClearPageMovable(struct page *page)
  98 {
  99 }
 100 #endif
 101
 102 #ifdef CONFIG_NUMA_BALANCING
 103 extern bool pmd_trans_migrating(pmd_t pmd);
 104 extern int migrate_misplaced_page(struct page *page,
 105                                   struct vm_area_struct *vma, int node);
 106 #else
 107 static inline bool pmd_trans_migrating(pmd_t pmd)
 108 {
 109         return false;
 110 }
 111 static 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)
 119 extern 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
 125 static 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
 149 static 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
 156 static inline unsigned long migrate_pfn(unsigned long pfn)
 157 {
 158         return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 159 }
 160
 161 enum migrate_vma_direction {
 162         MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 163         MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
 164 };
 165
 166 struct 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
 195 int migrate_vma_setup(struct migrate_vma *args);
 196 void migrate_vma_pages(struct migrate_vma *migrate);
 197 void migrate_vma_finalize(struct migrate_vma *migrate);
 198
 199 #endif /* CONFIG_MIGRATION */
 200
 201 #endif /* _LINUX_MIGRATE_H */