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_LONGTERM_PIN,
  31         MR_TYPES
  32 };
  33
  34 /* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
  35 extern const char *migrate_reason_names[MR_TYPES];
  36
  37 #ifdef CONFIG_MIGRATION
  38
  39 extern void putback_movable_pages(struct list_head *l);
  40 extern int migrate_page(struct address_space *mapping,
  41                         struct page *newpage, struct page *page,
  42                         enum migrate_mode mode);
  43 extern 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);
  45 extern struct page *alloc_migration_target(struct page *page, unsigned long private);
  46 extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
  47
  48 extern void migrate_page_states(struct page *newpage, struct page *page);
  49 extern void migrate_page_copy(struct page *newpage, struct page *page);
  50 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  51                                   struct page *newpage, struct page *page);
  52 extern int migrate_page_move_mapping(struct address_space *mapping,
  53                 struct page *newpage, struct page *page, int extra_count);
  54 #else
  55
  56 static inline void putback_movable_pages(struct list_head *l) {}
  57 static 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; }
  61 static inline struct page *alloc_migration_target(struct page *page,
  62                 unsigned long private)
  63         { return NULL; }
  64 static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
  65         { return -EBUSY; }
  66
  67 static inline void migrate_page_states(struct page *newpage, struct page *page)
  68 {
  69 }
  70
  71 static inline void migrate_page_copy(struct page *newpage,
  72                                      struct page *page) {}
  73
  74 static 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
  83 extern int PageMovable(struct page *page);
  84 extern void __SetPageMovable(struct page *page, struct address_space *mapping);
  85 extern void __ClearPageMovable(struct page *page);
  86 #else
  87 static inline int PageMovable(struct page *page) { return 0; }
  88 static inline void __SetPageMovable(struct page *page,
  89                                 struct address_space *mapping)
  90 {
  91 }
  92 static inline void __ClearPageMovable(struct page *page)
  93 {
  94 }
  95 #endif
  96
  97 #ifdef CONFIG_NUMA_BALANCING
  98 extern bool pmd_trans_migrating(pmd_t pmd);
  99 extern int migrate_misplaced_page(struct page *page,
 100                                   struct vm_area_struct *vma, int node);
 101 #else
 102 static inline bool pmd_trans_migrating(pmd_t pmd)
 103 {
 104         return false;
 105 }
 106 static 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)
 114 extern 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
 120 static 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
 144 static 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
 151 static inline unsigned long migrate_pfn(unsigned long pfn)
 152 {
 153         return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 154 }
 155
 156 enum migrate_vma_direction {
 157         MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 158         MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
 159 };
 160
 161 struct 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
 190 int migrate_vma_setup(struct migrate_vma *args);
 191 void migrate_vma_pages(struct migrate_vma *migrate);
 192 void migrate_vma_finalize(struct migrate_vma *migrate);
 193
 194 #endif /* CONFIG_MIGRATION */
 195
 196 #endif /* _LINUX_MIGRATE_H */