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 extern void copy_huge_page(struct page *dst, struct page *src);
  55 #else
  56
  57 static inline void putback_movable_pages(struct list_head *l) {}
  58 static inline int migrate_pages(struct list_head *l, new_page_t new,
  59                 free_page_t free, unsigned long private, enum migrate_mode mode,
  60                 int reason)
  61         { return -ENOSYS; }
  62 static inline struct page *alloc_migration_target(struct page *page,
  63                 unsigned long private)
  64         { return NULL; }
  65 static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
  66         { return -EBUSY; }
  67
  68 static inline void migrate_page_states(struct page *newpage, struct page *page)
  69 {
  70 }
  71
  72 static inline void migrate_page_copy(struct page *newpage,
  73                                      struct page *page) {}
  74
  75 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
  76                                   struct page *newpage, struct page *page)
  77 {
  78         return -ENOSYS;
  79 }
  80
  81 static inline void copy_huge_page(struct page *dst, struct page *src)
  82 {
  83 }
  84 #endif /* CONFIG_MIGRATION */
  85
  86 #ifdef CONFIG_COMPACTION
  87 extern int PageMovable(struct page *page);
  88 extern void __SetPageMovable(struct page *page, struct address_space *mapping);
  89 extern void __ClearPageMovable(struct page *page);
  90 #else
  91 static inline int PageMovable(struct page *page) { return 0; }
  92 static inline void __SetPageMovable(struct page *page,
  93                                 struct address_space *mapping)
  94 {
  95 }
  96 static inline void __ClearPageMovable(struct page *page)
  97 {
  98 }
  99 #endif
 100
 101 #ifdef CONFIG_NUMA_BALANCING
 102 extern int migrate_misplaced_page(struct page *page,
 103                                   struct vm_area_struct *vma, int node);
 104 #else
 105 static inline int migrate_misplaced_page(struct page *page,
 106                                          struct vm_area_struct *vma, int node)
 107 {
 108         return -EAGAIN; /* can't migrate now */
 109 }
 110 #endif /* CONFIG_NUMA_BALANCING */
 111
 112 #ifdef CONFIG_MIGRATION
 113
 114 /*
 115  * Watch out for PAE architecture, which has an unsigned long, and might not
 116  * have enough bits to store all physical address and flags. So far we have
 117  * enough room for all our flags.
 118  */
 119 #define MIGRATE_PFN_VALID       (1UL << 0)
 120 #define MIGRATE_PFN_MIGRATE     (1UL << 1)
 121 #define MIGRATE_PFN_LOCKED      (1UL << 2)
 122 #define MIGRATE_PFN_WRITE       (1UL << 3)
 123 #define MIGRATE_PFN_SHIFT       6
 124
 125 static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
 126 {
 127         if (!(mpfn & MIGRATE_PFN_VALID))
 128                 return NULL;
 129         return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
 130 }
 131
 132 static inline unsigned long migrate_pfn(unsigned long pfn)
 133 {
 134         return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 135 }
 136
 137 enum migrate_vma_direction {
 138         MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 139         MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
 140 };
 141
 142 struct migrate_vma {
 143         struct vm_area_struct   *vma;
 144         /*
 145          * Both src and dst array must be big enough for
 146          * (end - start) >> PAGE_SHIFT entries.
 147          *
 148          * The src array must not be modified by the caller after
 149          * migrate_vma_setup(), and must not change the dst array after
 150          * migrate_vma_pages() returns.
 151          */
 152         unsigned long           *dst;
 153         unsigned long           *src;
 154         unsigned long           cpages;
 155         unsigned long           npages;
 156         unsigned long           start;
 157         unsigned long           end;
 158
 159         /*
 160          * Set to the owner value also stored in page->pgmap->owner for
 161          * migrating out of device private memory. The flags also need to
 162          * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
 163          * The caller should always set this field when using mmu notifier
 164          * callbacks to avoid device MMU invalidations for device private
 165          * pages that are not being migrated.
 166          */
 167         void                    *pgmap_owner;
 168         unsigned long           flags;
 169 };
 170
 171 int migrate_vma_setup(struct migrate_vma *args);
 172 void migrate_vma_pages(struct migrate_vma *migrate);
 173 void migrate_vma_finalize(struct migrate_vma *migrate);
 174
 175 #endif /* CONFIG_MIGRATION */
 176
 177 #endif /* _LINUX_MIGRATE_H */