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_DEMOTION,
  32         MR_TYPES
  33 };
  34
  35 /* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
  36 extern const char *migrate_reason_names[MR_TYPES];
  37
  38 #ifdef CONFIG_MIGRATION
  39
  40 extern void putback_movable_pages(struct list_head *l);
  41 extern int migrate_page(struct address_space *mapping,
  42                         struct page *newpage, struct page *page,
  43                         enum migrate_mode mode);
  44 extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
  45                 unsigned long private, enum migrate_mode mode, int reason,
  46                 unsigned int *ret_succeeded);
  47 extern struct page *alloc_migration_target(struct page *page, unsigned long private);
  48 extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
  49
  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, unsigned int *ret_succeeded)
  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 void migrate_page_states(struct page *newpage, struct page *page)
  70 {
  71 }
  72
  73 static inline void migrate_page_copy(struct page *newpage,
  74                                      struct page *page) {}
  75
  76 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
  77                                   struct page *newpage, struct page *page)
  78 {
  79         return -ENOSYS;
  80 }
  81 #endif /* CONFIG_MIGRATION */
  82
  83 #ifdef CONFIG_COMPACTION
  84 extern int PageMovable(struct page *page);
  85 extern void __SetPageMovable(struct page *page, struct address_space *mapping);
  86 extern void __ClearPageMovable(struct page *page);
  87 #else
  88 static inline int PageMovable(struct page *page) { return 0; }
  89 static inline void __SetPageMovable(struct page *page,
  90                                 struct address_space *mapping)
  91 {
  92 }
  93 static inline void __ClearPageMovable(struct page *page)
  94 {
  95 }
  96 #endif
  97
  98 #ifdef CONFIG_NUMA_BALANCING
  99 extern int migrate_misplaced_page(struct page *page,
 100                                   struct vm_area_struct *vma, int node);
 101 #else
 102 static inline int migrate_misplaced_page(struct page *page,
 103                                          struct vm_area_struct *vma, int node)
 104 {
 105         return -EAGAIN; /* can't migrate now */
 106 }
 107 #endif /* CONFIG_NUMA_BALANCING */
 108
 109 #ifdef CONFIG_MIGRATION
 110
 111 /*
 112  * Watch out for PAE architecture, which has an unsigned long, and might not
 113  * have enough bits to store all physical address and flags. So far we have
 114  * enough room for all our flags.
 115  */
 116 #define MIGRATE_PFN_VALID       (1UL << 0)
 117 #define MIGRATE_PFN_MIGRATE     (1UL << 1)
 118 #define MIGRATE_PFN_LOCKED      (1UL << 2)
 119 #define MIGRATE_PFN_WRITE       (1UL << 3)
 120 #define MIGRATE_PFN_SHIFT       6
 121
 122 static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
 123 {
 124         if (!(mpfn & MIGRATE_PFN_VALID))
 125                 return NULL;
 126         return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
 127 }
 128
 129 static inline unsigned long migrate_pfn(unsigned long pfn)
 130 {
 131         return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 132 }
 133
 134 enum migrate_vma_direction {
 135         MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 136         MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
 137 };
 138
 139 struct migrate_vma {
 140         struct vm_area_struct   *vma;
 141         /*
 142          * Both src and dst array must be big enough for
 143          * (end - start) >> PAGE_SHIFT entries.
 144          *
 145          * The src array must not be modified by the caller after
 146          * migrate_vma_setup(), and must not change the dst array after
 147          * migrate_vma_pages() returns.
 148          */
 149         unsigned long           *dst;
 150         unsigned long           *src;
 151         unsigned long           cpages;
 152         unsigned long           npages;
 153         unsigned long           start;
 154         unsigned long           end;
 155
 156         /*
 157          * Set to the owner value also stored in page->pgmap->owner for
 158          * migrating out of device private memory. The flags also need to
 159          * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
 160          * The caller should always set this field when using mmu notifier
 161          * callbacks to avoid device MMU invalidations for device private
 162          * pages that are not being migrated.
 163          */
 164         void                    *pgmap_owner;
 165         unsigned long           flags;
 166 };
 167
 168 int migrate_vma_setup(struct migrate_vma *args);
 169 void migrate_vma_pages(struct migrate_vma *migrate);
 170 void migrate_vma_finalize(struct migrate_vma *migrate);
 171 int next_demotion_node(int node);
 172
 173 #else /* CONFIG_MIGRATION disabled: */
 174
 175 static inline int next_demotion_node(int node)
 176 {
 177         return NUMA_NO_NODE;
 178 }
 179
 180 #endif /* CONFIG_MIGRATION */
 181
 182 #endif /* _LINUX_MIGRATE_H */