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