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 /*
  14  * Return values from addresss_space_operations.migratepage():
  15  * - negative errno on page migration failure;
  16  * - zero on page migration success;
  17  */
  18 #define MIGRATEPAGE_SUCCESS             0
  19
  20 enum migrate_reason {
  21         MR_COMPACTION,
  22         MR_MEMORY_FAILURE,
  23         MR_MEMORY_HOTPLUG,
  24         MR_SYSCALL,             /* also applies to cpusets */
  25         MR_MEMPOLICY_MBIND,
  26         MR_NUMA_MISPLACED,
  27         MR_CONTIG_RANGE,
  28         MR_TYPES
  29 };
  30
  31 /* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
  32 extern const char *migrate_reason_names[MR_TYPES];
  33
  34 static inline struct page *new_page_nodemask(struct page *page,
  35                                 int preferred_nid, nodemask_t *nodemask)
  36 {
  37         gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL;
  38         unsigned int order = 0;
  39         struct page *new_page = NULL;
  40
  41         if (PageHuge(page))
  42                 return alloc_huge_page_nodemask(page_hstate(compound_head(page)),
  43                                 preferred_nid, nodemask);
  44
  45         if (PageTransHuge(page)) {
  46                 gfp_mask |= GFP_TRANSHUGE;
  47                 order = HPAGE_PMD_ORDER;
  48         }
  49
  50         if (PageHighMem(page) || (zone_idx(page_zone(page)) == ZONE_MOVABLE))
  51                 gfp_mask |= __GFP_HIGHMEM;
  52
  53         new_page = __alloc_pages_nodemask(gfp_mask, order,
  54                                 preferred_nid, nodemask);
  55
  56         if (new_page && PageTransHuge(new_page))
  57                 prep_transhuge_page(new_page);
  58
  59         return new_page;
  60 }
  61
  62 #ifdef CONFIG_MIGRATION
  63
  64 extern void putback_movable_pages(struct list_head *l);
  65 extern int migrate_page(struct address_space *mapping,
  66                         struct page *newpage, struct page *page,
  67                         enum migrate_mode mode);
  68 extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
  69                 unsigned long private, enum migrate_mode mode, int reason);
  70 extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
  71 extern void putback_movable_page(struct page *page);
  72
  73 extern int migrate_prep(void);
  74 extern int migrate_prep_local(void);
  75 extern void migrate_page_states(struct page *newpage, struct page *page);
  76 extern void migrate_page_copy(struct page *newpage, struct page *page);
  77 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
  78                                   struct page *newpage, struct page *page);
  79 extern int migrate_page_move_mapping(struct address_space *mapping,
  80                 struct page *newpage, struct page *page, int extra_count);
  81 #else
  82
  83 static inline void putback_movable_pages(struct list_head *l) {}
  84 static inline int migrate_pages(struct list_head *l, new_page_t new,
  85                 free_page_t free, unsigned long private, enum migrate_mode mode,
  86                 int reason)
  87         { return -ENOSYS; }
  88 static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
  89         { return -EBUSY; }
  90
  91 static inline int migrate_prep(void) { return -ENOSYS; }
  92 static inline int migrate_prep_local(void) { return -ENOSYS; }
  93
  94 static inline void migrate_page_states(struct page *newpage, struct page *page)
  95 {
  96 }
  97
  98 static inline void migrate_page_copy(struct page *newpage,
  99                                      struct page *page) {}
 100
 101 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
 102                                   struct page *newpage, struct page *page)
 103 {
 104         return -ENOSYS;
 105 }
 106
 107 #endif /* CONFIG_MIGRATION */
 108
 109 #ifdef CONFIG_COMPACTION
 110 extern int PageMovable(struct page *page);
 111 extern void __SetPageMovable(struct page *page, struct address_space *mapping);
 112 extern void __ClearPageMovable(struct page *page);
 113 #else
 114 static inline int PageMovable(struct page *page) { return 0; };
 115 static inline void __SetPageMovable(struct page *page,
 116                                 struct address_space *mapping)
 117 {
 118 }
 119 static inline void __ClearPageMovable(struct page *page)
 120 {
 121 }
 122 #endif
 123
 124 #ifdef CONFIG_NUMA_BALANCING
 125 extern bool pmd_trans_migrating(pmd_t pmd);
 126 extern int migrate_misplaced_page(struct page *page,
 127                                   struct vm_area_struct *vma, int node);
 128 #else
 129 static inline bool pmd_trans_migrating(pmd_t pmd)
 130 {
 131         return false;
 132 }
 133 static inline int migrate_misplaced_page(struct page *page,
 134                                          struct vm_area_struct *vma, int node)
 135 {
 136         return -EAGAIN; /* can't migrate now */
 137 }
 138 #endif /* CONFIG_NUMA_BALANCING */
 139
 140 #if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 141 extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 142                         struct vm_area_struct *vma,
 143                         pmd_t *pmd, pmd_t entry,
 144                         unsigned long address,
 145                         struct page *page, int node);
 146 #else
 147 static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 148                         struct vm_area_struct *vma,
 149                         pmd_t *pmd, pmd_t entry,
 150                         unsigned long address,
 151                         struct page *page, int node)
 152 {
 153         return -EAGAIN;
 154 }
 155 #endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
 156
 157
 158 #ifdef CONFIG_MIGRATION
 159
 160 /*
 161  * Watch out for PAE architecture, which has an unsigned long, and might not
 162  * have enough bits to store all physical address and flags. So far we have
 163  * enough room for all our flags.
 164  */
 165 #define MIGRATE_PFN_VALID       (1UL << 0)
 166 #define MIGRATE_PFN_MIGRATE     (1UL << 1)
 167 #define MIGRATE_PFN_LOCKED      (1UL << 2)
 168 #define MIGRATE_PFN_WRITE       (1UL << 3)
 169 #define MIGRATE_PFN_SHIFT       6
 170
 171 static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
 172 {
 173         if (!(mpfn & MIGRATE_PFN_VALID))
 174                 return NULL;
 175         return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
 176 }
 177
 178 static inline unsigned long migrate_pfn(unsigned long pfn)
 179 {
 180         return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 181 }
 182
 183 struct migrate_vma {
 184         struct vm_area_struct   *vma;
 185         /*
 186          * Both src and dst array must be big enough for
 187          * (end - start) >> PAGE_SHIFT entries.
 188          *
 189          * The src array must not be modified by the caller after
 190          * migrate_vma_setup(), and must not change the dst array after
 191          * migrate_vma_pages() returns.
 192          */
 193         unsigned long           *dst;
 194         unsigned long           *src;
 195         unsigned long           cpages;
 196         unsigned long           npages;
 197         unsigned long           start;
 198         unsigned long           end;
 199 };
 200
 201 int migrate_vma_setup(struct migrate_vma *args);
 202 void migrate_vma_pages(struct migrate_vma *migrate);
 203 void migrate_vma_finalize(struct migrate_vma *migrate);
 204
 205 #endif /* CONFIG_MIGRATION */
 206
 207 #endif /* _LINUX_MIGRATE_H */