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_TYPES
31 };
32
33 /* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
34 extern const char *migrate_reason_names[MR_TYPES];
35
36 #ifdef CONFIG_MIGRATION
37
38 extern void putback_movable_pages(struct list_head *l);
39 extern int migrate_page(struct address_space *mapping,
40 struct page *newpage, struct page *page,
41 enum migrate_mode mode);
42 extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
43 unsigned long private, enum migrate_mode mode, int reason);
44 extern struct page *alloc_migration_target(struct page *page, unsigned long private);
45 extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
46 extern void putback_movable_page(struct page *page);
47
48 extern int migrate_prep(void);
49 extern int migrate_prep_local(void);
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
putback_movable_pages(struct list_head * l)58 static inline void putback_movable_pages(struct list_head *l) {}
migrate_pages(struct list_head * l,new_page_t new,free_page_t free,unsigned long private,enum migrate_mode mode,int reason)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)
62 { return -ENOSYS; }
alloc_migration_target(struct page * page,unsigned long private)63 static inline struct page *alloc_migration_target(struct page *page,
64 unsigned long private)
65 { return NULL; }
isolate_movable_page(struct page * page,isolate_mode_t mode)66 static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
67 { return -EBUSY; }
68
migrate_prep(void)69 static inline int migrate_prep(void) { return -ENOSYS; }
migrate_prep_local(void)70 static inline int migrate_prep_local(void) { return -ENOSYS; }
71
migrate_page_states(struct page * newpage,struct page * page)72 static inline void migrate_page_states(struct page *newpage, struct page *page)
73 {
74 }
75
migrate_page_copy(struct page * newpage,struct page * page)76 static inline void migrate_page_copy(struct page *newpage,
77 struct page *page) {}
78
migrate_huge_page_move_mapping(struct address_space * mapping,struct page * newpage,struct page * page)79 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
80 struct page *newpage, struct page *page)
81 {
82 return -ENOSYS;
83 }
84
85 #endif /* CONFIG_MIGRATION */
86
87 #ifdef CONFIG_COMPACTION
88 extern int PageMovable(struct page *page);
89 extern void __SetPageMovable(struct page *page, struct address_space *mapping);
90 extern void __ClearPageMovable(struct page *page);
91 #else
PageMovable(struct page * page)92 static inline int PageMovable(struct page *page) { return 0; };
__SetPageMovable(struct page * page,struct address_space * mapping)93 static inline void __SetPageMovable(struct page *page,
94 struct address_space *mapping)
95 {
96 }
__ClearPageMovable(struct page * page)97 static inline void __ClearPageMovable(struct page *page)
98 {
99 }
100 #endif
101
102 #ifdef CONFIG_NUMA_BALANCING
103 extern bool pmd_trans_migrating(pmd_t pmd);
104 extern int migrate_misplaced_page(struct page *page,
105 struct vm_area_struct *vma, int node);
106 #else
pmd_trans_migrating(pmd_t pmd)107 static inline bool pmd_trans_migrating(pmd_t pmd)
108 {
109 return false;
110 }
migrate_misplaced_page(struct page * page,struct vm_area_struct * vma,int node)111 static inline int migrate_misplaced_page(struct page *page,
112 struct vm_area_struct *vma, int node)
113 {
114 return -EAGAIN; /* can't migrate now */
115 }
116 #endif /* CONFIG_NUMA_BALANCING */
117
118 #if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
119 extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
120 struct vm_area_struct *vma,
121 pmd_t *pmd, pmd_t entry,
122 unsigned long address,
123 struct page *page, int node);
124 #else
migrate_misplaced_transhuge_page(struct mm_struct * mm,struct vm_area_struct * vma,pmd_t * pmd,pmd_t entry,unsigned long address,struct page * page,int node)125 static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
126 struct vm_area_struct *vma,
127 pmd_t *pmd, pmd_t entry,
128 unsigned long address,
129 struct page *page, int node)
130 {
131 return -EAGAIN;
132 }
133 #endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
134
135
136 #ifdef CONFIG_MIGRATION
137
138 /*
139 * Watch out for PAE architecture, which has an unsigned long, and might not
140 * have enough bits to store all physical address and flags. So far we have
141 * enough room for all our flags.
142 */
143 #define MIGRATE_PFN_VALID (1UL << 0)
144 #define MIGRATE_PFN_MIGRATE (1UL << 1)
145 #define MIGRATE_PFN_LOCKED (1UL << 2)
146 #define MIGRATE_PFN_WRITE (1UL << 3)
147 #define MIGRATE_PFN_SHIFT 6
148
migrate_pfn_to_page(unsigned long mpfn)149 static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
150 {
151 if (!(mpfn & MIGRATE_PFN_VALID))
152 return NULL;
153 return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
154 }
155
migrate_pfn(unsigned long pfn)156 static inline unsigned long migrate_pfn(unsigned long pfn)
157 {
158 return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
159 }
160
161 enum migrate_vma_direction {
162 MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
163 MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
164 };
165
166 struct migrate_vma {
167 struct vm_area_struct *vma;
168 /*
169 * Both src and dst array must be big enough for
170 * (end - start) >> PAGE_SHIFT entries.
171 *
172 * The src array must not be modified by the caller after
173 * migrate_vma_setup(), and must not change the dst array after
174 * migrate_vma_pages() returns.
175 */
176 unsigned long *dst;
177 unsigned long *src;
178 unsigned long cpages;
179 unsigned long npages;
180 unsigned long start;
181 unsigned long end;
182
183 /*
184 * Set to the owner value also stored in page->pgmap->owner for
185 * migrating out of device private memory. The flags also need to
186 * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
187 * The caller should always set this field when using mmu notifier
188 * callbacks to avoid device MMU invalidations for device private
189 * pages that are not being migrated.
190 */
191 void *pgmap_owner;
192 unsigned long flags;
193 };
194
195 int migrate_vma_setup(struct migrate_vma *args);
196 void migrate_vma_pages(struct migrate_vma *migrate);
197 void migrate_vma_finalize(struct migrate_vma *migrate);
198
199 #endif /* CONFIG_MIGRATION */
200
201 #endif /* _LINUX_MIGRATE_H */
202
