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 folio *new_folio_t(struct folio *folio, unsigned long private); |
11 | typedef void free_folio_t(struct folio *folio, 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 | #define MIGRATEPAGE_UNMAP 1 |
22 | |
23 | /** |
24 | * struct movable_operations - Driver page migration |
25 | * @isolate_page: |
26 | * The VM calls this function to prepare the page to be moved. The page |
27 | * is locked and the driver should not unlock it. The driver should |
28 | * return ``true`` if the page is movable and ``false`` if it is not |
29 | * currently movable. After this function returns, the VM uses the |
30 | * page->lru field, so the driver must preserve any information which |
31 | * is usually stored here. |
32 | * |
33 | * @migrate_page: |
34 | * After isolation, the VM calls this function with the isolated |
35 | * @src page. The driver should copy the contents of the |
36 | * @src page to the @dst page and set up the fields of @dst page. |
37 | * Both pages are locked. |
38 | * If page migration is successful, the driver should call |
39 | * __ClearPageMovable(@src) and return MIGRATEPAGE_SUCCESS. |
40 | * If the driver cannot migrate the page at the moment, it can return |
41 | * -EAGAIN. The VM interprets this as a temporary migration failure and |
42 | * will retry it later. Any other error value is a permanent migration |
43 | * failure and migration will not be retried. |
44 | * The driver shouldn't touch the @src->lru field while in the |
45 | * migrate_page() function. It may write to @dst->lru. |
46 | * |
47 | * @putback_page: |
48 | * If migration fails on the isolated page, the VM informs the driver |
49 | * that the page is no longer a candidate for migration by calling |
50 | * this function. The driver should put the isolated page back into |
51 | * its own data structure. |
52 | */ |
53 | struct movable_operations { |
54 | bool (*isolate_page)(struct page *, isolate_mode_t); |
55 | int (*migrate_page)(struct page *dst, struct page *src, |
56 | enum migrate_mode); |
57 | void (*putback_page)(struct page *); |
58 | }; |
59 | |
60 | /* Defined in mm/debug.c: */ |
61 | extern const char *migrate_reason_names[MR_TYPES]; |
62 | |
63 | #ifdef CONFIG_MIGRATION |
64 | |
65 | void putback_movable_pages(struct list_head *l); |
66 | int (struct address_space *mapping, struct folio *dst, |
67 | struct folio *src, enum migrate_mode mode, int ); |
68 | int migrate_folio(struct address_space *mapping, struct folio *dst, |
69 | struct folio *src, enum migrate_mode mode); |
70 | int migrate_pages(struct list_head *l, new_folio_t new, free_folio_t free, |
71 | unsigned long private, enum migrate_mode mode, int reason, |
72 | unsigned int *ret_succeeded); |
73 | struct folio *alloc_migration_target(struct folio *src, unsigned long private); |
74 | bool isolate_movable_page(struct page *page, isolate_mode_t mode); |
75 | |
76 | int migrate_huge_page_move_mapping(struct address_space *mapping, |
77 | struct folio *dst, struct folio *src); |
78 | void migration_entry_wait_on_locked(swp_entry_t entry, spinlock_t *ptl) |
79 | __releases(ptl); |
80 | void folio_migrate_flags(struct folio *newfolio, struct folio *folio); |
81 | void folio_migrate_copy(struct folio *newfolio, struct folio *folio); |
82 | int folio_migrate_mapping(struct address_space *mapping, |
83 | struct folio *newfolio, struct folio *folio, int ); |
84 | |
85 | #else |
86 | |
87 | static inline void putback_movable_pages(struct list_head *l) {} |
88 | static inline int migrate_pages(struct list_head *l, new_folio_t new, |
89 | free_folio_t free, unsigned long private, |
90 | enum migrate_mode mode, int reason, unsigned int *ret_succeeded) |
91 | { return -ENOSYS; } |
92 | static inline struct folio *alloc_migration_target(struct folio *src, |
93 | unsigned long private) |
94 | { return NULL; } |
95 | static inline bool isolate_movable_page(struct page *page, isolate_mode_t mode) |
96 | { return false; } |
97 | |
98 | static inline int migrate_huge_page_move_mapping(struct address_space *mapping, |
99 | struct folio *dst, struct folio *src) |
100 | { |
101 | return -ENOSYS; |
102 | } |
103 | |
104 | #endif /* CONFIG_MIGRATION */ |
105 | |
106 | #ifdef CONFIG_COMPACTION |
107 | bool PageMovable(struct page *page); |
108 | void __SetPageMovable(struct page *page, const struct movable_operations *ops); |
109 | void __ClearPageMovable(struct page *page); |
110 | #else |
111 | static inline bool PageMovable(struct page *page) { return false; } |
112 | static inline void __SetPageMovable(struct page *page, |
113 | const struct movable_operations *ops) |
114 | { |
115 | } |
116 | static inline void __ClearPageMovable(struct page *page) |
117 | { |
118 | } |
119 | #endif |
120 | |
121 | static inline bool folio_test_movable(struct folio *folio) |
122 | { |
123 | return PageMovable(page: &folio->page); |
124 | } |
125 | |
126 | static inline |
127 | const struct movable_operations *folio_movable_ops(struct folio *folio) |
128 | { |
129 | VM_BUG_ON(!__folio_test_movable(folio)); |
130 | |
131 | return (const struct movable_operations *) |
132 | ((unsigned long)folio->mapping - PAGE_MAPPING_MOVABLE); |
133 | } |
134 | |
135 | static inline |
136 | const struct movable_operations *page_movable_ops(struct page *page) |
137 | { |
138 | VM_BUG_ON(!__PageMovable(page)); |
139 | |
140 | return (const struct movable_operations *) |
141 | ((unsigned long)page->mapping - PAGE_MAPPING_MOVABLE); |
142 | } |
143 | |
144 | #ifdef CONFIG_NUMA_BALANCING |
145 | int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma, |
146 | int node); |
147 | #else |
148 | static inline int migrate_misplaced_folio(struct folio *folio, |
149 | struct vm_area_struct *vma, int node) |
150 | { |
151 | return -EAGAIN; /* can't migrate now */ |
152 | } |
153 | #endif /* CONFIG_NUMA_BALANCING */ |
154 | |
155 | #ifdef CONFIG_MIGRATION |
156 | |
157 | /* |
158 | * Watch out for PAE architecture, which has an unsigned long, and might not |
159 | * have enough bits to store all physical address and flags. So far we have |
160 | * enough room for all our flags. |
161 | */ |
162 | #define MIGRATE_PFN_VALID (1UL << 0) |
163 | #define MIGRATE_PFN_MIGRATE (1UL << 1) |
164 | #define MIGRATE_PFN_WRITE (1UL << 3) |
165 | #define MIGRATE_PFN_SHIFT 6 |
166 | |
167 | static inline struct page *migrate_pfn_to_page(unsigned long mpfn) |
168 | { |
169 | if (!(mpfn & MIGRATE_PFN_VALID)) |
170 | return NULL; |
171 | return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT); |
172 | } |
173 | |
174 | static inline unsigned long migrate_pfn(unsigned long pfn) |
175 | { |
176 | return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID; |
177 | } |
178 | |
179 | enum migrate_vma_direction { |
180 | MIGRATE_VMA_SELECT_SYSTEM = 1 << 0, |
181 | MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1, |
182 | MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2, |
183 | }; |
184 | |
185 | struct migrate_vma { |
186 | struct vm_area_struct *vma; |
187 | /* |
188 | * Both src and dst array must be big enough for |
189 | * (end - start) >> PAGE_SHIFT entries. |
190 | * |
191 | * The src array must not be modified by the caller after |
192 | * migrate_vma_setup(), and must not change the dst array after |
193 | * migrate_vma_pages() returns. |
194 | */ |
195 | unsigned long *dst; |
196 | unsigned long *src; |
197 | unsigned long cpages; |
198 | unsigned long npages; |
199 | unsigned long start; |
200 | unsigned long end; |
201 | |
202 | /* |
203 | * Set to the owner value also stored in page->pgmap->owner for |
204 | * migrating out of device private memory. The flags also need to |
205 | * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE. |
206 | * The caller should always set this field when using mmu notifier |
207 | * callbacks to avoid device MMU invalidations for device private |
208 | * pages that are not being migrated. |
209 | */ |
210 | void *pgmap_owner; |
211 | unsigned long flags; |
212 | |
213 | /* |
214 | * Set to vmf->page if this is being called to migrate a page as part of |
215 | * a migrate_to_ram() callback. |
216 | */ |
217 | struct page *fault_page; |
218 | }; |
219 | |
220 | int migrate_vma_setup(struct migrate_vma *args); |
221 | void migrate_vma_pages(struct migrate_vma *migrate); |
222 | void migrate_vma_finalize(struct migrate_vma *migrate); |
223 | int migrate_device_range(unsigned long *src_pfns, unsigned long start, |
224 | unsigned long npages); |
225 | void migrate_device_pages(unsigned long *src_pfns, unsigned long *dst_pfns, |
226 | unsigned long npages); |
227 | void migrate_device_finalize(unsigned long *src_pfns, |
228 | unsigned long *dst_pfns, unsigned long npages); |
229 | |
230 | #endif /* CONFIG_MIGRATION */ |
231 | |
232 | #endif /* _LINUX_MIGRATE_H */ |
233 | |