projects/linux·blob v6.1 · refs

222 lines · 7.3 KiB

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
10typedef struct page *new_page_t(struct page *page, unsigned long private);
11typedef void free_page_t(struct page *page, unsigned long private);
12
13struct 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/**
23 * struct movable_operations - Driver page migration
24 * @isolate_page:
25 * The VM calls this function to prepare the page to be moved. The page
26 * is locked and the driver should not unlock it. The driver should
27 * return ``true`` if the page is movable and ``false`` if it is not
28 * currently movable. After this function returns, the VM uses the
29 * page->lru field, so the driver must preserve any information which
30 * is usually stored here.
31 *
32 * @migrate_page:
33 * After isolation, the VM calls this function with the isolated
34 * @src page. The driver should copy the contents of the
35 * @src page to the @dst page and set up the fields of @dst page.
36 * Both pages are locked.
37 * If page migration is successful, the driver should call
38 * __ClearPageMovable(@src) and return MIGRATEPAGE_SUCCESS.
39 * If the driver cannot migrate the page at the moment, it can return
40 * -EAGAIN. The VM interprets this as a temporary migration failure and
41 * will retry it later. Any other error value is a permanent migration
42 * failure and migration will not be retried.
43 * The driver shouldn't touch the @src->lru field while in the
44 * migrate_page() function. It may write to @dst->lru.
45 *
46 * @putback_page:
47 * If migration fails on the isolated page, the VM informs the driver
48 * that the page is no longer a candidate for migration by calling
49 * this function. The driver should put the isolated page back into
50 * its own data structure.
51 */
52struct movable_operations {
53 bool (*isolate_page)(struct page *, isolate_mode_t);
54 int (*migrate_page)(struct page *dst, struct page *src,
55 enum migrate_mode);
56 void (*putback_page)(struct page *);
57};
58
59/* Defined in mm/debug.c: */
60extern const char *migrate_reason_names[MR_TYPES];
61
62#ifdef CONFIG_MIGRATION
63
64extern void putback_movable_pages(struct list_head *l);
65int migrate_folio_extra(struct address_space *mapping, struct folio *dst,
66 struct folio *src, enum migrate_mode mode, int extra_count);
67int migrate_folio(struct address_space *mapping, struct folio *dst,
68 struct folio *src, enum migrate_mode mode);
69extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
70 unsigned long private, enum migrate_mode mode, int reason,
71 unsigned int *ret_succeeded);
72extern struct page *alloc_migration_target(struct page *page, unsigned long private);
73extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
74
75int migrate_huge_page_move_mapping(struct address_space *mapping,
76 struct folio *dst, struct folio *src);
77void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
78 spinlock_t *ptl);
79void folio_migrate_flags(struct folio *newfolio, struct folio *folio);
80void folio_migrate_copy(struct folio *newfolio, struct folio *folio);
81int folio_migrate_mapping(struct address_space *mapping,
82 struct folio *newfolio, struct folio *folio, int extra_count);
83
84#else
85
86static inline void putback_movable_pages(struct list_head *l) {}
87static inline int migrate_pages(struct list_head *l, new_page_t new,
88 free_page_t free, unsigned long private, enum migrate_mode mode,
89 int reason, unsigned int *ret_succeeded)
90 { return -ENOSYS; }
91static inline struct page *alloc_migration_target(struct page *page,
92 unsigned long private)
93 { return NULL; }
94static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
95 { return -EBUSY; }
96
97static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
98 struct folio *dst, struct folio *src)
99{
100 return -ENOSYS;
101}
102
103#endif /* CONFIG_MIGRATION */
104
105#ifdef CONFIG_COMPACTION
106bool PageMovable(struct page *page);
107void __SetPageMovable(struct page *page, const struct movable_operations *ops);
108void __ClearPageMovable(struct page *page);
109#else
110static inline bool PageMovable(struct page *page) { return false; }
111static inline void __SetPageMovable(struct page *page,
112 const struct movable_operations *ops)
113{
114}
115static inline void __ClearPageMovable(struct page *page)
116{
117}
118#endif
119
120static inline bool folio_test_movable(struct folio *folio)
121{
122 return PageMovable(&folio->page);
123}
124
125static inline
126const struct movable_operations *page_movable_ops(struct page *page)
127{
128 VM_BUG_ON(!__PageMovable(page));
129
130 return (const struct movable_operations *)
131 ((unsigned long)page->mapping - PAGE_MAPPING_MOVABLE);
132}
133
134#ifdef CONFIG_NUMA_BALANCING
135extern int migrate_misplaced_page(struct page *page,
136 struct vm_area_struct *vma, int node);
137#else
138static inline int migrate_misplaced_page(struct page *page,
139 struct vm_area_struct *vma, int node)
140{
141 return -EAGAIN; /* can't migrate now */
142}
143#endif /* CONFIG_NUMA_BALANCING */
144
145#ifdef CONFIG_MIGRATION
146
147/*
148 * Watch out for PAE architecture, which has an unsigned long, and might not
149 * have enough bits to store all physical address and flags. So far we have
150 * enough room for all our flags.
151 */
152#define MIGRATE_PFN_VALID (1UL << 0)
153#define MIGRATE_PFN_MIGRATE (1UL << 1)
154#define MIGRATE_PFN_WRITE (1UL << 3)
155#define MIGRATE_PFN_SHIFT 6
156
157static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
158{
159 if (!(mpfn & MIGRATE_PFN_VALID))
160 return NULL;
161 return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
162}
163
164static inline unsigned long migrate_pfn(unsigned long pfn)
165{
166 return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
167}
168
169enum migrate_vma_direction {
170 MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
171 MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
172 MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
173};
174
175struct migrate_vma {
176 struct vm_area_struct *vma;
177 /*
178 * Both src and dst array must be big enough for
179 * (end - start) >> PAGE_SHIFT entries.
180 *
181 * The src array must not be modified by the caller after
182 * migrate_vma_setup(), and must not change the dst array after
183 * migrate_vma_pages() returns.
184 */
185 unsigned long *dst;
186 unsigned long *src;
187 unsigned long cpages;
188 unsigned long npages;
189 unsigned long start;
190 unsigned long end;
191
192 /*
193 * Set to the owner value also stored in page->pgmap->owner for
194 * migrating out of device private memory. The flags also need to
195 * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
196 * The caller should always set this field when using mmu notifier
197 * callbacks to avoid device MMU invalidations for device private
198 * pages that are not being migrated.
199 */
200 void *pgmap_owner;
201 unsigned long flags;
202
203 /*
204 * Set to vmf->page if this is being called to migrate a page as part of
205 * a migrate_to_ram() callback.
206 */
207 struct page *fault_page;
208};
209
210int migrate_vma_setup(struct migrate_vma *args);
211void migrate_vma_pages(struct migrate_vma *migrate);
212void migrate_vma_finalize(struct migrate_vma *migrate);
213int migrate_device_range(unsigned long *src_pfns, unsigned long start,
214 unsigned long npages);
215void migrate_device_pages(unsigned long *src_pfns, unsigned long *dst_pfns,
216 unsigned long npages);
217void migrate_device_finalize(unsigned long *src_pfns,
218 unsigned long *dst_pfns, unsigned long npages);
219
220#endif /* CONFIG_MIGRATION */
221
222#endif /* _LINUX_MIGRATE_H */