Linux kernel mirror (for testing)
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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/* Defined in mm/debug.c: */
23extern const char *migrate_reason_names[MR_TYPES];
24
25#ifdef CONFIG_MIGRATION
26
27extern void putback_movable_pages(struct list_head *l);
28extern int migrate_page(struct address_space *mapping,
29 struct page *newpage, struct page *page,
30 enum migrate_mode mode);
31extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
32 unsigned long private, enum migrate_mode mode, int reason,
33 unsigned int *ret_succeeded);
34extern struct page *alloc_migration_target(struct page *page, unsigned long private);
35extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
36
37extern void migrate_page_states(struct page *newpage, struct page *page);
38extern void migrate_page_copy(struct page *newpage, struct page *page);
39extern int migrate_huge_page_move_mapping(struct address_space *mapping,
40 struct page *newpage, struct page *page);
41extern int migrate_page_move_mapping(struct address_space *mapping,
42 struct page *newpage, struct page *page, int extra_count);
43void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
44 spinlock_t *ptl);
45void folio_migrate_flags(struct folio *newfolio, struct folio *folio);
46void folio_migrate_copy(struct folio *newfolio, struct folio *folio);
47int folio_migrate_mapping(struct address_space *mapping,
48 struct folio *newfolio, struct folio *folio, int extra_count);
49
50#else
51
52static inline void putback_movable_pages(struct list_head *l) {}
53static inline int migrate_pages(struct list_head *l, new_page_t new,
54 free_page_t free, unsigned long private, enum migrate_mode mode,
55 int reason, unsigned int *ret_succeeded)
56 { return -ENOSYS; }
57static inline struct page *alloc_migration_target(struct page *page,
58 unsigned long private)
59 { return NULL; }
60static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
61 { return -EBUSY; }
62
63static inline void migrate_page_states(struct page *newpage, struct page *page)
64{
65}
66
67static inline void migrate_page_copy(struct page *newpage,
68 struct page *page) {}
69
70static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
71 struct page *newpage, struct page *page)
72{
73 return -ENOSYS;
74}
75
76#endif /* CONFIG_MIGRATION */
77
78#if defined(CONFIG_MIGRATION) && defined(CONFIG_NUMA)
79extern void set_migration_target_nodes(void);
80extern void migrate_on_reclaim_init(void);
81extern bool numa_demotion_enabled;
82extern int next_demotion_node(int node);
83#else
84static inline void set_migration_target_nodes(void) {}
85static inline void migrate_on_reclaim_init(void) {}
86static inline int next_demotion_node(int node)
87{
88 return NUMA_NO_NODE;
89}
90#define numa_demotion_enabled false
91#endif
92
93#ifdef CONFIG_COMPACTION
94extern int PageMovable(struct page *page);
95extern void __SetPageMovable(struct page *page, struct address_space *mapping);
96extern void __ClearPageMovable(struct page *page);
97#else
98static inline int PageMovable(struct page *page) { return 0; }
99static inline void __SetPageMovable(struct page *page,
100 struct address_space *mapping)
101{
102}
103static inline void __ClearPageMovable(struct page *page)
104{
105}
106#endif
107
108static inline bool folio_test_movable(struct folio *folio)
109{
110 return PageMovable(&folio->page);
111}
112
113#ifdef CONFIG_NUMA_BALANCING
114extern int migrate_misplaced_page(struct page *page,
115 struct vm_area_struct *vma, int node);
116#else
117static inline int migrate_misplaced_page(struct page *page,
118 struct vm_area_struct *vma, int node)
119{
120 return -EAGAIN; /* can't migrate now */
121}
122#endif /* CONFIG_NUMA_BALANCING */
123
124#ifdef CONFIG_MIGRATION
125
126/*
127 * Watch out for PAE architecture, which has an unsigned long, and might not
128 * have enough bits to store all physical address and flags. So far we have
129 * enough room for all our flags.
130 */
131#define MIGRATE_PFN_VALID (1UL << 0)
132#define MIGRATE_PFN_MIGRATE (1UL << 1)
133#define MIGRATE_PFN_WRITE (1UL << 3)
134#define MIGRATE_PFN_SHIFT 6
135
136static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
137{
138 if (!(mpfn & MIGRATE_PFN_VALID))
139 return NULL;
140 return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
141}
142
143static inline unsigned long migrate_pfn(unsigned long pfn)
144{
145 return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
146}
147
148enum migrate_vma_direction {
149 MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
150 MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
151};
152
153struct migrate_vma {
154 struct vm_area_struct *vma;
155 /*
156 * Both src and dst array must be big enough for
157 * (end - start) >> PAGE_SHIFT entries.
158 *
159 * The src array must not be modified by the caller after
160 * migrate_vma_setup(), and must not change the dst array after
161 * migrate_vma_pages() returns.
162 */
163 unsigned long *dst;
164 unsigned long *src;
165 unsigned long cpages;
166 unsigned long npages;
167 unsigned long start;
168 unsigned long end;
169
170 /*
171 * Set to the owner value also stored in page->pgmap->owner for
172 * migrating out of device private memory. The flags also need to
173 * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
174 * The caller should always set this field when using mmu notifier
175 * callbacks to avoid device MMU invalidations for device private
176 * pages that are not being migrated.
177 */
178 void *pgmap_owner;
179 unsigned long flags;
180};
181
182int migrate_vma_setup(struct migrate_vma *args);
183void migrate_vma_pages(struct migrate_vma *migrate);
184void migrate_vma_finalize(struct migrate_vma *migrate);
185#endif /* CONFIG_MIGRATION */
186
187#endif /* _LINUX_MIGRATE_H */