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- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef _LINUX_MIGRATE_H
- #define _LINUX_MIGRATE_H
- #include <linux/mm.h>
- #include <linux/mempolicy.h>
- #include <linux/migrate_mode.h>
- #include <linux/hugetlb.h>
- typedef struct page *new_page_t(struct page *page, unsigned long private);
- typedef void free_page_t(struct page *page, unsigned long private);
- struct migration_target_control;
- /*
- * Return values from addresss_space_operations.migratepage():
- * - negative errno on page migration failure;
- * - zero on page migration success;
- */
- #define MIGRATEPAGE_SUCCESS 0
- /**
- * struct movable_operations - Driver page migration
- * @isolate_page:
- * The VM calls this function to prepare the page to be moved. The page
- * is locked and the driver should not unlock it. The driver should
- * return ``true`` if the page is movable and ``false`` if it is not
- * currently movable. After this function returns, the VM uses the
- * page->lru field, so the driver must preserve any information which
- * is usually stored here.
- *
- * @migrate_page:
- * After isolation, the VM calls this function with the isolated
- * @src page. The driver should copy the contents of the
- * @src page to the @dst page and set up the fields of @dst page.
- * Both pages are locked.
- * If page migration is successful, the driver should call
- * __ClearPageMovable(@src) and return MIGRATEPAGE_SUCCESS.
- * If the driver cannot migrate the page at the moment, it can return
- * -EAGAIN. The VM interprets this as a temporary migration failure and
- * will retry it later. Any other error value is a permanent migration
- * failure and migration will not be retried.
- * The driver shouldn't touch the @src->lru field while in the
- * migrate_page() function. It may write to @dst->lru.
- *
- * @putback_page:
- * If migration fails on the isolated page, the VM informs the driver
- * that the page is no longer a candidate for migration by calling
- * this function. The driver should put the isolated page back into
- * its own data structure.
- */
- struct movable_operations {
- bool (*isolate_page)(struct page *, isolate_mode_t);
- int (*migrate_page)(struct page *dst, struct page *src,
- enum migrate_mode);
- void (*putback_page)(struct page *);
- };
- /* Defined in mm/debug.c: */
- extern const char *migrate_reason_names[MR_TYPES];
- #ifdef CONFIG_MIGRATION
- extern void putback_movable_pages(struct list_head *l);
- int migrate_folio_extra(struct address_space *mapping, struct folio *dst,
- struct folio *src, enum migrate_mode mode, int extra_count);
- int migrate_folio(struct address_space *mapping, struct folio *dst,
- struct folio *src, enum migrate_mode mode);
- extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
- unsigned long private, enum migrate_mode mode, int reason,
- unsigned int *ret_succeeded);
- extern struct page *alloc_migration_target(struct page *page, unsigned long private);
- extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
- int migrate_huge_page_move_mapping(struct address_space *mapping,
- struct folio *dst, struct folio *src);
- void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
- spinlock_t *ptl);
- void folio_migrate_flags(struct folio *newfolio, struct folio *folio);
- void folio_migrate_copy(struct folio *newfolio, struct folio *folio);
- int folio_migrate_mapping(struct address_space *mapping,
- struct folio *newfolio, struct folio *folio, int extra_count);
- #else
- static inline void putback_movable_pages(struct list_head *l) {}
- static inline int migrate_pages(struct list_head *l, new_page_t new,
- free_page_t free, unsigned long private, enum migrate_mode mode,
- int reason, unsigned int *ret_succeeded)
- { return -ENOSYS; }
- static inline struct page *alloc_migration_target(struct page *page,
- unsigned long private)
- { return NULL; }
- static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
- { return -EBUSY; }
- static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
- struct folio *dst, struct folio *src)
- {
- return -ENOSYS;
- }
- #endif /* CONFIG_MIGRATION */
- #ifdef CONFIG_COMPACTION
- bool PageMovable(struct page *page);
- void __SetPageMovable(struct page *page, const struct movable_operations *ops);
- void __ClearPageMovable(struct page *page);
- #else
- static inline bool PageMovable(struct page *page) { return false; }
- static inline void __SetPageMovable(struct page *page,
- const struct movable_operations *ops)
- {
- }
- static inline void __ClearPageMovable(struct page *page)
- {
- }
- #endif
- static inline bool folio_test_movable(struct folio *folio)
- {
- return PageMovable(&folio->page);
- }
- static inline
- const struct movable_operations *page_movable_ops(struct page *page)
- {
- VM_BUG_ON(!__PageMovable(page));
- return (const struct movable_operations *)
- ((unsigned long)page->mapping - PAGE_MAPPING_MOVABLE);
- }
- #ifdef CONFIG_NUMA_BALANCING
- extern int migrate_misplaced_page(struct page *page,
- struct vm_area_struct *vma, int node);
- #else
- static inline int migrate_misplaced_page(struct page *page,
- struct vm_area_struct *vma, int node)
- {
- return -EAGAIN; /* can't migrate now */
- }
- #endif /* CONFIG_NUMA_BALANCING */
- #ifdef CONFIG_MIGRATION
- /*
- * Watch out for PAE architecture, which has an unsigned long, and might not
- * have enough bits to store all physical address and flags. So far we have
- * enough room for all our flags.
- */
- #define MIGRATE_PFN_VALID (1UL << 0)
- #define MIGRATE_PFN_MIGRATE (1UL << 1)
- #define MIGRATE_PFN_WRITE (1UL << 3)
- #define MIGRATE_PFN_SHIFT 6
- static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
- {
- if (!(mpfn & MIGRATE_PFN_VALID))
- return NULL;
- return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
- }
- static inline unsigned long migrate_pfn(unsigned long pfn)
- {
- return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
- }
- enum migrate_vma_direction {
- MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
- MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
- MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
- };
- struct migrate_vma {
- struct vm_area_struct *vma;
- /*
- * Both src and dst array must be big enough for
- * (end - start) >> PAGE_SHIFT entries.
- *
- * The src array must not be modified by the caller after
- * migrate_vma_setup(), and must not change the dst array after
- * migrate_vma_pages() returns.
- */
- unsigned long *dst;
- unsigned long *src;
- unsigned long cpages;
- unsigned long npages;
- unsigned long start;
- unsigned long end;
- /*
- * Set to the owner value also stored in page->pgmap->owner for
- * migrating out of device private memory. The flags also need to
- * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
- * The caller should always set this field when using mmu notifier
- * callbacks to avoid device MMU invalidations for device private
- * pages that are not being migrated.
- */
- void *pgmap_owner;
- unsigned long flags;
- /*
- * Set to vmf->page if this is being called to migrate a page as part of
- * a migrate_to_ram() callback.
- */
- struct page *fault_page;
- };
- int migrate_vma_setup(struct migrate_vma *args);
- void migrate_vma_pages(struct migrate_vma *migrate);
- void migrate_vma_finalize(struct migrate_vma *migrate);
- int migrate_device_range(unsigned long *src_pfns, unsigned long start,
- unsigned long npages);
- void migrate_device_pages(unsigned long *src_pfns, unsigned long *dst_pfns,
- unsigned long npages);
- void migrate_device_finalize(unsigned long *src_pfns,
- unsigned long *dst_pfns, unsigned long npages);
- #endif /* CONFIG_MIGRATION */
- #endif /* _LINUX_MIGRATE_H */
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