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