Commit 5490da4f authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

fs: Add aops->migrate_folio 



Provide a folio-based replacement for aops->migratepage.  Update the
documentation to document migrate_folio instead of migratepage.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 68f2736a

Documentation/filesystems/locking.rst

+3 −2
Original line number Diff line number Diff line
@@ -252,7 +252,8 @@ prototypes:: 
	bool (*release_folio)(struct folio *, gfp_t);

	void (*free_folio)(struct folio *);

	int (*direct_IO)(struct kiocb *, struct iov_iter *iter);

	int (*migratepage)(struct address_space *, struct page *, struct page *);

	int (*migrate_folio)(struct address_space *, struct folio *dst,

			struct folio *src, enum migrate_mode);

	int (*launder_folio)(struct folio *);

	bool (*is_partially_uptodate)(struct folio *, size_t from, size_t count);

	int (*error_remove_page)(struct address_space *, struct page *);
@@ -278,7 +279,7 @@ invalidate_folio: yes exclusive 
release_folio:		yes

free_folio:		yes

direct_IO:

migratepage:		yes (both)

migrate_folio:		yes (both)

launder_folio:		yes

is_partially_uptodate:	yes

error_remove_page:	yes

Documentation/filesystems/vfs.rst

+7 −7
Original line number Diff line number Diff line
@@ -737,8 +737,8 @@ cache in your filesystem. The following members are defined: 
		bool (*release_folio)(struct folio *, gfp_t);

		void (*free_folio)(struct folio *);

		ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);

		/* migrate the contents of a page to the specified target */

		int (*migratepage) (struct page *, struct page *);

		int (*migrate_folio)(struct mapping *, struct folio *dst,

				struct folio *src, enum migrate_mode);

		int (*launder_folio) (struct folio *);



		bool (*is_partially_uptodate) (struct folio *, size_t from,
@@ -926,12 +926,12 @@ cache in your filesystem. The following members are defined: 
	data directly between the storage and the application's address

	space.



``migrate_page``

``migrate_folio``

	This is used to compact the physical memory usage.  If the VM

	wants to relocate a page (maybe off a memory card that is

	signalling imminent failure) it will pass a new page and an old

	page to this function.  migrate_page should transfer any private

	data across and update any references that it has to the page.

	wants to relocate a folio (maybe from a memory device that is

	signalling imminent failure) it will pass a new folio and an old

	folio to this function.  migrate_folio should transfer any private

	data across and update any references that it has to the folio.



``launder_folio``

	Called before freeing a folio - it writes back the dirty folio.

include/linux/fs.h

+3 −1
Original line number Diff line number Diff line
@@ -362,9 +362,11 @@ struct address_space_operations { 
	void (*free_folio)(struct folio *folio);

	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);

	/*

	 * migrate the contents of a page to the specified target. If

	 * migrate the contents of a folio to the specified target. If

	 * migrate_mode is MIGRATE_ASYNC, it must not block.

	 */

	int (*migrate_folio)(struct address_space *, struct folio *dst,

			struct folio *src, enum migrate_mode);

	int (*migratepage) (struct address_space *,

			struct page *, struct page *, enum migrate_mode);

	int (*launder_folio)(struct folio *);

mm/compaction.c

+3 −1
Original line number Diff line number Diff line
@@ -1042,7 +1042,9 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, 
				goto isolate_fail_put;



			mapping = page_mapping(page);

			migrate_dirty = !mapping || mapping->a_ops->migratepage;

			migrate_dirty = !mapping ||

					mapping->a_ops->migrate_folio ||

					mapping->a_ops->migratepage;

			unlock_page(page);

			if (!migrate_dirty)

				goto isolate_fail_put;

mm/migrate.c

+7 −4
Original line number Diff line number Diff line
@@ -856,14 +856,17 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, 


		if (!mapping)

			rc = migrate_page(mapping, &dst->page, &src->page, mode);

		else if (mapping->a_ops->migratepage)

		else if (mapping->a_ops->migrate_folio)

			/*

			 * Most pages have a mapping and most filesystems

			 * provide a migratepage callback. Anonymous pages

			 * Most folios have a mapping and most filesystems

			 * provide a migrate_folio callback. Anonymous folios

			 * are part of swap space which also has its own

			 * migratepage callback. This is the most common path

			 * migrate_folio callback. This is the most common path

			 * for page migration.

			 */

			rc = mapping->a_ops->migrate_folio(mapping, dst, src,

								mode);

		else if (mapping->a_ops->migratepage)

			rc = mapping->a_ops->migratepage(mapping, &dst->page,

							&src->page, mode);

		else