Commit 3417013e authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

mm/migrate: Add folio_migrate_mapping() 



Reimplement migrate_page_move_mapping() as a wrapper around
folio_migrate_mapping().  Saves 193 bytes of kernel text.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
parent d9c08e22

include/linux/migrate.h

+2 −0
Original line number Diff line number Diff line
@@ -57,6 +57,8 @@ extern int migrate_huge_page_move_mapping(struct address_space *mapping, 
				  struct page *newpage, struct page *page);

extern int migrate_page_move_mapping(struct address_space *mapping,

		struct page *newpage, struct page *page, int extra_count);

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) {}

mm/folio-compat.c

+11 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
 * eventually.

 */



#include <linux/migrate.h>

#include <linux/pagemap.h>

#include <linux/swap.h>
@@ -48,3 +49,13 @@ void mark_page_accessed(struct page *page) 
	folio_mark_accessed(page_folio(page));

}

EXPORT_SYMBOL(mark_page_accessed);



#ifdef CONFIG_MIGRATION

int migrate_page_move_mapping(struct address_space *mapping,

		struct page *newpage, struct page *page, int extra_count)

{

	return folio_migrate_mapping(mapping, page_folio(newpage),

					page_folio(page), extra_count);

}

EXPORT_SYMBOL(migrate_page_move_mapping);

#endif

mm/migrate.c

+44 −41
Original line number Diff line number Diff line
@@ -364,7 +364,7 @@ static int expected_page_refs(struct address_space *mapping, struct page *page) 
	 */

	expected_count += is_device_private_page(page);

	if (mapping)

		expected_count += thp_nr_pages(page) + page_has_private(page);

		expected_count += compound_nr(page) + page_has_private(page);



	return expected_count;

}
@@ -377,74 +377,75 @@ static int expected_page_refs(struct address_space *mapping, struct page *page) 
 * 2 for pages with a mapping

 * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.

 */

int migrate_page_move_mapping(struct address_space *mapping,

		struct page *newpage, struct page *page, int extra_count)

int folio_migrate_mapping(struct address_space *mapping,

		struct folio *newfolio, struct folio *folio, int extra_count)

{

	XA_STATE(xas, &mapping->i_pages, page_index(page));

	XA_STATE(xas, &mapping->i_pages, folio_index(folio));

	struct zone *oldzone, *newzone;

	int dirty;

	int expected_count = expected_page_refs(mapping, page) + extra_count;

	int nr = thp_nr_pages(page);

	int expected_count = expected_page_refs(mapping, &folio->page) + extra_count;

	long nr = folio_nr_pages(folio);



	if (!mapping) {

		/* Anonymous page without mapping */

		if (page_count(page) != expected_count)

		if (folio_ref_count(folio) != expected_count)

			return -EAGAIN;



		/* No turning back from here */

		newpage->index = page->index;

		newpage->mapping = page->mapping;

		if (PageSwapBacked(page))

			__SetPageSwapBacked(newpage);

		newfolio->index = folio->index;

		newfolio->mapping = folio->mapping;

		if (folio_test_swapbacked(folio))

			__folio_set_swapbacked(newfolio);



		return MIGRATEPAGE_SUCCESS;

	}



	oldzone = page_zone(page);

	newzone = page_zone(newpage);

	oldzone = folio_zone(folio);

	newzone = folio_zone(newfolio);



	xas_lock_irq(&xas);

	if (page_count(page) != expected_count || xas_load(&xas) != page) {

	if (folio_ref_count(folio) != expected_count ||

	    xas_load(&xas) != folio) {

		xas_unlock_irq(&xas);

		return -EAGAIN;

	}



	if (!page_ref_freeze(page, expected_count)) {

	if (!folio_ref_freeze(folio, expected_count)) {

		xas_unlock_irq(&xas);

		return -EAGAIN;

	}



	/*

	 * Now we know that no one else is looking at the page:

	 * Now we know that no one else is looking at the folio:

	 * no turning back from here.

	 */

	newpage->index = page->index;

	newpage->mapping = page->mapping;

	page_ref_add(newpage, nr); /* add cache reference */

	if (PageSwapBacked(page)) {

		__SetPageSwapBacked(newpage);

		if (PageSwapCache(page)) {

			SetPageSwapCache(newpage);

			set_page_private(newpage, page_private(page));

	newfolio->index = folio->index;

	newfolio->mapping = folio->mapping;

	folio_ref_add(newfolio, nr); /* add cache reference */

	if (folio_test_swapbacked(folio)) {

		__folio_set_swapbacked(newfolio);

		if (folio_test_swapcache(folio)) {

			folio_set_swapcache(newfolio);

			newfolio->private = folio_get_private(folio);

		}

	} else {

		VM_BUG_ON_PAGE(PageSwapCache(page), page);

		VM_BUG_ON_FOLIO(folio_test_swapcache(folio), folio);

	}



	/* Move dirty while page refs frozen and newpage not yet exposed */

	dirty = PageDirty(page);

	dirty = folio_test_dirty(folio);

	if (dirty) {

		ClearPageDirty(page);

		SetPageDirty(newpage);

		folio_clear_dirty(folio);

		folio_set_dirty(newfolio);

	}



	xas_store(&xas, newpage);

	if (PageTransHuge(page)) {

	xas_store(&xas, newfolio);

	if (nr > 1) {

		int i;



		for (i = 1; i < nr; i++) {

			xas_next(&xas);

			xas_store(&xas, newpage);

			xas_store(&xas, newfolio);

		}

	}
@@ -453,7 +454,7 @@ int migrate_page_move_mapping(struct address_space *mapping, 
	 * to one less reference.

	 * We know this isn't the last reference.

	 */

	page_ref_unfreeze(page, expected_count - nr);

	folio_ref_unfreeze(folio, expected_count - nr);



	xas_unlock(&xas);

	/* Leave irq disabled to prevent preemption while updating stats */
@@ -472,18 +473,18 @@ int migrate_page_move_mapping(struct address_space *mapping, 
		struct lruvec *old_lruvec, *new_lruvec;

		struct mem_cgroup *memcg;



		memcg = page_memcg(page);

		memcg = folio_memcg(folio);

		old_lruvec = mem_cgroup_lruvec(memcg, oldzone->zone_pgdat);

		new_lruvec = mem_cgroup_lruvec(memcg, newzone->zone_pgdat);



		__mod_lruvec_state(old_lruvec, NR_FILE_PAGES, -nr);

		__mod_lruvec_state(new_lruvec, NR_FILE_PAGES, nr);

		if (PageSwapBacked(page) && !PageSwapCache(page)) {

		if (folio_test_swapbacked(folio) && !folio_test_swapcache(folio)) {

			__mod_lruvec_state(old_lruvec, NR_SHMEM, -nr);

			__mod_lruvec_state(new_lruvec, NR_SHMEM, nr);

		}

#ifdef CONFIG_SWAP

		if (PageSwapCache(page)) {

		if (folio_test_swapcache(folio)) {

			__mod_lruvec_state(old_lruvec, NR_SWAPCACHE, -nr);

			__mod_lruvec_state(new_lruvec, NR_SWAPCACHE, nr);

		}
@@ -499,11 +500,11 @@ int migrate_page_move_mapping(struct address_space *mapping, 


	return MIGRATEPAGE_SUCCESS;

}

EXPORT_SYMBOL(migrate_page_move_mapping);

EXPORT_SYMBOL(folio_migrate_mapping);



/*

 * The expected number of remaining references is the same as that

 * of migrate_page_move_mapping().

 * of folio_migrate_mapping().

 */

int migrate_huge_page_move_mapping(struct address_space *mapping,

				   struct page *newpage, struct page *page)
@@ -564,7 +565,7 @@ void migrate_page_states(struct page *newpage, struct page *page) 
	if (PageMappedToDisk(page))

		SetPageMappedToDisk(newpage);



	/* Move dirty on pages not done by migrate_page_move_mapping() */

	/* Move dirty on pages not done by folio_migrate_mapping() */

	if (PageDirty(page))

		SetPageDirty(newpage);
@@ -640,11 +641,13 @@ int migrate_page(struct address_space *mapping, 
		struct page *newpage, struct page *page,

		enum migrate_mode mode)

{

	struct folio *newfolio = page_folio(newpage);

	struct folio *folio = page_folio(page);

	int rc;



	BUG_ON(PageWriteback(page));	/* Writeback must be complete */

	BUG_ON(folio_test_writeback(folio));	/* Writeback must be complete */



	rc = migrate_page_move_mapping(mapping, newpage, page, 0);

	rc = folio_migrate_mapping(mapping, newfolio, folio, 0);



	if (rc != MIGRATEPAGE_SUCCESS)

		return rc;
@@ -2470,7 +2473,7 @@ static void migrate_vma_collect(struct migrate_vma *migrate) 
 * @page: struct page to check

 *

 * Pinned pages cannot be migrated. This is the same test as in

 * migrate_page_move_mapping(), except that here we allow migration of a

 * folio_migrate_mapping(), except that here we allow migration of a

 * ZONE_DEVICE page.

 */

static bool migrate_vma_check_page(struct page *page)