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mm/migrate: Add folio_migrate_mapping()

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

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
This commit is contained in:
Matthew Wilcox (Oracle) 2021-05-07 07:28:40 -04:00
parent d9c08e2232
commit 3417013e0d
3 changed files with 57 additions and 41 deletions
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2
include/linux/migrate.h
View File

@ -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) {}

11
mm/folio-compat.c
View File

@ -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

85
mm/migrate.c
View File

@ -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)