migrate: don't account swapcache as shmem

swapcache will reach the below code path in migrate_page_move_mapping,
and swapcache is accounted as NR_FILE_PAGES but it's not accounted as
NR_SHMEM.

Hugh pointed out we must use PageSwapCache instead of comparing
mapping to &swapper_space, to avoid build failure with CONFIG_SWAP=n.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrea Arcangeli 2011-06-16 12:56:19 -07:00 committed by Linus Torvalds
parent 7cc2ed0589
commit 99a15e21d9

View File

@ -288,7 +288,7 @@ static int migrate_page_move_mapping(struct address_space *mapping,
*/
__dec_zone_page_state(page, NR_FILE_PAGES);
__inc_zone_page_state(newpage, NR_FILE_PAGES);
if (PageSwapBacked(page)) {
if (!PageSwapCache(page) && PageSwapBacked(page)) {
__dec_zone_page_state(page, NR_SHMEM);
__inc_zone_page_state(newpage, NR_SHMEM);
}