From 74d4a5797b89048a5b20746da7e80af1e73b8547 Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Sat, 30 Nov 2019 17:57:12 -0800 Subject: mm/migrate.c: handle freed page at the first place When doing migration if the freed page is met, we just return without migrating it since it is pointless to migrate a freed page. But, the current code allocates target page unconditionally before handling freed page, if the page is freed, the newly allocated will be just freed. It doesn't make too much sense and is just a waste of time although migrating freed page is rare. So, handle freed page at the before that to avoid unnecessary page allocation and free. Link: http://lkml.kernel.org/r/1573755869-106954-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi Acked-by: Michal Hocko Reviewed-by: Andrew Morton Cc: Mel Gorman Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/migrate.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) (limited to 'mm') diff --git a/mm/migrate.c b/mm/migrate.c index 4fe45d1428c8..a8f87cb43251 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1168,15 +1168,11 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page, enum migrate_reason reason) { int rc = MIGRATEPAGE_SUCCESS; - struct page *newpage; + struct page *newpage = NULL; if (!thp_migration_supported() && PageTransHuge(page)) return -ENOMEM; - newpage = get_new_page(page, private); - if (!newpage) - return -ENOMEM; - if (page_count(page) == 1) { /* page was freed from under us. So we are done. */ ClearPageActive(page); @@ -1187,13 +1183,13 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page, __ClearPageIsolated(page); unlock_page(page); } - if (put_new_page) - put_new_page(newpage, private); - else - put_page(newpage); goto out; } + newpage = get_new_page(page, private); + if (!newpage) + return -ENOMEM; + rc = __unmap_and_move(page, newpage, force, mode); if (rc == MIGRATEPAGE_SUCCESS) set_page_owner_migrate_reason(newpage, reason); -- cgit v1.2.3-59-g8ed1b