From fdf1cdb91b6ab7a8a91df68c384f36b8a0909cab Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Tue, 15 Mar 2016 14:57:25 -0700 Subject: mm: remove unnecessary uses of lock_page_memcg() There are several users that nest lock_page_memcg() inside lock_page() to prevent page->mem_cgroup from changing. But the page lock prevents pages from moving between cgroups, so that is unnecessary overhead. Remove lock_page_memcg() in contexts with locked contexts and fix the debug code in the page stat functions to be okay with the page lock. Signed-off-by: Johannes Weiner Acked-by: Vladimir Davydov Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page-writeback.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'mm/page-writeback.c') diff --git a/mm/page-writeback.c b/mm/page-writeback.c index d7cf2c53d125..11ff8f758631 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2700,7 +2700,6 @@ int clear_page_dirty_for_io(struct page *page) * always locked coming in here, so we get the desired * exclusion. */ - lock_page_memcg(page); wb = unlocked_inode_to_wb_begin(inode, &locked); if (TestClearPageDirty(page)) { mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY); @@ -2709,7 +2708,6 @@ int clear_page_dirty_for_io(struct page *page) ret = 1; } unlocked_inode_to_wb_end(inode, locked); - unlock_page_memcg(page); return ret; } return TestClearPageDirty(page); -- cgit v1.2.3