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authorJohannes Weiner <hannes@cmpxchg.org>2016-03-15 14:57:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-15 16:55:16 -0700
commitfdf1cdb91b6ab7a8a91df68c384f36b8a0909cab (patch)
tree828ad38946acad9990dcc733a10ebdeed0c1fbd5 /mm/page-writeback.c
parent62cccb8c8e7a3ca233f49d5e7dcb1557d25465cd (diff)
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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 <hannes@cmpxchg.org> Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r--mm/page-writeback.c2
1 files changed, 0 insertions, 2 deletions
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);
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