tree 828ad38946acad9990dcc733a10ebdeed0c1fbd5
parent 62cccb8c8e7a3ca233f49d5e7dcb1557d25465cd
author Johannes Weiner <hannes@cmpxchg.org> 1458079045 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1458086116 -0700

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>