Commit d08afa14 authored Nov 29, 2017 by Shakeel Butt Committed by Linus Torvalds Nov 29, 2017

mm, memcg: fix mem_cgroup_swapout() for THPs

Commit d6810d73 ("memcg, THP, swap: make mem_cgroup_swapout()
support THP") changed mem_cgroup_swapout() to support transparent huge
page (THP).

However the patch missed one location which should be changed for
correctly handling THPs.  The resulting bug will cause the memory
cgroups whose THPs were swapped out to become zombies on deletion.

Link: http://lkml.kernel.org/r/20171128161941.20931-1-shakeelb@google.com


Fixes: d6810d73 ("memcg, THP, swap: make mem_cgroup_swapout() support THP")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: <stable@vger.kernel.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 40a899ed

mm/memcontrol.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -6044,7 +6044,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
		memcg_check_events(memcg, page);

		if (!mem_cgroup_is_root(memcg))
		css_put(&memcg->css);
		css_put_many(&memcg->css, nr_entries);
		}

		/**

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