From: Shakeel Butt shakeelb@google.com Subject: mm, memcg: fix mem_cgroup_swapout() for THPs

d6810d730022 ("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: d6810d730022 ("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 ---

mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN mm/memcontrol.c~mm-memcg-fix-mem_cgroup_swapout-for-thps mm/memcontrol.c --- a/mm/memcontrol.c~mm-memcg-fix-mem_cgroup_swapout-for-thps +++ a/mm/memcontrol.c @@ -6044,7 +6044,7 @@ void mem_cgroup_swapout(struct page *pag memcg_check_events(memcg, page);

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

/** _