From: "Huang\, Ying" Subject: Re: [PATCH] mm, memcg: fix mem_cgroup_swapout() for THPs Date: Wed, 29 Nov 2017 08:38:08 +0800 Message-ID: <87o9nlc427.fsf@yhuang-dev.intel.com> References: <20171128161941.20931-1-shakeelb@google.com> Mime-Version: 1.0 Return-path: In-Reply-To: <20171128161941.20931-1-shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> (Shakeel Butt's message of "Tue, 28 Nov 2017 08:19:41 -0800") Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Shakeel Butt Cc: Huang Ying , Vladimir Davydov , Michal Hocko , Greg Thelen , Johannes Weiner , Andrew Morton , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Shakeel Butt writes: > The commit 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. Good catch! Thanks a lot for fixing! Best Regards, Huang, Ying > Fixes: d6810d730022 ("memcg, THP, swap: make mem_cgroup_swapout() support THP") > Signed-off-by: Shakeel Butt > Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > --- > mm/memcontrol.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 50e6906314f8..ac2ffd5e02b9 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -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); > } > > /**