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From: Shakeel Butt <shakeelb@google.com>
Date: Tue, 28 Nov 2017 12:09:23 -0800
Message-ID: <CALvZod6AK08kugQveutunDsOUabSZ0PUKEeb+-a2RdQ16+uO4Q@mail.gmail.com>
Subject: Re: [PATCH] mm, memcg: fix mem_cgroup_swapout() for THPs
To: Michal Hocko <mhocko@kernel.org>
Cc: Huang Ying <ying.huang@intel.com>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Greg Thelen <gthelen@google.com>, Johannes Weiner <hannes@cmpxchg.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>,
        Cgroups <cgroups@vger.kernel.org>, stable@vger.kernel.org
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On Tue, Nov 28, 2017 at 12:00 PM, Michal Hocko <mhocko@kernel.org> wrote:
> On Tue 28-11-17 08:19:41, Shakeel Butt wrote:
>> 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.
>
> Very well spotted! Have you seen this triggering or you found it by the
> code inspection?
>

By code inspection.