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From:   Vasily Averin <vvs@virtuozzo.com>
Subject: [PATCH memcg v3 0/3] memcg: prohibit unconditional exceeding the
 limit of dying tasks
To:     Michal Hocko <mhocko@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Roman Gushchin <guro@fb.com>, Uladzislau Rezki <urezki@gmail.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Shakeel Butt <shakeelb@google.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        cgroups@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, kernel@openvz.org
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Message-ID: <20e50917-3589-bcb7-0174-b6fccfd15c66@virtuozzo.com>
Date:   Sat, 23 Oct 2021 16:18:58 +0300
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Memory cgroup charging allows killed or exiting tasks to exceed the hard
limit. It can be misused and allow to trigger global OOM from inside
memcg-limited container. On the other hand if memcg fail allocation,
called from inside #PF handler it trigger global OOM from inside
pagefault_out_of_memory().

To prevent these problems this patch set:
a) removes execution of out_of_memory() from pagefault_out_of_memory(),
   becasue nobody can explain why it is necessary.
b) allow memcg to fail allocation of dying/killed tasks.

v3: resplit, improved patch descriptions
v2: resplit,
    use old patch from Michal Hocko removing out_of_memory() from
      pagefault_out_of_memory()


Michal Hocko (1):
  mm, oom: do not trigger out_of_memory from the #PF

Vasily Averin (2):
  mm, oom: pagefault_out_of_memory: don't force global OOM for dying
    tasks
  memcg: prohibit unconditional exceeding the limit of dying tasks

 mm/memcontrol.c | 27 ++++++++-------------------
 mm/oom_kill.c   | 23 ++++++++++-------------
 2 files changed, 18 insertions(+), 32 deletions(-)

-- 
2.32.0