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From:   Vasily Averin <vvs@virtuozzo.com>
Subject: [PATCH memcg v2 0/2] 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
References: <YXGZoVhROdFG2Wym@dhcp22.suse.cz>
Message-ID: <21d79b86-476c-a8f2-e950-2339606f1253@virtuozzo.com>
Date:   Fri, 22 Oct 2021 11:10:40 +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:
1) removes execution of out_of_memory() from pagefault_out_of_memory(),
   becasue nobody can explain why it is necessary.
2) allows memcg to fail the allocations of dying/killed tasks. 

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 (1):
  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