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[66.187.233.206]) by smtp.gmail.com with ESMTPSA id d45sm2982613qtc.70.2019.09.06.06.48.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 06 Sep 2019 06:48:33 -0700 (PDT) Message-ID: <1567777712.5576.111.camel@lca.pw> Subject: Re: [RFC PATCH] mm, oom: disable dump_tasks by default From: Qian Cai To: Tetsuo Handa Cc: linux-mm@kvack.org, Michal Hocko Date: Fri, 06 Sep 2019 09:48:32 -0400 In-Reply-To: <7eada349-90d0-a12f-701c-adac3c395e3c@i-love.sakura.ne.jp> References: <20190903144512.9374-1-mhocko@kernel.org> <1567522966.5576.51.camel@lca.pw> <20190903151307.GZ14028@dhcp22.suse.cz> <1567699853.5576.98.camel@lca.pw> <8ea5da51-a1ac-4450-17d9-0ea7be346765@i-love.sakura.ne.jp> <1567718475.5576.108.camel@lca.pw> <192f2cb9-172e-06f4-d9e4-a58b5e167231@i-love.sakura.ne.jp> <1567775335.5576.110.camel@lca.pw> <7eada349-90d0-a12f-701c-adac3c395e3c@i-love.sakura.ne.jp> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6 (3.22.6-10.el7) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 2019-09-06 at 22:41 +0900, Tetsuo Handa wrote: > On 2019/09/06 22:08, Qian Cai wrote: > > Yes, mlocked is troublesome. I have other incidents where crond and systemd- > > udevd were killed by mistake, > > Yes. How to mitigate this regression is a controversial topic. > Michal thinks that we should make mlocked pages reclaimable, but > we haven't reached there. I think that we can monitor whether > counters decay over time (with timeout), but Michal refuses any > timeout based approach. We are deadlocked there. > > > and it even tried to kill kworker/0. > > No. The OOM killer never tries to kill kernel threads like kworker/0. I meant, [40040.401575] kworker/0:1 invoked oom-killer: gfp_mask=0x40cc0(GFP_KERNEL|__GFP_COMP), order=2, oom_score_adj=0 > > > > > https://cailca.github.io/files/dmesg.txt > >