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[195.135.220.15]) by mx.google.com with ESMTPS id a6si5661197ejj.232.2019.06.16.23.31.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 16 Jun 2019 23:31:21 -0700 (PDT) Received-SPF: softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 6195FAFAC; Mon, 17 Jun 2019 06:31:20 +0000 (UTC) Date: Mon, 17 Jun 2019 08:31:18 +0200 From: Michal Hocko To: Tetsuo Handa Cc: Shakeel Butt , syzbot , Andrew Morton , "Eric W. Biederman" , Roman Gushchin , Johannes Weiner , =?iso-8859-1?B?Suly9G1l?= Glisse , LKML , Linux MM , syzkaller-bugs , yuzhoujian@didichuxing.com Subject: Re: general protection fault in oom_unkillable_task Message-ID: <20190617063118.GA30420@dhcp22.suse.cz> References: <0000000000004143a5058b526503@google.com> <20190615134955.GA28441@dhcp22.suse.cz> <5bb1fe5d-f0e1-678b-4f64-82c8d5d81f61@i-love.sakura.ne.jp> <791594c6-45a3-d78a-70b5-901aa580ed9f@i-love.sakura.ne.jp> <840fa9f1-07e2-e206-2fc0-725392f96baf@i-love.sakura.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon 17-06-19 00:13:47, Tetsuo Handa wrote: [...] > >From 415e52cf55bc4ad931e4f005421b827f0b02693d Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa > Date: Mon, 17 Jun 2019 00:09:38 +0900 > Subject: [PATCH] mm: memcontrol: Use CSS_TASK_ITER_PROCS at mem_cgroup_scan_tasks(). > > Since commit c03cd7738a83b137 ("cgroup: Include dying leaders with live > threads in PROCS iterations") corrected how CSS_TASK_ITER_PROCS works, > mem_cgroup_scan_tasks() can use CSS_TASK_ITER_PROCS in order to check > only one thread from each thread group. O(Threads#) is definitely much worse than O(proc#) > Signed-off-by: Tetsuo Handa Acked-by: Michal Hocko Thanks! > --- > mm/memcontrol.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index ba9138a..b09ff45 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1163,7 +1163,7 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg, > struct css_task_iter it; > struct task_struct *task; > > - css_task_iter_start(&iter->css, 0, &it); > + css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it); > while (!ret && (task = css_task_iter_next(&it))) > ret = fn(task, arg); > css_task_iter_end(&it); > -- > 1.8.3.1 -- Michal Hocko SUSE Labs