From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f51.google.com (mail-pa0-f51.google.com [209.85.220.51]) by kanga.kvack.org (Postfix) with ESMTP id 9D9C6828DE for ; Thu, 7 Jan 2016 10:38:59 -0500 (EST) Received: by mail-pa0-f51.google.com with SMTP id yy13so168844290pab.3 for ; Thu, 07 Jan 2016 07:38:59 -0800 (PST) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [202.181.97.72]) by mx.google.com with ESMTPS id hp4si67566681pad.113.2016.01.07.07.38.58 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 07 Jan 2016 07:38:58 -0800 (PST) Subject: Re: [PATCH] mm,oom: Exclude TIF_MEMDIE processes from candidates. From: Tetsuo Handa References: <201512292258.ABF87505.OFOSJLHMFVOQFt@I-love.SAKURA.ne.jp> <20160107091512.GB27868@dhcp22.suse.cz> <201601072231.DGG78695.OOFVLHJFFQOStM@I-love.SAKURA.ne.jp> <20160107145841.GN27868@dhcp22.suse.cz> In-Reply-To: <20160107145841.GN27868@dhcp22.suse.cz> Message-Id: <201601080038.CIF04698.VFJHSOQLOFFMOt@I-love.SAKURA.ne.jp> Date: Fri, 8 Jan 2016 00:38:43 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org List-ID: To: mhocko@kernel.org Cc: rientjes@google.com, akpm@linux-foundation.org, mgorman@suse.de, torvalds@linux-foundation.org, oleg@redhat.com, hughd@google.com, andrea@kernel.org, riel@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Michal Hocko wrote: > @@ -333,6 +333,14 @@ static struct task_struct *select_bad_process(struct oom_control *oc, > if (points == chosen_points && thread_group_leader(chosen)) > continue; > > + /* > + * If the current major task is already ooom killed and this > + * is sysrq+f request then we rather choose somebody else > + * because the current oom victim might be stuck. > + */ > + if (is_sysrq_oom(sc) && test_tsk_thread_flag(p, TIF_MEMDIE)) > + continue; > + > chosen = p; > chosen_points = points; > } Do we want to require SysRq-f for each thread in a process? If g has 1024 p, dump_tasks() will do pr_info("[%5d] %5d %5d %8lu %8lu %7ld %7ld %8lu %5hd %s\n", for 1024 times? I think one SysRq-f per one process is sufficient. How can we guarantee that find_lock_task_mm() from oom_kill_process() chooses !TIF_MEMDIE thread when try_to_sacrifice_child() somehow chose !TIF_MEMDIE thread? I think choosing !TIF_MEMDIE thread at find_lock_task_mm() is the simplest way. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org