From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 663BEC43331 for ; Fri, 6 Sep 2019 11:02:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2CD6F206BB for ; Fri, 6 Sep 2019 11:02:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567767757; bh=shvV/Zk/BQkSbVSg065+YUhljAGOjzdleh/m0itSkjs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=W1o7vHyaP6vZ14pjby7UpCvVUvELo5duUMX1L3/85dwWWTuZTZxNZWXNcuwzv4xp1 GpO6SzkbvckOzHvAZoxDQxyY119OghDKeSuoG5c9uX5RY3tku2c0JB5JxICVlaXRDD PaLRcmO2Dh8NaibN40sOz5TcSTEZHHNuJPz/t2pA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392159AbfIFLCg (ORCPT ); Fri, 6 Sep 2019 07:02:36 -0400 Received: from mx2.suse.de ([195.135.220.15]:54840 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731418AbfIFLCg (ORCPT ); Fri, 6 Sep 2019 07:02:36 -0400 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 6B409AF2C; Fri, 6 Sep 2019 11:02:34 +0000 (UTC) Date: Fri, 6 Sep 2019 13:02:33 +0200 From: Michal Hocko To: Tetsuo Handa Cc: David Rientjes , linux-mm@kvack.org, Andrew Morton , LKML Subject: Re: [RFC PATCH] mm, oom: disable dump_tasks by default Message-ID: <20190906110233.GE14491@dhcp22.suse.cz> References: <20190903144512.9374-1-mhocko@kernel.org> <20190904054004.GA3838@dhcp22.suse.cz> <12bcade2-4190-5e5e-35c6-7a04485d74b9@i-love.sakura.ne.jp> <20190905140833.GB3838@dhcp22.suse.cz> <20ec856d-0f1e-8903-dbe0-bbc8b7a1847a@i-love.sakura.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20ec856d-0f1e-8903-dbe0-bbc8b7a1847a@i-love.sakura.ne.jp> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 06-09-19 19:46:10, Tetsuo Handa wrote: > On 2019/09/05 23:08, Michal Hocko wrote: > > On Thu 05-09-19 22:39:47, Tetsuo Handa wrote: > > [...] > >> There is nothing that prevents users from enabling oom_dump_tasks by sysctl. > >> But that requires a solution for OOM stalling problem. > > > > You can hardly remove stalling if you are not reducing the amount of > > output or get it into a different context. Whether the later is > > reasonable is another question but you are essentially losing "at the > > OOM event state". > > > > I am not losing "at the OOM event state". Please find "struct oom_task_info" > (for now) embedded into "struct task_struct" which holds "at the OOM event state". > > And my patch moves "printk() from dump_tasks()" from OOM context to WQ context. Workers might be blocked for unbound amount of time and so this information might be printed late. -- Michal Hocko SUSE Labs