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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 698F2C64EAD for ; Tue, 9 Oct 2018 13:14:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 10B7A21479 for ; Tue, 9 Oct 2018 13:14:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 10B7A21479 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=i-love.sakura.ne.jp Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727029AbeJIUbW (ORCPT ); Tue, 9 Oct 2018 16:31:22 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:52890 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726418AbeJIUbV (ORCPT ); Tue, 9 Oct 2018 16:31:21 -0400 Received: from fsav401.sakura.ne.jp (fsav401.sakura.ne.jp [133.242.250.100]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id w99DERVW059881; Tue, 9 Oct 2018 22:14:27 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav401.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav401.sakura.ne.jp); Tue, 09 Oct 2018 22:14:27 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav401.sakura.ne.jp) Received: from [192.168.1.8] (softbank060157066051.bbtec.net [60.157.66.51]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id w99DER5h059869 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 9 Oct 2018 22:14:27 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [PATCH] mm, oom_adj: avoid meaningless loop to find processes sharing mm To: Michal Hocko Cc: ytk.lee@samsung.com, "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Oleg Nesterov , David Rientjes , Vladimir Davydov , Andrew Morton , Linus Torvalds References: <20181008011931epcms1p82dd01b7e5c067ea99946418bc97de46a@epcms1p8> <20181008061407epcms1p519703ae6373a770160c8f912c7aa9521@epcms1p5> <20181008083855epcms1p20e691e5a001f3b94b267997c24e91128@epcms1p2> <20181009063541.GB8528@dhcp22.suse.cz> <20181009075015.GC8528@dhcp22.suse.cz> <20181009111005.GK8528@dhcp22.suse.cz> <99008444-b6b1-efc9-8670-f3eac4d2305f@i-love.sakura.ne.jp> <20181009125841.GP8528@dhcp22.suse.cz> From: Tetsuo Handa Message-ID: <41754dfe-3be7-f64e-45c9-2525d3b20d62@i-love.sakura.ne.jp> Date: Tue, 9 Oct 2018 22:14:24 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181009125841.GP8528@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/10/09 21:58, Michal Hocko wrote: > On Tue 09-10-18 21:52:12, Tetsuo Handa wrote: >> On 2018/10/09 20:10, Michal Hocko wrote: >>> On Tue 09-10-18 19:00:44, Tetsuo Handa wrote: >>>>> 2) add OOM_SCORE_ADJ_MIN and do not kill tasks sharing mm and do not >>>>> reap the mm in the rare case of the race. >>>> >>>> That is no problem. The mistake we made in 4.6 was that we updated oom_score_adj >>>> to -1000 (and allowed unprivileged users to OOM-lockup the system). >>> >>> I do not follow. >>> >> >> http://tomoyo.osdn.jp/cgi-bin/lxr/source/mm/oom_kill.c?v=linux-4.6.7#L493 > > Ahh, so you are not referring to the current upstream code. Do you see > any specific problem with the current one (well, except for the possible > race which I have tried to evaluate). > Yes. "task_will_free_mem(current) in out_of_memory() returns false due to MMF_OOM_SKIP being already set" is a problem for clone(CLONE_VM without CLONE_THREAD/CLONE_SIGHAND) with the current code.