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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT 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 91E16C31E44 for ; Mon, 17 Jun 2019 06:31:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5496D218C9 for ; Mon, 17 Jun 2019 06:31:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560753083; bh=E1N41cylcCvClx041UaN3kZbEpO1JBbXfqyUD8vU8Ec=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=yJt0n01O5qDeOLbwjYrnKGNpTUA7uzT9GzROtpC+rsjS3rkwIoPcIVvDHxZT+bjJG AkYmfONDLw4Jc1PkPC5ubRC9MpimdXq4x6AFwW4CLZeg15TbFIUggkQeXbMnTHG3pw B+kwnA1aG+AVztht+QBHZEnS7JM4wAtV0vnXeP3k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725886AbfFQGbW (ORCPT ); Mon, 17 Jun 2019 02:31:22 -0400 Received: from mx2.suse.de ([195.135.220.15]:46972 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725554AbfFQGbW (ORCPT ); Mon, 17 Jun 2019 02:31:22 -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 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) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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