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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 F3A08C2BA83 for ; Thu, 13 Feb 2020 14:36:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CC358218AC for ; Thu, 13 Feb 2020 14:36:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727558AbgBMOgo (ORCPT ); Thu, 13 Feb 2020 09:36:44 -0500 Received: from foss.arm.com ([217.140.110.172]:47346 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726300AbgBMOgn (ORCPT ); Thu, 13 Feb 2020 09:36:43 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3D3771FB; Thu, 13 Feb 2020 06:36:43 -0800 (PST) Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.195.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 724E83F68F; Thu, 13 Feb 2020 06:36:42 -0800 (PST) Date: Thu, 13 Feb 2020 14:36:40 +0000 From: Qais Yousef To: Tejun Heo Cc: Li Zefan , Johannes Weiner , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] cgroup/cpuset: Fix a race condition when reading cpuset.* Message-ID: <20200213143639.6jw2kiadjzyu6unr@e107158-lin.cambridge.arm.com> References: <20200211141554.24181-1-qais.yousef@arm.com> <20200212221543.GL80993@mtj.thefacebook.com> <20200213115015.hkd6uqwfjosxjfpm@e107158-lin.cambridge.arm.com> <20200213135645.GG88887@mtj.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200213135645.GG88887@mtj.thefacebook.com> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/13/20 08:56, Tejun Heo wrote: > Hello, > > On Thu, Feb 13, 2020 at 11:50:16AM +0000, Qais Yousef wrote: > > I ran 500 iterations of cpuset_hotplug_test.sh on the branch, it passed. > > > > I also cherry-picked commit 6426bfb1d5f0 ("cpuset: Make cpuset hotplug synchronous") > > into v5.6-rc1 and ran 100 iterations and it passed too. > > Awesome, thanks for verifying. > > > While investigating the problem, I could reproduce it all the way back to v5.0. > > Stopped there so earlier versions could still have the problem. > > > > Do you think it's worth porting the change to stable trees? Admittedly the > > problem should be benign, but it did trigger an LTP failure. > > I'm afraid not. It's not an issue which would affect actual use cases > and there's (as always) some risks involved with backporting it, so > the benefit just doesn't seem justifiable here. Yeah I can't see how a real application would depend on this functionality other than for informational reasons. Or testing like in this case. Thanks -- Qais Yousef