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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 50973C43331 for ; Thu, 26 Mar 2020 20:23:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24CCE2070A for ; Thu, 26 Mar 2020 20:23:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="dY7wSC08" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728650AbgCZUXo (ORCPT ); Thu, 26 Mar 2020 16:23:44 -0400 Received: from mail-qk1-f196.google.com ([209.85.222.196]:44417 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727446AbgCZUXn (ORCPT ); Thu, 26 Mar 2020 16:23:43 -0400 Received: by mail-qk1-f196.google.com with SMTP id j4so8334246qkc.11 for ; Thu, 26 Mar 2020 13:23:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=hJWp5t89/iwbfn8Ca+Lrz1rZRbdYA2KCpWmXHJOj3y4=; b=dY7wSC0838pzka4AzUdCK19Pqo/xSg0AU8qIfHTom1OXY5mFHlZIYMENXzpLnBMDcC NwYnyykFW1mIgRuaJe2SIZNN+JLl1bR6XMi/axhztQ+3Lol92UZB9R5juK0hc6a1xaWl o5DOw2ARWnmKhSSoBhVBErNkXtykPQzMjcX8c= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=hJWp5t89/iwbfn8Ca+Lrz1rZRbdYA2KCpWmXHJOj3y4=; b=nDWzljTZFPrnQHPLyHDqAbeNdENkR0qykl+fwlE6BBjKgGdK21m4312sGrUpe1WzaR f3tQm8YDFskv01KUg4Cwcum17NF5SIOq+CFx9kJH6PVcuWo6dRheIGO4sYRCokzPjX1y O15Sn+3VYl1iGnGsmbsArfjrnSi1Vt/mKHPJlTMzFN73m0yfbVT+kbnaFbWmhZHtHe4q EVctcFgta5ieG4fcI1C56xJxjrw2x5OdcQS2Pwgm1u48TKOOfdPeKYr7egkY/u/aTUjK ZT8AtCKQR/4kxaKtHAcnAlhHcJV0yMJAr4X9/POG9QLItBbAiHBOz/BqaXmpR5yq9qW9 v6Vg== X-Gm-Message-State: ANhLgQ3rbB2abfGZkMoP6K7Wag2H58DVgtt4x9lRprHijQzyVa/UdEo7 8Z8mMH0eUh0cp++u3y10MlPgpw== X-Google-Smtp-Source: ADFU+vvdfgPWrcllkj1WQ8cugXCsD6gKi4uamCH0UN8ejJIKkiAcGgtzhXH9Q2UhVC/2+6inHbi62w== X-Received: by 2002:a05:620a:539:: with SMTP id h25mr10212915qkh.395.1585254222181; Thu, 26 Mar 2020 13:23:42 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id z6sm2092718qka.34.2020.03.26.13.23.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Mar 2020 13:23:40 -0700 (PDT) Date: Thu, 26 Mar 2020 16:23:40 -0400 From: Joel Fernandes To: Tejun Heo Cc: Sonny Rao , Waiman Long , linux-kernel@vger.kernel.org, Dmitry Shmidt , Amit Pundir , kernel-team@android.com, Jesse Barnes , vpillai@digitalocean.com, Peter Zijlstra , Guenter Roeck , Greg Kerr , cgroups@vger.kernel.org, Johannes Weiner , Li Zefan Subject: Re: [PATCH RFC] cpuset: Make cpusets get restored on hotplug Message-ID: <20200326202340.GA146657@google.com> References: <20200326191623.129285-1-joel@joelfernandes.org> <20200326192035.GO162390@mtj.duckdns.org> <20200326194448.GA133524@google.com> <972a5c1b-6721-ac20-cec5-617af67e617d@redhat.com> <20200326201649.GQ162390@mtj.duckdns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200326201649.GQ162390@mtj.duckdns.org> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 26, 2020 at 04:18:59PM -0400, Tejun Heo wrote: > On Thu, Mar 26, 2020 at 01:05:04PM -0700, Sonny Rao wrote: > > I am surprised if anyone actually wants this behavior, we (Chrome OS) > > The behavior is silly but consistent in that it doesn't allow empty active > cpusets and it has been like that for many many years now. > > > found out about it accidentally, and then found that Android had been > > carrying a patch to fix it. And if it were a desirable behavior then > > why isn't it an option in v2? > > Nobody is saying it's a good behavior (hence the change in cgroup2) and there > are situations where changing things like this is justifiable, but, here: > > * The proposed change makes the interface inconsistent and does so > unconditionally on what is now a mostly legacy interface. > > * There already is a newer version of the interface which includes the > desired behavior. > > * I forgot but as Waiman pointed out, you can even opt-in to the new > behavior, which is more comprehensive without the inconsitencies, > while staying on cgroup1. Thank you Tejun, Waiman and Sonny. I confirmed the cgroup_v2_mode option fixes cgroup v1's broken behavior. We will use this mount option on our systems to fix it. thanks, - Joel