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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 0C4D0C43331 for ; Thu, 26 Mar 2020 20:19:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D610E2070A for ; Thu, 26 Mar 2020 20:19:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585253945; bh=XIa929sQg0TwUS+E+E3NB3nQS995O0VirrbbDv+k/RQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=qs/Mt8PWQKLL1X5if/Bc89yYutfGTBL2WZ+9+29sekgDv/QW91S+ZR+kWrfdtmmMk pvwu9Ebe5TRFWD/gV7ekReIiJmDcRrYavQDcsJ3R0+vvSI8cueW6l8bfvMtLR7e0aI bPjj+V9PkFe1Fz26fOEVks1vhb2HUU4or2T1UDoo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728712AbgCZUTE (ORCPT ); Thu, 26 Mar 2020 16:19:04 -0400 Received: from mail-qk1-f193.google.com ([209.85.222.193]:44619 "EHLO mail-qk1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726363AbgCZUTE (ORCPT ); Thu, 26 Mar 2020 16:19:04 -0400 Received: by mail-qk1-f193.google.com with SMTP id j4so8313474qkc.11; Thu, 26 Mar 2020 13:19:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=rzV++PjycMf1C6DNb3Bvn/qTQ5TRkWt2M63e9VE4bbI=; b=D2TAtx8FfNkFcX/x5Nkw002dVxBLRsFTu4IS+wnPcNna/HdEd9nkWgy9PEdV/ryXF8 irjFtYV0LC17Obpl11YhzuGa4+N49pl/Aw74ddi4HOsG7AcwArBKjooG8cYpmyV+wwG3 yibNMAa48vwV9r3a6ZMHEhyFvTcE++PToGoR7eY/ZIYkLYDLGbMGtaAJWOMahom5CPlk Vv25JfW5GVTqTUL+SEfUtYSbpUIsAsEawlnnwhwDMr0Q0XOlFf7Q+n31hCeooERR5YRU 7te2t0z/N8pjtGy7z0t+TH242ZaiAP/vaXLtsZWat51yM+LIaQ6wvz1Hj3xqTzPFhUL+ erew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=rzV++PjycMf1C6DNb3Bvn/qTQ5TRkWt2M63e9VE4bbI=; b=lzKrFi41CWZ6JjqUInmeUaSnvvC1DL5ranzfTROGTX4iK0pA+Y1frhq7h90U2otwFY PHOCqurGv0pbO2WaU+gdAMBr4cF0L49aH+YD85CESXiw3jsIrI3f2oLLIL1TL67Dy7UG 9dvzwPfvs0ErPaqcD/QDOsO1up9xsYjzLuyXUmGdTl7q9b6Y1XO/ioihlW5VTouHV/ux iWcYrbSAS2ZFyD9iOAKgZcP7jw90a5wjwBy6VvWVotqg+H0E9fXIvWTonkaS7gYrYh40 yWhV8LLW2xLNjjU7E52c7n7YIFNvMl6xeE22bvEPeibpJAz+31ZR3Y0Lqdk3Nsy8s42+ 5B9A== X-Gm-Message-State: ANhLgQ1kJK259zF/drsPr4vQyp9zzhncwyeQAhUcFM7wW9S/Yv9HprcK 0eYOfnkkmk/HKsvMNq09Oh8= X-Google-Smtp-Source: ADFU+vtJtabC1yJ4OPnSe9XH97DFyXt86qeuRZ6tOIR6sMiY5i6rwl1XVXWfnzOhBmdPC3oyIg/dyw== X-Received: by 2002:a37:d285:: with SMTP id f127mr10513039qkj.107.1585253941971; Thu, 26 Mar 2020 13:19:01 -0700 (PDT) Received: from localhost ([199.96.181.106]) by smtp.gmail.com with ESMTPSA id n38sm2252946qtk.64.2020.03.26.13.19.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Mar 2020 13:19:01 -0700 (PDT) Date: Thu, 26 Mar 2020 16:18:59 -0400 From: Tejun Heo To: Sonny Rao Cc: Waiman Long , Joel Fernandes , 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: <20200326201649.GQ162390@mtj.duckdns.org> References: <20200326191623.129285-1-joel@joelfernandes.org> <20200326192035.GO162390@mtj.duckdns.org> <20200326194448.GA133524@google.com> <972a5c1b-6721-ac20-cec5-617af67e617d@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 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. Thanks. -- tejun