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, MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID,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 199CAC433F5 for ; Mon, 27 Aug 2018 16:40:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A16B1208D5 for ; Mon, 27 Aug 2018 16:40:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="phuNN0F4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A16B1208D5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1727307AbeH0U12 (ORCPT ); Mon, 27 Aug 2018 16:27:28 -0400 Received: from mail-yb0-f195.google.com ([209.85.213.195]:39877 "EHLO mail-yb0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726995AbeH0U12 (ORCPT ); Mon, 27 Aug 2018 16:27:28 -0400 Received: by mail-yb0-f195.google.com with SMTP id c4-v6so6255087ybl.6; Mon, 27 Aug 2018 09:40:08 -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:user-agent; bh=UvrArh45BLr7dWBLMCweGOwgpp4+m2LYlxRRHm51Jzo=; b=phuNN0F4ps2C5485v2LFVyv4QPgAcc44HNZUyH4veVibq87+zzQadCt9vn8UKN6j/A OeyOWgOQpiXbHIW7L2BZKgWoJAyJk5rRk8LkWO+19ZcIVTM42n8b4if3hTHaDwN91/qD zDFuyAeTJGV/SyfGym+mWhE//yaBjxFU+ochk6dWNwgWljA65lgKcfQ61FMCsVxTbHnc YmxnxfyautknIUs+TKlNOA8CDByHcgR0FBfAeHD9yt5Yw8Adr9pAg36pFAg0RlstopCK q/TzU5Kw+QwRLyahiKaE8dlz0kM3NPXbwqtEIWGqWzSBhpaTo5haNublN9L0L7/bls5A 7J9g== 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:user-agent; bh=UvrArh45BLr7dWBLMCweGOwgpp4+m2LYlxRRHm51Jzo=; b=ew+TFc2oqusK0isa4HrPe0PnNdTPRul33HIraE4+DJQVG2MPqlCoA+IT8kHXfb6tYx kLl7EDzuOWwGe1qBaXnqkDq7jNjSfAGFZecYR/m+Xl2+lX4yWoqGPaWYG+wIWwW8lKFX 3DAo7RysEwqYH4JR4t2DfH1IndnUDdSz7koGrYwImNhSgx7f6x0+FXO3WTCKcUU7RqNi pdY3OtH4B7DlXL0CFYR2Sqe6ftHAshB7H3cp8kraUUY3eeKwFaDnNwQZkZEZfy7spADf Fejwvt5b4rM3SEYo438igQWmcGHZzCelJVCixUoDfDuRG/7bs3tCCS9tX7FxlXoNApxd QC1w== X-Gm-Message-State: APzg51DrmOJsluf5M41+t1lvazVgtjXRKkCutJ7EmPZXOABnm90/l+Re TbGYAoKelXrNxg1/oh9ZibE= X-Google-Smtp-Source: ANB0VdbibjDDSiTJtPTXELmox5dMNF+0enhdXx07txC9yphFPfdP3E3aIZPs/3tt+A6wt80uNopuLg== X-Received: by 2002:a25:b4b:: with SMTP id 72-v6mr7341982ybl.415.1535388007399; Mon, 27 Aug 2018 09:40:07 -0700 (PDT) Received: from localhost ([2620:10d:c091:200::1:2a0f]) by smtp.gmail.com with ESMTPSA id 138-v6sm6697388ywj.30.2018.08.27.09.40.06 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 27 Aug 2018 09:40:06 -0700 (PDT) Date: Mon, 27 Aug 2018 09:40:04 -0700 From: Tejun Heo To: Waiman Long Cc: Li Zefan , Johannes Weiner , Peter Zijlstra , Ingo Molnar , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kernel-team@fb.com, pjt@google.com, luto@amacapital.net, Mike Galbraith , torvalds@linux-foundation.org, Roman Gushchin , Juri Lelli , Patrick Bellasi Subject: Re: [PATCH v12 9/9] cpuset: Support forced turning off of partition flag Message-ID: <20180827164004.GE3978217@devbig004.ftw2.facebook.com> References: <1535380884-31308-1-git-send-email-longman@redhat.com> <1535380884-31308-10-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1535380884-31308-10-git-send-email-longman@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Waiman. On Mon, Aug 27, 2018 at 10:41:24AM -0400, Waiman Long wrote: > Cpuset allows arbitrary modification of cpu list in "cpuset.cpus" > even if the requested CPUs won't be granted in "cpuset.cpus.effective" > as restricted by its parent. However, the validate_change() function > will inhibit removal of CPUs that have been used in child cpusets. > > Being a partition root, however, limits the kind of cpu list > modification that is allowed. Adding CPUs is not allowed if the new > CPUs are not in the parent's effective cpu list that can be put into > "cpuset.cpus.reserved". In addition, a child partition cannot exhaust > all the parent's effective CPUs. > > Because of the implicit cpu exclusive nature of the partition root, > cpu changes that break that cpu exclusivity will not be allowed. Other > changes that break the conditions of being a partition root is generally > allowed. However, the partition flag of the cpuset as well those of > the descendant partitions will be forcefully turned off. First of all, thanks a lot for your persistence. I'm not necessarily against the flag being forced off but wonder whether the same config/effective approach can be used as in .cpus and .mems. Can you elaborate a bit on the choice here? Thank you. -- tejun