From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.6 required=5.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 9F36C7D062 for ; Fri, 25 May 2018 07:16:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935134AbeEYHPu (ORCPT ); Fri, 25 May 2018 03:15:50 -0400 Received: from merlin.infradead.org ([205.233.59.134]:36994 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934393AbeEYHPt (ORCPT ); Fri, 25 May 2018 03:15:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ccSGORzi1kauMm9VoF/P9IEFnX4OPSySDEXnF3jN2C8=; b=wKVe4SZEc9Gn53UoLaWFvXM8h E9xZ1B4TcXPwXv0ZruOHpmFClM4UD1u4HcDRaX/NlrfByFFPoQczdrBpMuVCUu3hWkBKbljfhAmR0 EQnGuj5AiirNCjgF1S+DxoUB8rjZKHN8wkXs4VcE1fWz3WiJnb4oQ9c03qlbOkUHDJE1HuRHcND94 fpDQS4ErE1peJC8+XyVLysOobjgD9Xpug2sLZkdh2V5G8yk02SizUa4aTtA2ej2wbPjvaM3aBcD9/ kb634XPIHGd1zbOfxK+ngkeaTHDcyKzG11jESQpkmcv1AFzDqPtgYZxxdhsoemurT/0Pk9hMjkSXJ cwqI+hAnQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fM6wh-000505-LD; Fri, 25 May 2018 07:15:28 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 6483F2029F1CB; Fri, 25 May 2018 09:15:24 +0200 (CEST) Date: Fri, 25 May 2018 09:15:24 +0200 From: Peter Zijlstra To: Waiman Long Cc: Tejun Heo , Li Zefan , Johannes Weiner , 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 Subject: Re: [PATCH v8 2/6] cpuset: Add new v2 cpuset.sched.domain flag Message-ID: <20180525071524.GQ12198@hirez.programming.kicks-ass.net> References: <1526590545-3350-1-git-send-email-longman@redhat.com> <1526590545-3350-3-git-send-email-longman@redhat.com> <20180524154156.GI12198@hirez.programming.kicks-ass.net> <675f0f38-9154-4e73-1679-179eefdb7c9f@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <675f0f38-9154-4e73-1679-179eefdb7c9f@redhat.com> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu, May 24, 2018 at 02:53:31PM -0400, Waiman Long wrote: > On 05/24/2018 11:41 AM, Peter Zijlstra wrote: > > On Thu, May 17, 2018 at 04:55:41PM -0400, Waiman Long wrote: > >> A new cpuset.sched.domain boolean flag is added to cpuset v2. This new > >> flag indicates that the CPUs in the current cpuset should be treated > >> as a separate scheduling domain. > > The traditional name for this is a partition. > > Do you want to call it cpuset.sched.partition? That name sounds strange > to me. Let me explore the whole domain x load-balance space first. I'm thinking the two parameters are mostly redundant, but I might be overlooking something (trivial or otherwise). > >> + cpuset.sched.domain > >> + A read-write single value file which exists on non-root > >> + cpuset-enabled cgroups. It is a binary value flag that accepts > >> + either "0" (off) or a non-zero value (on). > > I would be conservative and only allow 0/1. > > I stated that because echoing other integer value like 2 into the flag > file won't return any error. I will modify it to say just 0 and 1. Ah, I would make the file error on >1. Because then you can always extend the meaning afterwards because you know it won't be written to with the new value. > >> + 3) There is no child cgroups with cpuset enabled. > >> + > >> + Setting this flag will take the CPUs away from the effective > >> + CPUs of the parent cgroup. Once it is set, this flag cannot be > >> + cleared if there are any child cgroups with cpuset enabled. > > This I'm not clear on. Why? > > > That is for pragmatic reason as it is easier to code this way. We could > remove this restriction but that will make the code more complex. Best to mention that I think. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html