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[2603:800c:1a02:1bae:e24f:43ff:fee6:449f]) by smtp.gmail.com with ESMTPSA id x13sm7290038pjh.30.2021.08.27.14.27.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Aug 2021 14:27:45 -0700 (PDT) Sender: Tejun Heo Date: Fri, 27 Aug 2021 11:27:44 -1000 From: Tejun Heo To: Waiman Long Cc: Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , Michal =?iso-8859-1?Q?Koutn=FD?= Subject: Re: [PATCH v7 5/6] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Message-ID: References: <20210825213750.6933-1-longman@redhat.com> <20210825213750.6933-6-longman@redhat.com> <32e27fcc-32f1-b26c-ae91-9e03f7e433af@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Fri, Aug 27, 2021 at 05:19:31PM -0400, Waiman Long wrote: > Well, that is a valid point. The cpus may have been offlined when a > partition is being created. I can certainly relent on this check in forming > a partition. IOW, cpus_allowed can contain some or all offline cpus and a > valid (some are online) or invalid (all are offline) partition can be > formed. I can also allow an invalid child partition to be formed with an > invalid parent partition. However, the cpu exclusivity rules will still > apply. > > Other than that, do you envision any other circumstances where we should > allow an invalid partition to be formed? Now that most restrictions are removed from configuration side, just go all the way? Given that the user must check the status afterwards anyway, I don't see technical or even usability reasons for leaving some pieces behind. Going all the way would be easier to use too - bang in the target config and read the resulting state to reliably find out why a partition isn't valid, especially if we list *all* the reasons so that the user can tell whether the configuration is as intended immediately. Thanks. -- tejun