From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753531AbeE3OSO (ORCPT ); Wed, 30 May 2018 10:18:14 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:40528 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753262AbeE3OSI (ORCPT ); Wed, 30 May 2018 10:18:08 -0400 X-Google-Smtp-Source: ADUXVKIXWLZdzo8pC2x6TllLmzJAhLWWmeoreIIIRHuYIY5NigE/xk8PfRaope4KBD6AULzhxWQQsw== Date: Wed, 30 May 2018 16:18:04 +0200 From: Juri Lelli To: Waiman Long Cc: Tejun Heo , 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 , Patrick Bellasi Subject: Re: [PATCH v9 2/7] cpuset: Add new v2 cpuset.sched.domain_root flag Message-ID: <20180530141804.GG3320@localhost.localdomain> References: <1527601294-3444-1-git-send-email-longman@redhat.com> <1527601294-3444-3-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1527601294-3444-3-git-send-email-longman@redhat.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 29/05/18 09:41, Waiman Long wrote: [...] > + cpuset.sched.domain_root > + 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 "1" (on). This flag is set by the parent > + and is not delegatable. > + > + If set, it indicates that the current cgroup is the root of a > + new scheduling domain or partition that comprises itself and > + all its descendants except those that are scheduling domain > + roots themselves and their descendants. The root cgroup is > + always a scheduling domain root. > + > + There are constraints on where this flag can be set. It can > + only be set in a cgroup if all the following conditions are true. > + > + 1) The "cpuset.cpus" is not empty and the list of CPUs are > + exclusive, i.e. they are not shared by any of its siblings. > + 2) The parent cgroup is also a scheduling domain root. > + 3) There is no child cgroups with cpuset enabled. This is > + for eliminating corner cases that have to be handled if such > + a condition is allowed. > + > + 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. > + Further changes made to "cpuset.cpus" is allowed as long as > + the first condition above is still true. IIUC, with the configuration below cpuset.cpus.effective:6-11 cgroup.controllers:cpuset cpuset.mems.effective:0-1 cgroup.subtree_control:cpuset g1/cpuset.cpus.effective:0-5 g1/cgroup.controllers:cpuset g1/cpuset.sched.load_balance:1 g1/cpuset.mems.effective:0-1 g1/cpuset.cpus:0-5 g1/cpuset.sched.domain_root:1 user.slice/cpuset.cpus.effective:6-11 user.slice/cgroup.controllers:cpuset user.slice/cpuset.sched.load_balance:1 user.slice/cpuset.mems.effective:0-1 user.slice/cpuset.cpus:6-11 user.slice/cpuset.sched.domain_root:0 init.scope/cpuset.cpus.effective:6-11 init.scope/cgroup.controllers:cpuset init.scope/cpuset.sched.load_balance:1 init.scope/cpuset.mems.effective:0-1 init.scope/cpuset.cpus:6-11 init.scope/cpuset.sched.domain_root:0 system.slice/cpuset.cpus.effective:6-11 system.slice/cgroup.controllers:cpuset system.slice/cpuset.sched.load_balance:1 system.slice/cpuset.mems.effective:0-1 system.slice/cpuset.cpus:6-11 system.slice/cpuset.sched.domain_root:0 machine.slice/cpuset.cpus.effective:6-11 machine.slice/cgroup.controllers:cpuset machine.slice/cpuset.sched.load_balance:1 machine.slice/cpuset.mems.effective:0-1 machine.slice/cpuset.cpus:6-11 machine.slice/cpuset.sched.domain_root:0 I should be able to # echo 0-4 >g1/cpuset.cpus ? It doesn't let me. I'm not sure we actually want to allow that, but that's what would I expect as per your text above. Thanks, - Juri BTW: thanks a lot for your prompt feedback and hope it's OK if I keep playing and asking questions. :)