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From: Waiman Long <longman@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>,
	"Zefan Li" <lizefan.x@bytedance.com>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Shuah Khan" <shuah@kernel.org>,
	cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Roman Gushchin" <guro@fb.com>, "Phil Auld" <pauld@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Juri Lelli" <juri.lelli@redhat.com>,
	"Frederic Weisbecker" <frederic@kernel.org>,
	"Marcelo Tosatti" <mtosatti@redhat.com>
Subject: Re: [PATCH v8 5/6] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst
Date: Wed, 1 Dec 2021 12:49:15 -0500	[thread overview]
Message-ID: <e16ccf4f-7302-8891-d9f6-081e0bc41c04@redhat.com> (raw)
In-Reply-To: <YaelRiqWOIzT5uRs@slm.duckdns.org>


On 12/1/21 11:39, Tejun Heo wrote:
> On Wed, Dec 01, 2021 at 09:56:21AM -0500, Waiman Long wrote:
>> Right, I shouldn't say corner cases. Having task in an intermediate
>> partition is possible depending on event sequence. I am aware that there are
>> code in the cpuset code to prevent that, but it didn't block all cases.
>>>> A valid parent partition may distribute out all its CPUs to
>>>>    its child partitions as long as there is no task associated with it.
>>> Assuming there's always at least one kernel thread in the root cgroup
>>> that can't be migrated anyway.]
>> I am aware of that. That is why I said root cgroup must have at least one
>> cpu in its "cpuset.cpus.effective".
> In that case, let's explicitly describe that condition.

Yes, I will. Only non-root cgroup can distribute out all its CPUs. I 
thought I said that in the documentation, maybe it is very clear.

Cheers,
Longman


WARNING: multiple messages have this Message-ID (diff)
From: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: "Michal Koutný" <mkoutny-IBi9RG/b67k@public.gmane.org>,
	"Zefan Li" <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>,
	"Johannes Weiner"
	<hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
	"Jonathan Corbet" <corbet-T1hC0tSOHrs@public.gmane.org>,
	"Shuah Khan" <shuah-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kselftest-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	"Andrew Morton"
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	"Roman Gushchin" <guro-b10kYP2dOMg@public.gmane.org>,
	"Phil Auld" <pauld-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"Peter Zijlstra" <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
	"Juri Lelli" <juri.lelli-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"Frederic Weisbecker"
	<frederic-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	"Marcelo Tosatti"
	<mtosatti-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH v8 5/6] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst
Date: Wed, 1 Dec 2021 12:49:15 -0500	[thread overview]
Message-ID: <e16ccf4f-7302-8891-d9f6-081e0bc41c04@redhat.com> (raw)
In-Reply-To: <YaelRiqWOIzT5uRs-NiLfg/pYEd1N0TnZuCh8vA@public.gmane.org>


On 12/1/21 11:39, Tejun Heo wrote:
> On Wed, Dec 01, 2021 at 09:56:21AM -0500, Waiman Long wrote:
>> Right, I shouldn't say corner cases. Having task in an intermediate
>> partition is possible depending on event sequence. I am aware that there are
>> code in the cpuset code to prevent that, but it didn't block all cases.
>>>> A valid parent partition may distribute out all its CPUs to
>>>>    its child partitions as long as there is no task associated with it.
>>> Assuming there's always at least one kernel thread in the root cgroup
>>> that can't be migrated anyway.]
>> I am aware of that. That is why I said root cgroup must have at least one
>> cpu in its "cpuset.cpus.effective".
> In that case, let's explicitly describe that condition.

Yes, I will. Only non-root cgroup can distribute out all its CPUs. I 
thought I said that in the documentation, maybe it is very clear.

Cheers,
Longman


  reply	other threads:[~2021-12-01 17:49 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-18 14:36 [PATCH v8 0/6] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus Waiman Long
2021-10-18 14:36 ` Waiman Long
2021-10-18 14:36 ` [PATCH v8 1/6] cgroup/cpuset: Allow no-task partition to have empty cpuset.cpus.effective Waiman Long
2021-10-18 14:36   ` Waiman Long
2021-10-18 14:36 ` [PATCH v8 2/6] cgroup/cpuset: Refining features and constraints of a partition Waiman Long
2021-10-18 14:36   ` Waiman Long
2021-10-18 14:36 ` [PATCH v8 3/6] cgroup/cpuset: Add a new isolated cpus.partition type Waiman Long
2021-10-18 14:36 ` [PATCH v8 4/6] cgroup/cpuset: Show invalid partition reason string Waiman Long
2021-10-18 14:36 ` [PATCH v8 5/6] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Waiman Long
2021-11-15 19:31   ` Michal Koutný
2021-11-15 19:31     ` Michal Koutný
2021-11-15 20:11     ` Tejun Heo
2021-11-15 20:11       ` Tejun Heo
2021-11-15 21:27       ` Waiman Long
2021-11-15 21:27         ` Waiman Long
2021-11-15 21:10     ` Waiman Long
2021-11-16 17:54       ` Michal Koutný
2021-11-30 15:35         ` Waiman Long
2021-11-30 17:11           ` Tejun Heo
2021-11-30 17:11             ` Tejun Heo
2021-12-01  3:56             ` Waiman Long
2021-12-01 14:13               ` Michal Koutný
2021-12-01 14:13                 ` Michal Koutný
2021-12-01 14:56                 ` Waiman Long
2021-12-01 14:56                   ` Waiman Long
2021-12-01 16:39                   ` Tejun Heo
2021-12-01 17:49                     ` Waiman Long [this message]
2021-12-01 17:49                       ` Waiman Long
2021-12-01 14:26               ` Waiman Long
2021-12-01 14:26                 ` Waiman Long
2021-12-01 16:46               ` Tejun Heo
2021-12-01 16:46                 ` Tejun Heo
2021-12-01 18:05                 ` Waiman Long
2021-12-02  1:28                   ` Waiman Long
2021-12-03 18:25                     ` Michal Koutný
2021-12-03 18:25                       ` Michal Koutný
2021-12-03 19:27                       ` Waiman Long
2021-10-18 14:36 ` [PATCH v8 6/6] kselftest/cgroup: Add cpuset v2 partition root state test Waiman Long
2021-10-18 14:36   ` Waiman Long
2021-10-27 23:05 ` [PATCH v8 0/6] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus Waiman Long
2021-11-10 11:13 ` Felix Moessbauer
2021-11-10 13:21   ` Marcelo Tosatti
2021-11-10 13:56   ` Michal Koutný
2021-11-10 15:21     ` Moessbauer, Felix
2021-11-10 15:21       ` Moessbauer, Felix
2021-11-10 16:10       ` Marcelo Tosatti
2021-11-10 16:10         ` Marcelo Tosatti
2021-11-10 16:14         ` Marcelo Tosatti
2021-11-10 16:14           ` Marcelo Tosatti
2021-11-10 16:15         ` Jan Kiszka
2021-11-10 16:15           ` Jan Kiszka
2021-11-10 17:29           ` Marcelo Tosatti
2021-11-10 17:29             ` Marcelo Tosatti
2021-11-10 18:30             ` Waiman Long
2021-11-10 18:30               ` Waiman Long
2021-11-10 17:52           ` Michal Koutný
2021-11-10 17:52             ` Michal Koutný
2021-11-10 18:04             ` Jan Kiszka
2021-11-10 18:04               ` Jan Kiszka
2021-11-10 18:15       ` Michal Koutný
2021-11-10 18:15         ` Michal Koutný
2021-11-10 15:20   ` Waiman Long

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