From: Tejun Heo <tj@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: 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>
Subject: Re: [PATCH 3/5] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs
Date: Wed, 16 Jun 2021 16:57:48 -0400 [thread overview]
Message-ID: <YMplzNzg7mMCU4JJ@slm.duckdns.org> (raw)
In-Reply-To: <20210603212416.25934-4-longman@redhat.com>
Hello,
On Thu, Jun 03, 2021 at 05:24:14PM -0400, Waiman Long wrote:
> @@ -2181,6 +2192,13 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
> (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
> goto out_unlock;
>
> + /*
> + * On default hierarchy, task cannot be moved to a cpuset with empty
> + * effective cpus.
> + */
> + if (is_in_v2_mode() && cpumask_empty(cs->effective_cpus))
> + goto out_unlock;
> +
This is inconsistent with how other events which leave a root partition
empty is handled. Woudln't it be more consistent to switch the parent to
PRS_ERROR and behave accordingly but allow it to have valid child roots?
Thanks.
--
tejun
WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: 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>
Subject: Re: [PATCH 3/5] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs
Date: Wed, 16 Jun 2021 16:57:48 -0400 [thread overview]
Message-ID: <YMplzNzg7mMCU4JJ@slm.duckdns.org> (raw)
In-Reply-To: <20210603212416.25934-4-longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Hello,
On Thu, Jun 03, 2021 at 05:24:14PM -0400, Waiman Long wrote:
> @@ -2181,6 +2192,13 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
> (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
> goto out_unlock;
>
> + /*
> + * On default hierarchy, task cannot be moved to a cpuset with empty
> + * effective cpus.
> + */
> + if (is_in_v2_mode() && cpumask_empty(cs->effective_cpus))
> + goto out_unlock;
> +
This is inconsistent with how other events which leave a root partition
empty is handled. Woudln't it be more consistent to switch the parent to
PRS_ERROR and behave accordingly but allow it to have valid child roots?
Thanks.
--
tejun
next prev parent reply other threads:[~2021-06-16 20:57 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-03 21:24 [PATCH 0/5] cgroup/cpuset: Enable cpuset partition with no load balancing Waiman Long
2021-06-03 21:24 ` [PATCH 1/5] cgroup/cpuset: Don't call validate_change() for some flag changes Waiman Long
2021-06-16 20:39 ` Tejun Heo
2021-06-17 2:53 ` Waiman Long
2021-06-03 21:24 ` [PATCH 2/5] cgroup/cpuset: Add new cpus.partition type with no load balancing Waiman Long
2021-06-10 18:50 ` Peter Zijlstra
2021-06-10 18:50 ` Peter Zijlstra
2021-06-10 19:16 ` Waiman Long
2021-06-10 19:39 ` Peter Zijlstra
2021-06-10 19:00 ` Peter Zijlstra
2021-06-10 19:00 ` Peter Zijlstra
2021-06-10 19:21 ` Waiman Long
2021-06-16 20:47 ` Tejun Heo
2021-06-17 2:57 ` Waiman Long
2021-06-17 2:57 ` Waiman Long
2021-06-03 21:24 ` [PATCH 3/5] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs Waiman Long
2021-06-03 21:24 ` Waiman Long
2021-06-16 20:57 ` Tejun Heo [this message]
2021-06-16 20:57 ` Tejun Heo
2021-06-17 20:45 ` Waiman Long
2021-06-17 20:45 ` Waiman Long
2021-06-03 21:24 ` [PATCH 4/5] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Waiman Long
2021-06-03 21:24 ` [PATCH 5/5] kselftest/cgroup: Add cpuset v2 partition root state test Waiman Long
2021-06-10 14:19 ` [PATCH 0/5] cgroup/cpuset: Enable cpuset partition with no load balancing Phil Auld
2021-06-10 14:19 ` Phil Auld
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