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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

  reply	other threads:[~2021-06-16 20:57 UTC|newest]

Thread overview: 18+ 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 19:16     ` Waiman Long
2021-06-10 19:39       ` 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
2021-06-03 21:24 ` [PATCH 3/5] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs Waiman Long
2021-06-16 20:57   ` Tejun Heo [this message]
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

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