Re: [PATCH 3/5] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs

[Tejun Heo]

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