Messages in this thread | | | From | Waiman Long <> | Subject | Re: [PATCH 3/5] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs | Date | Thu, 17 Jun 2021 16:45:35 -0400 |
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On 6/16/21 4:57 PM, Tejun Heo wrote: > 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?
From my point of view, PRS_ERROR is used when cpus are gone because of cpu hotplug (offline). It can be a temporary condition that will be corrected later on. I don't want to use PRS_ERROR for the particular case that the users have explicitly distributed out all the cpus to child partitions. I will clarify it in the next version and double check to make sure that this rule is consistently apply.
Thanks, Longman
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