Re: [PATCH v3 2/9] cgroup/cpuset: Fix a partition bug with hotplug

From: Tejun Heo
Date: Mon Jul 26 2021 - 19:00:06 EST

On Tue, Jul 20, 2021 at 10:18:27AM -0400, Waiman Long wrote:
> In cpuset_hotplug_workfn(), the detection of whether the cpu list
> has been changed is done by comparing the effective cpus of the top
> cpuset with the cpu_active_mask. However, in the rare case that just
> all the CPUs in the subparts_cpus are offlined, the detection fails
> and the partition states are not updated correctly. Fix it by forcing
> the cpus_updated flag to true in this particular case.
> Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition")
> Signed-off-by: Waiman Long <longman@xxxxxxxxxx>

Applied to cgroup/for-5.15 w/ a minor update to the comment (I dropped
"just" before "all". It read weird to me.)