Commit 15d428e6 authored by Waiman Long's avatar Waiman Long Committed by Tejun Heo
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cgroup/cpuset: Fix a partition bug with hotplug 



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: 4b842da2 ("cpuset: Make CPU hotplug work with partition")
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 0f3adb8a

kernel/cgroup/cpuset.c

+7 −0
Original line number Diff line number Diff line
@@ -3166,6 +3166,13 @@ static void cpuset_hotplug_workfn(struct work_struct *work) 
	cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);

	mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);



	/*

	 * In the rare case that hotplug removes all the cpus in subparts_cpus,

	 * we assumed that cpus are updated.

	 */

	if (!cpus_updated && top_cpuset.nr_subparts_cpus)

		cpus_updated = true;



	/* synchronize cpus_allowed to cpu_active_mask */

	if (cpus_updated) {

		spin_lock_irq(&callback_lock);