Commit 99570300 authored by Waiman Long's avatar Waiman Long Committed by Tejun Heo
Browse files

cgroup/cpuset: Check for partition roots with overlapping CPUs 



With the previous commit that eliminates the overlapping partition
root corner cases in the hotplug code, the partition roots passed down
to generate_sched_domains() should not have overlapping CPUs. Enable
overlapping cpuset check for v2 and warn if that happens.

This patch also has the benefit of increasing test coverage of the new
Union-Find cpuset merging code to cgroup v2.

Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent bc3c2751

kernel/cgroup/cpuset.c

+18 −16
Original line number Diff line number Diff line
@@ -1127,26 +1127,28 @@ static int generate_sched_domains(cpumask_var_t **domains, 
	if (root_load_balance && (csn == 1))

		goto single_root_domain;



	if (!cgrpv2) {

	for (i = 0; i < csn; i++)

		uf_node_init(&csa[i]->node);



	/* Merge overlapping cpusets */

	for (i = 0; i < csn; i++) {

		for (j = i + 1; j < csn; j++) {

				if (cpusets_overlap(csa[i], csa[j]))

			if (cpusets_overlap(csa[i], csa[j])) {

				/*

				 * Cgroup v2 shouldn't pass down overlapping

				 * partition root cpusets.

				 */

				WARN_ON_ONCE(cgrpv2);

				uf_union(&csa[i]->node, &csa[j]->node);

			}

		}

	}



	/* Count the total number of domains */

	for (i = 0; i < csn; i++) {

		if (uf_find(&csa[i]->node) == &csa[i]->node)

			ndoms++;

	}

	} else {

		ndoms = csn;

	}



	/*

	 * Now we know how many domains to create.