Commit 283cb41f authored Feb 13, 2015 by Jason Low Committed by Tejun Heo Mar 02, 2015

cpuset: Fix cpuset sched_relax_domain_level



The cpuset.sched_relax_domain_level can control how far we do
immediate load balancing on a system. However, it was found on recent
kernels that echo'ing a value into cpuset.sched_relax_domain_level
did not reduce any immediate load balancing.

The reason this occurred was because the update_domain_attr_tree() traversal
did not update for the "top_cpuset". This resulted in nothing being changed
when modifying the sched_relax_domain_level parameter.

This patch is able to address that problem by having update_domain_attr_tree()
allow updates for the root in the cpuset traversal.

Fixes: fc560a26 ("cpuset: replace cpuset->stack_list with cpuset_for_each_descendant_pre()")
Cc: <stable@vger.kernel.org> # 3.9+
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Serge Hallyn <serge.hallyn@canonical.com>

parent 79063bff

kernel/cpuset.c

+0 −3

Original line number	Original line	Diff line number	Diff line
	@@ -548,9 +548,6 @@ static void update_domain_attr_tree(struct sched_domain_attr *dattr,

	rcu_read_lock();		rcu_read_lock();
	cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {		cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
	if (cp == root_cs)
	continue;

	/* skip the whole subtree if @cp doesn't have any CPU */		/* skip the whole subtree if @cp doesn't have any CPU */
	if (cpumask_empty(cp->cpus_allowed)) {		if (cpumask_empty(cp->cpus_allowed)) {
	pos_css = css_rightmost_descendant(pos_css);		pos_css = css_rightmost_descendant(pos_css);