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 fc560a26acce ("cpuset: replace cpuset->stack_list with cpuset_for_each_descendant_pre()")

Cc <[email protected]> # 3.9+

Signed-off-by Jason Low <[email protected]>

---
 kernel/cpuset.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

kernel/cpuset.c +0 -3

index 64b257f..b589e57 100644
@@ -548,9 +548,6 @@ static void update_domain_attr_tree(struct sched_domain_attr *dattr,
 
 	rcu_read_lock();
 	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 */
 		if (cpumask_empty(cp->cpus_allowed)) {
 			pos_css = css_rightmost_descendant(pos_css);