[PATCH 3.18 25/28] sched/topology: Optimize build_group_mask()

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lauro Ramos Venancio <lvenanci@xxxxxxxxxx>

commit f32d782e31bf079f600dcec126ed117b0577e85c upstream.

The group mask is always used in intersection with the group CPUs. So,
when building the group mask, we don't have to care about CPUs that are
not part of the group.

Signed-off-by: Lauro Ramos Venancio <lvenanci@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: lwang@xxxxxxxxxx
Cc: riel@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1492717903-5195-2-git-send-email-lvenanci@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/sched/core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5863,12 +5863,12 @@ enum s_alloc {
  */
 static void build_group_mask(struct sched_domain *sd, struct sched_group *sg)
 {
-	const struct cpumask *span = sched_domain_span(sd);
+	const struct cpumask *sg_span = sched_group_cpus(sg);
 	struct sd_data *sdd = sd->private;
 	struct sched_domain *sibling;
 	int i;
 
-	for_each_cpu(i, span) {
+	for_each_cpu(i, sg_span) {
 		sibling = *per_cpu_ptr(sdd->sd, i);
 		if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
 			continue;