sched/topology: Optimize build_group_mask()

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@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: lwang@redhat.com
Cc: riel@redhat.com
Link: http://lkml.kernel.org/r/1492717903-5195-2-git-send-email-lvenanci@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.16:
 - Update another reference to 'span' introduced by an earlier backport of
   sched/topology changes
 - Adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 68bc1bf9f5abe3fa3bb0b7022f46a1520c0a0e4a..e6c9458f4b4938ef66834d26fda9e1fc51162939 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5782,14 +5782,14 @@ enum s_alloc {
 static void
 build_group_mask(struct sched_domain *sd, struct sched_group *sg, struct cpumask *mask)
 {
-       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;
 
        cpumask_clear(mask);
 
-       for_each_cpu(i, span) {
+       for_each_cpu(i, sg_span) {
                sibling = *per_cpu_ptr(sdd->sd, i);
 
                /*
@@ -5801,7 +5801,7 @@ build_group_mask(struct sched_domain *sd, struct sched_group *sg, struct cpumask
                        continue;
 
                /* If we would not end up here, we can't continue from here */
-               if (!cpumask_equal(span, sched_domain_span(sibling->child)))
+               if (!cpumask_equal(sg_span, sched_domain_span(sibling->child)))
                        continue;
 
                cpumask_set_cpu(i, mask);