[tip: sched/core] sched/fair: Optimize checking for group_asym_packing

[tip-bot2 for Ricardo Neri]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     6025643596895695956c27119c6b0bfa40d8035b
Gitweb:        https://git.kernel.org/tip/6025643596895695956c27119c6b0bfa40d8035b
Author:        Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
AuthorDate:    Fri, 10 Sep 2021 18:18:16 -07:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 05 Oct 2021 15:52:02 +02:00

sched/fair: Optimize checking for group_asym_packing

sched_asmy_prefer() always returns false when called on the local group. By
checking local_group, we can avoid additional checks and invoking
sched_asmy_prefer() when it is not needed. No functional changes are
introduced.

Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Reviewed-by: Len Brown <len.brown@xxxxxxxxx>
Reviewed-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20210911011819.12184-4-ricardo.neri-calderon@xxxxxxxxxxxxxxx
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 71b30ef..e050b1d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8631,7 +8631,7 @@ static inline void update_sg_lb_stats(struct lb_env *env,
 	}
 
 	/* Check if dst CPU is idle and preferred to this group */
-	if (env->sd->flags & SD_ASYM_PACKING &&
+	if (!local_group && env->sd->flags & SD_ASYM_PACKING &&
 	    env->idle != CPU_NOT_IDLE &&
 	    sgs->sum_h_nr_running &&
 	    sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu)) {