[RFCv3 PATCH 41/48] sched: Introduce energy awareness into find_busiest_group

[Morten Rasmussen]

From: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>

In case that after the gathering of sched domain statistics the current
load balancing operation is still in energy-aware mode, just return the
least efficient (costliest) reference. That implies the system is
considered to be balanced in case no least efficient sched group was
found.

cc: Ingo Molnar <mingo@xxxxxxxxxx>
cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
---
 kernel/sched/fair.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 36f3c77..199ffff 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7133,6 +7133,9 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
 	local = &sds.local_stat;
 	busiest = &sds.busiest_stat;
 
+	if (env->use_ea)
+		return sds.costliest;
+
 	/* ASYM feature bypasses nice load balance check */
 	if ((env->idle == CPU_IDLE || env->idle == CPU_NEWLY_IDLE) &&
 	    check_asym_packing(env, &sds))
-- 
1.9.1

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