[PATCH 1/3] sched/fair: Fix statistics for find_idlest_group()

[Mel Gorman]

From: Vincent Guittot <vincent.guittot@xxxxxxxxxx>

From: Vincent Guittot <vincent.guittot@xxxxxxxxxx>

sgs->group_weight is not set while gathering statistics in
update_sg_wakeup_stats(). This means that a group can be classified as
fully busy with 0 running tasks if utilization is high enough.

This path is mainly used for fork and exec.

Fixes: 57abff067a08 ("sched/fair: Rework find_idlest_group()")
Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200218144534.4564-1-vincent.guittot@xxxxxxxxxx
---
 kernel/sched/fair.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index fcc968669aea..4b5d5e5e701e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8561,6 +8561,8 @@ static inline void update_sg_wakeup_stats(struct sched_domain *sd,
 
 	sgs->group_capacity = group->sgc->capacity;
 
+	sgs->group_weight = group->group_weight;
+
 	sgs->group_type = group_classify(sd->imbalance_pct, group, sgs);
 
 	/*
-- 
2.16.4