[PATCH v3 08/10] sched/fair: use utilization to select misfit task

From: Vincent Guittot
Date: Thu Sep 19 2019 - 03:34:18 EST


utilization is used to detect a misfit task but the load is then used to
select the task on the CPU which can lead to select a small task with
high weight instead of the task that triggered the misfit migration.

Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Acked-by: Valentin Schneider <valentin.schneider@xxxxxxx>
---
kernel/sched/fair.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a7c8ee6..acca869 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7429,14 +7429,8 @@ static int detach_tasks(struct lb_env *env)
break;

case migrate_misfit:
- load = task_h_load(p);
-
- /*
- * utilization of misfit task might decrease a bit
- * since it has been recorded. Be conservative in the
- * condition.
- */
- if (load < env->imbalance)
+ /* This is not a misfit task */
+ if (task_fits_capacity(p, capacity_of(env->src_cpu)))
goto next;

env->imbalance = 0;
--
2.7.4