Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

893e2c5c · Linus Torvalds <[email protected]> · 2016-10-19 10:03:55 -07:00

Pull scheduler fix from Ingo Molnar:
 "This fixes a group scheduling related performance/interactivity
  regression introduced in v4.8, which affects certain hardware
  environments where cpu_possible_mask != cpu_present_mask"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix incorrect task group ->load_avg

Commit: 893e2c5c9fedeccf89653b0ad17df69e88dbd707
Parents: 8a1e377e · b5a9b340

Merge commit. Changes below are compared with the first parent: 8a1e377e.

Changes

1 files changed · +8 −1

File	Status	Add	Del	Content
kernel/sched/fair.c	modified	+8	−1	View file

kernel/sched/fair.c

View file

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 76ee7de..d941c97 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -690,7 +690,14 @@ void init_entity_runnable_average(struct sched_entity *se)
 	 * will definitely be update (after enqueue).
 	 */
 	sa->period_contrib = 1023;
-	sa->load_avg = scale_load_down(se->load.weight);
+	/*
+	 * Tasks are intialized with full load to be seen as heavy tasks until
+	 * they get a chance to stabilize to their real load level.
+	 * Group entities are intialized with zero load to reflect the fact that
+	 * nothing has been attached to the task group yet.
+	 */
+	if (entity_is_task(se))
+		sa->load_avg = scale_load_down(se->load.weight);
 	sa->load_sum = sa->load_avg * LOAD_AVG_MAX;
 	/*
 	 * At this point, util_avg won't be used in select_task_rq_fair anyway