sched: Split WAKEUP_OVERLAP

It consists of two conditions, split them out in separate toggles
so we can test them independently.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched_fair.c

@@ -1526,9 +1526,10 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
 	if (!sched_feat(WAKEUP_PREEMPT))
 		return;
 
-	if (sched_feat(WAKEUP_OVERLAP) && (sync ||
-			(se->avg_overlap < sysctl_sched_migration_cost &&
-			 pse->avg_overlap < sysctl_sched_migration_cost))) {
+	if ((sched_feat(WAKEUP_SYNC) && sync) ||
+	    (sched_feat(WAKEUP_OVERLAP) &&
+	     (se->avg_overlap < sysctl_sched_migration_cost &&
+	      pse->avg_overlap < sysctl_sched_migration_cost))) {
 		resched_task(curr);
 		return;
 	}

kernel/sched_features.h

@@ -12,6 +12,7 @@ SCHED_FEAT(ASYM_GRAN, 1)
 SCHED_FEAT(LB_BIAS, 1)
 SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
 SCHED_FEAT(ASYM_EFF_LOAD, 1)
+SCHED_FEAT(WAKEUP_SYNC, 0)
 SCHED_FEAT(WAKEUP_OVERLAP, 0)
 SCHED_FEAT(LAST_BUDDY, 1)
 SCHED_FEAT(OWNER_SPIN, 1)