sched: do not wakeup-preempt with SCHED_BATCH tasks

do not wakeup-preempt with SCHED_BATCH tasks, their preemption is batched too, driven by the tick. Signed-off-by: Ingo Molnar <mingo@elte.hu>
git-mirror · Oct 15, 2007 · 91c234b · 91c234b
1 parent fb7dde3
commit 91c234b
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
@@ -828,6 +828,12 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
 		resched_task(curr);
 		return;
 	}
+	/*
+	 * Batch tasks do not preempt (their preemption is driven by
+	 * the tick):
+	 */
+	if (unlikely(p->policy == SCHED_BATCH))
+		return;
 
 	if (sched_feat(WAKEUP_PREEMPT)) {
 		while (!is_same_group(se, pse)) {