sched: wakeup preemption fix

wakeup preemption fix: do not make it dependent on p->prio.
Preemption purely depends on ->vruntime.

This improves preemption in mixed-nice-level workloads.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/sched_fair.c

@@ -863,11 +863,9 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
 		if (unlikely(se->load.weight != NICE_0_LOAD))
 			gran = calc_delta_fair(gran, &se->load);
 
-		if (delta > gran) {
-			if (p->prio < curr->prio)
+		if (delta > gran)
 			resched_task(curr);
 	}
-	}
 }
 
 static struct task_struct *pick_next_task_fair(struct rq *rq)