sched: clean up the wakeup preempt check, #2

clean up the preemption check to not use unnecessary 64-bit
variables. This improves code size:

   text    data     bss     dec     hex filename
  44227    3326      36   47589    b9e5 sched.o.before
  44201    3326      36   47563    b9cb sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched_fair.c

@@ -837,7 +837,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
 	struct task_struct *curr = rq->curr;
 	struct cfs_rq *cfs_rq = task_cfs_rq(curr);
 	struct sched_entity *se = &curr->se, *pse = &p->se;
-	s64 delta, gran;
+	unsigned long gran;
 
 	if (unlikely(rt_prio(p->prio))) {
 		update_rq_clock(rq);
@@ -860,12 +860,11 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
 		pse = parent_entity(pse);
 	}
 
-	delta = se->vruntime - pse->vruntime;
 	gran = sysctl_sched_wakeup_granularity;
 	if (unlikely(se->load.weight != NICE_0_LOAD))
 		gran = calc_delta_fair(gran, &se->load);
 
-	if (delta > gran)
+	if (pse->vruntime + gran < se->vruntime)
 		resched_task(curr);
 }