sched: entity_key() fix

entity_key() fix - we'd occasionally end up with a 0 vruntime
in the !initial case.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

kernel/sched_fair.c

@@ -479,7 +479,8 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
 	if (initial && sched_feat(START_DEBIT))
 		vruntime += __sched_vslice(cfs_rq->nr_running + 1);
 
-	if (!initial && sched_feat(NEW_FAIR_SLEEPERS)) {
+	if (!initial) {
+		if (sched_feat(NEW_FAIR_SLEEPERS)) {
 			s64 latency = cfs_rq->min_vruntime - se->last_min_vruntime;
 			if (latency < 0 || !cfs_rq->nr_running)
 				latency = 0;
@@ -487,6 +488,8 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
 				latency = min_t(s64, latency, sysctl_sched_latency);
 			vruntime -= latency;
 		}
+		vruntime = max(vruntime, se->vruntime);
+	}
 
 	se->vruntime = vruntime;