sched: Remove WAKEUP_SYNC feature

This feature never earned its keep, remove it.
Signed-off-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268301591.6785.42.camel@marge.simson.net>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/sched_fair.c

@@ -1658,7 +1658,6 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
 	struct task_struct *curr = rq->curr;
 	struct sched_entity *se = &curr->se, *pse = &p->se;
 	struct cfs_rq *cfs_rq = task_cfs_rq(curr);
-	int sync = wake_flags & WF_SYNC;
 	int scale = cfs_rq->nr_running >= sched_nr_latency;
 
 	if (unlikely(rt_prio(p->prio)))
@@ -1691,9 +1690,6 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
 	if (unlikely(curr->policy == SCHED_IDLE))
 		goto preempt;
 
-	if (sched_feat(WAKEUP_SYNC) && sync)
-		goto preempt;
-
 	if (!sched_feat(WAKEUP_PREEMPT))
 		return;
 

kernel/sched_features.h

@@ -22,11 +22,6 @@ SCHED_FEAT(WAKEUP_PREEMPT, 1)
  */
 SCHED_FEAT(ASYM_GRAN, 1)
 
-/*
- * Always wakeup-preempt SYNC wakeups, see SYNC_WAKEUPS.
- */
-SCHED_FEAT(WAKEUP_SYNC, 0)
-
 /*
  * Use the SYNC wakeup hint, pipes and the likes use this to indicate
  * the remote end is likely to consume the data we just wrote, and