sched: cleanup old and rarely used 'debug' features.

TREE_AVG and APPROX_AVG are initial task placement policies that have been
disabled for a long while.. time to remove them.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
CC: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -594,18 +594,14 @@ enum {
 	SCHED_FEAT_NEW_FAIR_SLEEPERS	= 1,
 	SCHED_FEAT_WAKEUP_PREEMPT	= 2,
 	SCHED_FEAT_START_DEBIT		= 4,
-	SCHED_FEAT_TREE_AVG		= 8,
-	SCHED_FEAT_APPROX_AVG		= 16,
-	SCHED_FEAT_HRTICK		= 32,
-	SCHED_FEAT_DOUBLE_TICK		= 64,
+	SCHED_FEAT_HRTICK		= 8,
+	SCHED_FEAT_DOUBLE_TICK		= 16,
 };
 
 const_debug unsigned int sysctl_sched_features =
 		SCHED_FEAT_NEW_FAIR_SLEEPERS	* 1 |
 		SCHED_FEAT_WAKEUP_PREEMPT	* 1 |
 		SCHED_FEAT_START_DEBIT		* 1 |
-		SCHED_FEAT_TREE_AVG		* 0 |
-		SCHED_FEAT_APPROX_AVG		* 0 |
 		SCHED_FEAT_HRTICK		* 1 |
 		SCHED_FEAT_DOUBLE_TICK		* 0;
 

kernel/sched_fair.c

@@ -302,11 +302,6 @@ static u64 __sched_vslice(unsigned long rq_weight, unsigned long nr_running)
 	return vslice;
 }
 
-static u64 sched_vslice(struct cfs_rq *cfs_rq)
-{
-	return __sched_vslice(cfs_rq->load.weight, cfs_rq->nr_running);
-}
-
 static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 	return __sched_vslice(cfs_rq->load.weight + se->load.weight,
@@ -504,15 +499,6 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
 	} else
 		vruntime = cfs_rq->min_vruntime;
 
-	if (sched_feat(TREE_AVG)) {
-		struct sched_entity *last = __pick_last_entity(cfs_rq);
-		if (last) {
-			vruntime += last->vruntime;
-			vruntime >>= 1;
-		}
-	} else if (sched_feat(APPROX_AVG) && cfs_rq->nr_running)
-		vruntime += sched_vslice(cfs_rq)/2;
-
 	/*
 	 * The 'current' period is already promised to the current tasks,
 	 * however the extra weight of the new task will slow them down a