Create rebalance_domains() from rebalance_tick().

Essentially rebalance_domains = rebalance_tick. However, we
do the idle calculation on our own. This removes some processing
from scheduler_tick into rebalance_domains().

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.19-rc3/kernel/sched.c
===================================================================
--- linux-2.6.19-rc3.orig/kernel/sched.c	2006-10-27 12:52:02.436697548 -0500
+++ linux-2.6.19-rc3/kernel/sched.c	2006-10-27 12:56:34.727358115 -0500
@@ -2841,16 +2841,17 @@ static void update_load(struct rq *this_
 }
 
 /*
- * rebalance_tick will get called every timer tick, on every CPU.
+ * rebalance_domains is called from the scheduler_tick.
  *
  * It checks each scheduling domain to see if it is due to be balanced,
  * and initiates a balancing operation if so.
  *
  * Balancing parameters are set up in arch_init_sched_domains.
  */
-static void
-rebalance_tick(int this_cpu, struct rq *this_rq)
+static void rebalance_domains(unsigned long dummy)
 {
+	int this_cpu = smp_processor_id();
+	struct rq *this_rq = cpu_rq(this_cpu);
 	struct sched_domain *sd;
 	/*
 	 * A task is idle if this is the idle queue
@@ -2892,37 +2893,26 @@ rebalance_tick(int this_cpu, struct rq *
 /*
  * on UP we do not need to balance between CPUs:
  */
-static inline void rebalance_tick(int cpu, struct rq *rq)
-{
-}
 static inline void idle_balance(int cpu, struct rq *rq)
 {
 }
-static inline void update_load(struct rq *this_rq)
-{
-}
 #endif
 
-static inline int wake_priority_sleeper(struct rq *rq)
+static inline void wake_priority_sleeper(struct rq *rq)
 {
-	int ret = 0;
-
 #ifdef CONFIG_SCHED_SMT
 	if (!rq->nr_running)
-		return 0;
+		return;
 
 	spin_lock(&rq->lock);
 	/*
 	 * If an SMT sibling task has been put to sleep for priority
 	 * reasons reschedule the idle task to see if it can now run.
 	 */
-	if (rq->nr_running) {
+	if (rq->nr_running)
 		resched_task(rq->idle);
-		ret = 1;
-	}
 	spin_unlock(&rq->lock);
 #endif
-	return ret;
 }
 
 DEFINE_PER_CPU(struct kernel_stat, kstat);
@@ -3148,8 +3138,10 @@ void scheduler_tick(void)
 		wake_priority_sleeper(rq);
 	else
 		task_running_tick(rq, p);
+#ifdef CONFIG_SMP
 	update_load(rq);
-	rebalance_tick(cpu, rq);
+	rebalance_domains(0);
+#endif
 }
 
 #ifdef CONFIG_SCHED_SMT