Fix up jiffy comparison function in the scheduler.

The jiffy comparison in reblance_tick() has always used a simple integer
comparison and I have followed that convention for the patchset that
rebalances sched domains via a tasklet.

However, jiffies may wrap around zero. If we do not use the time_after()
function then comparisons may not give the intended results.

Fix this up by using jiffy comparison functions.

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

Index: linux-2.6.19-rc5-mm1/kernel/sched.c
===================================================================
--- linux-2.6.19-rc5-mm1.orig/kernel/sched.c	2006-11-10 23:04:14.000000000 -0600
+++ linux-2.6.19-rc5-mm1/kernel/sched.c	2006-11-10 23:05:55.460108319 -0600
@@ -2898,7 +2898,7 @@ static void run_rebalance_domains(struct
 		if (unlikely(!interval))
 			interval = 1;
 
-		if (jiffies - sd->last_balance >= interval) {
+		if (time_after_eq(jiffies, sd->last_balance + interval)) {
 			if (load_balance(this_cpu, this_rq, sd, idle)) {
 				/*
 				 * We've pulled tasks over so either we're no
@@ -3165,7 +3165,7 @@ void scheduler_tick(void)
 		task_running_tick(rq, p);
 #ifdef CONFIG_SMP
 	update_load(rq);
-	if (jiffies >= rq->next_balance)
+	if (time_after_eq(jiffies, rq->next_balance))
 		raise_softirq(SCHED_SOFTIRQ);
 #endif
 }