sched: fix sched_balance_self() smp group balancing

Finding the least idle cpu is more accurate when done with updated shares.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -2128,6 +2128,9 @@ static int sched_balance_self(int cpu, int flag)
 			sd = tmp;
 	}
 
+	if (sd)
+		update_shares(sd);
+
 	while (sd) {
 		cpumask_t span, tmpmask;
 		struct sched_group *group;