sched: Update shares on idle_balance

Since shares updates are no longer expensive and effectively local, update them
at idle_balance().  This allows us to more quickly redistribute shares to
another cpu when our load becomes idle.

Signed-off-by: Paul Turner <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

kernel/sched_fair.c

@@ -3343,6 +3343,7 @@ static void idle_balance(int this_cpu, struct rq *this_rq)
 	 */
 	raw_spin_unlock(&this_rq->lock);
 
+	update_shares(this_cpu);
 	for_each_domain(this_cpu, sd) {
 		unsigned long interval;
 		int balance = 1;