sched: Factor out the on_null_domain() checks in trigger_load_balance()

The test on_null_domain is done twice in the trigger_load_balance function.

Move the test at the begin of the function, so there is only one check.

Signed-off-by: Daniel Lezcano <[e-mail]>
Signed-off-by: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

kernel/sched/fair.c

···
 void trigger_load_balance(struct rq *rq)
 {
 	/* Don't need to rebalance while attached to NULL domain */
-	if (time_after_eq(jiffies, rq->next_balance) &&
-	    likely(!on_null_domain(rq)))
+	if (unlikely(on_null_domain(rq)))
+		return;
+
+	if (time_after_eq(jiffies, rq->next_balance))
 		raise_softirq(SCHED_SOFTIRQ);
 #ifdef CONFIG_NO_HZ_COMMON
-	if (nohz_kick_needed(rq) && likely(!on_null_domain(rq)))
+	if (nohz_kick_needed(rq))
 		nohz_balancer_kick();
 #endif
 }