linux-kernel - [PATCH V2 8/8] sched: factor out on_null_domain check in trigger_load

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Date:	Mon,  6 Jan 2014 12:34:45 +0100
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	mingo@...hat.com, peterz@...radead.org
Cc:	linux-kernel@...r.kernel.org, linaro-kernel@...ts.linaro.org,
	preeti.lkml@...il.com
Subject: [PATCH V2 8/8] sched: factor out on_null_domain check in trigger_load_balance function

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 <daniel.lezcano@...aro.org>
---
 kernel/sched/fair.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 59c57e7..ef95ddf 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6871,11 +6871,13 @@ static inline int on_null_domain(struct rq *rq)
 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
 }
-- 
1.7.9.5

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