linux-kernel - [PATCH] Remove useless test during exchanging values

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Message-Id: <1461241708-812-1-git-send-email-mnghuan@gmail.com>
Date:	Thu, 21 Apr 2016 20:28:28 +0800
From:	Minfei Huang <mnghuan@...il.com>
To:	mingo@...hat.com, peterz@...radead.org
Cc:	linux-kernel@...r.kernel.org, Minfei Huang <mnghuan@...il.com>
Subject: [PATCH] Remove useless test during exchanging values

The value delta is correct as well, although calc_load_idle[idx] is
equal to 0. Remove this useless test to improve performance, since this
function is called more frequently.

Signed-off-by: Minfei Huang <mnghuan@...il.com>
---
 kernel/sched/loadavg.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c
index ef71590..5a5d7ae 100644
--- a/kernel/sched/loadavg.c
+++ b/kernel/sched/loadavg.c
@@ -216,10 +216,9 @@ void calc_load_exit_idle(void)
 static long calc_load_fold_idle(void)
 {
 	int idx = calc_load_read_idx();
-	long delta = 0;
+	long delta;
 
-	if (atomic_long_read(&calc_load_idle[idx]))
-		delta = atomic_long_xchg(&calc_load_idle[idx], 0);
+	delta = atomic_long_xchg(&calc_load_idle[idx], 0);
 
 	return delta;
 }
-- 
2.6.3