From: Pranith Kumar Subject: [RFC PATCH] cpuidle: Use a lighter barrier in snooze_loop() Date: Sat, 15 Nov 2014 21:00:07 -0500 Message-ID: <1416103207-18293-1-git-send-email-bobby.prani@gmail.com> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" , Daniel Lezcano , "open list:CPUIDLE DRIVERS" , open list List-Id: linux-pm@vger.kernel.org Using smp_mb() here so that the bit clear is not reordered is an overkill. It is more appropriate to use smp_mb__after_atomic() which ensures that the bit clear is not reordered. Signed-off-by: Pranith Kumar --- drivers/cpuidle/cpuidle-powernv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index 7d3a349..b0bfcbe 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -48,7 +48,8 @@ static int snooze_loop(struct cpuidle_device *dev, HMT_medium(); ppc64_runlatch_on(); clear_thread_flag(TIF_POLLING_NRFLAG); - smp_mb(); + /* ensure bit clear is not reordered */ + smp_mb__after_atomic(); return index; } -- 1.9.1