From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754958AbaKPCAI (ORCPT ); Sat, 15 Nov 2014 21:00:08 -0500 Received: from mail-yh0-f44.google.com ([209.85.213.44]:53022 "EHLO mail-yh0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751024AbaKPCAG (ORCPT ); Sat, 15 Nov 2014 21:00:06 -0500 From: Pranith Kumar To: "Rafael J. Wysocki" , Daniel Lezcano , linux-pm@vger.kernel.org (open list:CPUIDLE DRIVERS), linux-kernel@vger.kernel.org (open list) 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> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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