From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933283Ab2JKAYi (ORCPT ); Wed, 10 Oct 2012 20:24:38 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:42642 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933185Ab2JKAYb (ORCPT ); Wed, 10 Oct 2012 20:24:31 -0400 X-Sasl-enc: XTjX+oU3e9yhkf3wMMd0voPqjLqd67QLK3tJ1yf7D91O 1349915070 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, "Paul E. McKenney" , Frederic Weisbecker , Yoshinori Sato , Josh Triplett Subject: [ 088/122] h8300: Add missing RCU idle APIs on idle loop Date: Thu, 11 Oct 2012 07:54:14 +0900 Message-Id: <20121010225353.892165407@linuxfoundation.org> X-Mailer: git-send-email 1.8.0.rc0.18.gf84667d In-Reply-To: <20121010225337.989799482@linuxfoundation.org> References: <20121010225337.989799482@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Frederic Weisbecker commit b2fe1430d4115c74d007c825cb9dc3317f28bb16 upstream. In the old times, the whole idle task was considered as an RCU quiescent state. But as RCU became more and more successful overtime, some RCU read side critical section have been added even in the code of some architectures idle tasks, for tracing for example. So nowadays, rcu_idle_enter() and rcu_idle_exit() must be called by the architecture to tell RCU about the part in the idle loop that doesn't make use of rcu read side critical sections, typically the part that puts the CPU in low power mode. This is necessary for RCU to find the quiescent states in idle in order to complete grace periods. Add this missing pair of calls in the h8300's idle loop. Reported-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Cc: Yoshinori Sato Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett Signed-off-by: Greg Kroah-Hartman --- arch/h8300/kernel/process.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/h8300/kernel/process.c +++ b/arch/h8300/kernel/process.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include @@ -78,8 +79,10 @@ void (*idle)(void) = default_idle; void cpu_idle(void) { while (1) { + rcu_idle_enter(); while (!need_resched()) idle(); + rcu_idle_exit(); schedule_preempt_disabled(); } }