From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932912Ab2JKBMm (ORCPT ); Wed, 10 Oct 2012 21:12:42 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:34731 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932865Ab2JKBMj (ORCPT ); Wed, 10 Oct 2012 21:12:39 -0400 X-Sasl-enc: 0xQmos5tvraVPcS/jmjNg9fy6OhQcmBFCOdvtvQgsy4M 1349917957 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" , "Paul E. McKenney" , Josh Triplett Subject: [ 086/120] ia64: Add missing RCU idle APIs on idle loop Date: Thu, 11 Oct 2012 10:00:38 +0900 Message-Id: <20121011005842.444629092@linuxfoundation.org> X-Mailer: git-send-email 1.8.0.rc0.18.gf84667d In-Reply-To: <20121011005825.364610894@linuxfoundation.org> References: <20121011005825.364610894@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 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Paul E. McKenney" commit 93482f4ef1093f5961a63359a34612183d6beea0 upstream. Traditionally, the entire idle task served as an RCU quiescent state. But when RCU read side critical sections started appearing within the idle loop, this traditional strategy became untenable. The fix was to create new RCU APIs named rcu_idle_enter() and rcu_idle_exit(), which must be called by each architecture's idle loop so that RCU can tell when it is safe to ignore a given idle CPU. Unfortunately, this fix was never applied to ia64, a shortcoming remedied by this commit. Reported by: Tony Luck Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Tested by: Tony Luck Reviewed-by: Josh Triplett Signed-off-by: Greg Kroah-Hartman --- arch/ia64/kernel/process.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include @@ -301,6 +302,7 @@ cpu_idle (void) /* endless idle loop with no priority at all */ while (1) { + rcu_idle_enter(); if (can_do_pal_halt) { current_thread_info()->status &= ~TS_POLLING; /* @@ -331,6 +333,7 @@ cpu_idle (void) normal_xtp(); #endif } + rcu_idle_exit(); schedule_preempt_disabled(); check_pgt_cache(); if (cpu_is_offline(cpu))