From patchwork Thu Aug 30 21:05:40 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 1389971 Return-Path: X-Original-To: patchwork-linux-parisc@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id BC0293FC33 for ; Thu, 30 Aug 2012 21:18:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753021Ab2H3VOV (ORCPT ); Thu, 30 Aug 2012 17:14:21 -0400 Received: from e37.co.us.ibm.com ([32.97.110.158]:47316 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752927Ab2H3VOR (ORCPT ); Thu, 30 Aug 2012 17:14:17 -0400 Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 30 Aug 2012 15:14:15 -0600 Received: from d03dlp02.boulder.ibm.com (9.17.202.178) by e37.co.us.ibm.com (192.168.1.137) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Thu, 30 Aug 2012 15:13:52 -0600 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id A69B93E40044; Thu, 30 Aug 2012 15:13:51 -0600 (MDT) Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q7ULDpbD161232; Thu, 30 Aug 2012 15:13:51 -0600 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q7ULDXQl009139; Thu, 30 Aug 2012 15:13:50 -0600 Received: from paulmck-ThinkPad-W500 (sig-9-65-153-225.mts.ibm.com [9.65.153.225]) by d03av01.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id q7ULDWJT009014; Thu, 30 Aug 2012 15:13:33 -0600 Received: by paulmck-ThinkPad-W500 (Postfix, from userid 1000) id 8ABC4EA850; Thu, 30 Aug 2012 14:05:47 -0700 (PDT) From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, patches@linaro.org, "James E.J. Bottomley" , Helge Deller , Parisc , "3.2.x.." , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 23/26] parisc: Add missing RCU idle APIs on idle loop Date: Thu, 30 Aug 2012 14:05:40 -0700 Message-Id: <1346360743-3628-23-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.8 In-Reply-To: <1346360743-3628-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20120830210520.GA2824@linux.vnet.ibm.com> <1346360743-3628-1-git-send-email-paulmck@linux.vnet.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12083021-7408-0000-0000-0000080B5696 Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org From: Frederic Weisbecker 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 parisc's idle loop. Reported-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Cc: James E.J. Bottomley Cc: Helge Deller Cc: Parisc Cc: 3.2.x.. Cc: Paul E. McKenney Reviewed-by: Josh Triplett --- arch/parisc/kernel/process.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c index d4b94b3..c54a4db 100644 --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -48,6 +48,7 @@ #include #include #include +#include #include #include @@ -69,8 +70,10 @@ void cpu_idle(void) /* endless idle loop with no priority at all */ while (1) { + rcu_idle_enter(); while (!need_resched()) barrier(); + rcu_idle_exit(); schedule_preempt_disabled(); check_pgt_cache(); }