Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753140Ab2H3VOa (ORCPT ); Thu, 30 Aug 2012 17:14:30 -0400 Received: from e37.co.us.ibm.com ([32.97.110.158]:47599 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753002Ab2H3VO2 (ORCPT ); Thu, 30 Aug 2012 17:14:28 -0400 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, "3.2.x.." , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 18/26] frv: Add missing RCU idle APIs on idle loop Date: Thu, 30 Aug 2012 14:05:35 -0700 Message-Id: <1346360743-3628-18-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: 12083021-7408-0000-0000-0000080B5783 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1947 Lines: 63 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 Frv's idle loop. Reported-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Cc: David Howells Cc: 3.2.x.. Cc: Paul E. McKenney --- arch/frv/kernel/process.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/arch/frv/kernel/process.c b/arch/frv/kernel/process.c index ff95f50..2eb7fa5 100644 --- a/arch/frv/kernel/process.c +++ b/arch/frv/kernel/process.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -69,12 +70,14 @@ void cpu_idle(void) { /* endless idle loop with no priority at all */ while (1) { + rcu_idle_enter(); while (!need_resched()) { check_pgt_cache(); if (!frv_dma_inprogress && idle) idle(); } + rcu_idle_exit(); schedule_preempt_disabled(); } -- 1.7.8 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/