From patchwork Thu Aug 23 14:58:33 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frederic Weisbecker X-Patchwork-Id: 1367771 Return-Path: X-Original-To: patchwork-linux-parisc@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 41B8DDF2AB for ; Thu, 23 Aug 2012 15:00:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934030Ab2HWPAF (ORCPT ); Thu, 23 Aug 2012 11:00:05 -0400 Received: from mail-qa0-f53.google.com ([209.85.216.53]:40650 "EHLO mail-qa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752626Ab2HWO7L (ORCPT ); Thu, 23 Aug 2012 10:59:11 -0400 Received: by mail-qa0-f53.google.com with SMTP id s11so552631qaa.19 for ; Thu, 23 Aug 2012 07:59:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=UPqhjraVWQYyYIGEGXPpnmvLOnJB2Hsdz894UfAoYc8=; b=Lv0yp0PvfyozzDSQbzu71F4E5E/OpctAj3dlg2qI8b5fKXtsc3v32+uGT1Rw5VxD0j wX+SUBXhVaOV+tWAULeOqC7g6g9Y28qVHysuVCMIUHgaMBtDUpRkcyME5PUrU8bFrPMo FsLHCS+/4UDKr5LFl0+KTjSSICZP5aIp8EPw8NB7boBJ3d8UE81LE9tdjk8Rl65+KKMU q5PBheRsRhUIeGQ5E/IJrUmOzhLtNKPckaobdKlf/LHC0d6O96caBdL+9RFE5e6tlbjs f3pYuEN9M0aQoawrmh5AmSKSBd6vkUWTmLj8jCHOpQMUQm7O+5LdsfnF2NJjdClJZFnY ETmQ== Received: by 10.224.222.16 with SMTP id ie16mr3235958qab.73.1345733951202; Thu, 23 Aug 2012 07:59:11 -0700 (PDT) Received: from somewhere.redhat.com (53.20.196.77.rev.sfr.net. [77.196.20.53]) by mx.google.com with ESMTPS id hq10sm5411962qab.1.2012.08.23.07.59.07 (version=SSLv3 cipher=OTHER); Thu, 23 Aug 2012 07:59:09 -0700 (PDT) From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , "James E.J. Bottomley" , Helge Deller , Parisc , "3.2.x.." , "Paul E. McKenney" Subject: [PATCH 09/11] parisc: Add missing RCU idle APIs on idle loop Date: Thu, 23 Aug 2012 16:58:33 +0200 Message-Id: <1345733915-20040-10-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1345733915-20040-1-git-send-email-fweisbec@gmail.com> References: <1345733915-20040-1-git-send-email-fweisbec@gmail.com> Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org 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 --- 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(); }