From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753298AbYGPRP6 (ORCPT ); Wed, 16 Jul 2008 13:15:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751424AbYGPRPu (ORCPT ); Wed, 16 Jul 2008 13:15:50 -0400 Received: from mga05.intel.com ([192.55.52.89]:7887 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751406AbYGPRPu (ORCPT ); Wed, 16 Jul 2008 13:15:50 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.30,374,1212390000"; d="scan'208";a="362128093" Date: Wed, 16 Jul 2008 10:15:47 -0700 From: mark gross To: "Jakub W. Jozwicki" Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 2.6.25.10] pm_qos_params: change spinlock to rwlock Message-ID: <20080716171547.GA13478@linux.intel.com> Reply-To: mgross@linux.intel.com References: <200807130119.19663.jozwicki@aster.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200807130119.19663.jozwicki@aster.pl> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) X-OriginalArrivalTime: 16 Jul 2008 17:15:47.0114 (UTC) FILETIME=[966888A0:01C8E767] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org nack. On Sun, Jul 13, 2008 at 01:19:19AM +0200, Jakub W. Jozwicki wrote: > Concurrent calls to pm_qos_requirement shouldn't block each other. This patch > changes spinlock to rwlock and fixes issues with PREEMPT_RT. > > Signed-off-by: Jakub Jozwicki > > --- linux-2.6.25.10/kernel/pm_qos_params.c 2008-07-03 05:46:47.000000000 +0200 > +++ linux-2.6.25.10-rt7/kernel/pm_qos_params.c 2008-07-12 23:18:20.696615771 > +0200 > @@ -110,7 +110,7 @@ > &network_throughput_pm_qos > }; > > -static DEFINE_SPINLOCK(pm_qos_lock); > +static DEFINE_RWLOCK(pm_qos_lock); I don't see a problem with using spinlocks, and as this issues only shows up running the PREEMPT-RT I feel that perhaps this would be better in the RT tree. Sorry, --mgross > > static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, > size_t count, loff_t *f_pos); > @@ -142,7 +142,7 @@ > unsigned long flags; > int call_notifier = 0; > > - spin_lock_irqsave(&pm_qos_lock, flags); > + write_lock_irqsave(&pm_qos_lock, flags); > extreme_value = pm_qos_array[target]->default_value; > list_for_each_entry(node, > &pm_qos_array[target]->requirements.list, list) { > @@ -155,7 +155,7 @@ > pr_debug(KERN_ERR "new target for qos %d is %d\n", target, > pm_qos_array[target]->target_value); > } > - spin_unlock_irqrestore(&pm_qos_lock, flags); > + write_unlock_irqrestore(&pm_qos_lock, flags); > > if (call_notifier) > blocking_notifier_call_chain(pm_qos_array[target]->notifiers, > @@ -195,9 +195,9 @@ > int ret_val; > unsigned long flags; > > - spin_lock_irqsave(&pm_qos_lock, flags); > + read_lock_irqsave(&pm_qos_lock, flags); > ret_val = pm_qos_array[pm_qos_class]->target_value; > - spin_unlock_irqrestore(&pm_qos_lock, flags); > + read_unlock_irqrestore(&pm_qos_lock, flags); > > return ret_val; > } > @@ -228,10 +228,10 @@ > if (!dep->name) > goto cleanup; > > - spin_lock_irqsave(&pm_qos_lock, flags); > + write_lock_irqsave(&pm_qos_lock, flags); > list_add(&dep->list, > &pm_qos_array[pm_qos_class]->requirements.list); > - spin_unlock_irqrestore(&pm_qos_lock, flags); > + write_unlock_irqrestore(&pm_qos_lock, flags); > update_target(pm_qos_class); > > return 0; > @@ -260,7 +260,7 @@ > struct requirement_list *node; > int pending_update = 0; > > - spin_lock_irqsave(&pm_qos_lock, flags); > + write_lock_irqsave(&pm_qos_lock, flags); > list_for_each_entry(node, > &pm_qos_array[pm_qos_class]->requirements.list, list) { > if (strcmp(node->name, name) == 0) { > @@ -273,7 +273,7 @@ > break; > } > } > - spin_unlock_irqrestore(&pm_qos_lock, flags); > + write_unlock_irqrestore(&pm_qos_lock, flags); > if (pending_update) > update_target(pm_qos_class); > > @@ -295,7 +295,7 @@ > struct requirement_list *node; > int pending_update = 0; > > - spin_lock_irqsave(&pm_qos_lock, flags); > + write_lock_irqsave(&pm_qos_lock, flags); > list_for_each_entry(node, > &pm_qos_array[pm_qos_class]->requirements.list, list) { > if (strcmp(node->name, name) == 0) { > @@ -306,7 +306,7 @@ > break; > } > } > - spin_unlock_irqrestore(&pm_qos_lock, flags); > + write_unlock_irqrestore(&pm_qos_lock, flags); > if (pending_update) > update_target(pm_qos_class); > }