From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753495AbbG0M2z (ORCPT ); Mon, 27 Jul 2015 08:28:55 -0400 Received: from mail-pa0-f50.google.com ([209.85.220.50]:36575 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753305AbbG0M2w (ORCPT ); Mon, 27 Jul 2015 08:28:52 -0400 From: Viresh Kumar To: Rafael Wysocki Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org, preeti.lkml@gmail.com, Viresh Kumar , linux-kernel@vger.kernel.org (open list) Subject: [PATCH V2 5/9] cpufreq: ondemand: Drop unnecessary locks from update_sampling_rate() Date: Mon, 27 Jul 2015 17:58:10 +0530 Message-Id: X-Mailer: git-send-email 2.4.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 'timer_mutex' is required to sync work-handlers of policy->cpus. update_sampling_rate() is just canceling the works and queuing them again. This isn't protecting anything at all in update_sampling_rate() and is not gonna be of any use. Even if a work-handler is already running for a CPU, cancel_delayed_work_sync() will wait for it to finish. Drop these unnecessary locks. Reviewed-by: Preeti U Murthy Signed-off-by: Viresh Kumar --- drivers/cpufreq/cpufreq_ondemand.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 2474c9c34022..f1551fc7b4fd 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -267,28 +267,20 @@ static void update_sampling_rate(struct dbs_data *dbs_data, dbs_info = &per_cpu(od_cpu_dbs_info, cpu); cpufreq_cpu_put(policy); - mutex_lock(&dbs_info->cdbs.shared->timer_mutex); - - if (!delayed_work_pending(&dbs_info->cdbs.dwork)) { - mutex_unlock(&dbs_info->cdbs.shared->timer_mutex); + if (!delayed_work_pending(&dbs_info->cdbs.dwork)) continue; - } next_sampling = jiffies + usecs_to_jiffies(new_rate); appointed_at = dbs_info->cdbs.dwork.timer.expires; if (time_before(next_sampling, appointed_at)) { - - mutex_unlock(&dbs_info->cdbs.shared->timer_mutex); cancel_delayed_work_sync(&dbs_info->cdbs.dwork); - mutex_lock(&dbs_info->cdbs.shared->timer_mutex); gov_queue_work(dbs_data, policy, usecs_to_jiffies(new_rate), cpumask_of(cpu)); } - mutex_unlock(&dbs_info->cdbs.shared->timer_mutex); } } -- 2.4.0