From patchwork Tue Oct 13 08:09:01 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viresh Kumar X-Patchwork-Id: 7381921 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 11D7FBEEA4 for ; Tue, 13 Oct 2015 08:11:42 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2D69D20793 for ; Tue, 13 Oct 2015 08:11:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A84520747 for ; Tue, 13 Oct 2015 08:11:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752605AbbJMIJZ (ORCPT ); Tue, 13 Oct 2015 04:09:25 -0400 Received: from mail-pa0-f48.google.com ([209.85.220.48]:33207 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752602AbbJMIJX (ORCPT ); Tue, 13 Oct 2015 04:09:23 -0400 Received: by pabrc13 with SMTP id rc13so14376725pab.0 for ; Tue, 13 Oct 2015 01:09:22 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:in-reply-to:references; bh=JJUrqH3iV+uiwNNhvKkATWHogwGOtWaae8kvWJHyFAI=; b=XNo6BUhvrQs6Ofn6CjVyn5gUppvKz2KyrSd1sINdWUtkK0ZvDE/b/qXIJJjhyaKdrS Q2BThN7zkulI888oFK/mdq+9uprg1HnY0KykLv+3Wa9D7fAAclSW+eilDArfJxwLiHJ5 Ptp4D85iaLrrg7ovxeN2TzccqKh+f5N11vbV9K27pxatplOBoLHqsnozujH00uUo1SLb Vs2Dx+uJuEsCB2PwnZw+ryZwcvbFrYuueXG5rxglTLIJ4Pb1sjJtyT2zA8ZP3VX/6X1u n9OIT3xWMM3c9/9lffwpFU46yF4SeRvwoIipSJ/O8E4Q5CVteFUmI9olqaTrtMXo8OKB Wryg== X-Gm-Message-State: ALoCoQmZFrPOkFAFHhykYKb0ndWY8gMnVwE/4JtBFl/IB6sYFgFmPLCjtPEosaELIj4/94FJkj62 X-Received: by 10.66.141.42 with SMTP id rl10mr39294706pab.18.1444723762172; Tue, 13 Oct 2015 01:09:22 -0700 (PDT) Received: from localhost ([223.227.239.124]) by smtp.gmail.com with ESMTPSA id nu5sm2225186pbb.65.2015.10.13.01.09.20 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Tue, 13 Oct 2015 01:09:21 -0700 (PDT) From: Viresh Kumar To: Rafael Wysocki Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org, Viresh Kumar , Preeti U Murthy , linux-kernel@vger.kernel.org (open list) Subject: [PATCH V3 1/5] cpufreq: ondemand: Drop unnecessary locks from update_sampling_rate() Date: Tue, 13 Oct 2015 13:39:01 +0530 Message-Id: <56084623b2c27372a4c2c598151dd47176c3e26f.1444723240.git.viresh.kumar@linaro.org> X-Mailer: git-send-email 2.4.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP '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 1fa9088c84a8..03ac6ce54042 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -267,27 +267,19 @@ 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), true); } - mutex_unlock(&dbs_info->cdbs.shared->timer_mutex); } }