From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C44BFC433E2 for ; Thu, 3 Sep 2020 14:11:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A7CC20658 for ; Thu, 3 Sep 2020 14:11:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729184AbgICOLr (ORCPT ); Thu, 3 Sep 2020 10:11:47 -0400 Received: from foss.arm.com ([217.140.110.172]:34436 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729015AbgICOKI (ORCPT ); Thu, 3 Sep 2020 10:10:08 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 66D841063; Thu, 3 Sep 2020 06:45:10 -0700 (PDT) Received: from localhost (e108754-lin.cambridge.arm.com [10.1.199.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 067F03F66F; Thu, 3 Sep 2020 06:45:09 -0700 (PDT) Date: Thu, 3 Sep 2020 14:45:08 +0100 From: Ionela Voinescu To: Sudeep Holla Cc: rjw@rjwysocki.net, viresh.kumar@linaro.org, dietmar.eggemann@arm.com, catalin.marinas@arm.com, will@kernel.org, valentin.schneider@arm.com, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 3/5] cpufreq: report whether cpufreq supports Frequency Invariance (FI) Message-ID: <20200903134508.GB29370@arm.com> References: <20200901205549.30096-1-ionela.voinescu@arm.com> <20200901205549.30096-4-ionela.voinescu@arm.com> <20200902132838.GF25462@bogus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200902132838.GF25462@bogus> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sudeep, Thank you for your review here and for the other patches. On Wednesday 02 Sep 2020 at 14:28:38 (+0100), Sudeep Holla wrote: [..] > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > > index 4d5fe777184a..570bf2ebe9d4 100644 > > --- a/drivers/cpufreq/cpufreq.c > > +++ b/drivers/cpufreq/cpufreq.c > > @@ -61,6 +61,12 @@ static struct cpufreq_driver *cpufreq_driver; > > static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); > > static DEFINE_RWLOCK(cpufreq_driver_lock); > > > > +static DEFINE_STATIC_KEY_FALSE(cpufreq_freq_invariance); > > +bool cpufreq_supports_freq_invariance(void) > > +{ > > + return static_branch_likely(&cpufreq_freq_invariance); > > +} > > + > > /* Flag to suspend/resume CPUFreq governors */ > > static bool cpufreq_suspended; > > > > @@ -2720,6 +2726,15 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) > > cpufreq_driver = driver_data; > > write_unlock_irqrestore(&cpufreq_driver_lock, flags); > > > > + /* > > + * Mark support for the scheduler's frequency invariance engine for > > + * drivers that implement target(), target_index() or fast_switch(). > > + */ > > + if (!cpufreq_driver->setpolicy) { > > + static_branch_enable_cpuslocked(&cpufreq_freq_invariance); > > + pr_debug("supports frequency invariance"); > > + } > > + > > if (driver_data->setpolicy) > > [super nit] while I understand cpufreq_driver = driver_data, it looks odd > if 2 consecutive statements refer it with different variables. Or am I > confusing myself hugely. > No, you are right. If you look at the rest of the register function, after cpufreq_driver = driver_data, both driver_data and cpufreq_driver are used. For me using cpufreq_driver seemed more natural as after being assigned driver_data, it will continue to be used after registration. If it's alright with you I won't make this change for now. It's possible that a better solution is to change the other occurrences of either cpufreq_driver or driver_data in a separate patch, to make things consistent across the function. Thank you, Ionela. > -- > Regards, > Sudeep