From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Srivatsa S. Bhat" Subject: Re: [PATCH 2/2] cpufreq: don't call cpufreq_update_policy() on CPU addition Date: Mon, 17 Feb 2014 14:13:26 +0530 Message-ID: <5301CBAE.3000102@linux.vnet.ibm.com> References: <15ccc0609cb9ee3db0ad3a95b29bf69d11ea197c.1392375504.git.viresh.kumar@linaro.org> <8f2fc4d6240b567fdb69a0b47f073d174b7ef9b2.1392375504.git.viresh.kumar@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from e28smtp08.in.ibm.com ([122.248.162.8]:52238 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752134AbaBQIs7 (ORCPT ); Mon, 17 Feb 2014 03:48:59 -0500 Received: from /spool/local by e28smtp08.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 17 Feb 2014 14:18:54 +0530 In-Reply-To: <8f2fc4d6240b567fdb69a0b47f073d174b7ef9b2.1392375504.git.viresh.kumar@linaro.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Viresh Kumar Cc: rjw@rjwysocki.net, linaro-kernel@lists.linaro.org, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, pierre-list@ossman.eu On 02/14/2014 04:30 PM, Viresh Kumar wrote: > cpufreq_update_policy() is called from two places currently. From a workqueue > handled queued from cpufreq_bp_resume() for boot CPU and from > cpufreq_cpu_callback() whenever a CPU is added. > > The first one makes sure that boot CPU is running on the frequency present in > policy->cpu. But we don't really need a call from cpufreq_cpu_callback(), > because we always call cpufreq_driver->init() (which will set policy->cur > correctly) whenever first CPU of any policy is added back. And so every policy > structure is guaranteed to have the right frequency in policy->cur. > This wording is slightly inaccurate. ->init() may or may not set policy->cur (for example, powernowk8 driver doesn't set it in the init routine).. But we set it for sure in __cpufreq_add_dev(): 1117 if (cpufreq_driver->get) { 1118 policy->cur = cpufreq_driver->get(policy->cpu); 1119 if (!policy->cur) { 1120 pr_err("%s: ->get() failed\n", __func__); 1121 goto err_get_freq; 1122 } 1123 } > Signed-off-by: Viresh Kumar The reasoning and the code looks good to me. Reviewed-by: Srivatsa S. Bhat Regards, Srivatsa S. Bhat > --- > drivers/cpufreq/cpufreq.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 383362b..b6eb4ed 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -2194,7 +2194,6 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, > switch (action & ~CPU_TASKS_FROZEN) { > case CPU_ONLINE: > __cpufreq_add_dev(dev, NULL, frozen); > - cpufreq_update_policy(cpu); > break; > > case CPU_DOWN_PREPARE: >