Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755432Ab3FEM2O (ORCPT ); Wed, 5 Jun 2013 08:28:14 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:58348 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755220Ab3FEM2L (ORCPT ); Wed, 5 Jun 2013 08:28:11 -0400 From: "Rafael J. Wysocki" To: Viresh Kumar Cc: linaro-kernel@lists.linaro.org, patches@linaro.org, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, robin.randhawa@arm.com, Steve.Bannister@arm.com, Liviu.Dudau@arm.com, charles.garcia-tobin@arm.com, arvind.chauhan@arm.com, chenxg.marvell@gmail.com Subject: Re: [PATCH] cpufreq: userspace: Simplify governor Date: Wed, 05 Jun 2013 14:37:15 +0200 Message-ID: <1855098.3p2j9hWHoD@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.10.0-rc4+; KDE/4.9.5; x86_64; ; ) In-Reply-To: <68ae523282b494da0e8f67536af1df874c326675.1370422554.git.viresh.kumar@linaro.org> References: <68ae523282b494da0e8f67536af1df874c326675.1370422554.git.viresh.kumar@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6712 Lines: 205 On Wednesday, June 05, 2013 02:34:33 PM Viresh Kumar wrote: > Userspace governor has got more code than what it needs for its functioning. > Lets simplify it. OK Why exactly is the code you're removing unnecessary? > Over that it will fix issues in cpufreq_governor_userspace(), which isn't doing > right things in START/STOP. What exactly is the problem? > It is working per-cpu currently whereas it just > required to manage policy->cpu. > > Reported-by: Xiaoguang Chen > Signed-off-by: Viresh Kumar > --- > @Rafael: > > I don't know why this code was initially added. Please let me know if I am doing > something stupid. > > Also, please apply it as a fix for 3.10 as it is broken recently in 3.9. I'd love to, but I need answers to the above questions before I do that. Thanks, Rafael > drivers/cpufreq/cpufreq_userspace.c | 108 ++++-------------------------------- > 1 file changed, 12 insertions(+), 96 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c > index bbeb9c0..5dc77b7 100644 > --- a/drivers/cpufreq/cpufreq_userspace.c > +++ b/drivers/cpufreq/cpufreq_userspace.c > @@ -13,55 +13,13 @@ > > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > > -#include > -#include > -#include > -#include > -#include > -#include > #include > -#include > -#include > -#include > -#include > +#include > +#include > #include > > -/** > - * A few values needed by the userspace governor > - */ > -static DEFINE_PER_CPU(unsigned int, cpu_max_freq); > -static DEFINE_PER_CPU(unsigned int, cpu_min_freq); > -static DEFINE_PER_CPU(unsigned int, cpu_cur_freq); /* current CPU freq */ > -static DEFINE_PER_CPU(unsigned int, cpu_set_freq); /* CPU freq desired by > - userspace */ > static DEFINE_PER_CPU(unsigned int, cpu_is_managed); > - > static DEFINE_MUTEX(userspace_mutex); > -static int cpus_using_userspace_governor; > - > -/* keep track of frequency transitions */ > -static int > -userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val, > - void *data) > -{ > - struct cpufreq_freqs *freq = data; > - > - if (!per_cpu(cpu_is_managed, freq->cpu)) > - return 0; > - > - if (val == CPUFREQ_POSTCHANGE) { > - pr_debug("saving cpu_cur_freq of cpu %u to be %u kHz\n", > - freq->cpu, freq->new); > - per_cpu(cpu_cur_freq, freq->cpu) = freq->new; > - } > - > - return 0; > -} > - > -static struct notifier_block userspace_cpufreq_notifier_block = { > - .notifier_call = userspace_cpufreq_notifier > -}; > - > > /** > * cpufreq_set - set the CPU frequency > @@ -80,13 +38,6 @@ static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq) > if (!per_cpu(cpu_is_managed, policy->cpu)) > goto err; > > - per_cpu(cpu_set_freq, policy->cpu) = freq; > - > - if (freq < per_cpu(cpu_min_freq, policy->cpu)) > - freq = per_cpu(cpu_min_freq, policy->cpu); > - if (freq > per_cpu(cpu_max_freq, policy->cpu)) > - freq = per_cpu(cpu_max_freq, policy->cpu); > - > /* > * We're safe from concurrent calls to ->target() here > * as we hold the userspace_mutex lock. If we were calling > @@ -107,7 +58,7 @@ static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq) > > static ssize_t show_speed(struct cpufreq_policy *policy, char *buf) > { > - return sprintf(buf, "%u\n", per_cpu(cpu_cur_freq, policy->cpu)); > + return sprintf(buf, "%u\n", policy->cur); > } > > static int cpufreq_governor_userspace(struct cpufreq_policy *policy, > @@ -119,66 +70,31 @@ static int cpufreq_governor_userspace(struct cpufreq_policy *policy, > switch (event) { > case CPUFREQ_GOV_START: > BUG_ON(!policy->cur); > - mutex_lock(&userspace_mutex); > - > - if (cpus_using_userspace_governor == 0) { > - cpufreq_register_notifier( > - &userspace_cpufreq_notifier_block, > - CPUFREQ_TRANSITION_NOTIFIER); > - } > - cpus_using_userspace_governor++; > + pr_debug("started managing cpu %u\n", cpu); > > + mutex_lock(&userspace_mutex); > per_cpu(cpu_is_managed, cpu) = 1; > - per_cpu(cpu_min_freq, cpu) = policy->min; > - per_cpu(cpu_max_freq, cpu) = policy->max; > - per_cpu(cpu_cur_freq, cpu) = policy->cur; > - per_cpu(cpu_set_freq, cpu) = policy->cur; > - pr_debug("managing cpu %u started " > - "(%u - %u kHz, currently %u kHz)\n", > - cpu, > - per_cpu(cpu_min_freq, cpu), > - per_cpu(cpu_max_freq, cpu), > - per_cpu(cpu_cur_freq, cpu)); > - > mutex_unlock(&userspace_mutex); > break; > case CPUFREQ_GOV_STOP: > - mutex_lock(&userspace_mutex); > - cpus_using_userspace_governor--; > - if (cpus_using_userspace_governor == 0) { > - cpufreq_unregister_notifier( > - &userspace_cpufreq_notifier_block, > - CPUFREQ_TRANSITION_NOTIFIER); > - } > + pr_debug("managing cpu %u stopped\n", cpu); > > + mutex_lock(&userspace_mutex); > per_cpu(cpu_is_managed, cpu) = 0; > - per_cpu(cpu_min_freq, cpu) = 0; > - per_cpu(cpu_max_freq, cpu) = 0; > - per_cpu(cpu_set_freq, cpu) = 0; > - pr_debug("managing cpu %u stopped\n", cpu); > mutex_unlock(&userspace_mutex); > break; > case CPUFREQ_GOV_LIMITS: > mutex_lock(&userspace_mutex); > - pr_debug("limit event for cpu %u: %u - %u kHz, " > - "currently %u kHz, last set to %u kHz\n", > + pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz\n", > cpu, policy->min, policy->max, > - per_cpu(cpu_cur_freq, cpu), > - per_cpu(cpu_set_freq, cpu)); > - if (policy->max < per_cpu(cpu_set_freq, cpu)) { > + policy->cur); > + > + if (policy->max < policy->cur) > __cpufreq_driver_target(policy, policy->max, > CPUFREQ_RELATION_H); > - } else if (policy->min > per_cpu(cpu_set_freq, cpu)) { > + else if (policy->min > policy->cur) > __cpufreq_driver_target(policy, policy->min, > CPUFREQ_RELATION_L); > - } else { > - __cpufreq_driver_target(policy, > - per_cpu(cpu_set_freq, cpu), > - CPUFREQ_RELATION_L); > - } > - per_cpu(cpu_min_freq, cpu) = policy->min; > - per_cpu(cpu_max_freq, cpu) = policy->max; > - per_cpu(cpu_cur_freq, cpu) = policy->cur; > mutex_unlock(&userspace_mutex); > break; > } > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/