From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757647Ab3DAUdz (ORCPT ); Mon, 1 Apr 2013 16:33:55 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:49583 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757085Ab3DAUdx (ORCPT ); Mon, 1 Apr 2013 16:33:53 -0400 From: "Rafael J. Wysocki" To: Nathan Zimmer Cc: viresh.kumar@linaro.org, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 2/2] cpufreq: covert the cpufreq_data_lock to a spinlock Date: Mon, 01 Apr 2013 22:41:27 +0200 Message-ID: <1479737.lmOfIzUVqh@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.9.0-rc4+; KDE/4.9.5; x86_64; ; ) In-Reply-To: <1364847069-2887-3-git-send-email-nzimmer@sgi.com> References: <5159C147.70800@sgi.com> <1364847069-2887-1-git-send-email-nzimmer@sgi.com> <1364847069-2887-3-git-send-email-nzimmer@sgi.com> 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 On Monday, April 01, 2013 03:11:09 PM Nathan Zimmer wrote: > This eliminates the rest of the contention found in __cpufreq_cpu_get. > I am not seeing a way to use the rcu so we will have to make due with a > rwlock for now. > > Cc: Viresh Kumar > Cc: "Rafael J. Wysocki" > Signed-off-by: Nathan Zimmer I've already applied this one. Can you please check if the version in my tree is OK? Rafael > --- > drivers/cpufreq/cpufreq.c | 38 +++++++++++++++++++------------------- > 1 file changed, 19 insertions(+), 19 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 5139eab..7438c34 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -42,7 +42,7 @@ > static struct cpufreq_driver __rcu *cpufreq_driver; > static DEFINE_SPINLOCK(cpufreq_driver_lock); > > -static DEFINE_SPINLOCK(cpufreq_data_lock); > +static DEFINE_RWLOCK(cpufreq_data_lock); > static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); > #ifdef CONFIG_HOTPLUG_CPU > /* This one keeps track of the previously set governor of a removed CPU */ > @@ -150,7 +150,7 @@ static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs) > goto err_out_unlock; > > /* get the CPU */ > - spin_lock_irqsave(&cpufreq_data_lock, flags); > + read_lock_irqsave(&cpufreq_data_lock, flags); > data = per_cpu(cpufreq_cpu_data, cpu); > > if (!data) > @@ -159,13 +159,13 @@ static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs) > if (!sysfs && !kobject_get(&data->kobj)) > goto err_out_put_module; > > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + read_unlock_irqrestore(&cpufreq_data_lock, flags); > rcu_read_unlock(); > return data; > > err_out_put_module: > module_put(driver->owner); > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + read_unlock_irqrestore(&cpufreq_data_lock, flags); > err_out_unlock: > rcu_read_unlock(); > err_out: > @@ -276,9 +276,9 @@ void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state) > pr_debug("notification %u of frequency transition to %u kHz\n", > state, freqs->new); > > - spin_lock_irqsave(&cpufreq_data_lock, flags); > + read_lock_irqsave(&cpufreq_data_lock, flags); > policy = per_cpu(cpufreq_cpu_data, freqs->cpu); > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + read_unlock_irqrestore(&cpufreq_data_lock, flags); > > switch (state) { > > @@ -802,12 +802,12 @@ static int cpufreq_add_dev_interface(unsigned int cpu, > } > rcu_read_unlock(); > > - spin_lock_irqsave(&cpufreq_data_lock, flags); > + write_lock_irqsave(&cpufreq_data_lock, flags); > for_each_cpu(j, policy->cpus) { > per_cpu(cpufreq_cpu_data, j) = policy; > per_cpu(cpufreq_policy_cpu, j) = policy->cpu; > } > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + write_unlock_irqrestore(&cpufreq_data_lock, flags); > > ret = cpufreq_add_dev_symlink(cpu, policy); > if (ret) > @@ -858,12 +858,12 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, > > lock_policy_rwsem_write(sibling); > > - spin_lock_irqsave(&cpufreq_data_lock, flags); > + write_lock_irqsave(&cpufreq_data_lock, flags); > > cpumask_set_cpu(cpu, policy->cpus); > per_cpu(cpufreq_policy_cpu, cpu) = policy->cpu; > per_cpu(cpufreq_cpu_data, cpu) = policy; > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + write_unlock_irqrestore(&cpufreq_data_lock, flags); > > unlock_policy_rwsem_write(sibling); > > @@ -918,15 +918,15 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) > > #ifdef CONFIG_HOTPLUG_CPU > /* Check if this cpu was hot-unplugged earlier and has siblings */ > - spin_lock_irqsave(&cpufreq_data_lock, flags); > + read_lock_irqsave(&cpufreq_data_lock, flags); > for_each_online_cpu(sibling) { > struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling); > if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) { > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + read_unlock_irqrestore(&cpufreq_data_lock, flags); > return cpufreq_add_policy_cpu(cpu, sibling, dev); > } > } > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + read_unlock_irqrestore(&cpufreq_data_lock, flags); > #endif > #endif > > @@ -1006,10 +1006,10 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) > return 0; > > err_out_unregister: > - spin_lock_irqsave(&cpufreq_data_lock, flags); > + write_lock_irqsave(&cpufreq_data_lock, flags); > for_each_cpu(j, policy->cpus) > per_cpu(cpufreq_cpu_data, j) = NULL; > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + write_unlock_irqrestore(&cpufreq_data_lock, flags); > > kobject_put(&policy->kobj); > wait_for_completion(&policy->kobj_unregister); > @@ -1067,12 +1067,12 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif > > pr_debug("%s: unregistering CPU %u\n", __func__, cpu); > > - spin_lock_irqsave(&cpufreq_data_lock, flags); > + write_lock_irqsave(&cpufreq_data_lock, flags); > > data = per_cpu(cpufreq_cpu_data, cpu); > per_cpu(cpufreq_cpu_data, cpu) = NULL; > > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + write_unlock_irqrestore(&cpufreq_data_lock, flags); > > if (!data) { > pr_debug("%s: No cpu_data found\n", __func__); > @@ -1111,9 +1111,9 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif > WARN_ON(lock_policy_rwsem_write(cpu)); > cpumask_set_cpu(cpu, data->cpus); > > - spin_lock_irqsave(&cpufreq_data_lock, flags); > + write_lock_irqsave(&cpufreq_data_lock, flags); > per_cpu(cpufreq_cpu_data, cpu) = data; > - spin_unlock_irqrestore(&cpufreq_data_lock, flags); > + write_unlock_irqrestore(&cpufreq_data_lock, flags); > > unlock_policy_rwsem_write(cpu); > > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.