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Message-Id: <2c7a751a58adb4ce6f345dab9714b924504009b6.1562583394.git.viresh.kumar@linaro.org>
Date: Mon, 8 Jul 2019 16:27:52 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Rafael Wysocki <rjw@...ysocki.net>
Cc: Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org,
Vincent Guittot <vincent.guittot@...aro.org>, mka@...omium.org,
ulf.hansson@...aro.org, sfr@...b.auug.org.au, pavel@....cz,
"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH V7 5/7] cpufreq: Register notifiers with the PM QoS framework
This registers the notifiers for min/max frequency constraints with the
PM QoS framework. The constraints are also taken into consideration in
cpufreq_set_policy().
This also relocates cpufreq_policy_put_kobj() as it is required to be
called from cpufreq_policy_alloc() now.
refresh_frequency_limits() is updated to avoid calling
cpufreq_set_policy() for inactive policies and handle_update() is
updated to have proper locking in place.
No constraints are added until now though.
Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
V6->V7:
- All callers of refresh_frequency_limits(), except handle_update(),
take the policy->rwsem and result in deadlock as
refresh_frequency_limits() also takes the same lock again. Fix that
by taking the rwsem from handle_update() instead.
@Rafael: Sending it before Pavel has verified it as I would be offline
later, in case you want to apply this today itself.
drivers/cpufreq/cpufreq.c | 135 +++++++++++++++++++++++++++++---------
include/linux/cpufreq.h | 3 +
2 files changed, 108 insertions(+), 30 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index ceb57af15ca0..b96ef6db1bfe 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -26,6 +26,7 @@
#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/mutex.h>
+#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/suspend.h>
#include <linux/syscore_ops.h>
@@ -999,7 +1000,7 @@ static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
- if (!dev)
+ if (unlikely(!dev))
return;
if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
@@ -1117,14 +1118,16 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cp
static void refresh_frequency_limits(struct cpufreq_policy *policy)
{
- struct cpufreq_policy new_policy = *policy;
-
- pr_debug("updating policy for CPU %u\n", policy->cpu);
+ struct cpufreq_policy new_policy;
- new_policy.min = policy->user_policy.min;
- new_policy.max = policy->user_policy.max;
+ if (!policy_is_inactive(policy)) {
+ new_policy = *policy;
+ pr_debug("updating policy for CPU %u\n", policy->cpu);
- cpufreq_set_policy(policy, &new_policy);
+ new_policy.min = policy->user_policy.min;
+ new_policy.max = policy->user_policy.max;
+ cpufreq_set_policy(policy, &new_policy);
+ }
}
static void handle_update(struct work_struct *work)
@@ -1133,14 +1136,60 @@ static void handle_update(struct work_struct *work)
container_of(work, struct cpufreq_policy, update);
pr_debug("handle_update for cpu %u called\n", policy->cpu);
+ down_write(&policy->rwsem);
refresh_frequency_limits(policy);
+ up_write(&policy->rwsem);
+}
+
+static int cpufreq_notifier_min(struct notifier_block *nb, unsigned long freq,
+ void *data)
+{
+ struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_min);
+
+ schedule_work(&policy->update);
+ return 0;
+}
+
+static int cpufreq_notifier_max(struct notifier_block *nb, unsigned long freq,
+ void *data)
+{
+ struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_max);
+
+ schedule_work(&policy->update);
+ return 0;
+}
+
+static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
+{
+ struct kobject *kobj;
+ struct completion *cmp;
+
+ down_write(&policy->rwsem);
+ cpufreq_stats_free_table(policy);
+ kobj = &policy->kobj;
+ cmp = &policy->kobj_unregister;
+ up_write(&policy->rwsem);
+ kobject_put(kobj);
+
+ /*
+ * We need to make sure that the underlying kobj is
+ * actually not referenced anymore by anybody before we
+ * proceed with unloading.
+ */
+ pr_debug("waiting for dropping of refcount\n");
+ wait_for_completion(cmp);
+ pr_debug("wait complete\n");
}
static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
{
struct cpufreq_policy *policy;
+ struct device *dev = get_cpu_device(cpu);
int ret;
+ if (!dev)
+ return NULL;
+
policy = kzalloc(sizeof(*policy), GFP_KERNEL);
if (!policy)
return NULL;
@@ -1157,7 +1206,7 @@ static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
cpufreq_global_kobject, "policy%u", cpu);
if (ret) {
- pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
+ dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret);
/*
* The entire policy object will be freed below, but the extra
* memory allocated for the kobject name needs to be freed by
@@ -1167,6 +1216,25 @@ static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
goto err_free_real_cpus;
}
+ policy->nb_min.notifier_call = cpufreq_notifier_min;
+ policy->nb_max.notifier_call = cpufreq_notifier_max;
+
+ ret = dev_pm_qos_add_notifier(dev, &policy->nb_min,
+ DEV_PM_QOS_MIN_FREQUENCY);
+ if (ret) {
+ dev_err(dev, "Failed to register MIN QoS notifier: %d (%*pbl)\n",
+ ret, cpumask_pr_args(policy->cpus));
+ goto err_kobj_remove;
+ }
+
+ ret = dev_pm_qos_add_notifier(dev, &policy->nb_max,
+ DEV_PM_QOS_MAX_FREQUENCY);
+ if (ret) {
+ dev_err(dev, "Failed to register MAX QoS notifier: %d (%*pbl)\n",
+ ret, cpumask_pr_args(policy->cpus));
+ goto err_min_qos_notifier;
+ }
+
INIT_LIST_HEAD(&policy->policy_list);
init_rwsem(&policy->rwsem);
spin_lock_init(&policy->transition_lock);
@@ -1177,6 +1245,11 @@ static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
policy->cpu = cpu;
return policy;
+err_min_qos_notifier:
+ dev_pm_qos_remove_notifier(dev, &policy->nb_min,
+ DEV_PM_QOS_MIN_FREQUENCY);
+err_kobj_remove:
+ cpufreq_policy_put_kobj(policy);
err_free_real_cpus:
free_cpumask_var(policy->real_cpus);
err_free_rcpumask:
@@ -1189,30 +1262,9 @@ static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
return NULL;
}
-static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
-{
- struct kobject *kobj;
- struct completion *cmp;
-
- down_write(&policy->rwsem);
- cpufreq_stats_free_table(policy);
- kobj = &policy->kobj;
- cmp = &policy->kobj_unregister;
- up_write(&policy->rwsem);
- kobject_put(kobj);
-
- /*
- * We need to make sure that the underlying kobj is
- * actually not referenced anymore by anybody before we
- * proceed with unloading.
- */
- pr_debug("waiting for dropping of refcount\n");
- wait_for_completion(cmp);
- pr_debug("wait complete\n");
-}
-
static void cpufreq_policy_free(struct cpufreq_policy *policy)
{
+ struct device *dev = get_cpu_device(policy->cpu);
unsigned long flags;
int cpu;
@@ -1224,6 +1276,11 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy)
per_cpu(cpufreq_cpu_data, cpu) = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+ dev_pm_qos_remove_notifier(dev, &policy->nb_max,
+ DEV_PM_QOS_MAX_FREQUENCY);
+ dev_pm_qos_remove_notifier(dev, &policy->nb_min,
+ DEV_PM_QOS_MIN_FREQUENCY);
+
cpufreq_policy_put_kobj(policy);
free_cpumask_var(policy->real_cpus);
free_cpumask_var(policy->related_cpus);
@@ -2283,6 +2340,8 @@ int cpufreq_set_policy(struct cpufreq_policy *policy,
struct cpufreq_policy *new_policy)
{
struct cpufreq_governor *old_gov;
+ struct device *cpu_dev = get_cpu_device(policy->cpu);
+ unsigned long min, max;
int ret;
pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
@@ -2297,11 +2356,27 @@ int cpufreq_set_policy(struct cpufreq_policy *policy,
if (new_policy->min > new_policy->max)
return -EINVAL;
+ /*
+ * PM QoS framework collects all the requests from users and provide us
+ * the final aggregated value here.
+ */
+ min = dev_pm_qos_read_value(cpu_dev, DEV_PM_QOS_MIN_FREQUENCY);
+ max = dev_pm_qos_read_value(cpu_dev, DEV_PM_QOS_MAX_FREQUENCY);
+
+ if (min > new_policy->min)
+ new_policy->min = min;
+ if (max < new_policy->max)
+ new_policy->max = max;
+
/* verify the cpu speed can be set within this limit */
ret = cpufreq_driver->verify(new_policy);
if (ret)
return ret;
+ /*
+ * The notifier-chain shall be removed once all the users of
+ * CPUFREQ_ADJUST are moved to use the QoS framework.
+ */
/* adjust if necessary - all reasons */
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_ADJUST, new_policy);
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index a1467aa7f58b..95425941f46d 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -147,6 +147,9 @@ struct cpufreq_policy {
/* Pointer to the cooling device if used for thermal mitigation */
struct thermal_cooling_device *cdev;
+
+ struct notifier_block nb_min;
+ struct notifier_block nb_max;
};
struct cpufreq_freqs {
--
2.21.0.rc0.269.g1a574e7a288b
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