From 67d874c3b2c69d65274fa5ce44ba939788d5729d Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 8 Jul 2019 16:27:52 +0530 Subject: [PATCH] cpufreq: Register notifiers with the PM QoS framework Register 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 Reviewed-by: Ulf Hansson Signed-off-by: Viresh Kumar Tested-by: Pavel Machek Signed-off-by: Rafael J. Wysocki --- 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 ceb57af15ca083..b96ef6db1bfe84 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include @@ -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 a1467aa7f58b6d..95425941f46d8e 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 {