On Monday, June 10, 2019 12:51:35 PM CEST Viresh Kumar wrote:
> 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.
>
> No constraints are added until now though.
>
> Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
> ---
> drivers/cpufreq/cpufreq.c | 139 +++++++++++++++++++++++++++++++-------
> include/linux/cpufreq.h | 4 ++
> 2 files changed, 120 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 85ff958e01f1..547d221b2ff2 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>
> @@ -1126,11 +1127,77 @@ static void handle_update(struct work_struct *work)
> cpufreq_update_policy(cpu);
> }
>
> +static void cpufreq_update_freq_work(struct work_struct *work)
> +{
> + struct cpufreq_policy *policy =
> + container_of(work, struct cpufreq_policy, req_work);
> + struct cpufreq_policy new_policy = *policy;
> +
> + /* We should read constraint values from QoS layer */
> + new_policy.min = 0;
> + new_policy.max = UINT_MAX;
> +
> + down_write(&policy->rwsem);
> +
> + if (!policy_is_inactive(policy))
> + cpufreq_set_policy(policy, &new_policy);
> +
> + up_write(&policy->rwsem);
> +}
> +
> +static int cpufreq_update_freq(struct cpufreq_policy *policy)
> +{
> + schedule_work(&policy->req_work);
> + return 0;
> +}
> +
> +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);
> +
> + return cpufreq_update_freq(policy);
> +}
> +
> +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);
> +
> + return cpufreq_update_freq(policy);
> +}
> +
> +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;
> @@ -1147,7 +1214,7 @@ 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
> @@ -1157,16 +1224,41 @@ 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);
> init_waitqueue_head(&policy->transition_wait);
> init_completion(&policy->kobj_unregister);
> INIT_WORK(&policy->update, handle_update);
> + INIT_WORK(&policy->req_work, cpufreq_update_freq_work);
One more thing.
handle_update() is very similar to cpufreq_update_freq_work().
Why are both of them needed?
