1 files changed, 579 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
new file mode 100644
index 000000000..85da677c4
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -0,0 +1,579 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * drivers/cpufreq/cpufreq_governor.c
+ *
+ * CPUFREQ governors common code
+ *
+ * Copyright	(C) 2001 Russell King
+ *		(C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
+ *		(C) 2003 Jun Nakajima <jun.nakajima@intel.com>
+ *		(C) 2009 Alexander Clouter <alex@digriz.org.uk>
+ *		(c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/export.h>
+#include <linux/kernel_stat.h>
+#include <linux/slab.h>
+
+#include "cpufreq_governor.h"
+
+#define CPUFREQ_DBS_MIN_SAMPLING_INTERVAL	(2 * TICK_NSEC / NSEC_PER_USEC)
+
+static DEFINE_PER_CPU(struct cpu_dbs_info, cpu_dbs);
+
+static DEFINE_MUTEX(gov_dbs_data_mutex);
+
+/* Common sysfs tunables */
+/*
+ * sampling_rate_store - update sampling rate effective immediately if needed.
+ *
+ * If new rate is smaller than the old, simply updating
+ * dbs.sampling_rate might not be appropriate. For example, if the
+ * original sampling_rate was 1 second and the requested new sampling rate is 10
+ * ms because the user needs immediate reaction from ondemand governor, but not
+ * sure if higher frequency will be required or not, then, the governor may
+ * change the sampling rate too late; up to 1 second later. Thus, if we are
+ * reducing the sampling rate, we need to make the new value effective
+ * immediately.
+ *
+ * This must be called with dbs_data->mutex held, otherwise traversing
+ * policy_dbs_list isn't safe.
+ */
+ssize_t sampling_rate_store(struct gov_attr_set *attr_set, const char *buf,
+			    size_t count)
+{
+	struct dbs_data *dbs_data = to_dbs_data(attr_set);
+	struct policy_dbs_info *policy_dbs;
+	unsigned int sampling_interval;
+	int ret;
+
+	ret = sscanf(buf, "%u", &sampling_interval);
+	if (ret != 1 || sampling_interval < CPUFREQ_DBS_MIN_SAMPLING_INTERVAL)
+		return -EINVAL;
+
+	dbs_data->sampling_rate = sampling_interval;
+
+	/*
+	 * We are operating under dbs_data->mutex and so the list and its
+	 * entries can't be freed concurrently.
+	 */
+	list_for_each_entry(policy_dbs, &attr_set->policy_list, list) {
+		mutex_lock(&policy_dbs->update_mutex);
+		/*
+		 * On 32-bit architectures this may race with the
+		 * sample_delay_ns read in dbs_update_util_handler(), but that
+		 * really doesn't matter.  If the read returns a value that's
+		 * too big, the sample will be skipped, but the next invocation
+		 * of dbs_update_util_handler() (when the update has been
+		 * completed) will take a sample.
+		 *
+		 * If this runs in parallel with dbs_work_handler(), we may end
+		 * up overwriting the sample_delay_ns value that it has just
+		 * written, but it will be corrected next time a sample is
+		 * taken, so it shouldn't be significant.
+		 */
+		gov_update_sample_delay(policy_dbs, 0);
+		mutex_unlock(&policy_dbs->update_mutex);
+	}
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(sampling_rate_store);
+
+/**
+ * gov_update_cpu_data - Update CPU load data.
+ * @dbs_data: Top-level governor data pointer.
+ *
+ * Update CPU load data for all CPUs in the domain governed by @dbs_data
+ * (that may be a single policy or a bunch of them if governor tunables are
+ * system-wide).
+ *
+ * Call under the @dbs_data mutex.
+ */
+void gov_update_cpu_data(struct dbs_data *dbs_data)
+{
+	struct policy_dbs_info *policy_dbs;
+
+	list_for_each_entry(policy_dbs, &dbs_data->attr_set.policy_list, list) {
+		unsigned int j;
+
+		for_each_cpu(j, policy_dbs->policy->cpus) {
+			struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
+
+			j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time,
+								  dbs_data->io_is_busy);
+			if (dbs_data->ignore_nice_load)
+				j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(gov_update_cpu_data);
+
+unsigned int dbs_update(struct cpufreq_policy *policy)
+{
+	struct policy_dbs_info *policy_dbs = policy->governor_data;
+	struct dbs_data *dbs_data = policy_dbs->dbs_data;
+	unsigned int ignore_nice = dbs_data->ignore_nice_load;
+	unsigned int max_load = 0, idle_periods = UINT_MAX;
+	unsigned int sampling_rate, io_busy, j;
+
+	/*
+	 * Sometimes governors may use an additional multiplier to increase
+	 * sample delays temporarily.  Apply that multiplier to sampling_rate
+	 * so as to keep the wake-up-from-idle detection logic a bit
+	 * conservative.
+	 */
+	sampling_rate = dbs_data->sampling_rate * policy_dbs->rate_mult;
+	/*
+	 * For the purpose of ondemand, waiting for disk IO is an indication
+	 * that you're performance critical, and not that the system is actually
+	 * idle, so do not add the iowait time to the CPU idle time then.
+	 */
+	io_busy = dbs_data->io_is_busy;
+
+	/* Get Absolute Load */
+	for_each_cpu(j, policy->cpus) {
+		struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
+		u64 update_time, cur_idle_time;
+		unsigned int idle_time, time_elapsed;
+		unsigned int load;
+
+		cur_idle_time = get_cpu_idle_time(j, &update_time, io_busy);
+
+		time_elapsed = update_time - j_cdbs->prev_update_time;
+		j_cdbs->prev_update_time = update_time;
+
+		idle_time = cur_idle_time - j_cdbs->prev_cpu_idle;
+		j_cdbs->prev_cpu_idle = cur_idle_time;
+
+		if (ignore_nice) {
+			u64 cur_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
+
+			idle_time += div_u64(cur_nice - j_cdbs->prev_cpu_nice, NSEC_PER_USEC);
+			j_cdbs->prev_cpu_nice = cur_nice;
+		}
+
+		if (unlikely(!time_elapsed)) {
+			/*
+			 * That can only happen when this function is called
+			 * twice in a row with a very short interval between the
+			 * calls, so the previous load value can be used then.
+			 */
+			load = j_cdbs->prev_load;
+		} else if (unlikely((int)idle_time > 2 * sampling_rate &&
+				    j_cdbs->prev_load)) {
+			/*
+			 * If the CPU had gone completely idle and a task has
+			 * just woken up on this CPU now, it would be unfair to
+			 * calculate 'load' the usual way for this elapsed
+			 * time-window, because it would show near-zero load,
+			 * irrespective of how CPU intensive that task actually
+			 * was. This is undesirable for latency-sensitive bursty
+			 * workloads.
+			 *
+			 * To avoid this, reuse the 'load' from the previous
+			 * time-window and give this task a chance to start with
+			 * a reasonably high CPU frequency. However, that
+			 * shouldn't be over-done, lest we get stuck at a high
+			 * load (high frequency) for too long, even when the
+			 * current system load has actually dropped down, so
+			 * clear prev_load to guarantee that the load will be
+			 * computed again next time.
+			 *
+			 * Detecting this situation is easy: an unusually large
+			 * 'idle_time' (as compared to the sampling rate)
+			 * indicates this scenario.
+			 */
+			load = j_cdbs->prev_load;
+			j_cdbs->prev_load = 0;
+		} else {
+			if (time_elapsed >= idle_time) {
+				load = 100 * (time_elapsed - idle_time) / time_elapsed;
+			} else {
+				/*
+				 * That can happen if idle_time is returned by
+				 * get_cpu_idle_time_jiffy().  In that case
+				 * idle_time is roughly equal to the difference
+				 * between time_elapsed and "busy time" obtained
+				 * from CPU statistics.  Then, the "busy time"
+				 * can end up being greater than time_elapsed
+				 * (for example, if jiffies_64 and the CPU
+				 * statistics are updated by different CPUs),
+				 * so idle_time may in fact be negative.  That
+				 * means, though, that the CPU was busy all
+				 * the time (on the rough average) during the
+				 * last sampling interval and 100 can be
+				 * returned as the load.
+				 */
+				load = (int)idle_time < 0 ? 100 : 0;
+			}
+			j_cdbs->prev_load = load;
+		}
+
+		if (unlikely((int)idle_time > 2 * sampling_rate)) {
+			unsigned int periods = idle_time / sampling_rate;
+
+			if (periods < idle_periods)
+				idle_periods = periods;
+		}
+
+		if (load > max_load)
+			max_load = load;
+	}
+
+	policy_dbs->idle_periods = idle_periods;
+
+	return max_load;
+}
+EXPORT_SYMBOL_GPL(dbs_update);
+
+static void dbs_work_handler(struct work_struct *work)
+{
+	struct policy_dbs_info *policy_dbs;
+	struct cpufreq_policy *policy;
+	struct dbs_governor *gov;
+
+	policy_dbs = container_of(work, struct policy_dbs_info, work);
+	policy = policy_dbs->policy;
+	gov = dbs_governor_of(policy);
+
+	/*
+	 * Make sure cpufreq_governor_limits() isn't evaluating load or the
+	 * ondemand governor isn't updating the sampling rate in parallel.
+	 */
+	mutex_lock(&policy_dbs->update_mutex);
+	gov_update_sample_delay(policy_dbs, gov->gov_dbs_update(policy));
+	mutex_unlock(&policy_dbs->update_mutex);
+
+	/* Allow the utilization update handler to queue up more work. */
+	atomic_set(&policy_dbs->work_count, 0);
+	/*
+	 * If the update below is reordered with respect to the sample delay
+	 * modification, the utilization update handler may end up using a stale
+	 * sample delay value.
+	 */
+	smp_wmb();
+	policy_dbs->work_in_progress = false;
+}
+
+static void dbs_irq_work(struct irq_work *irq_work)
+{
+	struct policy_dbs_info *policy_dbs;
+
+	policy_dbs = container_of(irq_work, struct policy_dbs_info, irq_work);
+	schedule_work_on(smp_processor_id(), &policy_dbs->work);
+}
+
+static void dbs_update_util_handler(struct update_util_data *data, u64 time,
+				    unsigned int flags)
+{
+	struct cpu_dbs_info *cdbs = container_of(data, struct cpu_dbs_info, update_util);
+	struct policy_dbs_info *policy_dbs = cdbs->policy_dbs;
+	u64 delta_ns, lst;
+
+	if (!cpufreq_this_cpu_can_update(policy_dbs->policy))
+		return;
+
+	/*
+	 * The work may not be allowed to be queued up right now.
+	 * Possible reasons:
+	 * - Work has already been queued up or is in progress.
+	 * - It is too early (too little time from the previous sample).
+	 */
+	if (policy_dbs->work_in_progress)
+		return;
+
+	/*
+	 * If the reads below are reordered before the check above, the value
+	 * of sample_delay_ns used in the computation may be stale.
+	 */
+	smp_rmb();
+	lst = READ_ONCE(policy_dbs->last_sample_time);
+	delta_ns = time - lst;
+	if ((s64)delta_ns < policy_dbs->sample_delay_ns)
+		return;
+
+	/*
+	 * If the policy is not shared, the irq_work may be queued up right away
+	 * at this point.  Otherwise, we need to ensure that only one of the
+	 * CPUs sharing the policy will do that.
+	 */
+	if (policy_dbs->is_shared) {
+		if (!atomic_add_unless(&policy_dbs->work_count, 1, 1))
+			return;
+
+		/*
+		 * If another CPU updated last_sample_time in the meantime, we
+		 * shouldn't be here, so clear the work counter and bail out.
+		 */
+		if (unlikely(lst != READ_ONCE(policy_dbs->last_sample_time))) {
+			atomic_set(&policy_dbs->work_count, 0);
+			return;
+		}
+	}
+
+	policy_dbs->last_sample_time = time;
+	policy_dbs->work_in_progress = true;
+	irq_work_queue(&policy_dbs->irq_work);
+}
+
+static void gov_set_update_util(struct policy_dbs_info *policy_dbs,
+				unsigned int delay_us)
+{
+	struct cpufreq_policy *policy = policy_dbs->policy;
+	int cpu;
+
+	gov_update_sample_delay(policy_dbs, delay_us);
+	policy_dbs->last_sample_time = 0;
+
+	for_each_cpu(cpu, policy->cpus) {
+		struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu);
+
+		cpufreq_add_update_util_hook(cpu, &cdbs->update_util,
+					     dbs_update_util_handler);
+	}
+}
+
+static inline void gov_clear_update_util(struct cpufreq_policy *policy)
+{
+	int i;
+
+	for_each_cpu(i, policy->cpus)
+		cpufreq_remove_update_util_hook(i);
+
+	synchronize_rcu();
+}
+
+static struct policy_dbs_info *alloc_policy_dbs_info(struct cpufreq_policy *policy,
+						     struct dbs_governor *gov)
+{
+	struct policy_dbs_info *policy_dbs;
+	int j;
+
+	/* Allocate memory for per-policy governor data. */
+	policy_dbs = gov->alloc();
+	if (!policy_dbs)
+		return NULL;
+
+	policy_dbs->policy = policy;
+	mutex_init(&policy_dbs->update_mutex);
+	atomic_set(&policy_dbs->work_count, 0);
+	init_irq_work(&policy_dbs->irq_work, dbs_irq_work);
+	INIT_WORK(&policy_dbs->work, dbs_work_handler);
+
+	/* Set policy_dbs for all CPUs, online+offline */
+	for_each_cpu(j, policy->related_cpus) {
+		struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
+
+		j_cdbs->policy_dbs = policy_dbs;
+	}
+	return policy_dbs;
+}
+
+static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs,
+				 struct dbs_governor *gov)
+{
+	int j;
+
+	mutex_destroy(&policy_dbs->update_mutex);
+
+	for_each_cpu(j, policy_dbs->policy->related_cpus) {
+		struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
+
+		j_cdbs->policy_dbs = NULL;
+		j_cdbs->update_util.func = NULL;
+	}
+	gov->free(policy_dbs);
+}
+
+static void cpufreq_dbs_data_release(struct kobject *kobj)
+{
+	struct dbs_data *dbs_data = to_dbs_data(to_gov_attr_set(kobj));
+	struct dbs_governor *gov = dbs_data->gov;
+
+	gov->exit(dbs_data);
+	kfree(dbs_data);
+}
+
+int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
+{
+	struct dbs_governor *gov = dbs_governor_of(policy);
+	struct dbs_data *dbs_data;
+	struct policy_dbs_info *policy_dbs;
+	int ret = 0;
+
+	/* State should be equivalent to EXIT */
+	if (policy->governor_data)
+		return -EBUSY;
+
+	policy_dbs = alloc_policy_dbs_info(policy, gov);
+	if (!policy_dbs)
+		return -ENOMEM;
+
+	/* Protect gov->gdbs_data against concurrent updates. */
+	mutex_lock(&gov_dbs_data_mutex);
+
+	dbs_data = gov->gdbs_data;
+	if (dbs_data) {
+		if (WARN_ON(have_governor_per_policy())) {
+			ret = -EINVAL;
+			goto free_policy_dbs_info;
+		}
+		policy_dbs->dbs_data = dbs_data;
+		policy->governor_data = policy_dbs;
+
+		gov_attr_set_get(&dbs_data->attr_set, &policy_dbs->list);
+		goto out;
+	}
+
+	dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
+	if (!dbs_data) {
+		ret = -ENOMEM;
+		goto free_policy_dbs_info;
+	}
+
+	dbs_data->gov = gov;
+	gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list);
+
+	ret = gov->init(dbs_data);
+	if (ret)
+		goto free_policy_dbs_info;
+
+	/*
+	 * The sampling interval should not be less than the transition latency
+	 * of the CPU and it also cannot be too small for dbs_update() to work
+	 * correctly.
+	 */
+	dbs_data->sampling_rate = max_t(unsigned int,
+					CPUFREQ_DBS_MIN_SAMPLING_INTERVAL,
+					cpufreq_policy_transition_delay_us(policy));
+
+	if (!have_governor_per_policy())
+		gov->gdbs_data = dbs_data;
+
+	policy_dbs->dbs_data = dbs_data;
+	policy->governor_data = policy_dbs;
+
+	gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
+	gov->kobj_type.release = cpufreq_dbs_data_release;
+	ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type,
+				   get_governor_parent_kobj(policy),
+				   "%s", gov->gov.name);
+	if (!ret)
+		goto out;
+
+	/* Failure, so roll back. */
+	pr_err("initialization failed (dbs_data kobject init error %d)\n", ret);
+
+	kobject_put(&dbs_data->attr_set.kobj);
+
+	policy->governor_data = NULL;
+
+	if (!have_governor_per_policy())
+		gov->gdbs_data = NULL;
+	gov->exit(dbs_data);
+	kfree(dbs_data);
+
+free_policy_dbs_info:
+	free_policy_dbs_info(policy_dbs, gov);
+
+out:
+	mutex_unlock(&gov_dbs_data_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_init);
+
+void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy)
+{
+	struct dbs_governor *gov = dbs_governor_of(policy);
+	struct policy_dbs_info *policy_dbs = policy->governor_data;
+	struct dbs_data *dbs_data = policy_dbs->dbs_data;
+	unsigned int count;
+
+	/* Protect gov->gdbs_data against concurrent updates. */
+	mutex_lock(&gov_dbs_data_mutex);
+
+	count = gov_attr_set_put(&dbs_data->attr_set, &policy_dbs->list);
+
+	policy->governor_data = NULL;
+
+	if (!count && !have_governor_per_policy())
+		gov->gdbs_data = NULL;
+
+	free_policy_dbs_info(policy_dbs, gov);
+
+	mutex_unlock(&gov_dbs_data_mutex);
+}
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_exit);
+
+int cpufreq_dbs_governor_start(struct cpufreq_policy *policy)
+{
+	struct dbs_governor *gov = dbs_governor_of(policy);
+	struct policy_dbs_info *policy_dbs = policy->governor_data;
+	struct dbs_data *dbs_data = policy_dbs->dbs_data;
+	unsigned int sampling_rate, ignore_nice, j;
+	unsigned int io_busy;
+
+	if (!policy->cur)
+		return -EINVAL;
+
+	policy_dbs->is_shared = policy_is_shared(policy);
+	policy_dbs->rate_mult = 1;
+
+	sampling_rate = dbs_data->sampling_rate;
+	ignore_nice = dbs_data->ignore_nice_load;
+	io_busy = dbs_data->io_is_busy;
+
+	for_each_cpu(j, policy->cpus) {
+		struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
+
+		j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time, io_busy);
+		/*
+		 * Make the first invocation of dbs_update() compute the load.
+		 */
+		j_cdbs->prev_load = 0;
+
+		if (ignore_nice)
+			j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
+	}
+
+	gov->start(policy);
+
+	gov_set_update_util(policy_dbs, sampling_rate);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_start);
+
+void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy)
+{
+	struct policy_dbs_info *policy_dbs = policy->governor_data;
+
+	gov_clear_update_util(policy_dbs->policy);
+	irq_work_sync(&policy_dbs->irq_work);
+	cancel_work_sync(&policy_dbs->work);
+	atomic_set(&policy_dbs->work_count, 0);
+	policy_dbs->work_in_progress = false;
+}
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_stop);
+
+void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy)
+{
+	struct policy_dbs_info *policy_dbs;
+
+	/* Protect gov->gdbs_data against cpufreq_dbs_governor_exit() */
+	mutex_lock(&gov_dbs_data_mutex);
+	policy_dbs = policy->governor_data;
+	if (!policy_dbs)
+		goto out;
+
+	mutex_lock(&policy_dbs->update_mutex);
+	cpufreq_policy_apply_limits(policy);
+	gov_update_sample_delay(policy_dbs, 0);
+	mutex_unlock(&policy_dbs->update_mutex);
+
+out:
+	mutex_unlock(&gov_dbs_data_mutex);
+}
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_limits);