Message-ID: <3567040.O8oI5B24Ng@vostro.rjw.lan>
Date:	Wed, 02 Mar 2016 03:08:31 +0100
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Linux PM list <linux-pm@...r.kernel.org>
Cc:	Juri Lelli <juri.lelli@....com>,
	Steve Muckle <steve.muckle@...aro.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Michael Turquette <mturquette@...libre.com>
Subject: [PATCH 3/6] cpufreq: governor: New data type for management part of dbs_data

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

In addition to fields representing governor tunables, struct dbs_data
contains some fields needed for the management of objects of that
type.  As it turns out, that part of struct dbs_data may be shared
with (future) governors that won't use the common code used by
"ondemand" and "conservative", so move it to a separate struct type
and modify the code using struct dbs_data to follow.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/cpufreq/cpufreq_conservative.c |   15 +++--
 drivers/cpufreq/cpufreq_governor.c     |   90 ++++++++++++++++++++-------------
 drivers/cpufreq/cpufreq_governor.h     |   36 +++++++------
 drivers/cpufreq/cpufreq_ondemand.c     |   19 ++++--
 4 files changed, 97 insertions(+), 63 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq_governor.h
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_governor.h
+++ linux-pm/drivers/cpufreq/cpufreq_governor.h
@@ -41,6 +41,13 @@
 /* Ondemand Sampling types */
 enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
 
+struct gov_tunables {
+	struct kobject kobj;
+	struct list_head policy_list;
+	struct mutex update_lock;
+	int usage_count;
+};
+
 /*
  * Abbreviations:
  * dbs: used as a shortform for demand based switching It helps to keep variable
@@ -52,7 +59,7 @@ enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
 
 /* Governor demand based switching data (per-policy or global). */
 struct dbs_data {
-	int usage_count;
+	struct gov_tunables gt;
 	void *tuners;
 	unsigned int min_sampling_rate;
 	unsigned int ignore_nice_load;
@@ -60,37 +67,34 @@ struct dbs_data {
 	unsigned int sampling_down_factor;
 	unsigned int up_threshold;
 	unsigned int io_is_busy;
-
-	struct kobject kobj;
-	struct list_head policy_dbs_list;
-	/*
-	 * Protect concurrent updates to governor tunables from sysfs,
-	 * policy_dbs_list and usage_count.
-	 */
-	struct mutex mutex;
 };
 
+static inline struct dbs_data *to_dbs_data(struct gov_tunables *gt)
+{
+	return container_of(gt, struct dbs_data, gt);
+}
+
 /* Governor's specific attributes */
-struct dbs_data;
 struct governor_attr {
 	struct attribute attr;
-	ssize_t (*show)(struct dbs_data *dbs_data, char *buf);
-	ssize_t (*store)(struct dbs_data *dbs_data, const char *buf,
-			 size_t count);
+	ssize_t (*show)(struct gov_tunables *gt, char *buf);
+	ssize_t (*store)(struct gov_tunables *gt, const char *buf, size_t count);
 };
 
 #define gov_show_one(_gov, file_name)					\
 static ssize_t show_##file_name						\
-(struct dbs_data *dbs_data, char *buf)					\
+(struct gov_tunables *gt, char *buf)					\
 {									\
+	struct dbs_data *dbs_data = to_dbs_data(gt);			\
 	struct _gov##_dbs_tuners *tuners = dbs_data->tuners;		\
 	return sprintf(buf, "%u\n", tuners->file_name);			\
 }
 
 #define gov_show_one_common(file_name)					\
 static ssize_t show_##file_name						\
-(struct dbs_data *dbs_data, char *buf)					\
+(struct gov_tunables *gt, char *buf)					\
 {									\
+	struct dbs_data *dbs_data = to_dbs_data(gt);			\
 	return sprintf(buf, "%u\n", dbs_data->file_name);		\
 }
 
@@ -184,7 +188,7 @@ void od_register_powersave_bias_handler(
 		(struct cpufreq_policy *, unsigned int, unsigned int),
 		unsigned int powersave_bias);
 void od_unregister_powersave_bias_handler(void);
-ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
+ssize_t store_sampling_rate(struct gov_tunables *gt, const char *buf,
 			    size_t count);
 void gov_update_cpu_data(struct dbs_data *dbs_data);
 #endif /* _CPUFREQ_GOVERNOR_H */
Index: linux-pm/drivers/cpufreq/cpufreq_governor.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_governor.c
+++ linux-pm/drivers/cpufreq/cpufreq_governor.c
@@ -42,9 +42,10 @@ static DEFINE_MUTEX(gov_dbs_data_mutex);
  * This must be called with dbs_data->mutex held, otherwise traversing
  * policy_dbs_list isn't safe.
  */
-ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
+ssize_t store_sampling_rate(struct gov_tunables *gt, const char *buf,
 			    size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	struct policy_dbs_info *policy_dbs;
 	unsigned int rate;
 	int ret;
@@ -58,7 +59,7 @@ ssize_t store_sampling_rate(struct dbs_d
 	 * 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, &dbs_data->policy_dbs_list, list) {
+	list_for_each_entry(policy_dbs, &gt->policy_list, list) {
 		mutex_lock(&policy_dbs->timer_mutex);
 		/*
 		 * On 32-bit architectures this may race with the
@@ -95,7 +96,7 @@ void gov_update_cpu_data(struct dbs_data
 {
 	struct policy_dbs_info *policy_dbs;
 
-	list_for_each_entry(policy_dbs, &dbs_data->policy_dbs_list, list) {
+	list_for_each_entry(policy_dbs, &dbs_data->gt.policy_list, list) {
 		unsigned int j;
 
 		for_each_cpu(j, policy_dbs->policy->cpus) {
@@ -110,9 +111,9 @@ void gov_update_cpu_data(struct dbs_data
 }
 EXPORT_SYMBOL_GPL(gov_update_cpu_data);
 
-static inline struct dbs_data *to_dbs_data(struct kobject *kobj)
+static inline struct gov_tunables *to_gov_tunables(struct kobject *kobj)
 {
-	return container_of(kobj, struct dbs_data, kobj);
+	return container_of(kobj, struct gov_tunables, kobj);
 }
 
 static inline struct governor_attr *to_gov_attr(struct attribute *attr)
@@ -123,25 +124,24 @@ static inline struct governor_attr *to_g
 static ssize_t governor_show(struct kobject *kobj, struct attribute *attr,
 			     char *buf)
 {
-	struct dbs_data *dbs_data = to_dbs_data(kobj);
 	struct governor_attr *gattr = to_gov_attr(attr);
 
-	return gattr->show(dbs_data, buf);
+	return gattr->show(to_gov_tunables(kobj), buf);
 }
 
 static ssize_t governor_store(struct kobject *kobj, struct attribute *attr,
 			      const char *buf, size_t count)
 {
-	struct dbs_data *dbs_data = to_dbs_data(kobj);
+	struct gov_tunables *gt = to_gov_tunables(kobj);
 	struct governor_attr *gattr = to_gov_attr(attr);
 	int ret = -EBUSY;
 
-	mutex_lock(&dbs_data->mutex);
+	mutex_lock(&gt->update_lock);
 
-	if (dbs_data->usage_count)
-		ret = gattr->store(dbs_data, buf, count);
+	if (gt->usage_count)
+		ret = gattr->store(gt, buf, count);
 
-	mutex_unlock(&dbs_data->mutex);
+	mutex_unlock(&gt->update_lock);
 
 	return ret;
 }
@@ -424,6 +424,41 @@ static void free_policy_dbs_info(struct
 	gov->free(policy_dbs);
 }
 
+static void gov_tunables_init(struct gov_tunables *gt,
+			      struct list_head *list_node)
+{
+	INIT_LIST_HEAD(&gt->policy_list);
+	mutex_init(&gt->update_lock);
+	gt->usage_count = 1;
+	list_add(list_node, &gt->policy_list);
+}
+
+static void gov_tunables_get(struct gov_tunables *gt,
+			     struct list_head *list_node)
+{
+	mutex_lock(&gt->update_lock);
+	gt->usage_count++;
+	list_add(list_node, &gt->policy_list);
+	mutex_unlock(&gt->update_lock);
+}
+
+static unsigned int gov_tunables_put(struct gov_tunables *gt,
+				     struct list_head *list_node)
+{
+	unsigned int count;
+
+	mutex_lock(&gt->update_lock);
+	list_del(list_node);
+	count = --gt->usage_count;
+	mutex_unlock(&gt->update_lock);
+	if (count)
+		return count;
+
+	kobject_put(&gt->kobj);
+	mutex_destroy(&gt->update_lock);
+	return 0;
+}
+
 static int cpufreq_governor_init(struct cpufreq_policy *policy)
 {
 	struct dbs_governor *gov = dbs_governor_of(policy);
@@ -452,10 +487,7 @@ static int cpufreq_governor_init(struct
 		policy_dbs->dbs_data = dbs_data;
 		policy->governor_data = policy_dbs;
 
-		mutex_lock(&dbs_data->mutex);
-		dbs_data->usage_count++;
-		list_add(&policy_dbs->list, &dbs_data->policy_dbs_list);
-		mutex_unlock(&dbs_data->mutex);
+		gov_tunables_get(&dbs_data->gt, &policy_dbs->list);
 		goto out;
 	}
 
@@ -465,8 +497,7 @@ static int cpufreq_governor_init(struct
 		goto free_policy_dbs_info;
 	}
 
-	INIT_LIST_HEAD(&dbs_data->policy_dbs_list);
-	mutex_init(&dbs_data->mutex);
+	gov_tunables_init(&dbs_data->gt, &policy_dbs->list);
 
 	ret = gov->init(dbs_data, !policy->governor->initialized);
 	if (ret)
@@ -486,14 +517,11 @@ static int cpufreq_governor_init(struct
 	if (!have_governor_per_policy())
 		gov->gdbs_data = dbs_data;
 
-	policy->governor_data = policy_dbs;
-
 	policy_dbs->dbs_data = dbs_data;
-	dbs_data->usage_count = 1;
-	list_add(&policy_dbs->list, &dbs_data->policy_dbs_list);
+	policy->governor_data = policy_dbs;
 
 	gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
-	ret = kobject_init_and_add(&dbs_data->kobj, &gov->kobj_type,
+	ret = kobject_init_and_add(&dbs_data->gt.kobj, &gov->kobj_type,
 				   get_governor_parent_kobj(policy),
 				   "%s", gov->gov.name);
 	if (!ret)
@@ -522,29 +550,21 @@ static int cpufreq_governor_exit(struct
 	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;
-	int count;
+	unsigned int count;
 
 	/* Protect gov->gdbs_data against concurrent updates. */
 	mutex_lock(&gov_dbs_data_mutex);
 
-	mutex_lock(&dbs_data->mutex);
-	list_del(&policy_dbs->list);
-	count = --dbs_data->usage_count;
-	mutex_unlock(&dbs_data->mutex);
+	count = gov_tunables_put(&dbs_data->gt, &policy_dbs->list);
 
-	if (!count) {
-		kobject_put(&dbs_data->kobj);
-
-		policy->governor_data = NULL;
+	policy->governor_data = NULL;
 
+	if (!count) {
 		if (!have_governor_per_policy())
 			gov->gdbs_data = NULL;
 
 		gov->exit(dbs_data, policy->governor->initialized == 1);
-		mutex_destroy(&dbs_data->mutex);
 		kfree(dbs_data);
-	} else {
-		policy->governor_data = NULL;
 	}
 
 	free_policy_dbs_info(policy_dbs, gov);
Index: linux-pm/drivers/cpufreq/cpufreq_ondemand.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_ondemand.c
+++ linux-pm/drivers/cpufreq/cpufreq_ondemand.c
@@ -207,9 +207,10 @@ static unsigned int od_dbs_timer(struct
 /************************** sysfs interface ************************/
 static struct dbs_governor od_dbs_gov;
 
-static ssize_t store_io_is_busy(struct dbs_data *dbs_data, const char *buf,
+static ssize_t store_io_is_busy(struct gov_tunables *gt, const char *buf,
 		size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	unsigned int input;
 	int ret;
 
@@ -224,9 +225,10 @@ static ssize_t store_io_is_busy(struct d
 	return count;
 }
 
-static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf,
+static ssize_t store_up_threshold(struct gov_tunables *gt, const char *buf,
 		size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	unsigned int input;
 	int ret;
 	ret = sscanf(buf, "%u", &input);
@@ -240,9 +242,10 @@ static ssize_t store_up_threshold(struct
 	return count;
 }
 
-static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data,
+static ssize_t store_sampling_down_factor(struct gov_tunables *gt,
 		const char *buf, size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	struct policy_dbs_info *policy_dbs;
 	unsigned int input;
 	int ret;
@@ -254,7 +257,7 @@ static ssize_t store_sampling_down_facto
 	dbs_data->sampling_down_factor = input;
 
 	/* Reset down sampling multiplier in case it was active */
-	list_for_each_entry(policy_dbs, &dbs_data->policy_dbs_list, list) {
+	list_for_each_entry(policy_dbs, &gt->policy_list, list) {
 		/*
 		 * Doing this without locking might lead to using different
 		 * rate_mult values in od_update() and od_dbs_timer().
@@ -267,9 +270,10 @@ static ssize_t store_sampling_down_facto
 	return count;
 }
 
-static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data,
+static ssize_t store_ignore_nice_load(struct gov_tunables *gt,
 		const char *buf, size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	unsigned int input;
 	int ret;
 
@@ -291,9 +295,10 @@ static ssize_t store_ignore_nice_load(st
 	return count;
 }
 
-static ssize_t store_powersave_bias(struct dbs_data *dbs_data, const char *buf,
+static ssize_t store_powersave_bias(struct gov_tunables *gt, const char *buf,
 		size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 	struct policy_dbs_info *policy_dbs;
 	unsigned int input;
@@ -308,7 +313,7 @@ static ssize_t store_powersave_bias(stru
 
 	od_tuners->powersave_bias = input;
 
-	list_for_each_entry(policy_dbs, &dbs_data->policy_dbs_list, list)
+	list_for_each_entry(policy_dbs, &gt->policy_list, list)
 		ondemand_powersave_bias_init(policy_dbs->policy);
 
 	return count;
Index: linux-pm/drivers/cpufreq/cpufreq_conservative.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_conservative.c
+++ linux-pm/drivers/cpufreq/cpufreq_conservative.c
@@ -129,9 +129,10 @@ static struct notifier_block cs_cpufreq_
 /************************** sysfs interface ************************/
 static struct dbs_governor cs_dbs_gov;
 
-static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data,
+static ssize_t store_sampling_down_factor(struct gov_tunables *gt,
 		const char *buf, size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	unsigned int input;
 	int ret;
 	ret = sscanf(buf, "%u", &input);
@@ -143,9 +144,10 @@ static ssize_t store_sampling_down_facto
 	return count;
 }
 
-static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf,
+static ssize_t store_up_threshold(struct gov_tunables *gt, const char *buf,
 		size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
 	unsigned int input;
 	int ret;
@@ -158,9 +160,10 @@ static ssize_t store_up_threshold(struct
 	return count;
 }
 
-static ssize_t store_down_threshold(struct dbs_data *dbs_data, const char *buf,
+static ssize_t store_down_threshold(struct gov_tunables *gt, const char *buf,
 		size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
 	unsigned int input;
 	int ret;
@@ -175,9 +178,10 @@ static ssize_t store_down_threshold(stru
 	return count;
 }
 
-static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data,
+static ssize_t store_ignore_nice_load(struct gov_tunables *gt,
 		const char *buf, size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	unsigned int input;
 	int ret;
 
@@ -199,9 +203,10 @@ static ssize_t store_ignore_nice_load(st
 	return count;
 }
 
-static ssize_t store_freq_step(struct dbs_data *dbs_data, const char *buf,
+static ssize_t store_freq_step(struct gov_tunables *gt, const char *buf,
 		size_t count)
 {
+	struct dbs_data *dbs_data = to_dbs_data(gt);
 	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
 	unsigned int input;
 	int ret;

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