[RFC PATCH 3/5] thermal: support statistics table resizing at runtime

From: Zhang Rui <rui.zhang@intel.com>
To: linux-pm@vger.kernel.org
Cc: rui.zhang@intel.com, daniel.lezcano@linaro.org, tiwai@suse.de,
	viresh.kumar@linaro.org
Subject: [RFC PATCH 3/5] thermal: support statistics table resizing at runtime
Date: Wed,  8 Apr 2020 12:19:15 +0800	[thread overview]
Message-ID: <20200408041917.2329-3-rui.zhang@intel.com> (raw)
In-Reply-To: <20200408041917.2329-1-rui.zhang@intel.com>

Introduce thermal_cdev_stats_update_max() which can be used to update
the cooling device statistics table when maximum cooling state of a
cooling device is changed.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
 drivers/thermal/thermal_sysfs.c | 65 ++++++++++++++++++++++++++-------
 include/linux/thermal.h         |  7 ++++
 2 files changed, 58 insertions(+), 14 deletions(-)

diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index 45cfc2746874..96e4a445952f 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c
@@ -745,6 +745,10 @@ static const struct attribute_group *cooling_device_attr_groups[] = {
 };
 
 #ifdef CONFIG_THERMAL_STATISTICS
+static int cooling_device_stats_resize(struct thermal_cooling_device *cdev,
+					unsigned long cur_state,
+					unsigned long max_state);
+
 struct cooling_dev_stats {
 	spinlock_t lock;
 	unsigned int total_trans;
@@ -787,6 +791,23 @@ void thermal_cdev_stats_update_cur(struct thermal_cooling_device *cdev,
 	spin_unlock(&stats->lock);
 }
 
+void thermal_cdev_stats_update_max(struct thermal_cooling_device *cdev)
+{
+	struct cooling_dev_stats *stats = cdev->stats;
+	unsigned long cur_state, max_state;
+
+	if (!stats)
+		return;
+
+	if (cdev->ops->get_max_state(cdev, &max_state))
+		return;
+
+	if (cdev->ops->get_cur_state(cdev, &cur_state))
+		return;
+
+	cooling_device_stats_resize(cdev, cur_state, max_state);
+}
+
 static ssize_t total_trans_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
@@ -907,36 +928,44 @@ static const struct attribute_group cooling_device_stats_attr_group = {
 	.name = "stats"
 };
 
-static int cooling_device_stats_resize(struct thermal_cooling_device *cdev)
+static int cooling_device_stats_resize(struct thermal_cooling_device *cdev,
+					unsigned long cur_state,
+					unsigned long max_state)
 {
 	struct cooling_dev_stats *stats = cdev->stats;
-	unsigned long states;
-	int ret;
-
-	ret = cdev->ops->get_max_state(cdev, &states);
-	if (ret)
-		return ret;
+	unsigned long states = max_state + 1;
+	void *time_in_state, *trans_table;
 
-	states++; /* Total number of states is highest state + 1 */
+	if (stats->max_states == states)
+		return 0;
 
-	stats->time_in_state = kcalloc(states, sizeof(*stats->time_in_state), GFP_KERNEL);
-	if (!stats->time_in_state)
+	time_in_state = kcalloc(states, sizeof(*stats->time_in_state), GFP_KERNEL);
+	if (!time_in_state)
 		return -ENOMEM;
 
-	stats->trans_table = kcalloc(states, sizeof(*stats->trans_table) * states, GFP_KERNEL);
-	if (!stats->trans_table) {
-		kfree(stats->time_in_state);
+	trans_table = kcalloc(states, sizeof(*stats->trans_table) * states, GFP_KERNEL);
+	if (!trans_table) {
+		kfree(time_in_state);
 		return -ENOMEM;
 	}
 
+	spin_lock(&stats->lock);
+	kfree(stats->time_in_state);
+	kfree(stats->trans_table);
+	stats->time_in_state = time_in_state;
+	stats->trans_table = trans_table;
 	stats->last_time = ktime_get();
 	stats->max_states = states;
+	stats->state = cur_state;
+	stats->total_trans = 0;
+	spin_unlock(&stats->lock);
 
 	return 0;
 }
 static void cooling_device_stats_setup(struct thermal_cooling_device *cdev)
 {
 	struct cooling_dev_stats *stats;
+	unsigned long max_state;
 	int var, ret;
 
 	stats = kzalloc(sizeof(*stats), GFP_KERNEL);
@@ -946,7 +975,15 @@ static void cooling_device_stats_setup(struct thermal_cooling_device *cdev)
 	cdev->stats = stats;
 	spin_lock_init(&stats->lock);
 
-	ret = cooling_device_stats_resize(cdev);
+	ret = cdev->ops->get_max_state(cdev, &max_state);
+	if (ret)
+		return;
+
+	/**
+	 *  cooling device current state will be updated soon
+	 *  during registration
+	 **/
+	ret = cooling_device_stats_resize(cdev, 0, max_state);
 	if (ret) {
 		kfree(cdev->stats);
 		cdev->stats = NULL;
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 126913c6a53b..cf3fad92f473 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -533,4 +533,11 @@ static inline void thermal_notify_framework(struct thermal_zone_device *tz,
 { }
 #endif /* CONFIG_THERMAL */
 
+#ifdef CONFIG_THERMAL_STATISTICS
+void thermal_cdev_stats_update_max(struct thermal_cooling_device *cdev);
+#else
+static inline void
+thermal_cdev_stats_update_max(struct thermal_cooling_device *cdev) {}
+#endif /* CONFIG_THERMAL_STATISTICS */
+
 #endif /* __THERMAL_H__ */
-- 
2.17.1

