[PATCH 0/7] devfreq: improve devfreq statistics counting

[PATCH 0/7] devfreq: improve devfreq statistics counting

[Kamil Konieczny]

Hi,

this patch series improves devfreq statistics:

- do conversion to use 64-bit jiffies for storing elapsed time and prevent counters
  overflow,

- add ability to reset statistics using sysfs,

- move statistics data to separate structure for improved code
  readability and maintenance,

- make devfreq statistics code more similar to cpufreq statistics
  code for improved long-term maintainability

The first four patches fix time stats to use 64-bits, add spinlock for protecting data
access, add new function in sysfs for clearing statistics counters and change var name
used in time counters. Remaining patches make steps to moving stats into separate
structure devfreq_stats.

Best regards,
Kamil Konieczny
Samsung R&D Institute Poland

Kamil Konieczny (7):
  devfreq: change time stats to 64-bit
  devfreq: protect devfreq stats data with spinlock
  devfreq: add clearing transitions stats in sysfs
  devfreq: change var name used in time statistics
  devfreq: move transition statistics to devfreq profile structure
  devfreq: move transition statistics allocations to set_freq_stats()
  devfreq: move statistics to separate struct

 drivers/devfreq/devfreq.c          | 199 ++++++++++++++++++-----------
 drivers/devfreq/exynos-bus.c       |   6 +-
 drivers/devfreq/governor_passive.c |  26 ++--
 include/linux/devfreq.h            |  41 +++---
 4 files changed, 167 insertions(+), 105 deletions(-)

-- 
2.24.0

[PATCH 0/7] devfreq: improve devfreq statistics counting

[Kamil Konieczny]

Hi,

this patch series improves devfreq statistics:

- do conversion to use 64-bit jiffies for storing elapsed time and prevent counters
  overflow,

- add ability to reset statistics using sysfs,

- move statistics data to separate structure for improved code
  readability and maintenance,

- make devfreq statistics code more similar to cpufreq statistics
  code for improved long-term maintainability

The first four patches fix time stats to use 64-bits, add spinlock for protecting data
access, add new function in sysfs for clearing statistics counters and change var name
used in time counters. Remaining patches make steps to moving stats into separate
structure devfreq_stats.

Best regards,
Kamil Konieczny
Samsung R&D Institute Poland

Kamil Konieczny (7):
  devfreq: change time stats to 64-bit
  devfreq: protect devfreq stats data with spinlock
  devfreq: add clearing transitions stats in sysfs
  devfreq: change var name used in time statistics
  devfreq: move transition statistics to devfreq profile structure
  devfreq: move transition statistics allocations to set_freq_stats()
  devfreq: move statistics to separate struct

 drivers/devfreq/devfreq.c          | 199 ++++++++++++++++++-----------
 drivers/devfreq/exynos-bus.c       |   6 +-
 drivers/devfreq/governor_passive.c |  26 ++--
 include/linux/devfreq.h            |  41 +++---
 4 files changed, 167 insertions(+), 105 deletions(-)

-- 
2.24.0


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[PATCH 1/7] devfreq: change time stats to 64-bit

[Kamil Konieczny]

Change time stats counting to bigger type by using 64-bit jiffies.
This will make devfreq stats code look similar to cpufreq stats and
prevents overflow (for HZ = 1000 after 49.7 days).

Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
---
 drivers/devfreq/devfreq.c | 14 +++++++-------
 include/linux/devfreq.h   |  4 ++--
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index ab22bf8a12d6..1602cca20fc4 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -158,9 +158,9 @@ static int set_freq_table(struct devfreq *devfreq)
 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 {
 	int lev, prev_lev, ret = 0;
-	unsigned long cur_time;
+	unsigned long long cur_time;
 
-	cur_time = jiffies;
+	cur_time = get_jiffies_64();
 
 	/* Immediately exit if previous_freq is not initialized yet. */
 	if (!devfreq->previous_freq)
@@ -478,7 +478,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
 		queue_delayed_work(devfreq_wq, &devfreq->work,
 			msecs_to_jiffies(devfreq->profile->polling_ms));
 
-	devfreq->last_stat_updated = jiffies;
+	devfreq->last_stat_updated = get_jiffies_64();
 	devfreq->stop_polling = false;
 
 	if (devfreq->profile->get_cur_freq &&
@@ -698,7 +698,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 
 	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
 			devfreq->profile->max_state,
-			sizeof(unsigned long),
+			sizeof(*devfreq->time_in_state),
 			GFP_KERNEL);
 	if (!devfreq->time_in_state) {
 		mutex_unlock(&devfreq->lock);
@@ -706,7 +706,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_devfreq;
 	}
 
-	devfreq->last_stat_updated = jiffies;
+	devfreq->last_stat_updated = get_jiffies_64();
 
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
@@ -1423,8 +1423,8 @@ static ssize_t trans_stat_show(struct device *dev,
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
 				devfreq->trans_table[(i * max_state) + j]);
-		len += sprintf(buf + len, "%10u\n",
-			jiffies_to_msecs(devfreq->time_in_state[i]));
+		len += sprintf(buf + len, "%10llu\n", (u64)
+			jiffies64_to_msecs(devfreq->time_in_state[i]));
 	}
 
 	len += sprintf(buf + len, "Total transition : %u\n",
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 2bae9ed3c783..b81a86e47fb9 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -174,8 +174,8 @@ struct devfreq {
 	/* information for device frequency transition */
 	unsigned int total_trans;
 	unsigned int *trans_table;
-	unsigned long *time_in_state;
-	unsigned long last_stat_updated;
+	u64 *time_in_state;
+	unsigned long long last_stat_updated;
 
 	struct srcu_notifier_head transition_notifier_list;
 };
-- 
2.24.0

Re: [PATCH 1/7] devfreq: change time stats to 64-bit

[Chanwoo Choi]

Hi,

On 11/13/19 6:13 PM, Kamil Konieczny wrote:
> Change time stats counting to bigger type by using 64-bit jiffies.
> This will make devfreq stats code look similar to cpufreq stats and
> prevents overflow (for HZ = 1000 after 49.7 days).
> 
> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
> ---
>  drivers/devfreq/devfreq.c | 14 +++++++-------
>  include/linux/devfreq.h   |  4 ++--
>  2 files changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index ab22bf8a12d6..1602cca20fc4 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -158,9 +158,9 @@ static int set_freq_table(struct devfreq *devfreq)
>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  {
>  	int lev, prev_lev, ret = 0;
> -	unsigned long cur_time;
> +	unsigned long long cur_time;
>  
> -	cur_time = jiffies;
> +	cur_time = get_jiffies_64();
>  
>  	/* Immediately exit if previous_freq is not initialized yet. */
>  	if (!devfreq->previous_freq)
> @@ -478,7 +478,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>  			msecs_to_jiffies(devfreq->profile->polling_ms));
>  
> -	devfreq->last_stat_updated = jiffies;
> +	devfreq->last_stat_updated = get_jiffies_64();
>  	devfreq->stop_polling = false;
>  
>  	if (devfreq->profile->get_cur_freq &&
> @@ -698,7 +698,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  
>  	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
>  			devfreq->profile->max_state,
> -			sizeof(unsigned long),
> +			sizeof(*devfreq->time_in_state),
>  			GFP_KERNEL);
>  	if (!devfreq->time_in_state) {
>  		mutex_unlock(&devfreq->lock);
> @@ -706,7 +706,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  		goto err_devfreq;
>  	}
>  
> -	devfreq->last_stat_updated = jiffies;
> +	devfreq->last_stat_updated = get_jiffies_64();
>  
>  	srcu_init_notifier_head(&devfreq->transition_notifier_list);
>  
> @@ -1423,8 +1423,8 @@ static ssize_t trans_stat_show(struct device *dev,
>  		for (j = 0; j < max_state; j++)
>  			len += sprintf(buf + len, "%10u",
>  				devfreq->trans_table[(i * max_state) + j]);
> -		len += sprintf(buf + len, "%10u\n",
> -			jiffies_to_msecs(devfreq->time_in_state[i]));
> +		len += sprintf(buf + len, "%10llu\n", (u64)
> +			jiffies64_to_msecs(devfreq->time_in_state[i]));
>  	}
>  
>  	len += sprintf(buf + len, "Total transition : %u\n",
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 2bae9ed3c783..b81a86e47fb9 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -174,8 +174,8 @@ struct devfreq {
>  	/* information for device frequency transition */
>  	unsigned int total_trans;
>  	unsigned int *trans_table;
> -	unsigned long *time_in_state;
> -	unsigned long last_stat_updated;
> +	u64 *time_in_state;
> +	unsigned long long last_stat_updated;
>  
>  	struct srcu_notifier_head transition_notifier_list;
>  };
> 

Looks good to me.

Acked-by: Chanwoo Choi <cw00.choi@samsung.com>

But, When I tried to apply it to devfreq-next branch[1],
the merge conflict happen. You need to rebase it on devfreq-next branch[1] or linux-next.git.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/ (branch : devfreq-next)

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

[PATCH 2/7] devfreq: protect devfreq stats data with spinlock

[Kamil Konieczny]

Protect access to devfreq transitions stats with spinlock.

Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
---
 drivers/devfreq/devfreq.c | 18 +++++++++++++++---
 include/linux/devfreq.h   |  3 +++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 1602cca20fc4..ac04b5baef70 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -163,10 +163,16 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 	cur_time = get_jiffies_64();
 
 	/* Immediately exit if previous_freq is not initialized yet. */
-	if (!devfreq->previous_freq)
-		goto out;
+	if (!devfreq->previous_freq) {
+		spin_lock(&devfreq->stats_lock);
+		devfreq->last_stat_updated = cur_time;
+		spin_unlock(&devfreq->stats_lock);
+		return 0;
+	}
 
 	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
+
+	spin_lock(&devfreq->stats_lock);
 	if (prev_lev < 0) {
 		ret = prev_lev;
 		goto out;
@@ -174,7 +180,6 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 
 	devfreq->time_in_state[prev_lev] +=
 			 cur_time - devfreq->last_stat_updated;
-
 	lev = devfreq_get_freq_level(devfreq, freq);
 	if (lev < 0) {
 		ret = lev;
@@ -189,6 +194,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 
 out:
 	devfreq->last_stat_updated = cur_time;
+	spin_unlock(&devfreq->stats_lock);
 	return ret;
 }
 EXPORT_SYMBOL(devfreq_update_status);
@@ -478,7 +484,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
 		queue_delayed_work(devfreq_wq, &devfreq->work,
 			msecs_to_jiffies(devfreq->profile->polling_ms));
 
+	spin_lock(&devfreq->stats_lock);
 	devfreq->last_stat_updated = get_jiffies_64();
+	spin_unlock(&devfreq->stats_lock);
 	devfreq->stop_polling = false;
 
 	if (devfreq->profile->get_cur_freq &&
@@ -707,6 +715,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	}
 
 	devfreq->last_stat_updated = get_jiffies_64();
+	spin_lock_init(&devfreq->stats_lock);
 
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
@@ -1405,6 +1414,8 @@ static ssize_t trans_stat_show(struct device *dev,
 
 	len = sprintf(buf, "     From  :   To\n");
 	len += sprintf(buf + len, "           :");
+
+	spin_lock(&devfreq->stats_lock);
 	for (i = 0; i < max_state; i++)
 		len += sprintf(buf + len, "%10lu",
 				devfreq->profile->freq_table[i]);
@@ -1429,6 +1440,7 @@ static ssize_t trans_stat_show(struct device *dev,
 
 	len += sprintf(buf + len, "Total transition : %u\n",
 					devfreq->total_trans);
+	spin_unlock(&devfreq->stats_lock);
 	return len;
 }
 static DEVICE_ATTR_RO(trans_stat);
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index b81a86e47fb9..a344e0be99f3 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -135,6 +135,8 @@ struct devfreq_dev_profile {
  * @trans_table:	Statistics of devfreq transitions
  * @time_in_state:	Statistics of devfreq states
  * @last_stat_updated:	The last time stat updated
+ * @stats_lock:		Lock protecting trans_table, time_in_state, last_time
+ *			and total_trans used for statistics
  * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
  *
  * This structure stores the devfreq information for a give device.
@@ -176,6 +178,7 @@ struct devfreq {
 	unsigned int *trans_table;
 	u64 *time_in_state;
 	unsigned long long last_stat_updated;
+	spinlock_t stats_lock;
 
 	struct srcu_notifier_head transition_notifier_list;
 };
-- 
2.24.0

Re: [PATCH 2/7] devfreq: protect devfreq stats data with spinlock

[Chanwoo Choi]

Hi,

On 11/13/19 6:13 PM, Kamil Konieczny wrote:
> Protect access to devfreq transitions stats with spinlock.

You have to add the more detailed reason why spinlock is necessary.
And are there any issue without spinlock? 

In my case, I used the devfreq sysfs entries on Tizen Platfrom
for a long time, there are no any issue without spinlock.

Regards,
Chanwoo Choi

> 
> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
> ---
>  drivers/devfreq/devfreq.c | 18 +++++++++++++++---
>  include/linux/devfreq.h   |  3 +++
>  2 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 1602cca20fc4..ac04b5baef70 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -163,10 +163,16 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  	cur_time = get_jiffies_64();
>  
>  	/* Immediately exit if previous_freq is not initialized yet. */
> -	if (!devfreq->previous_freq)
> -		goto out;
> +	if (!devfreq->previous_freq) {
> +		spin_lock(&devfreq->stats_lock);
> +		devfreq->last_stat_updated = cur_time;
> +		spin_unlock(&devfreq->stats_lock);
> +		return 0;
> +	}
>  
>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
> +
> +	spin_lock(&devfreq->stats_lock);
>  	if (prev_lev < 0) {
>  		ret = prev_lev;
>  		goto out;
> @@ -174,7 +180,6 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  
>  	devfreq->time_in_state[prev_lev] +=
>  			 cur_time - devfreq->last_stat_updated;
> -
>  	lev = devfreq_get_freq_level(devfreq, freq);
>  	if (lev < 0) {
>  		ret = lev;
> @@ -189,6 +194,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  
>  out:
>  	devfreq->last_stat_updated = cur_time;
> +	spin_unlock(&devfreq->stats_lock);
>  	return ret;
>  }
>  EXPORT_SYMBOL(devfreq_update_status);
> @@ -478,7 +484,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>  			msecs_to_jiffies(devfreq->profile->polling_ms));
>  
> +	spin_lock(&devfreq->stats_lock);
>  	devfreq->last_stat_updated = get_jiffies_64();
> +	spin_unlock(&devfreq->stats_lock);
>  	devfreq->stop_polling = false;
>  
>  	if (devfreq->profile->get_cur_freq &&
> @@ -707,6 +715,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  	}
>  
>  	devfreq->last_stat_updated = get_jiffies_64();
> +	spin_lock_init(&devfreq->stats_lock);
>  
>  	srcu_init_notifier_head(&devfreq->transition_notifier_list);
>  
> @@ -1405,6 +1414,8 @@ static ssize_t trans_stat_show(struct device *dev,
>  
>  	len = sprintf(buf, "     From  :   To\n");
>  	len += sprintf(buf + len, "           :");
> +
> +	spin_lock(&devfreq->stats_lock);
>  	for (i = 0; i < max_state; i++)
>  		len += sprintf(buf + len, "%10lu",
>  				devfreq->profile->freq_table[i]);
> @@ -1429,6 +1440,7 @@ static ssize_t trans_stat_show(struct device *dev,
>  
>  	len += sprintf(buf + len, "Total transition : %u\n",
>  					devfreq->total_trans);
> +	spin_unlock(&devfreq->stats_lock);
>  	return len;
>  }
>  static DEVICE_ATTR_RO(trans_stat);
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index b81a86e47fb9..a344e0be99f3 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -135,6 +135,8 @@ struct devfreq_dev_profile {
>   * @trans_table:	Statistics of devfreq transitions
>   * @time_in_state:	Statistics of devfreq states
>   * @last_stat_updated:	The last time stat updated
> + * @stats_lock:		Lock protecting trans_table, time_in_state, last_time
> + *			and total_trans used for statistics
>   * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
>   *
>   * This structure stores the devfreq information for a give device.
> @@ -176,6 +178,7 @@ struct devfreq {
>  	unsigned int *trans_table;
>  	u64 *time_in_state;
>  	unsigned long long last_stat_updated;
> +	spinlock_t stats_lock;
>  
>  	struct srcu_notifier_head transition_notifier_list;
>  };
> 

[PATCH 3/7] devfreq: add clearing transitions stats in sysfs

[Kamil Konieczny]

Add new function trans_reset in sysfs for clearing transition
table and time in states devfreq statistics.

Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
---
 drivers/devfreq/devfreq.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index ac04b5baef70..0a88055d1362 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1445,6 +1445,31 @@ static ssize_t trans_stat_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(trans_stat);
 
+static void defvreq_stats_clear_table(struct devfreq *devfreq)
+{
+	unsigned int count = devfreq->profile->max_state;
+
+	spin_lock(&devfreq->stats_lock);
+	memset(devfreq->time_in_state, 0, count * sizeof(u64));
+	memset(devfreq->trans_table, 0, count * count * sizeof(int));
+	devfreq->last_stat_updated = get_jiffies_64();
+	devfreq->total_trans = 0;
+	spin_unlock(&devfreq->stats_lock);
+}
+
+static ssize_t trans_reset_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf,
+				 size_t count)
+{
+	struct devfreq *devfreq = to_devfreq(dev);
+
+	defvreq_stats_clear_table(devfreq);
+
+	return count;
+}
+static DEVICE_ATTR_WO(trans_reset);
+
 static struct attribute *devfreq_attrs[] = {
 	&dev_attr_governor.attr,
 	&dev_attr_available_governors.attr,
@@ -1455,6 +1480,7 @@ static struct attribute *devfreq_attrs[] = {
 	&dev_attr_min_freq.attr,
 	&dev_attr_max_freq.attr,
 	&dev_attr_trans_stat.attr,
+	&dev_attr_trans_reset.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(devfreq);
-- 
2.24.0

Re: [PATCH 3/7] devfreq: add clearing transitions stats in sysfs

[Chanwoo Choi]

Hi,

If user only want to use the transitions stats information
from now, the user just read the sysfs twice and then
can calculate them between the read data. It is enough
to get the existing sysfs information. 

And I don't know the any other reason. So, I can't agree this patch.
So, Not ack.

Regards,
Chanwoo Choi


On 11/13/19 6:13 PM, Kamil Konieczny wrote:
> Add new function trans_reset in sysfs for clearing transition
> table and time in states devfreq statistics.> 
> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
> ---
>  drivers/devfreq/devfreq.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index ac04b5baef70..0a88055d1362 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -1445,6 +1445,31 @@ static ssize_t trans_stat_show(struct device *dev,
>  }
>  static DEVICE_ATTR_RO(trans_stat);
>  
> +static void defvreq_stats_clear_table(struct devfreq *devfreq)
> +{
> +	unsigned int count = devfreq->profile->max_state;
> +
> +	spin_lock(&devfreq->stats_lock);
> +	memset(devfreq->time_in_state, 0, count * sizeof(u64));
> +	memset(devfreq->trans_table, 0, count * count * sizeof(int));
> +	devfreq->last_stat_updated = get_jiffies_64();
> +	devfreq->total_trans = 0;
> +	spin_unlock(&devfreq->stats_lock);
> +}
> +
> +static ssize_t trans_reset_store(struct device *dev,
> +				 struct device_attribute *attr,
> +				 const char *buf,
> +				 size_t count)
> +{
> +	struct devfreq *devfreq = to_devfreq(dev);
> +
> +	defvreq_stats_clear_table(devfreq);
> +
> +	return count;
> +}
> +static DEVICE_ATTR_WO(trans_reset);
> +
>  static struct attribute *devfreq_attrs[] = {
>  	&dev_attr_governor.attr,
>  	&dev_attr_available_governors.attr,
> @@ -1455,6 +1480,7 @@ static struct attribute *devfreq_attrs[] = {
>  	&dev_attr_min_freq.attr,
>  	&dev_attr_max_freq.attr,
>  	&dev_attr_trans_stat.attr,
> +	&dev_attr_trans_reset.attr,
>  	NULL,
>  };
>  ATTRIBUTE_GROUPS(devfreq);
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

Re: [PATCH 3/7] devfreq: add clearing transitions stats in sysfs

[Bartlomiej Zolnierkiewicz]

Hi Chanwoo,

On 11/13/19 10:41 AM, Chanwoo Choi wrote:
> Hi,
> 
> If user only want to use the transitions stats information
> from now, the user just read the sysfs twice and then
> can calculate them between the read data. It is enough

IOW you are suggesting that user should invest his valuable time
into actually doing such calculations (or implementing some extra
script to do the data parsing and calculations automatically)
instead of doing simple write to special sysfs file?

Also similar patch for cpufreq has been applied not so long ago:

commit ee7930ee27fe5240398cc302fa8eb4454725f188
Author: Markus Mayer <mmayer@broadcom.com>
Date:   Mon Nov 7 10:02:23 2016 -0800

    cpufreq: stats: New sysfs attribute for clearing statistics
    
    Allow CPUfreq statistics to be cleared by writing anything to
    /sys/.../cpufreq/stats/reset.
    
    Signed-off-by: Markus Mayer <mmayer@broadcom.com>
    Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
...

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> to get the existing sysfs information. 
> 
> And I don't know the any other reason. So, I can't agree this patch.
> So, Not ack.
> 
> Regards,
> Chanwoo Choi
> 
> 
> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>> Add new function trans_reset in sysfs for clearing transition
>> table and time in states devfreq statistics.> 
>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>> ---
>>  drivers/devfreq/devfreq.c | 26 ++++++++++++++++++++++++++
>>  1 file changed, 26 insertions(+)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index ac04b5baef70..0a88055d1362 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -1445,6 +1445,31 @@ static ssize_t trans_stat_show(struct device *dev,
>>  }
>>  static DEVICE_ATTR_RO(trans_stat);
>>  
>> +static void defvreq_stats_clear_table(struct devfreq *devfreq)
>> +{
>> +	unsigned int count = devfreq->profile->max_state;
>> +
>> +	spin_lock(&devfreq->stats_lock);
>> +	memset(devfreq->time_in_state, 0, count * sizeof(u64));
>> +	memset(devfreq->trans_table, 0, count * count * sizeof(int));
>> +	devfreq->last_stat_updated = get_jiffies_64();
>> +	devfreq->total_trans = 0;
>> +	spin_unlock(&devfreq->stats_lock);
>> +}
>> +
>> +static ssize_t trans_reset_store(struct device *dev,
>> +				 struct device_attribute *attr,
>> +				 const char *buf,
>> +				 size_t count)
>> +{
>> +	struct devfreq *devfreq = to_devfreq(dev);
>> +
>> +	defvreq_stats_clear_table(devfreq);
>> +
>> +	return count;
>> +}
>> +static DEVICE_ATTR_WO(trans_reset);
>> +
>>  static struct attribute *devfreq_attrs[] = {
>>  	&dev_attr_governor.attr,
>>  	&dev_attr_available_governors.attr,
>> @@ -1455,6 +1480,7 @@ static struct attribute *devfreq_attrs[] = {
>>  	&dev_attr_min_freq.attr,
>>  	&dev_attr_max_freq.attr,
>>  	&dev_attr_trans_stat.attr,
>> +	&dev_attr_trans_reset.attr,
>>  	NULL,
>>  };
>>  ATTRIBUTE_GROUPS(devfreq);

Re: [PATCH 3/7] devfreq: add clearing transitions stats in sysfs

[Chanwoo Choi]

Hi Bartlomiej,

On 11/15/19 3:23 AM, Bartlomiej Zolnierkiewicz wrote:
> 
> Hi Chanwoo,
> 
> On 11/13/19 10:41 AM, Chanwoo Choi wrote:
>> Hi,
>>
>> If user only want to use the transitions stats information
>> from now, the user just read the sysfs twice and then
>> can calculate them between the read data. It is enough
> 
> IOW you are suggesting that user should invest his valuable time
> into actually doing such calculations (or implementing some extra
> script to do the data parsing and calculations automatically)
> instead of doing simple write to special sysfs file?

Actually, I wouldn't like to add the new node for the debugging.
If there are some requirement for the debugging, we better to
add the debugfs for devfreq (devfreq has not yet developed
the debugfs. I'll do that). If some node is necessary for the devfreq
core/device operation, Surely, I'll agree.

On the initial version of devfreq, it contained the 'trans_stat'.
In order to keep the compatibility, just could not move 'trans_stat'
to under debugfs path.

If there are any requirement for resetting for transition stats,
I prefer to use the following style without any extra debugging node.

	For resetting for transition stats as following,
	echo 0 > /sys/class/devfreq/devfreq0/trans_stat

> 
> Also similar patch for cpufreq has been applied not so long ago:
> 
> commit ee7930ee27fe5240398cc302fa8eb4454725f188
> Author: Markus Mayer <mmayer@broadcom.com>
> Date:   Mon Nov 7 10:02:23 2016 -0800
> 
>     cpufreq: stats: New sysfs attribute for clearing statistics
>     
>     Allow CPUfreq statistics to be cleared by writing anything to
>     /sys/.../cpufreq/stats/reset.
>     
>     Signed-off-by: Markus Mayer <mmayer@broadcom.com>
>     Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
>     Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ...
> 
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
> 
>> to get the existing sysfs information. 
>>
>> And I don't know the any other reason. So, I can't agree this patch.
>> So, Not ack.
>>
>> Regards,
>> Chanwoo Choi
>>
>>
>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>> Add new function trans_reset in sysfs for clearing transition
>>> table and time in states devfreq statistics.> 
>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>> ---
>>>  drivers/devfreq/devfreq.c | 26 ++++++++++++++++++++++++++
>>>  1 file changed, 26 insertions(+)
>>>
>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>> index ac04b5baef70..0a88055d1362 100644
>>> --- a/drivers/devfreq/devfreq.c
>>> +++ b/drivers/devfreq/devfreq.c
>>> @@ -1445,6 +1445,31 @@ static ssize_t trans_stat_show(struct device *dev,
>>>  }
>>>  static DEVICE_ATTR_RO(trans_stat);
>>>  
>>> +static void defvreq_stats_clear_table(struct devfreq *devfreq)
>>> +{
>>> +	unsigned int count = devfreq->profile->max_state;
>>> +
>>> +	spin_lock(&devfreq->stats_lock);
>>> +	memset(devfreq->time_in_state, 0, count * sizeof(u64));
>>> +	memset(devfreq->trans_table, 0, count * count * sizeof(int));
>>> +	devfreq->last_stat_updated = get_jiffies_64();
>>> +	devfreq->total_trans = 0;
>>> +	spin_unlock(&devfreq->stats_lock);
>>> +}
>>> +
>>> +static ssize_t trans_reset_store(struct device *dev,
>>> +				 struct device_attribute *attr,
>>> +				 const char *buf,
>>> +				 size_t count)
>>> +{
>>> +	struct devfreq *devfreq = to_devfreq(dev);
>>> +
>>> +	defvreq_stats_clear_table(devfreq);
>>> +
>>> +	return count;
>>> +}
>>> +static DEVICE_ATTR_WO(trans_reset);
>>> +
>>>  static struct attribute *devfreq_attrs[] = {
>>>  	&dev_attr_governor.attr,
>>>  	&dev_attr_available_governors.attr,
>>> @@ -1455,6 +1480,7 @@ static struct attribute *devfreq_attrs[] = {
>>>  	&dev_attr_min_freq.attr,
>>>  	&dev_attr_max_freq.attr,
>>>  	&dev_attr_trans_stat.attr,
>>> +	&dev_attr_trans_reset.attr,
>>>  	NULL,
>>>  };
>>>  ATTRIBUTE_GROUPS(devfreq);
> 
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

Re: [PATCH 3/7] devfreq: add clearing transitions stats in sysfs

[Kamil Konieczny]

Hi Chanwoo,

On 15.11.2019 03:47, Chanwoo Choi wrote:
> Hi Bartlomiej,
> 
> On 11/15/19 3:23 AM, Bartlomiej Zolnierkiewicz wrote:
>>
>> Hi Chanwoo,
>>
>> On 11/13/19 10:41 AM, Chanwoo Choi wrote:
>>> Hi,
>>>
>>> If user only want to use the transitions stats information
>>> from now, the user just read the sysfs twice and then
>>> can calculate them between the read data. It is enough
>>
>> IOW you are suggesting that user should invest his valuable time
>> into actually doing such calculations (or implementing some extra
>> script to do the data parsing and calculations automatically)
>> instead of doing simple write to special sysfs file?
> 
> Actually, I wouldn't like to add the new node for the debugging.
> If there are some requirement for the debugging, we better to
> add the debugfs for devfreq (devfreq has not yet developed
> the debugfs. I'll do that). If some node is necessary for the devfreq
> core/device operation, Surely, I'll agree.
> 
> On the initial version of devfreq, it contained the 'trans_stat'.
> In order to keep the compatibility, just could not move 'trans_stat'
> to under debugfs path.
> 
> If there are any requirement for resetting for transition stats,
> I prefer to use the following style without any extra debugging node.
> 
> 	For resetting for transition stats as following,
> 	echo 0 > /sys/class/devfreq/devfreq0/trans_stat

ok, I will change the stats reset to this.

>> Also similar patch for cpufreq has been applied not so long ago:
>>
>> commit ee7930ee27fe5240398cc302fa8eb4454725f188
>> Author: Markus Mayer <mmayer@broadcom.com>
>> Date:   Mon Nov 7 10:02:23 2016 -0800
>>
>>     cpufreq: stats: New sysfs attribute for clearing statistics
>>     
>>     Allow CPUfreq statistics to be cleared by writing anything to
>>     /sys/.../cpufreq/stats/reset.
>>     
>>     Signed-off-by: Markus Mayer <mmayer@broadcom.com>
>>     Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
>>     Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>> ...
>>
>> Best regards,
>> --
>> Bartlomiej Zolnierkiewicz
>> Samsung R&D Institute Poland
>> Samsung Electronics
>>
>>> to get the existing sysfs information. 
>>>
>>> And I don't know the any other reason. So, I can't agree this patch.
>>> So, Not ack.
>>>
>>> Regards,
>>> Chanwoo Choi
>>>
>>>
>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>> Add new function trans_reset in sysfs for clearing transition
>>>> table and time in states devfreq statistics.> 
>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>> ---
>>>>  drivers/devfreq/devfreq.c | 26 ++++++++++++++++++++++++++
>>>>  1 file changed, 26 insertions(+)
>>>>
>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>> index ac04b5baef70..0a88055d1362 100644
>>>> --- a/drivers/devfreq/devfreq.c
>>>> +++ b/drivers/devfreq/devfreq.c
>>>> @@ -1445,6 +1445,31 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>  }
>>>>  static DEVICE_ATTR_RO(trans_stat);
>>>>  
>>>> +static void defvreq_stats_clear_table(struct devfreq *devfreq)
>>>> +{
>>>> +	unsigned int count = devfreq->profile->max_state;
>>>> +
>>>> +	spin_lock(&devfreq->stats_lock);
>>>> +	memset(devfreq->time_in_state, 0, count * sizeof(u64));
>>>> +	memset(devfreq->trans_table, 0, count * count * sizeof(int));
>>>> +	devfreq->last_stat_updated = get_jiffies_64();
>>>> +	devfreq->total_trans = 0;
>>>> +	spin_unlock(&devfreq->stats_lock);
>>>> +}
>>>> +
>>>> +static ssize_t trans_reset_store(struct device *dev,
>>>> +				 struct device_attribute *attr,
>>>> +				 const char *buf,
>>>> +				 size_t count)
>>>> +{
>>>> +	struct devfreq *devfreq = to_devfreq(dev);
>>>> +
>>>> +	defvreq_stats_clear_table(devfreq);
>>>> +
>>>> +	return count;
>>>> +}
>>>> +static DEVICE_ATTR_WO(trans_reset);
>>>> +
>>>>  static struct attribute *devfreq_attrs[] = {
>>>>  	&dev_attr_governor.attr,
>>>>  	&dev_attr_available_governors.attr,
>>>> @@ -1455,6 +1480,7 @@ static struct attribute *devfreq_attrs[] = {
>>>>  	&dev_attr_min_freq.attr,
>>>>  	&dev_attr_max_freq.attr,
>>>>  	&dev_attr_trans_stat.attr,
>>>> +	&dev_attr_trans_reset.attr,
>>>>  	NULL,
>>>>  };
>>>>  ATTRIBUTE_GROUPS(devfreq);

-- 
Best regards,
Kamil Konieczny
Samsung R&D Institute Poland

[PATCH 4/7] devfreq: change var name used in time statistics

[Kamil Konieczny]

Change var name used in time statistics from last_stat_updated to
last_time. This will make it shorter and similar to cpufreq_stats.

Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
---
 drivers/devfreq/devfreq.c | 12 ++++++------
 include/linux/devfreq.h   |  4 ++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 0a88055d1362..6e5a17f4c92c 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -165,7 +165,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 	/* Immediately exit if previous_freq is not initialized yet. */
 	if (!devfreq->previous_freq) {
 		spin_lock(&devfreq->stats_lock);
-		devfreq->last_stat_updated = cur_time;
+		devfreq->last_time = cur_time;
 		spin_unlock(&devfreq->stats_lock);
 		return 0;
 	}
@@ -179,7 +179,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 	}
 
 	devfreq->time_in_state[prev_lev] +=
-			 cur_time - devfreq->last_stat_updated;
+			 cur_time - devfreq->last_time;
 	lev = devfreq_get_freq_level(devfreq, freq);
 	if (lev < 0) {
 		ret = lev;
@@ -193,7 +193,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 	}
 
 out:
-	devfreq->last_stat_updated = cur_time;
+	devfreq->last_time = cur_time;
 	spin_unlock(&devfreq->stats_lock);
 	return ret;
 }
@@ -485,7 +485,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
 			msecs_to_jiffies(devfreq->profile->polling_ms));
 
 	spin_lock(&devfreq->stats_lock);
-	devfreq->last_stat_updated = get_jiffies_64();
+	devfreq->last_time = get_jiffies_64();
 	spin_unlock(&devfreq->stats_lock);
 	devfreq->stop_polling = false;
 
@@ -714,7 +714,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_devfreq;
 	}
 
-	devfreq->last_stat_updated = get_jiffies_64();
+	devfreq->last_time = get_jiffies_64();
 	spin_lock_init(&devfreq->stats_lock);
 
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
@@ -1452,7 +1452,7 @@ static void defvreq_stats_clear_table(struct devfreq *devfreq)
 	spin_lock(&devfreq->stats_lock);
 	memset(devfreq->time_in_state, 0, count * sizeof(u64));
 	memset(devfreq->trans_table, 0, count * count * sizeof(int));
-	devfreq->last_stat_updated = get_jiffies_64();
+	devfreq->last_time = get_jiffies_64();
 	devfreq->total_trans = 0;
 	spin_unlock(&devfreq->stats_lock);
 }
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index a344e0be99f3..2ddf25993f7d 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -134,7 +134,7 @@ struct devfreq_dev_profile {
  * @total_trans:	Number of devfreq transitions
  * @trans_table:	Statistics of devfreq transitions
  * @time_in_state:	Statistics of devfreq states
- * @last_stat_updated:	The last time stat updated
+ * @last_time:		The last time stats were updated
  * @stats_lock:		Lock protecting trans_table, time_in_state, last_time
  *			and total_trans used for statistics
  * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
@@ -177,7 +177,7 @@ struct devfreq {
 	unsigned int total_trans;
 	unsigned int *trans_table;
 	u64 *time_in_state;
-	unsigned long long last_stat_updated;
+	unsigned long long last_time;
 	spinlock_t stats_lock;
 
 	struct srcu_notifier_head transition_notifier_list;
-- 
2.24.0

Re: [PATCH 4/7] devfreq: change var name used in time statistics

[Chanwoo Choi]

Hi,

Actually, it just change the variable name. I don't want to
change the name without any behavior improvement. Frankly,
we might make the many patches to rename the some variables
on various subsystem and driver. But, It is not necessary
if there are any critical beneficial.

Rather than just changing the name, it is more important to keep
the history. And devfreq is not cpufreq. There are no any reason
to follow the cpufreq for variable name.

So, Not ack of this patch. Thanks.

Regards,
Chanwoo Choi


On 11/13/19 6:13 PM, Kamil Konieczny wrote:
> Change var name used in time statistics from last_stat_updated to
> last_time. This will make it shorter and similar to cpufreq_stats.
> 
> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
> ---
>  drivers/devfreq/devfreq.c | 12 ++++++------
>  include/linux/devfreq.h   |  4 ++--
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 0a88055d1362..6e5a17f4c92c 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -165,7 +165,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  	/* Immediately exit if previous_freq is not initialized yet. */
>  	if (!devfreq->previous_freq) {
>  		spin_lock(&devfreq->stats_lock);
> -		devfreq->last_stat_updated = cur_time;
> +		devfreq->last_time = cur_time;
>  		spin_unlock(&devfreq->stats_lock);
>  		return 0;
>  	}
> @@ -179,7 +179,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  	}
>  
>  	devfreq->time_in_state[prev_lev] +=
> -			 cur_time - devfreq->last_stat_updated;
> +			 cur_time - devfreq->last_time;
>  	lev = devfreq_get_freq_level(devfreq, freq);
>  	if (lev < 0) {
>  		ret = lev;
> @@ -193,7 +193,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  	}
>  
>  out:
> -	devfreq->last_stat_updated = cur_time;
> +	devfreq->last_time = cur_time;
>  	spin_unlock(&devfreq->stats_lock);
>  	return ret;
>  }
> @@ -485,7 +485,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>  			msecs_to_jiffies(devfreq->profile->polling_ms));
>  
>  	spin_lock(&devfreq->stats_lock);
> -	devfreq->last_stat_updated = get_jiffies_64();
> +	devfreq->last_time = get_jiffies_64();
>  	spin_unlock(&devfreq->stats_lock);
>  	devfreq->stop_polling = false;
>  
> @@ -714,7 +714,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  		goto err_devfreq;
>  	}
>  
> -	devfreq->last_stat_updated = get_jiffies_64();
> +	devfreq->last_time = get_jiffies_64();
>  	spin_lock_init(&devfreq->stats_lock);
>  
>  	srcu_init_notifier_head(&devfreq->transition_notifier_list);
> @@ -1452,7 +1452,7 @@ static void defvreq_stats_clear_table(struct devfreq *devfreq)
>  	spin_lock(&devfreq->stats_lock);
>  	memset(devfreq->time_in_state, 0, count * sizeof(u64));
>  	memset(devfreq->trans_table, 0, count * count * sizeof(int));
> -	devfreq->last_stat_updated = get_jiffies_64();
> +	devfreq->last_time = get_jiffies_64();
>  	devfreq->total_trans = 0;
>  	spin_unlock(&devfreq->stats_lock);
>  }
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index a344e0be99f3..2ddf25993f7d 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -134,7 +134,7 @@ struct devfreq_dev_profile {
>   * @total_trans:	Number of devfreq transitions
>   * @trans_table:	Statistics of devfreq transitions
>   * @time_in_state:	Statistics of devfreq states
> - * @last_stat_updated:	The last time stat updated
> + * @last_time:		The last time stats were updated
>   * @stats_lock:		Lock protecting trans_table, time_in_state, last_time
>   *			and total_trans used for statistics
>   * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
> @@ -177,7 +177,7 @@ struct devfreq {
>  	unsigned int total_trans;
>  	unsigned int *trans_table;
>  	u64 *time_in_state;
> -	unsigned long long last_stat_updated;
> +	unsigned long long last_time;
>  	spinlock_t stats_lock;
>  
>  	struct srcu_notifier_head transition_notifier_list;
> 

[PATCH 5/7] devfreq: move transition statistics to devfreq profile structure

[Kamil Konieczny]

Move transition statistics to devfreq profile structure. This is for
preparation for moving transition statistics into separate struct.
It is safe to do as frequency table and maximum state information are
already present in devfreq profile structure and there are no devfreq
drivers using more than one instance of devfreq structure per devfreq
profile one.

It also makes devfreq code more similar to cpufreq one.

Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
---
 drivers/devfreq/devfreq.c | 115 +++++++++++++++++++-------------------
 include/linux/devfreq.h   |  25 ++++-----
 2 files changed, 70 insertions(+), 70 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 6e5a17f4c92c..70533b787744 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -128,7 +128,7 @@ static int set_freq_table(struct devfreq *devfreq)
 
 	profile->max_state = count;
 	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
-					profile->max_state,
+					count,
 					sizeof(*profile->freq_table),
 					GFP_KERNEL);
 	if (!profile->freq_table) {
@@ -157,29 +157,30 @@ static int set_freq_table(struct devfreq *devfreq)
  */
 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 {
-	int lev, prev_lev, ret = 0;
+	struct devfreq_dev_profile *profile = devfreq->profile;
 	unsigned long long cur_time;
+	int lev, prev_lev, ret = 0;
 
 	cur_time = get_jiffies_64();
 
 	/* Immediately exit if previous_freq is not initialized yet. */
 	if (!devfreq->previous_freq) {
-		spin_lock(&devfreq->stats_lock);
-		devfreq->last_time = cur_time;
-		spin_unlock(&devfreq->stats_lock);
+		spin_lock(&profile->stats_lock);
+		profile->last_time = cur_time;
+		spin_unlock(&profile->stats_lock);
 		return 0;
 	}
 
 	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 
-	spin_lock(&devfreq->stats_lock);
+	spin_lock(&profile->stats_lock);
 	if (prev_lev < 0) {
 		ret = prev_lev;
 		goto out;
 	}
 
-	devfreq->time_in_state[prev_lev] +=
-			 cur_time - devfreq->last_time;
+	profile->time_in_state[prev_lev] +=
+			 cur_time - profile->last_time;
 	lev = devfreq_get_freq_level(devfreq, freq);
 	if (lev < 0) {
 		ret = lev;
@@ -187,14 +188,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 	}
 
 	if (lev != prev_lev) {
-		devfreq->trans_table[(prev_lev *
-				devfreq->profile->max_state) + lev]++;
-		devfreq->total_trans++;
+		profile->trans_table[(prev_lev *
+				profile->max_state) + lev]++;
+		profile->total_trans++;
 	}
 
 out:
-	devfreq->last_time = cur_time;
-	spin_unlock(&devfreq->stats_lock);
+	profile->last_time = cur_time;
+	spin_unlock(&profile->stats_lock);
 	return ret;
 }
 EXPORT_SYMBOL(devfreq_update_status);
@@ -474,23 +475,23 @@ EXPORT_SYMBOL(devfreq_monitor_suspend);
 void devfreq_monitor_resume(struct devfreq *devfreq)
 {
 	unsigned long freq;
+	struct devfreq_dev_profile *profile = devfreq->profile;
 
 	mutex_lock(&devfreq->lock);
 	if (!devfreq->stop_polling)
 		goto out;
 
-	if (!delayed_work_pending(&devfreq->work) &&
-			devfreq->profile->polling_ms)
+	if (!delayed_work_pending(&devfreq->work) && profile->polling_ms)
 		queue_delayed_work(devfreq_wq, &devfreq->work,
-			msecs_to_jiffies(devfreq->profile->polling_ms));
+			msecs_to_jiffies(profile->polling_ms));
 
-	spin_lock(&devfreq->stats_lock);
-	devfreq->last_time = get_jiffies_64();
-	spin_unlock(&devfreq->stats_lock);
+	spin_lock(&profile->stats_lock);
+	profile->last_time = get_jiffies_64();
+	spin_unlock(&profile->stats_lock);
 	devfreq->stop_polling = false;
 
-	if (devfreq->profile->get_cur_freq &&
-		!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
+	if (profile->get_cur_freq &&
+	    !profile->get_cur_freq(devfreq->dev.parent, &freq))
 		devfreq->previous_freq = freq;
 
 out:
@@ -657,7 +658,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	devfreq->data = data;
 	devfreq->nb.notifier_call = devfreq_notifier_call;
 
-	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
+	if (!profile->max_state && !profile->freq_table) {
 		mutex_unlock(&devfreq->lock);
 		err = set_freq_table(devfreq);
 		if (err < 0)
@@ -693,29 +694,29 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_out;
 	}
 
-	devfreq->trans_table = devm_kzalloc(&devfreq->dev,
-			array3_size(sizeof(unsigned int),
-				    devfreq->profile->max_state,
-				    devfreq->profile->max_state),
-			GFP_KERNEL);
-	if (!devfreq->trans_table) {
+	profile->trans_table = devm_kzalloc(&devfreq->dev,
+					    array3_size(sizeof(unsigned int),
+							profile->max_state,
+							profile->max_state),
+					    GFP_KERNEL);
+	if (!profile->trans_table) {
 		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_devfreq;
 	}
 
-	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
-			devfreq->profile->max_state,
-			sizeof(*devfreq->time_in_state),
-			GFP_KERNEL);
-	if (!devfreq->time_in_state) {
+	profile->time_in_state = devm_kcalloc(&devfreq->dev,
+					      profile->max_state,
+					      sizeof(*profile->time_in_state),
+					      GFP_KERNEL);
+	if (!profile->time_in_state) {
 		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_devfreq;
 	}
 
-	devfreq->last_time = get_jiffies_64();
-	spin_lock_init(&devfreq->stats_lock);
+	profile->last_time = get_jiffies_64();
+	spin_lock_init(&profile->stats_lock);
 
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
@@ -1402,9 +1403,10 @@ static ssize_t trans_stat_show(struct device *dev,
 			       struct device_attribute *attr, char *buf)
 {
 	struct devfreq *devfreq = to_devfreq(dev);
+	struct devfreq_dev_profile *profile = devfreq->profile;
 	ssize_t len;
 	int i, j;
-	unsigned int max_state = devfreq->profile->max_state;
+	unsigned int max_state = profile->max_state;
 
 	if (!devfreq->stop_polling &&
 			devfreq_update_status(devfreq, devfreq->previous_freq))
@@ -1415,46 +1417,45 @@ static ssize_t trans_stat_show(struct device *dev,
 	len = sprintf(buf, "     From  :   To\n");
 	len += sprintf(buf + len, "           :");
 
-	spin_lock(&devfreq->stats_lock);
+	spin_lock(&profile->stats_lock);
 	for (i = 0; i < max_state; i++)
 		len += sprintf(buf + len, "%10lu",
-				devfreq->profile->freq_table[i]);
+				profile->freq_table[i]);
 
 	len += sprintf(buf + len, "   time(ms)\n");
 
 	for (i = 0; i < max_state; i++) {
-		if (devfreq->profile->freq_table[i]
-					== devfreq->previous_freq) {
+		if (profile->freq_table[i] == devfreq->previous_freq)
 			len += sprintf(buf + len, "*");
-		} else {
+		else
 			len += sprintf(buf + len, " ");
-		}
+
 		len += sprintf(buf + len, "%10lu:",
-				devfreq->profile->freq_table[i]);
+				profile->freq_table[i]);
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
-				devfreq->trans_table[(i * max_state) + j]);
+				profile->trans_table[(i * max_state) + j]);
 		len += sprintf(buf + len, "%10llu\n", (u64)
-			jiffies64_to_msecs(devfreq->time_in_state[i]));
+			jiffies64_to_msecs(profile->time_in_state[i]));
 	}
 
 	len += sprintf(buf + len, "Total transition : %u\n",
-					devfreq->total_trans);
-	spin_unlock(&devfreq->stats_lock);
+					profile->total_trans);
+	spin_unlock(&profile->stats_lock);
 	return len;
 }
 static DEVICE_ATTR_RO(trans_stat);
 
-static void defvreq_stats_clear_table(struct devfreq *devfreq)
+static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
 {
-	unsigned int count = devfreq->profile->max_state;
-
-	spin_lock(&devfreq->stats_lock);
-	memset(devfreq->time_in_state, 0, count * sizeof(u64));
-	memset(devfreq->trans_table, 0, count * count * sizeof(int));
-	devfreq->last_time = get_jiffies_64();
-	devfreq->total_trans = 0;
-	spin_unlock(&devfreq->stats_lock);
+	unsigned int count = profile->max_state;
+
+	spin_lock(&profile->stats_lock);
+	memset(profile->time_in_state, 0, count * sizeof(u64));
+	memset(profile->trans_table, 0, count * count * sizeof(int));
+	profile->last_time = get_jiffies_64();
+	profile->total_trans = 0;
+	spin_unlock(&profile->stats_lock);
 }
 
 static ssize_t trans_reset_store(struct device *dev,
@@ -1464,7 +1465,7 @@ static ssize_t trans_reset_store(struct device *dev,
 {
 	struct devfreq *devfreq = to_devfreq(dev);
 
-	defvreq_stats_clear_table(devfreq);
+	defvreq_stats_clear_table(devfreq->profile);
 
 	return count;
 }
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 2ddf25993f7d..4ceb2a517a9c 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -91,6 +91,12 @@ struct devfreq_dev_status {
  * @freq_table:		Optional list of frequencies to support statistics
  *			and freq_table must be generated in ascending order.
  * @max_state:		The size of freq_table.
+ * @total_trans:	Number of devfreq transitions
+ * @trans_table:	Statistics of devfreq transitions
+ * @time_in_state:	Statistics of devfreq states
+ * @last_time:		The last time stats were updated
+ * @stats_lock:		Lock protecting trans_table, time_in_state,
+ *			last_time and total_trans used for statistics
  */
 struct devfreq_dev_profile {
 	unsigned long initial_freq;
@@ -104,6 +110,12 @@ struct devfreq_dev_profile {
 
 	unsigned long *freq_table;
 	unsigned int max_state;
+	/* information for device frequency transition */
+	unsigned int total_trans;
+	unsigned int *trans_table;
+	u64 *time_in_state;
+	unsigned long long last_time;
+	spinlock_t stats_lock;
 };
 
 /**
@@ -131,12 +143,6 @@ struct devfreq_dev_profile {
  * @suspend_freq:	 frequency of a device set during suspend phase.
  * @resume_freq:	 frequency of a device set in resume phase.
  * @suspend_count:	 suspend requests counter for a device.
- * @total_trans:	Number of devfreq transitions
- * @trans_table:	Statistics of devfreq transitions
- * @time_in_state:	Statistics of devfreq states
- * @last_time:		The last time stats were updated
- * @stats_lock:		Lock protecting trans_table, time_in_state, last_time
- *			and total_trans used for statistics
  * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
  *
  * This structure stores the devfreq information for a give device.
@@ -173,13 +179,6 @@ struct devfreq {
 	unsigned long resume_freq;
 	atomic_t suspend_count;
 
-	/* information for device frequency transition */
-	unsigned int total_trans;
-	unsigned int *trans_table;
-	u64 *time_in_state;
-	unsigned long long last_time;
-	spinlock_t stats_lock;
-
 	struct srcu_notifier_head transition_notifier_list;
 };
 
-- 
2.24.0

Re: [PATCH 5/7] devfreq: move transition statistics to devfreq profile structure

[Chanwoo Choi]

Hi Kamil,

The devfreq_dev_profile structure have to only contain the each devfreq device
callback function/data which are used in the devfreq core.

The generated information after registered the devfreq device
with devfreq_add_device() should be stored in the 'struct device'.

The devfreq core need to split out the data between user input
data (struct devfreq_dev_profile) and the initialized/generated data
by core (struct devfreq). It is not same with cpufreq. cpufreq
don't require the any structure like 'devfreq_dev_profile'.

So, I can't agree.

Thanks.
Chanwoo Choi


On 11/13/19 6:13 PM, Kamil Konieczny wrote:
> Move transition statistics to devfreq profile structure. This is for
> preparation for moving transition statistics into separate struct.
> It is safe to do as frequency table and maximum state information are
> already present in devfreq profile structure and there are no devfreq
> drivers using more than one instance of devfreq structure per devfreq
> profile one.
> 
> It also makes devfreq code more similar to cpufreq one.
> 
> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
> ---
>  drivers/devfreq/devfreq.c | 115 +++++++++++++++++++-------------------
>  include/linux/devfreq.h   |  25 ++++-----
>  2 files changed, 70 insertions(+), 70 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 6e5a17f4c92c..70533b787744 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -128,7 +128,7 @@ static int set_freq_table(struct devfreq *devfreq)
>  
>  	profile->max_state = count;
>  	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
> -					profile->max_state,
> +					count,
>  					sizeof(*profile->freq_table),
>  					GFP_KERNEL);
>  	if (!profile->freq_table) {
> @@ -157,29 +157,30 @@ static int set_freq_table(struct devfreq *devfreq)
>   */
>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  {
> -	int lev, prev_lev, ret = 0;
> +	struct devfreq_dev_profile *profile = devfreq->profile;
>  	unsigned long long cur_time;
> +	int lev, prev_lev, ret = 0;
>  
>  	cur_time = get_jiffies_64();
>  
>  	/* Immediately exit if previous_freq is not initialized yet. */
>  	if (!devfreq->previous_freq) {
> -		spin_lock(&devfreq->stats_lock);
> -		devfreq->last_time = cur_time;
> -		spin_unlock(&devfreq->stats_lock);
> +		spin_lock(&profile->stats_lock);
> +		profile->last_time = cur_time;
> +		spin_unlock(&profile->stats_lock);
>  		return 0;
>  	}
>  
>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>  
> -	spin_lock(&devfreq->stats_lock);
> +	spin_lock(&profile->stats_lock);
>  	if (prev_lev < 0) {
>  		ret = prev_lev;
>  		goto out;
>  	}
>  
> -	devfreq->time_in_state[prev_lev] +=
> -			 cur_time - devfreq->last_time;
> +	profile->time_in_state[prev_lev] +=
> +			 cur_time - profile->last_time;
>  	lev = devfreq_get_freq_level(devfreq, freq);
>  	if (lev < 0) {
>  		ret = lev;
> @@ -187,14 +188,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  	}
>  
>  	if (lev != prev_lev) {
> -		devfreq->trans_table[(prev_lev *
> -				devfreq->profile->max_state) + lev]++;
> -		devfreq->total_trans++;
> +		profile->trans_table[(prev_lev *
> +				profile->max_state) + lev]++;
> +		profile->total_trans++;
>  	}
>  
>  out:
> -	devfreq->last_time = cur_time;
> -	spin_unlock(&devfreq->stats_lock);
> +	profile->last_time = cur_time;
> +	spin_unlock(&profile->stats_lock);
>  	return ret;
>  }
>  EXPORT_SYMBOL(devfreq_update_status);
> @@ -474,23 +475,23 @@ EXPORT_SYMBOL(devfreq_monitor_suspend);
>  void devfreq_monitor_resume(struct devfreq *devfreq)
>  {
>  	unsigned long freq;
> +	struct devfreq_dev_profile *profile = devfreq->profile;
>  
>  	mutex_lock(&devfreq->lock);
>  	if (!devfreq->stop_polling)
>  		goto out;
>  
> -	if (!delayed_work_pending(&devfreq->work) &&
> -			devfreq->profile->polling_ms)
> +	if (!delayed_work_pending(&devfreq->work) && profile->polling_ms)
>  		queue_delayed_work(devfreq_wq, &devfreq->work,
> -			msecs_to_jiffies(devfreq->profile->polling_ms));
> +			msecs_to_jiffies(profile->polling_ms));
>  
> -	spin_lock(&devfreq->stats_lock);
> -	devfreq->last_time = get_jiffies_64();
> -	spin_unlock(&devfreq->stats_lock);
> +	spin_lock(&profile->stats_lock);
> +	profile->last_time = get_jiffies_64();
> +	spin_unlock(&profile->stats_lock);
>  	devfreq->stop_polling = false;
>  
> -	if (devfreq->profile->get_cur_freq &&
> -		!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
> +	if (profile->get_cur_freq &&
> +	    !profile->get_cur_freq(devfreq->dev.parent, &freq))
>  		devfreq->previous_freq = freq;
>  
>  out:
> @@ -657,7 +658,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  	devfreq->data = data;
>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>  
> -	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
> +	if (!profile->max_state && !profile->freq_table) {
>  		mutex_unlock(&devfreq->lock);
>  		err = set_freq_table(devfreq);
>  		if (err < 0)
> @@ -693,29 +694,29 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  		goto err_out;
>  	}
>  
> -	devfreq->trans_table = devm_kzalloc(&devfreq->dev,
> -			array3_size(sizeof(unsigned int),
> -				    devfreq->profile->max_state,
> -				    devfreq->profile->max_state),
> -			GFP_KERNEL);
> -	if (!devfreq->trans_table) {
> +	profile->trans_table = devm_kzalloc(&devfreq->dev,
> +					    array3_size(sizeof(unsigned int),
> +							profile->max_state,
> +							profile->max_state),
> +					    GFP_KERNEL);
> +	if (!profile->trans_table) {
>  		mutex_unlock(&devfreq->lock);
>  		err = -ENOMEM;
>  		goto err_devfreq;
>  	}
>  
> -	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
> -			devfreq->profile->max_state,
> -			sizeof(*devfreq->time_in_state),
> -			GFP_KERNEL);
> -	if (!devfreq->time_in_state) {
> +	profile->time_in_state = devm_kcalloc(&devfreq->dev,
> +					      profile->max_state,
> +					      sizeof(*profile->time_in_state),
> +					      GFP_KERNEL);
> +	if (!profile->time_in_state) {
>  		mutex_unlock(&devfreq->lock);
>  		err = -ENOMEM;
>  		goto err_devfreq;
>  	}
>  
> -	devfreq->last_time = get_jiffies_64();
> -	spin_lock_init(&devfreq->stats_lock);
> +	profile->last_time = get_jiffies_64();
> +	spin_lock_init(&profile->stats_lock);
>  
>  	srcu_init_notifier_head(&devfreq->transition_notifier_list);
>  
> @@ -1402,9 +1403,10 @@ static ssize_t trans_stat_show(struct device *dev,
>  			       struct device_attribute *attr, char *buf)
>  {
>  	struct devfreq *devfreq = to_devfreq(dev);
> +	struct devfreq_dev_profile *profile = devfreq->profile;
>  	ssize_t len;
>  	int i, j;
> -	unsigned int max_state = devfreq->profile->max_state;
> +	unsigned int max_state = profile->max_state;
>  
>  	if (!devfreq->stop_polling &&
>  			devfreq_update_status(devfreq, devfreq->previous_freq))
> @@ -1415,46 +1417,45 @@ static ssize_t trans_stat_show(struct device *dev,
>  	len = sprintf(buf, "     From  :   To\n");
>  	len += sprintf(buf + len, "           :");
>  
> -	spin_lock(&devfreq->stats_lock);
> +	spin_lock(&profile->stats_lock);
>  	for (i = 0; i < max_state; i++)
>  		len += sprintf(buf + len, "%10lu",
> -				devfreq->profile->freq_table[i]);
> +				profile->freq_table[i]);
>  
>  	len += sprintf(buf + len, "   time(ms)\n");
>  
>  	for (i = 0; i < max_state; i++) {
> -		if (devfreq->profile->freq_table[i]
> -					== devfreq->previous_freq) {
> +		if (profile->freq_table[i] == devfreq->previous_freq)
>  			len += sprintf(buf + len, "*");
> -		} else {
> +		else
>  			len += sprintf(buf + len, " ");
> -		}
> +
>  		len += sprintf(buf + len, "%10lu:",
> -				devfreq->profile->freq_table[i]);
> +				profile->freq_table[i]);
>  		for (j = 0; j < max_state; j++)
>  			len += sprintf(buf + len, "%10u",
> -				devfreq->trans_table[(i * max_state) + j]);
> +				profile->trans_table[(i * max_state) + j]);
>  		len += sprintf(buf + len, "%10llu\n", (u64)
> -			jiffies64_to_msecs(devfreq->time_in_state[i]));
> +			jiffies64_to_msecs(profile->time_in_state[i]));
>  	}
>  
>  	len += sprintf(buf + len, "Total transition : %u\n",
> -					devfreq->total_trans);
> -	spin_unlock(&devfreq->stats_lock);
> +					profile->total_trans);
> +	spin_unlock(&profile->stats_lock);
>  	return len;
>  }
>  static DEVICE_ATTR_RO(trans_stat);
>  
> -static void defvreq_stats_clear_table(struct devfreq *devfreq)
> +static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>  {
> -	unsigned int count = devfreq->profile->max_state;
> -
> -	spin_lock(&devfreq->stats_lock);
> -	memset(devfreq->time_in_state, 0, count * sizeof(u64));
> -	memset(devfreq->trans_table, 0, count * count * sizeof(int));
> -	devfreq->last_time = get_jiffies_64();
> -	devfreq->total_trans = 0;
> -	spin_unlock(&devfreq->stats_lock);
> +	unsigned int count = profile->max_state;
> +
> +	spin_lock(&profile->stats_lock);
> +	memset(profile->time_in_state, 0, count * sizeof(u64));
> +	memset(profile->trans_table, 0, count * count * sizeof(int));
> +	profile->last_time = get_jiffies_64();
> +	profile->total_trans = 0;
> +	spin_unlock(&profile->stats_lock);
>  }
>  
>  static ssize_t trans_reset_store(struct device *dev,
> @@ -1464,7 +1465,7 @@ static ssize_t trans_reset_store(struct device *dev,
>  {
>  	struct devfreq *devfreq = to_devfreq(dev);
>  
> -	defvreq_stats_clear_table(devfreq);
> +	defvreq_stats_clear_table(devfreq->profile);
>  
>  	return count;
>  }
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 2ddf25993f7d..4ceb2a517a9c 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -91,6 +91,12 @@ struct devfreq_dev_status {
>   * @freq_table:		Optional list of frequencies to support statistics
>   *			and freq_table must be generated in ascending order.
>   * @max_state:		The size of freq_table.
> + * @total_trans:	Number of devfreq transitions
> + * @trans_table:	Statistics of devfreq transitions
> + * @time_in_state:	Statistics of devfreq states
> + * @last_time:		The last time stats were updated
> + * @stats_lock:		Lock protecting trans_table, time_in_state,
> + *			last_time and total_trans used for statistics
>   */
>  struct devfreq_dev_profile {
>  	unsigned long initial_freq;
> @@ -104,6 +110,12 @@ struct devfreq_dev_profile {
>  
>  	unsigned long *freq_table;
>  	unsigned int max_state;
> +	/* information for device frequency transition */
> +	unsigned int total_trans;
> +	unsigned int *trans_table;
> +	u64 *time_in_state;
> +	unsigned long long last_time;
> +	spinlock_t stats_lock;
>  };
>  
>  /**
> @@ -131,12 +143,6 @@ struct devfreq_dev_profile {
>   * @suspend_freq:	 frequency of a device set during suspend phase.
>   * @resume_freq:	 frequency of a device set in resume phase.
>   * @suspend_count:	 suspend requests counter for a device.
> - * @total_trans:	Number of devfreq transitions
> - * @trans_table:	Statistics of devfreq transitions
> - * @time_in_state:	Statistics of devfreq states
> - * @last_time:		The last time stats were updated
> - * @stats_lock:		Lock protecting trans_table, time_in_state, last_time
> - *			and total_trans used for statistics
>   * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
>   *
>   * This structure stores the devfreq information for a give device.
> @@ -173,13 +179,6 @@ struct devfreq {
>  	unsigned long resume_freq;
>  	atomic_t suspend_count;
>  
> -	/* information for device frequency transition */
> -	unsigned int total_trans;
> -	unsigned int *trans_table;
> -	u64 *time_in_state;
> -	unsigned long long last_time;
> -	spinlock_t stats_lock;
> -
>  	struct srcu_notifier_head transition_notifier_list;
>  };
>  
> 

Re: [PATCH 5/7] devfreq: move transition statistics to devfreq profile structure

[Bartlomiej Zolnierkiewicz]

Hi Chanwoo,

On 11/14/19 3:02 AM, Chanwoo Choi wrote:
> Hi Kamil,
> 
> The devfreq_dev_profile structure have to only contain the each devfreq device
> callback function/data which are used in the devfreq core.
> 
> The generated information after registered the devfreq device
> with devfreq_add_device() should be stored in the 'struct device'.
> 
> The devfreq core need to split out the data between user input
> data (struct devfreq_dev_profile) and the initialized/generated data
> by core (struct devfreq). It is not same with cpufreq. cpufreq

How's about doing it the other way around -> moving 'freq_table' and
'max_state' from 'struct devfreq_dev_profile' to 'struct devfreq'?

They are both initialized/generated by the core during
devfreq_add_device()->set_freq_table() for all in-kernel drivers.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics 

> don't require the any structure like 'devfreq_dev_profile'.
> 
> So, I can't agree.
> 
> Thanks.
> Chanwoo Choi
> 
> 
> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>> Move transition statistics to devfreq profile structure. This is for
>> preparation for moving transition statistics into separate struct.
>> It is safe to do as frequency table and maximum state information are
>> already present in devfreq profile structure and there are no devfreq
>> drivers using more than one instance of devfreq structure per devfreq
>> profile one.
>>
>> It also makes devfreq code more similar to cpufreq one.
>>
>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>> ---
>>  drivers/devfreq/devfreq.c | 115 +++++++++++++++++++-------------------
>>  include/linux/devfreq.h   |  25 ++++-----
>>  2 files changed, 70 insertions(+), 70 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 6e5a17f4c92c..70533b787744 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -128,7 +128,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>  
>>  	profile->max_state = count;
>>  	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>> -					profile->max_state,
>> +					count,
>>  					sizeof(*profile->freq_table),
>>  					GFP_KERNEL);
>>  	if (!profile->freq_table) {
>> @@ -157,29 +157,30 @@ static int set_freq_table(struct devfreq *devfreq)
>>   */
>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  {
>> -	int lev, prev_lev, ret = 0;
>> +	struct devfreq_dev_profile *profile = devfreq->profile;
>>  	unsigned long long cur_time;
>> +	int lev, prev_lev, ret = 0;
>>  
>>  	cur_time = get_jiffies_64();
>>  
>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>  	if (!devfreq->previous_freq) {
>> -		spin_lock(&devfreq->stats_lock);
>> -		devfreq->last_time = cur_time;
>> -		spin_unlock(&devfreq->stats_lock);
>> +		spin_lock(&profile->stats_lock);
>> +		profile->last_time = cur_time;
>> +		spin_unlock(&profile->stats_lock);
>>  		return 0;
>>  	}
>>  
>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>  
>> -	spin_lock(&devfreq->stats_lock);
>> +	spin_lock(&profile->stats_lock);
>>  	if (prev_lev < 0) {
>>  		ret = prev_lev;
>>  		goto out;
>>  	}
>>  
>> -	devfreq->time_in_state[prev_lev] +=
>> -			 cur_time - devfreq->last_time;
>> +	profile->time_in_state[prev_lev] +=
>> +			 cur_time - profile->last_time;
>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>  	if (lev < 0) {
>>  		ret = lev;
>> @@ -187,14 +188,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  	}
>>  
>>  	if (lev != prev_lev) {
>> -		devfreq->trans_table[(prev_lev *
>> -				devfreq->profile->max_state) + lev]++;
>> -		devfreq->total_trans++;
>> +		profile->trans_table[(prev_lev *
>> +				profile->max_state) + lev]++;
>> +		profile->total_trans++;
>>  	}
>>  
>>  out:
>> -	devfreq->last_time = cur_time;
>> -	spin_unlock(&devfreq->stats_lock);
>> +	profile->last_time = cur_time;
>> +	spin_unlock(&profile->stats_lock);
>>  	return ret;
>>  }
>>  EXPORT_SYMBOL(devfreq_update_status);
>> @@ -474,23 +475,23 @@ EXPORT_SYMBOL(devfreq_monitor_suspend);
>>  void devfreq_monitor_resume(struct devfreq *devfreq)
>>  {
>>  	unsigned long freq;
>> +	struct devfreq_dev_profile *profile = devfreq->profile;
>>  
>>  	mutex_lock(&devfreq->lock);
>>  	if (!devfreq->stop_polling)
>>  		goto out;
>>  
>> -	if (!delayed_work_pending(&devfreq->work) &&
>> -			devfreq->profile->polling_ms)
>> +	if (!delayed_work_pending(&devfreq->work) && profile->polling_ms)
>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>> -			msecs_to_jiffies(devfreq->profile->polling_ms));
>> +			msecs_to_jiffies(profile->polling_ms));
>>  
>> -	spin_lock(&devfreq->stats_lock);
>> -	devfreq->last_time = get_jiffies_64();
>> -	spin_unlock(&devfreq->stats_lock);
>> +	spin_lock(&profile->stats_lock);
>> +	profile->last_time = get_jiffies_64();
>> +	spin_unlock(&profile->stats_lock);
>>  	devfreq->stop_polling = false;
>>  
>> -	if (devfreq->profile->get_cur_freq &&
>> -		!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
>> +	if (profile->get_cur_freq &&
>> +	    !profile->get_cur_freq(devfreq->dev.parent, &freq))
>>  		devfreq->previous_freq = freq;
>>  
>>  out:
>> @@ -657,7 +658,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>  	devfreq->data = data;
>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>  
>> -	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
>> +	if (!profile->max_state && !profile->freq_table) {
>>  		mutex_unlock(&devfreq->lock);
>>  		err = set_freq_table(devfreq);
>>  		if (err < 0)
>> @@ -693,29 +694,29 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>  		goto err_out;
>>  	}
>>  
>> -	devfreq->trans_table = devm_kzalloc(&devfreq->dev,
>> -			array3_size(sizeof(unsigned int),
>> -				    devfreq->profile->max_state,
>> -				    devfreq->profile->max_state),
>> -			GFP_KERNEL);
>> -	if (!devfreq->trans_table) {
>> +	profile->trans_table = devm_kzalloc(&devfreq->dev,
>> +					    array3_size(sizeof(unsigned int),
>> +							profile->max_state,
>> +							profile->max_state),
>> +					    GFP_KERNEL);
>> +	if (!profile->trans_table) {
>>  		mutex_unlock(&devfreq->lock);
>>  		err = -ENOMEM;
>>  		goto err_devfreq;
>>  	}
>>  
>> -	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
>> -			devfreq->profile->max_state,
>> -			sizeof(*devfreq->time_in_state),
>> -			GFP_KERNEL);
>> -	if (!devfreq->time_in_state) {
>> +	profile->time_in_state = devm_kcalloc(&devfreq->dev,
>> +					      profile->max_state,
>> +					      sizeof(*profile->time_in_state),
>> +					      GFP_KERNEL);
>> +	if (!profile->time_in_state) {
>>  		mutex_unlock(&devfreq->lock);
>>  		err = -ENOMEM;
>>  		goto err_devfreq;
>>  	}
>>  
>> -	devfreq->last_time = get_jiffies_64();
>> -	spin_lock_init(&devfreq->stats_lock);
>> +	profile->last_time = get_jiffies_64();
>> +	spin_lock_init(&profile->stats_lock);
>>  
>>  	srcu_init_notifier_head(&devfreq->transition_notifier_list);
>>  
>> @@ -1402,9 +1403,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>  			       struct device_attribute *attr, char *buf)
>>  {
>>  	struct devfreq *devfreq = to_devfreq(dev);
>> +	struct devfreq_dev_profile *profile = devfreq->profile;
>>  	ssize_t len;
>>  	int i, j;
>> -	unsigned int max_state = devfreq->profile->max_state;
>> +	unsigned int max_state = profile->max_state;
>>  
>>  	if (!devfreq->stop_polling &&
>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>> @@ -1415,46 +1417,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>  	len = sprintf(buf, "     From  :   To\n");
>>  	len += sprintf(buf + len, "           :");
>>  
>> -	spin_lock(&devfreq->stats_lock);
>> +	spin_lock(&profile->stats_lock);
>>  	for (i = 0; i < max_state; i++)
>>  		len += sprintf(buf + len, "%10lu",
>> -				devfreq->profile->freq_table[i]);
>> +				profile->freq_table[i]);
>>  
>>  	len += sprintf(buf + len, "   time(ms)\n");
>>  
>>  	for (i = 0; i < max_state; i++) {
>> -		if (devfreq->profile->freq_table[i]
>> -					== devfreq->previous_freq) {
>> +		if (profile->freq_table[i] == devfreq->previous_freq)
>>  			len += sprintf(buf + len, "*");
>> -		} else {
>> +		else
>>  			len += sprintf(buf + len, " ");
>> -		}
>> +
>>  		len += sprintf(buf + len, "%10lu:",
>> -				devfreq->profile->freq_table[i]);
>> +				profile->freq_table[i]);
>>  		for (j = 0; j < max_state; j++)
>>  			len += sprintf(buf + len, "%10u",
>> -				devfreq->trans_table[(i * max_state) + j]);
>> +				profile->trans_table[(i * max_state) + j]);
>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>> -			jiffies64_to_msecs(devfreq->time_in_state[i]));
>> +			jiffies64_to_msecs(profile->time_in_state[i]));
>>  	}
>>  
>>  	len += sprintf(buf + len, "Total transition : %u\n",
>> -					devfreq->total_trans);
>> -	spin_unlock(&devfreq->stats_lock);
>> +					profile->total_trans);
>> +	spin_unlock(&profile->stats_lock);
>>  	return len;
>>  }
>>  static DEVICE_ATTR_RO(trans_stat);
>>  
>> -static void defvreq_stats_clear_table(struct devfreq *devfreq)
>> +static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>  {
>> -	unsigned int count = devfreq->profile->max_state;
>> -
>> -	spin_lock(&devfreq->stats_lock);
>> -	memset(devfreq->time_in_state, 0, count * sizeof(u64));
>> -	memset(devfreq->trans_table, 0, count * count * sizeof(int));
>> -	devfreq->last_time = get_jiffies_64();
>> -	devfreq->total_trans = 0;
>> -	spin_unlock(&devfreq->stats_lock);
>> +	unsigned int count = profile->max_state;
>> +
>> +	spin_lock(&profile->stats_lock);
>> +	memset(profile->time_in_state, 0, count * sizeof(u64));
>> +	memset(profile->trans_table, 0, count * count * sizeof(int));
>> +	profile->last_time = get_jiffies_64();
>> +	profile->total_trans = 0;
>> +	spin_unlock(&profile->stats_lock);
>>  }
>>  
>>  static ssize_t trans_reset_store(struct device *dev,
>> @@ -1464,7 +1465,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>  {
>>  	struct devfreq *devfreq = to_devfreq(dev);
>>  
>> -	defvreq_stats_clear_table(devfreq);
>> +	defvreq_stats_clear_table(devfreq->profile);
>>  
>>  	return count;
>>  }
>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>> index 2ddf25993f7d..4ceb2a517a9c 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -91,6 +91,12 @@ struct devfreq_dev_status {
>>   * @freq_table:		Optional list of frequencies to support statistics
>>   *			and freq_table must be generated in ascending order.
>>   * @max_state:		The size of freq_table.
>> + * @total_trans:	Number of devfreq transitions
>> + * @trans_table:	Statistics of devfreq transitions
>> + * @time_in_state:	Statistics of devfreq states
>> + * @last_time:		The last time stats were updated
>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>> + *			last_time and total_trans used for statistics
>>   */
>>  struct devfreq_dev_profile {
>>  	unsigned long initial_freq;
>> @@ -104,6 +110,12 @@ struct devfreq_dev_profile {
>>  
>>  	unsigned long *freq_table;
>>  	unsigned int max_state;
>> +	/* information for device frequency transition */
>> +	unsigned int total_trans;
>> +	unsigned int *trans_table;
>> +	u64 *time_in_state;
>> +	unsigned long long last_time;
>> +	spinlock_t stats_lock;
>>  };
>>  
>>  /**
>> @@ -131,12 +143,6 @@ struct devfreq_dev_profile {
>>   * @suspend_freq:	 frequency of a device set during suspend phase.
>>   * @resume_freq:	 frequency of a device set in resume phase.
>>   * @suspend_count:	 suspend requests counter for a device.
>> - * @total_trans:	Number of devfreq transitions
>> - * @trans_table:	Statistics of devfreq transitions
>> - * @time_in_state:	Statistics of devfreq states
>> - * @last_time:		The last time stats were updated
>> - * @stats_lock:		Lock protecting trans_table, time_in_state, last_time
>> - *			and total_trans used for statistics
>>   * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
>>   *
>>   * This structure stores the devfreq information for a give device.
>> @@ -173,13 +179,6 @@ struct devfreq {
>>  	unsigned long resume_freq;
>>  	atomic_t suspend_count;
>>  
>> -	/* information for device frequency transition */
>> -	unsigned int total_trans;
>> -	unsigned int *trans_table;
>> -	u64 *time_in_state;
>> -	unsigned long long last_time;
>> -	spinlock_t stats_lock;
>> -
>>  	struct srcu_notifier_head transition_notifier_list;
>>  };
>>  
>>

Re: [PATCH 5/7] devfreq: move transition statistics to devfreq profile structure

[Chanwoo Choi]

Hi Bartlomiej,

On 11/15/19 3:10 AM, Bartlomiej Zolnierkiewicz wrote:
> 
> Hi Chanwoo,
> 
> On 11/14/19 3:02 AM, Chanwoo Choi wrote:
>> Hi Kamil,
>>
>> The devfreq_dev_profile structure have to only contain the each devfreq device
>> callback function/data which are used in the devfreq core.
>>
>> The generated information after registered the devfreq device
>> with devfreq_add_device() should be stored in the 'struct device'.
>>
>> The devfreq core need to split out the data between user input
>> data (struct devfreq_dev_profile) and the initialized/generated data
>> by core (struct devfreq). It is not same with cpufreq. cpufreq
> 
> How's about doing it the other way around -> moving 'freq_table' and
> 'max_state' from 'struct devfreq_dev_profile' to 'struct devfreq'?

I agree to move 'freq_table' and 'max_state' to 'struct devfreq
as I replied on patch7 from your reply. But, it have to be touched
with the ordering issue of freq_table on drivers/thermal/devfreq_cooling.c.

Regards,
Chanwoo Choi

> 
> They are both initialized/generated by the core during
> devfreq_add_device()->set_freq_table() for all in-kernel drivers.
> 
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics 
> 
>> don't require the any structure like 'devfreq_dev_profile'.
>>
>> So, I can't agree.
>>
>> Thanks.
>> Chanwoo Choi
>>
>>
>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>> Move transition statistics to devfreq profile structure. This is for
>>> preparation for moving transition statistics into separate struct.
>>> It is safe to do as frequency table and maximum state information are
>>> already present in devfreq profile structure and there are no devfreq
>>> drivers using more than one instance of devfreq structure per devfreq
>>> profile one.
>>>
>>> It also makes devfreq code more similar to cpufreq one.
>>>
>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>> ---
>>>  drivers/devfreq/devfreq.c | 115 +++++++++++++++++++-------------------
>>>  include/linux/devfreq.h   |  25 ++++-----
>>>  2 files changed, 70 insertions(+), 70 deletions(-)
>>>
>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>> index 6e5a17f4c92c..70533b787744 100644
>>> --- a/drivers/devfreq/devfreq.c
>>> +++ b/drivers/devfreq/devfreq.c
>>> @@ -128,7 +128,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>  
>>>  	profile->max_state = count;
>>>  	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>> -					profile->max_state,
>>> +					count,
>>>  					sizeof(*profile->freq_table),
>>>  					GFP_KERNEL);
>>>  	if (!profile->freq_table) {
>>> @@ -157,29 +157,30 @@ static int set_freq_table(struct devfreq *devfreq)
>>>   */
>>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>  {
>>> -	int lev, prev_lev, ret = 0;
>>> +	struct devfreq_dev_profile *profile = devfreq->profile;
>>>  	unsigned long long cur_time;
>>> +	int lev, prev_lev, ret = 0;
>>>  
>>>  	cur_time = get_jiffies_64();
>>>  
>>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>>  	if (!devfreq->previous_freq) {
>>> -		spin_lock(&devfreq->stats_lock);
>>> -		devfreq->last_time = cur_time;
>>> -		spin_unlock(&devfreq->stats_lock);
>>> +		spin_lock(&profile->stats_lock);
>>> +		profile->last_time = cur_time;
>>> +		spin_unlock(&profile->stats_lock);
>>>  		return 0;
>>>  	}
>>>  
>>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>  
>>> -	spin_lock(&devfreq->stats_lock);
>>> +	spin_lock(&profile->stats_lock);
>>>  	if (prev_lev < 0) {
>>>  		ret = prev_lev;
>>>  		goto out;
>>>  	}
>>>  
>>> -	devfreq->time_in_state[prev_lev] +=
>>> -			 cur_time - devfreq->last_time;
>>> +	profile->time_in_state[prev_lev] +=
>>> +			 cur_time - profile->last_time;
>>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>>  	if (lev < 0) {
>>>  		ret = lev;
>>> @@ -187,14 +188,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>  	}
>>>  
>>>  	if (lev != prev_lev) {
>>> -		devfreq->trans_table[(prev_lev *
>>> -				devfreq->profile->max_state) + lev]++;
>>> -		devfreq->total_trans++;
>>> +		profile->trans_table[(prev_lev *
>>> +				profile->max_state) + lev]++;
>>> +		profile->total_trans++;
>>>  	}
>>>  
>>>  out:
>>> -	devfreq->last_time = cur_time;
>>> -	spin_unlock(&devfreq->stats_lock);
>>> +	profile->last_time = cur_time;
>>> +	spin_unlock(&profile->stats_lock);
>>>  	return ret;
>>>  }
>>>  EXPORT_SYMBOL(devfreq_update_status);
>>> @@ -474,23 +475,23 @@ EXPORT_SYMBOL(devfreq_monitor_suspend);
>>>  void devfreq_monitor_resume(struct devfreq *devfreq)
>>>  {
>>>  	unsigned long freq;
>>> +	struct devfreq_dev_profile *profile = devfreq->profile;
>>>  
>>>  	mutex_lock(&devfreq->lock);
>>>  	if (!devfreq->stop_polling)
>>>  		goto out;
>>>  
>>> -	if (!delayed_work_pending(&devfreq->work) &&
>>> -			devfreq->profile->polling_ms)
>>> +	if (!delayed_work_pending(&devfreq->work) && profile->polling_ms)
>>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>> -			msecs_to_jiffies(devfreq->profile->polling_ms));
>>> +			msecs_to_jiffies(profile->polling_ms));
>>>  
>>> -	spin_lock(&devfreq->stats_lock);
>>> -	devfreq->last_time = get_jiffies_64();
>>> -	spin_unlock(&devfreq->stats_lock);
>>> +	spin_lock(&profile->stats_lock);
>>> +	profile->last_time = get_jiffies_64();
>>> +	spin_unlock(&profile->stats_lock);
>>>  	devfreq->stop_polling = false;
>>>  
>>> -	if (devfreq->profile->get_cur_freq &&
>>> -		!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
>>> +	if (profile->get_cur_freq &&
>>> +	    !profile->get_cur_freq(devfreq->dev.parent, &freq))
>>>  		devfreq->previous_freq = freq;
>>>  
>>>  out:
>>> @@ -657,7 +658,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>  	devfreq->data = data;
>>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>>  
>>> -	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
>>> +	if (!profile->max_state && !profile->freq_table) {
>>>  		mutex_unlock(&devfreq->lock);
>>>  		err = set_freq_table(devfreq);
>>>  		if (err < 0)
>>> @@ -693,29 +694,29 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>  		goto err_out;
>>>  	}
>>>  
>>> -	devfreq->trans_table = devm_kzalloc(&devfreq->dev,
>>> -			array3_size(sizeof(unsigned int),
>>> -				    devfreq->profile->max_state,
>>> -				    devfreq->profile->max_state),
>>> -			GFP_KERNEL);
>>> -	if (!devfreq->trans_table) {
>>> +	profile->trans_table = devm_kzalloc(&devfreq->dev,
>>> +					    array3_size(sizeof(unsigned int),
>>> +							profile->max_state,
>>> +							profile->max_state),
>>> +					    GFP_KERNEL);
>>> +	if (!profile->trans_table) {
>>>  		mutex_unlock(&devfreq->lock);
>>>  		err = -ENOMEM;
>>>  		goto err_devfreq;
>>>  	}
>>>  
>>> -	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
>>> -			devfreq->profile->max_state,
>>> -			sizeof(*devfreq->time_in_state),
>>> -			GFP_KERNEL);
>>> -	if (!devfreq->time_in_state) {
>>> +	profile->time_in_state = devm_kcalloc(&devfreq->dev,
>>> +					      profile->max_state,
>>> +					      sizeof(*profile->time_in_state),
>>> +					      GFP_KERNEL);
>>> +	if (!profile->time_in_state) {
>>>  		mutex_unlock(&devfreq->lock);
>>>  		err = -ENOMEM;
>>>  		goto err_devfreq;
>>>  	}
>>>  
>>> -	devfreq->last_time = get_jiffies_64();
>>> -	spin_lock_init(&devfreq->stats_lock);
>>> +	profile->last_time = get_jiffies_64();
>>> +	spin_lock_init(&profile->stats_lock);
>>>  
>>>  	srcu_init_notifier_head(&devfreq->transition_notifier_list);
>>>  
>>> @@ -1402,9 +1403,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>  			       struct device_attribute *attr, char *buf)
>>>  {
>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>> +	struct devfreq_dev_profile *profile = devfreq->profile;
>>>  	ssize_t len;
>>>  	int i, j;
>>> -	unsigned int max_state = devfreq->profile->max_state;
>>> +	unsigned int max_state = profile->max_state;
>>>  
>>>  	if (!devfreq->stop_polling &&
>>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>>> @@ -1415,46 +1417,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>  	len = sprintf(buf, "     From  :   To\n");
>>>  	len += sprintf(buf + len, "           :");
>>>  
>>> -	spin_lock(&devfreq->stats_lock);
>>> +	spin_lock(&profile->stats_lock);
>>>  	for (i = 0; i < max_state; i++)
>>>  		len += sprintf(buf + len, "%10lu",
>>> -				devfreq->profile->freq_table[i]);
>>> +				profile->freq_table[i]);
>>>  
>>>  	len += sprintf(buf + len, "   time(ms)\n");
>>>  
>>>  	for (i = 0; i < max_state; i++) {
>>> -		if (devfreq->profile->freq_table[i]
>>> -					== devfreq->previous_freq) {
>>> +		if (profile->freq_table[i] == devfreq->previous_freq)
>>>  			len += sprintf(buf + len, "*");
>>> -		} else {
>>> +		else
>>>  			len += sprintf(buf + len, " ");
>>> -		}
>>> +
>>>  		len += sprintf(buf + len, "%10lu:",
>>> -				devfreq->profile->freq_table[i]);
>>> +				profile->freq_table[i]);
>>>  		for (j = 0; j < max_state; j++)
>>>  			len += sprintf(buf + len, "%10u",
>>> -				devfreq->trans_table[(i * max_state) + j]);
>>> +				profile->trans_table[(i * max_state) + j]);
>>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>>> -			jiffies64_to_msecs(devfreq->time_in_state[i]));
>>> +			jiffies64_to_msecs(profile->time_in_state[i]));
>>>  	}
>>>  
>>>  	len += sprintf(buf + len, "Total transition : %u\n",
>>> -					devfreq->total_trans);
>>> -	spin_unlock(&devfreq->stats_lock);
>>> +					profile->total_trans);
>>> +	spin_unlock(&profile->stats_lock);
>>>  	return len;
>>>  }
>>>  static DEVICE_ATTR_RO(trans_stat);
>>>  
>>> -static void defvreq_stats_clear_table(struct devfreq *devfreq)
>>> +static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>  {
>>> -	unsigned int count = devfreq->profile->max_state;
>>> -
>>> -	spin_lock(&devfreq->stats_lock);
>>> -	memset(devfreq->time_in_state, 0, count * sizeof(u64));
>>> -	memset(devfreq->trans_table, 0, count * count * sizeof(int));
>>> -	devfreq->last_time = get_jiffies_64();
>>> -	devfreq->total_trans = 0;
>>> -	spin_unlock(&devfreq->stats_lock);
>>> +	unsigned int count = profile->max_state;
>>> +
>>> +	spin_lock(&profile->stats_lock);
>>> +	memset(profile->time_in_state, 0, count * sizeof(u64));
>>> +	memset(profile->trans_table, 0, count * count * sizeof(int));
>>> +	profile->last_time = get_jiffies_64();
>>> +	profile->total_trans = 0;
>>> +	spin_unlock(&profile->stats_lock);
>>>  }
>>>  
>>>  static ssize_t trans_reset_store(struct device *dev,
>>> @@ -1464,7 +1465,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>  {
>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>  
>>> -	defvreq_stats_clear_table(devfreq);
>>> +	defvreq_stats_clear_table(devfreq->profile);
>>>  
>>>  	return count;
>>>  }
>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>> index 2ddf25993f7d..4ceb2a517a9c 100644
>>> --- a/include/linux/devfreq.h
>>> +++ b/include/linux/devfreq.h
>>> @@ -91,6 +91,12 @@ struct devfreq_dev_status {
>>>   * @freq_table:		Optional list of frequencies to support statistics
>>>   *			and freq_table must be generated in ascending order.
>>>   * @max_state:		The size of freq_table.
>>> + * @total_trans:	Number of devfreq transitions
>>> + * @trans_table:	Statistics of devfreq transitions
>>> + * @time_in_state:	Statistics of devfreq states
>>> + * @last_time:		The last time stats were updated
>>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>>> + *			last_time and total_trans used for statistics
>>>   */
>>>  struct devfreq_dev_profile {
>>>  	unsigned long initial_freq;
>>> @@ -104,6 +110,12 @@ struct devfreq_dev_profile {
>>>  
>>>  	unsigned long *freq_table;
>>>  	unsigned int max_state;
>>> +	/* information for device frequency transition */
>>> +	unsigned int total_trans;
>>> +	unsigned int *trans_table;
>>> +	u64 *time_in_state;
>>> +	unsigned long long last_time;
>>> +	spinlock_t stats_lock;
>>>  };
>>>  
>>>  /**
>>> @@ -131,12 +143,6 @@ struct devfreq_dev_profile {
>>>   * @suspend_freq:	 frequency of a device set during suspend phase.
>>>   * @resume_freq:	 frequency of a device set in resume phase.
>>>   * @suspend_count:	 suspend requests counter for a device.
>>> - * @total_trans:	Number of devfreq transitions
>>> - * @trans_table:	Statistics of devfreq transitions
>>> - * @time_in_state:	Statistics of devfreq states
>>> - * @last_time:		The last time stats were updated
>>> - * @stats_lock:		Lock protecting trans_table, time_in_state, last_time
>>> - *			and total_trans used for statistics
>>>   * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
>>>   *
>>>   * This structure stores the devfreq information for a give device.
>>> @@ -173,13 +179,6 @@ struct devfreq {
>>>  	unsigned long resume_freq;
>>>  	atomic_t suspend_count;
>>>  
>>> -	/* information for device frequency transition */
>>> -	unsigned int total_trans;
>>> -	unsigned int *trans_table;
>>> -	u64 *time_in_state;
>>> -	unsigned long long last_time;
>>> -	spinlock_t stats_lock;
>>> -
>>>  	struct srcu_notifier_head transition_notifier_list;
>>>  };
>>>  
>>>
> 
> 
> 

Re: [PATCH 5/7] devfreq: move transition statistics to devfreq profile structure

[Kamil Konieczny]

On 14.11.2019 03:02, Chanwoo Choi wrote:
> Hi Kamil,
> 
> The devfreq_dev_profile structure have to only contain the each devfreq device
> callback function/data which are used in the devfreq core.
> 
> The generated information after registered the devfreq device
> with devfreq_add_device() should be stored in the 'struct device'.
> 
> The devfreq core need to split out the data between user input
> data (struct devfreq_dev_profile) and the initialized/generated data
> by core (struct devfreq). It is not same with cpufreq. cpufreq
> don't require the any structure like 'devfreq_dev_profile'.
> 
> So, I can't agree.

What about putting stats structure inside devfreq ?

> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>> Move transition statistics to devfreq profile structure. This is for
>> preparation for moving transition statistics into separate struct.
>> It is safe to do as frequency table and maximum state information are
>> already present in devfreq profile structure and there are no devfreq
>> drivers using more than one instance of devfreq structure per devfreq
>> profile one.
>>
>> It also makes devfreq code more similar to cpufreq one.
>>
>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>> ---
>>  drivers/devfreq/devfreq.c | 115 +++++++++++++++++++-------------------
>>  include/linux/devfreq.h   |  25 ++++-----
>>  2 files changed, 70 insertions(+), 70 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 6e5a17f4c92c..70533b787744 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -128,7 +128,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>  
>>  	profile->max_state = count;
>>  	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>> -					profile->max_state,
>> +					count,
>>  					sizeof(*profile->freq_table),
>>  					GFP_KERNEL);
>>  	if (!profile->freq_table) {
>> @@ -157,29 +157,30 @@ static int set_freq_table(struct devfreq *devfreq)
>>   */
>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  {
>> -	int lev, prev_lev, ret = 0;
>> +	struct devfreq_dev_profile *profile = devfreq->profile;
>>  	unsigned long long cur_time;
>> +	int lev, prev_lev, ret = 0;
>>  
>>  	cur_time = get_jiffies_64();
>>  
>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>  	if (!devfreq->previous_freq) {
>> -		spin_lock(&devfreq->stats_lock);
>> -		devfreq->last_time = cur_time;
>> -		spin_unlock(&devfreq->stats_lock);
>> +		spin_lock(&profile->stats_lock);
>> +		profile->last_time = cur_time;
>> +		spin_unlock(&profile->stats_lock);
>>  		return 0;
>>  	}
>>  
>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>  
>> -	spin_lock(&devfreq->stats_lock);
>> +	spin_lock(&profile->stats_lock);
>>  	if (prev_lev < 0) {
>>  		ret = prev_lev;
>>  		goto out;
>>  	}
>>  
>> -	devfreq->time_in_state[prev_lev] +=
>> -			 cur_time - devfreq->last_time;
>> +	profile->time_in_state[prev_lev] +=
>> +			 cur_time - profile->last_time;
>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>  	if (lev < 0) {
>>  		ret = lev;
>> @@ -187,14 +188,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  	}
>>  
>>  	if (lev != prev_lev) {
>> -		devfreq->trans_table[(prev_lev *
>> -				devfreq->profile->max_state) + lev]++;
>> -		devfreq->total_trans++;
>> +		profile->trans_table[(prev_lev *
>> +				profile->max_state) + lev]++;
>> +		profile->total_trans++;
>>  	}
>>  
>>  out:
>> -	devfreq->last_time = cur_time;
>> -	spin_unlock(&devfreq->stats_lock);
>> +	profile->last_time = cur_time;
>> +	spin_unlock(&profile->stats_lock);
>>  	return ret;
>>  }
>>  EXPORT_SYMBOL(devfreq_update_status);
>> @@ -474,23 +475,23 @@ EXPORT_SYMBOL(devfreq_monitor_suspend);
>>  void devfreq_monitor_resume(struct devfreq *devfreq)
>>  {
>>  	unsigned long freq;
>> +	struct devfreq_dev_profile *profile = devfreq->profile;
>>  
>>  	mutex_lock(&devfreq->lock);
>>  	if (!devfreq->stop_polling)
>>  		goto out;
>>  
>> -	if (!delayed_work_pending(&devfreq->work) &&
>> -			devfreq->profile->polling_ms)
>> +	if (!delayed_work_pending(&devfreq->work) && profile->polling_ms)
>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>> -			msecs_to_jiffies(devfreq->profile->polling_ms));
>> +			msecs_to_jiffies(profile->polling_ms));
>>  
>> -	spin_lock(&devfreq->stats_lock);
>> -	devfreq->last_time = get_jiffies_64();
>> -	spin_unlock(&devfreq->stats_lock);
>> +	spin_lock(&profile->stats_lock);
>> +	profile->last_time = get_jiffies_64();
>> +	spin_unlock(&profile->stats_lock);
>>  	devfreq->stop_polling = false;
>>  
>> -	if (devfreq->profile->get_cur_freq &&
>> -		!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
>> +	if (profile->get_cur_freq &&
>> +	    !profile->get_cur_freq(devfreq->dev.parent, &freq))
>>  		devfreq->previous_freq = freq;
>>  
>>  out:
>> @@ -657,7 +658,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>  	devfreq->data = data;
>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>  
>> -	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
>> +	if (!profile->max_state && !profile->freq_table) {
>>  		mutex_unlock(&devfreq->lock);
>>  		err = set_freq_table(devfreq);
>>  		if (err < 0)
>> @@ -693,29 +694,29 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>  		goto err_out;
>>  	}
>>  
>> -	devfreq->trans_table = devm_kzalloc(&devfreq->dev,
>> -			array3_size(sizeof(unsigned int),
>> -				    devfreq->profile->max_state,
>> -				    devfreq->profile->max_state),
>> -			GFP_KERNEL);
>> -	if (!devfreq->trans_table) {
>> +	profile->trans_table = devm_kzalloc(&devfreq->dev,
>> +					    array3_size(sizeof(unsigned int),
>> +							profile->max_state,
>> +							profile->max_state),
>> +					    GFP_KERNEL);
>> +	if (!profile->trans_table) {
>>  		mutex_unlock(&devfreq->lock);
>>  		err = -ENOMEM;
>>  		goto err_devfreq;
>>  	}
>>  
>> -	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
>> -			devfreq->profile->max_state,
>> -			sizeof(*devfreq->time_in_state),
>> -			GFP_KERNEL);
>> -	if (!devfreq->time_in_state) {
>> +	profile->time_in_state = devm_kcalloc(&devfreq->dev,
>> +					      profile->max_state,
>> +					      sizeof(*profile->time_in_state),
>> +					      GFP_KERNEL);
>> +	if (!profile->time_in_state) {
>>  		mutex_unlock(&devfreq->lock);
>>  		err = -ENOMEM;
>>  		goto err_devfreq;
>>  	}
>>  
>> -	devfreq->last_time = get_jiffies_64();
>> -	spin_lock_init(&devfreq->stats_lock);
>> +	profile->last_time = get_jiffies_64();
>> +	spin_lock_init(&profile->stats_lock);
>>  
>>  	srcu_init_notifier_head(&devfreq->transition_notifier_list);
>>  
>> @@ -1402,9 +1403,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>  			       struct device_attribute *attr, char *buf)
>>  {
>>  	struct devfreq *devfreq = to_devfreq(dev);
>> +	struct devfreq_dev_profile *profile = devfreq->profile;
>>  	ssize_t len;
>>  	int i, j;
>> -	unsigned int max_state = devfreq->profile->max_state;
>> +	unsigned int max_state = profile->max_state;
>>  
>>  	if (!devfreq->stop_polling &&
>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>> @@ -1415,46 +1417,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>  	len = sprintf(buf, "     From  :   To\n");
>>  	len += sprintf(buf + len, "           :");
>>  
>> -	spin_lock(&devfreq->stats_lock);
>> +	spin_lock(&profile->stats_lock);
>>  	for (i = 0; i < max_state; i++)
>>  		len += sprintf(buf + len, "%10lu",
>> -				devfreq->profile->freq_table[i]);
>> +				profile->freq_table[i]);
>>  
>>  	len += sprintf(buf + len, "   time(ms)\n");
>>  
>>  	for (i = 0; i < max_state; i++) {
>> -		if (devfreq->profile->freq_table[i]
>> -					== devfreq->previous_freq) {
>> +		if (profile->freq_table[i] == devfreq->previous_freq)
>>  			len += sprintf(buf + len, "*");
>> -		} else {
>> +		else
>>  			len += sprintf(buf + len, " ");
>> -		}
>> +
>>  		len += sprintf(buf + len, "%10lu:",
>> -				devfreq->profile->freq_table[i]);
>> +				profile->freq_table[i]);
>>  		for (j = 0; j < max_state; j++)
>>  			len += sprintf(buf + len, "%10u",
>> -				devfreq->trans_table[(i * max_state) + j]);
>> +				profile->trans_table[(i * max_state) + j]);
>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>> -			jiffies64_to_msecs(devfreq->time_in_state[i]));
>> +			jiffies64_to_msecs(profile->time_in_state[i]));
>>  	}
>>  
>>  	len += sprintf(buf + len, "Total transition : %u\n",
>> -					devfreq->total_trans);
>> -	spin_unlock(&devfreq->stats_lock);
>> +					profile->total_trans);
>> +	spin_unlock(&profile->stats_lock);
>>  	return len;
>>  }
>>  static DEVICE_ATTR_RO(trans_stat);
>>  
>> -static void defvreq_stats_clear_table(struct devfreq *devfreq)
>> +static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>  {
>> -	unsigned int count = devfreq->profile->max_state;
>> -
>> -	spin_lock(&devfreq->stats_lock);
>> -	memset(devfreq->time_in_state, 0, count * sizeof(u64));
>> -	memset(devfreq->trans_table, 0, count * count * sizeof(int));
>> -	devfreq->last_time = get_jiffies_64();
>> -	devfreq->total_trans = 0;
>> -	spin_unlock(&devfreq->stats_lock);
>> +	unsigned int count = profile->max_state;
>> +
>> +	spin_lock(&profile->stats_lock);
>> +	memset(profile->time_in_state, 0, count * sizeof(u64));
>> +	memset(profile->trans_table, 0, count * count * sizeof(int));
>> +	profile->last_time = get_jiffies_64();
>> +	profile->total_trans = 0;
>> +	spin_unlock(&profile->stats_lock);
>>  }
>>  
>>  static ssize_t trans_reset_store(struct device *dev,
>> @@ -1464,7 +1465,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>  {
>>  	struct devfreq *devfreq = to_devfreq(dev);
>>  
>> -	defvreq_stats_clear_table(devfreq);
>> +	defvreq_stats_clear_table(devfreq->profile);
>>  
>>  	return count;
>>  }
>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>> index 2ddf25993f7d..4ceb2a517a9c 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -91,6 +91,12 @@ struct devfreq_dev_status {
>>   * @freq_table:		Optional list of frequencies to support statistics
>>   *			and freq_table must be generated in ascending order.
>>   * @max_state:		The size of freq_table.
>> + * @total_trans:	Number of devfreq transitions
>> + * @trans_table:	Statistics of devfreq transitions
>> + * @time_in_state:	Statistics of devfreq states
>> + * @last_time:		The last time stats were updated
>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>> + *			last_time and total_trans used for statistics
>>   */
>>  struct devfreq_dev_profile {
>>  	unsigned long initial_freq;
>> @@ -104,6 +110,12 @@ struct devfreq_dev_profile {
>>  
>>  	unsigned long *freq_table;
>>  	unsigned int max_state;
>> +	/* information for device frequency transition */
>> +	unsigned int total_trans;
>> +	unsigned int *trans_table;
>> +	u64 *time_in_state;
>> +	unsigned long long last_time;
>> +	spinlock_t stats_lock;
>>  };
>>  
>>  /**
>> @@ -131,12 +143,6 @@ struct devfreq_dev_profile {
>>   * @suspend_freq:	 frequency of a device set during suspend phase.
>>   * @resume_freq:	 frequency of a device set in resume phase.
>>   * @suspend_count:	 suspend requests counter for a device.
>> - * @total_trans:	Number of devfreq transitions
>> - * @trans_table:	Statistics of devfreq transitions
>> - * @time_in_state:	Statistics of devfreq states
>> - * @last_time:		The last time stats were updated
>> - * @stats_lock:		Lock protecting trans_table, time_in_state, last_time
>> - *			and total_trans used for statistics
>>   * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
>>   *
>>   * This structure stores the devfreq information for a give device.
>> @@ -173,13 +179,6 @@ struct devfreq {
>>  	unsigned long resume_freq;
>>  	atomic_t suspend_count;
>>  
>> -	/* information for device frequency transition */
>> -	unsigned int total_trans;
>> -	unsigned int *trans_table;
>> -	u64 *time_in_state;
>> -	unsigned long long last_time;
>> -	spinlock_t stats_lock;
>> -
>>  	struct srcu_notifier_head transition_notifier_list;
>>  };
>>  
>>
> 
> 

-- 
Best regards,
Kamil Konieczny
Samsung R&D Institute Poland

[PATCH 6/7] devfreq: move transition statistics allocations to set_freq_stats()

[Kamil Konieczny]

All users of [devm_]devfreq_add_device() don't set freq_table
nor max_state, and there is only one "struct devfreq_profile" per
every "struct devfreq", so move transition memory allocations to
function set_freq_stats() and initialize there other statistics fields.

Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
---
 drivers/devfreq/devfreq.c | 44 +++++++++++++++++----------------------
 1 file changed, 19 insertions(+), 25 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 70533b787744..d79412b0de59 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -147,7 +147,26 @@ static int set_freq_table(struct devfreq *devfreq)
 		profile->freq_table[i] = freq;
 	}
 
+	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
+					    array3_size(sizeof(unsigned int),
+							count, count),
+					    GFP_KERNEL);
+	if (!profile->trans_table)
+		goto err_no_mem;
+
+	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
+					      sizeof(*profile->time_in_state),
+					      GFP_KERNEL);
+	if (!profile->time_in_state)
+		goto err_no_mem;
+
+	profile->last_time = get_jiffies_64();
+	spin_lock_init(&profile->stats_lock);
+
 	return 0;
+err_no_mem:
+	profile->max_state = 0;
+	return -ENOMEM;
 }
 
 /**
@@ -694,30 +713,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_out;
 	}
 
-	profile->trans_table = devm_kzalloc(&devfreq->dev,
-					    array3_size(sizeof(unsigned int),
-							profile->max_state,
-							profile->max_state),
-					    GFP_KERNEL);
-	if (!profile->trans_table) {
-		mutex_unlock(&devfreq->lock);
-		err = -ENOMEM;
-		goto err_devfreq;
-	}
-
-	profile->time_in_state = devm_kcalloc(&devfreq->dev,
-					      profile->max_state,
-					      sizeof(*profile->time_in_state),
-					      GFP_KERNEL);
-	if (!profile->time_in_state) {
-		mutex_unlock(&devfreq->lock);
-		err = -ENOMEM;
-		goto err_devfreq;
-	}
-
-	profile->last_time = get_jiffies_64();
-	spin_lock_init(&profile->stats_lock);
-
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
 	mutex_unlock(&devfreq->lock);
@@ -749,7 +744,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
 
 err_init:
 	mutex_unlock(&devfreq_list_lock);
-err_devfreq:
 	devfreq_remove_device(devfreq);
 	devfreq = NULL;
 err_dev:
-- 
2.24.0

[PATCH 7/7] devfreq: move statistics to separate struct

[Kamil Konieczny]

Count time and transitions between devfreq frequencies in separate struct
for improved code readability and maintenance.

Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
---
 drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
 drivers/devfreq/exynos-bus.c       |   6 +-
 drivers/devfreq/governor_passive.c |  26 +++--
 include/linux/devfreq.h            |  43 ++++----
 4 files changed, 129 insertions(+), 102 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index d79412b0de59..d85867a91230 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
  */
 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 {
+	struct devfreq_stats *stats = devfreq->profile->stats;
 	int lev;
 
-	for (lev = 0; lev < devfreq->profile->max_state; lev++)
-		if (freq == devfreq->profile->freq_table[lev])
+	for (lev = 0; lev < stats->max_state; lev++)
+		if (freq == stats->freq_table[lev])
 			return lev;
 
 	return -EINVAL;
@@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 static int set_freq_table(struct devfreq *devfreq)
 {
 	struct devfreq_dev_profile *profile = devfreq->profile;
+	struct devfreq_stats *stats;
 	struct dev_pm_opp *opp;
 	unsigned long freq;
-	int i, count;
+	int i, count, err = -ENOMEM;
 
 	/* Initialize the freq_table from OPP table */
 	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 	if (count <= 0)
 		return -EINVAL;
 
-	profile->max_state = count;
-	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
-					count,
-					sizeof(*profile->freq_table),
-					GFP_KERNEL);
-	if (!profile->freq_table) {
-		profile->max_state = 0;
+	stats = devm_kzalloc(devfreq->dev.parent,
+			     sizeof(struct devfreq_stats), GFP_KERNEL);
+	if (!stats)
 		return -ENOMEM;
-	}
 
-	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
+	profile->stats = stats;
+	stats->max_state = count;
+	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
+					 count,
+					 sizeof(*stats->freq_table),
+					 GFP_KERNEL);
+	if (!stats->freq_table)
+		goto err_no_mem;
+
+	for (i = 0, freq = 0; i < count; i++, freq++) {
 		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 		if (IS_ERR(opp)) {
-			devm_kfree(devfreq->dev.parent, profile->freq_table);
-			profile->max_state = 0;
-			return PTR_ERR(opp);
+			devm_kfree(devfreq->dev.parent, stats->freq_table);
+			stats->max_state = 0;
+			err = PTR_ERR(opp);
+			goto err_no_mem;
 		}
 		dev_pm_opp_put(opp);
-		profile->freq_table[i] = freq;
+		stats->freq_table[i] = freq;
 	}
 
-	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
-					    array3_size(sizeof(unsigned int),
-							count, count),
-					    GFP_KERNEL);
-	if (!profile->trans_table)
+	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
+					  array3_size(sizeof(unsigned int),
+						      count, count),
+					  GFP_KERNEL);
+	if (!stats->trans_table)
 		goto err_no_mem;
 
-	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
-					      sizeof(*profile->time_in_state),
-					      GFP_KERNEL);
-	if (!profile->time_in_state)
+	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
+					    sizeof(*stats->time_in_state),
+					    GFP_KERNEL);
+	if (!stats->time_in_state)
 		goto err_no_mem;
 
-	profile->last_time = get_jiffies_64();
-	spin_lock_init(&profile->stats_lock);
+	stats->last_time = get_jiffies_64();
+	spin_lock_init(&stats->stats_lock);
 
 	return 0;
 err_no_mem:
-	profile->max_state = 0;
-	return -ENOMEM;
+	stats->max_state = 0;
+	devm_kfree(devfreq->dev.parent, profile->stats);
+	profile->stats = NULL;
+	return err;
 }
 
 /**
@@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
  */
 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 {
-	struct devfreq_dev_profile *profile = devfreq->profile;
+	struct devfreq_stats *stats = devfreq->profile->stats;
 	unsigned long long cur_time;
 	int lev, prev_lev, ret = 0;
 
@@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 
 	/* Immediately exit if previous_freq is not initialized yet. */
 	if (!devfreq->previous_freq) {
-		spin_lock(&profile->stats_lock);
-		profile->last_time = cur_time;
-		spin_unlock(&profile->stats_lock);
+		spin_lock(&stats->stats_lock);
+		stats->last_time = cur_time;
+		spin_unlock(&stats->stats_lock);
 		return 0;
 	}
 
 	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 
-	spin_lock(&profile->stats_lock);
+	spin_lock(&stats->stats_lock);
 	if (prev_lev < 0) {
 		ret = prev_lev;
 		goto out;
 	}
 
-	profile->time_in_state[prev_lev] +=
-			 cur_time - profile->last_time;
+	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
 	lev = devfreq_get_freq_level(devfreq, freq);
 	if (lev < 0) {
 		ret = lev;
@@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 	}
 
 	if (lev != prev_lev) {
-		profile->trans_table[(prev_lev *
-				profile->max_state) + lev]++;
-		profile->total_trans++;
+		stats->trans_table[(prev_lev *
+				stats->max_state) + lev]++;
+		stats->total_trans++;
 	}
 
 out:
-	profile->last_time = cur_time;
-	spin_unlock(&profile->stats_lock);
+	stats->last_time = cur_time;
+	spin_unlock(&stats->stats_lock);
 	return ret;
 }
 EXPORT_SYMBOL(devfreq_update_status);
@@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
 		queue_delayed_work(devfreq_wq, &devfreq->work,
 			msecs_to_jiffies(profile->polling_ms));
 
-	spin_lock(&profile->stats_lock);
-	profile->last_time = get_jiffies_64();
-	spin_unlock(&profile->stats_lock);
+	spin_lock(&profile->stats->stats_lock);
+	profile->stats->last_time = get_jiffies_64();
+	spin_unlock(&profile->stats->stats_lock);
 	devfreq->stop_polling = false;
 
 	if (profile->get_cur_freq &&
@@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	devfreq->data = data;
 	devfreq->nb.notifier_call = devfreq_notifier_call;
 
-	if (!profile->max_state && !profile->freq_table) {
+	if (!profile->stats) {
 		mutex_unlock(&devfreq->lock);
 		err = set_freq_table(devfreq);
 		if (err < 0)
@@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
 	struct devfreq *df = to_devfreq(dev);
+	struct devfreq_stats *stats = df->profile->stats;
 	unsigned long value;
 	int ret;
 
@@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
 			goto unlock;
 		}
 	} else {
-		unsigned long *freq_table = df->profile->freq_table;
+		unsigned long *freq_table = stats->freq_table;
 
 		/* Get minimum frequency according to sorting order */
-		if (freq_table[0] < freq_table[df->profile->max_state - 1])
+		if (freq_table[0] < freq_table[stats->max_state - 1])
 			value = freq_table[0];
 		else
-			value = freq_table[df->profile->max_state - 1];
+			value = freq_table[stats->max_state - 1];
 	}
 
 	df->min_freq = value;
@@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
 	struct devfreq *df = to_devfreq(dev);
+	struct devfreq_stats *stats = df->profile->stats;
 	unsigned long value;
 	int ret;
 
@@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
 			goto unlock;
 		}
 	} else {
-		unsigned long *freq_table = df->profile->freq_table;
+		unsigned long *freq_table = stats->freq_table;
 
 		/* Get maximum frequency according to sorting order */
-		if (freq_table[0] < freq_table[df->profile->max_state - 1])
-			value = freq_table[df->profile->max_state - 1];
+		if (freq_table[0] < freq_table[stats->max_state - 1])
+			value = freq_table[stats->max_state - 1];
 		else
 			value = freq_table[0];
 	}
@@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
 					  char *buf)
 {
 	struct devfreq *df = to_devfreq(d);
+	struct devfreq_stats *stats = df->profile->stats;
 	ssize_t count = 0;
 	int i;
 
 	mutex_lock(&df->lock);
 
-	for (i = 0; i < df->profile->max_state; i++)
+	for (i = 0; i < stats->max_state; i++)
 		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
-				"%lu ", df->profile->freq_table[i]);
+				"%lu ", stats->freq_table[i]);
 
 	mutex_unlock(&df->lock);
 	/* Truncate the trailing space */
@@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
 {
 	struct devfreq *devfreq = to_devfreq(dev);
 	struct devfreq_dev_profile *profile = devfreq->profile;
+	struct devfreq_stats *stats = profile->stats;
+	unsigned int max_state = stats->max_state;
 	ssize_t len;
 	int i, j;
-	unsigned int max_state = profile->max_state;
 
 	if (!devfreq->stop_polling &&
 			devfreq_update_status(devfreq, devfreq->previous_freq))
@@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
 	len = sprintf(buf, "     From  :   To\n");
 	len += sprintf(buf + len, "           :");
 
-	spin_lock(&profile->stats_lock);
+	spin_lock(&stats->stats_lock);
 	for (i = 0; i < max_state; i++)
 		len += sprintf(buf + len, "%10lu",
-				profile->freq_table[i]);
+				stats->freq_table[i]);
 
 	len += sprintf(buf + len, "   time(ms)\n");
 
 	for (i = 0; i < max_state; i++) {
-		if (profile->freq_table[i] == devfreq->previous_freq)
+		if (stats->freq_table[i] == devfreq->previous_freq)
 			len += sprintf(buf + len, "*");
 		else
 			len += sprintf(buf + len, " ");
 
 		len += sprintf(buf + len, "%10lu:",
-				profile->freq_table[i]);
+				stats->freq_table[i]);
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
-				profile->trans_table[(i * max_state) + j]);
+				stats->trans_table[(i * max_state) + j]);
 		len += sprintf(buf + len, "%10llu\n", (u64)
-			jiffies64_to_msecs(profile->time_in_state[i]));
+			jiffies64_to_msecs(stats->time_in_state[i]));
 	}
 
 	len += sprintf(buf + len, "Total transition : %u\n",
-					profile->total_trans);
-	spin_unlock(&profile->stats_lock);
+					stats->total_trans);
+	spin_unlock(&stats->stats_lock);
 	return len;
 }
 static DEVICE_ATTR_RO(trans_stat);
 
-static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
+static void defvreq_stats_clear_table(struct devfreq_stats *stats)
 {
-	unsigned int count = profile->max_state;
-
-	spin_lock(&profile->stats_lock);
-	memset(profile->time_in_state, 0, count * sizeof(u64));
-	memset(profile->trans_table, 0, count * count * sizeof(int));
-	profile->last_time = get_jiffies_64();
-	profile->total_trans = 0;
-	spin_unlock(&profile->stats_lock);
+	unsigned int count = stats->max_state;
+
+	spin_lock(&stats->stats_lock);
+	memset(stats->time_in_state, 0, count * sizeof(u64));
+	memset(stats->trans_table, 0, count * count * sizeof(int));
+	stats->last_time = get_jiffies_64();
+	stats->total_trans = 0;
+	spin_unlock(&stats->stats_lock);
 }
 
 static ssize_t trans_reset_store(struct device *dev,
@@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
 {
 	struct devfreq *devfreq = to_devfreq(dev);
 
-	defvreq_stats_clear_table(devfreq->profile);
+	defvreq_stats_clear_table(devfreq->profile->stats);
 
 	return count;
 }
diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
index d9f377912c10..b212aae2bb3e 100644
--- a/drivers/devfreq/exynos-bus.c
+++ b/drivers/devfreq/exynos-bus.c
@@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
 	}
 
 out:
-	max_state = bus->devfreq->profile->max_state;
-	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
-	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
+	max_state = profile->stats->max_state;
+	min_freq = (profile->stats->freq_table[0] / 1000);
+	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
 	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
 			dev_name(dev), min_freq, max_freq);
 
diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
index 58308948b863..b2d87a88335c 100644
--- a/drivers/devfreq/governor_passive.c
+++ b/drivers/devfreq/governor_passive.c
@@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
 	struct devfreq_passive_data *p_data
 			= (struct devfreq_passive_data *)devfreq->data;
 	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
+	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
+	struct devfreq_stats *stats;
 	unsigned long child_freq = ULONG_MAX;
 	struct dev_pm_opp *opp;
 	int i, count, ret = 0;
@@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
 	 * device. And then the index is used for getting the suitable
 	 * new frequency for passive devfreq device.
 	 */
-	if (!devfreq->profile || !devfreq->profile->freq_table
-		|| devfreq->profile->max_state <= 0)
+	if (!devfreq->profile || !devfreq->profile->stats ||
+	    devfreq->profile->stats->max_state <= 0 ||
+	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
+	    parent_devfreq->profile->stats->max_state <= 0)
 		return -EINVAL;
 
+	stats = devfreq->profile->stats;
+	parent_stats = parent_devfreq->profile->stats;
 	/*
 	 * The passive governor have to get the correct frequency from OPP
 	 * list of parent device. Because in this case, *freq is temporary
@@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
 	 * Get the OPP table's index of decided freqeuncy by governor
 	 * of parent device.
 	 */
-	for (i = 0; i < parent_devfreq->profile->max_state; i++)
-		if (parent_devfreq->profile->freq_table[i] == *freq)
+	for (i = 0; i < parent_stats->max_state; i++)
+		if (parent_stats->freq_table[i] == *freq)
 			break;
 
-	if (i == parent_devfreq->profile->max_state) {
+	if (i == parent_stats->max_state) {
 		ret = -EINVAL;
 		goto out;
 	}
 
 	/* Get the suitable frequency by using index of parent device. */
-	if (i < devfreq->profile->max_state) {
-		child_freq = devfreq->profile->freq_table[i];
+	if (i < stats->max_state) {
+		child_freq = stats->freq_table[i];
 	} else {
-		count = devfreq->profile->max_state;
-		child_freq = devfreq->profile->freq_table[count - 1];
+		count = stats->max_state;
+		child_freq = stats->freq_table[count - 1];
 	}
 
 	/* Return the suitable frequency for passive device. */
@@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
 	if (ret < 0)
 		goto out;
 
-	if (devfreq->profile->freq_table
+	if (devfreq->profile->stats
 		&& (devfreq_update_status(devfreq, freq)))
 		dev_err(&devfreq->dev,
 			"Couldn't update frequency transition information.\n");
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 4ceb2a517a9c..8459af1a1583 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -64,6 +64,30 @@ struct devfreq_dev_status {
  */
 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
 
+/**
+ * struct devfreq_stats - Devfreq's transitions stats counters
+ * @freq_table:		Optional list of frequencies to support statistics
+ *			and freq_table must be generated in ascending order.
+ * @max_state:		The size of freq_table.
+ * @total_trans:	Number of devfreq transitions
+ * @trans_table:	Statistics of devfreq transitions
+ * @time_in_state:	Statistics of devfreq states
+ * @last_time:		The last time stats were updated
+ * @stats_lock:		Lock protecting trans_table, time_in_state,
+ *			last_time and total_trans used for statistics
+ */
+struct devfreq_stats {
+	unsigned long *freq_table;
+	unsigned int max_state;
+
+	/* information for device frequency transition */
+	unsigned int total_trans;
+	unsigned int *trans_table;
+	u64 *time_in_state;
+	unsigned long long last_time;
+	spinlock_t stats_lock;
+};
+
 /**
  * struct devfreq_dev_profile - Devfreq's user device profile
  * @initial_freq:	The operating frequency when devfreq_add_device() is
@@ -88,15 +112,7 @@ struct devfreq_dev_status {
  *			from devfreq_remove_device() call. If the user
  *			has registered devfreq->nb at a notifier-head,
  *			this is the time to unregister it.
- * @freq_table:		Optional list of frequencies to support statistics
- *			and freq_table must be generated in ascending order.
- * @max_state:		The size of freq_table.
- * @total_trans:	Number of devfreq transitions
- * @trans_table:	Statistics of devfreq transitions
- * @time_in_state:	Statistics of devfreq states
- * @last_time:		The last time stats were updated
- * @stats_lock:		Lock protecting trans_table, time_in_state,
- *			last_time and total_trans used for statistics
+ * @stats:		Statistics of devfreq states and state transitions
  */
 struct devfreq_dev_profile {
 	unsigned long initial_freq;
@@ -108,14 +124,7 @@ struct devfreq_dev_profile {
 	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
 	void (*exit)(struct device *dev);
 
-	unsigned long *freq_table;
-	unsigned int max_state;
-	/* information for device frequency transition */
-	unsigned int total_trans;
-	unsigned int *trans_table;
-	u64 *time_in_state;
-	unsigned long long last_time;
-	spinlock_t stats_lock;
+	struct devfreq_stats *stats;
 };
 
 /**
-- 
2.24.0

[PATCH 7/7] devfreq: move statistics to separate struct

[Kamil Konieczny]

Count time and transitions between devfreq frequencies in separate struct
for improved code readability and maintenance.

Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
---
 drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
 drivers/devfreq/exynos-bus.c       |   6 +-
 drivers/devfreq/governor_passive.c |  26 +++--
 include/linux/devfreq.h            |  43 ++++----
 4 files changed, 129 insertions(+), 102 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index d79412b0de59..d85867a91230 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
  */
 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 {
+	struct devfreq_stats *stats = devfreq->profile->stats;
 	int lev;
 
-	for (lev = 0; lev < devfreq->profile->max_state; lev++)
-		if (freq == devfreq->profile->freq_table[lev])
+	for (lev = 0; lev < stats->max_state; lev++)
+		if (freq == stats->freq_table[lev])
 			return lev;
 
 	return -EINVAL;
@@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 static int set_freq_table(struct devfreq *devfreq)
 {
 	struct devfreq_dev_profile *profile = devfreq->profile;
+	struct devfreq_stats *stats;
 	struct dev_pm_opp *opp;
 	unsigned long freq;
-	int i, count;
+	int i, count, err = -ENOMEM;
 
 	/* Initialize the freq_table from OPP table */
 	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 	if (count <= 0)
 		return -EINVAL;
 
-	profile->max_state = count;
-	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
-					count,
-					sizeof(*profile->freq_table),
-					GFP_KERNEL);
-	if (!profile->freq_table) {
-		profile->max_state = 0;
+	stats = devm_kzalloc(devfreq->dev.parent,
+			     sizeof(struct devfreq_stats), GFP_KERNEL);
+	if (!stats)
 		return -ENOMEM;
-	}
 
-	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
+	profile->stats = stats;
+	stats->max_state = count;
+	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
+					 count,
+					 sizeof(*stats->freq_table),
+					 GFP_KERNEL);
+	if (!stats->freq_table)
+		goto err_no_mem;
+
+	for (i = 0, freq = 0; i < count; i++, freq++) {
 		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 		if (IS_ERR(opp)) {
-			devm_kfree(devfreq->dev.parent, profile->freq_table);
-			profile->max_state = 0;
-			return PTR_ERR(opp);
+			devm_kfree(devfreq->dev.parent, stats->freq_table);
+			stats->max_state = 0;
+			err = PTR_ERR(opp);
+			goto err_no_mem;
 		}
 		dev_pm_opp_put(opp);
-		profile->freq_table[i] = freq;
+		stats->freq_table[i] = freq;
 	}
 
-	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
-					    array3_size(sizeof(unsigned int),
-							count, count),
-					    GFP_KERNEL);
-	if (!profile->trans_table)
+	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
+					  array3_size(sizeof(unsigned int),
+						      count, count),
+					  GFP_KERNEL);
+	if (!stats->trans_table)
 		goto err_no_mem;
 
-	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
-					      sizeof(*profile->time_in_state),
-					      GFP_KERNEL);
-	if (!profile->time_in_state)
+	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
+					    sizeof(*stats->time_in_state),
+					    GFP_KERNEL);
+	if (!stats->time_in_state)
 		goto err_no_mem;
 
-	profile->last_time = get_jiffies_64();
-	spin_lock_init(&profile->stats_lock);
+	stats->last_time = get_jiffies_64();
+	spin_lock_init(&stats->stats_lock);
 
 	return 0;
 err_no_mem:
-	profile->max_state = 0;
-	return -ENOMEM;
+	stats->max_state = 0;
+	devm_kfree(devfreq->dev.parent, profile->stats);
+	profile->stats = NULL;
+	return err;
 }
 
 /**
@@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
  */
 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 {
-	struct devfreq_dev_profile *profile = devfreq->profile;
+	struct devfreq_stats *stats = devfreq->profile->stats;
 	unsigned long long cur_time;
 	int lev, prev_lev, ret = 0;
 
@@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 
 	/* Immediately exit if previous_freq is not initialized yet. */
 	if (!devfreq->previous_freq) {
-		spin_lock(&profile->stats_lock);
-		profile->last_time = cur_time;
-		spin_unlock(&profile->stats_lock);
+		spin_lock(&stats->stats_lock);
+		stats->last_time = cur_time;
+		spin_unlock(&stats->stats_lock);
 		return 0;
 	}
 
 	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 
-	spin_lock(&profile->stats_lock);
+	spin_lock(&stats->stats_lock);
 	if (prev_lev < 0) {
 		ret = prev_lev;
 		goto out;
 	}
 
-	profile->time_in_state[prev_lev] +=
-			 cur_time - profile->last_time;
+	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
 	lev = devfreq_get_freq_level(devfreq, freq);
 	if (lev < 0) {
 		ret = lev;
@@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 	}
 
 	if (lev != prev_lev) {
-		profile->trans_table[(prev_lev *
-				profile->max_state) + lev]++;
-		profile->total_trans++;
+		stats->trans_table[(prev_lev *
+				stats->max_state) + lev]++;
+		stats->total_trans++;
 	}
 
 out:
-	profile->last_time = cur_time;
-	spin_unlock(&profile->stats_lock);
+	stats->last_time = cur_time;
+	spin_unlock(&stats->stats_lock);
 	return ret;
 }
 EXPORT_SYMBOL(devfreq_update_status);
@@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
 		queue_delayed_work(devfreq_wq, &devfreq->work,
 			msecs_to_jiffies(profile->polling_ms));
 
-	spin_lock(&profile->stats_lock);
-	profile->last_time = get_jiffies_64();
-	spin_unlock(&profile->stats_lock);
+	spin_lock(&profile->stats->stats_lock);
+	profile->stats->last_time = get_jiffies_64();
+	spin_unlock(&profile->stats->stats_lock);
 	devfreq->stop_polling = false;
 
 	if (profile->get_cur_freq &&
@@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	devfreq->data = data;
 	devfreq->nb.notifier_call = devfreq_notifier_call;
 
-	if (!profile->max_state && !profile->freq_table) {
+	if (!profile->stats) {
 		mutex_unlock(&devfreq->lock);
 		err = set_freq_table(devfreq);
 		if (err < 0)
@@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
 	struct devfreq *df = to_devfreq(dev);
+	struct devfreq_stats *stats = df->profile->stats;
 	unsigned long value;
 	int ret;
 
@@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
 			goto unlock;
 		}
 	} else {
-		unsigned long *freq_table = df->profile->freq_table;
+		unsigned long *freq_table = stats->freq_table;
 
 		/* Get minimum frequency according to sorting order */
-		if (freq_table[0] < freq_table[df->profile->max_state - 1])
+		if (freq_table[0] < freq_table[stats->max_state - 1])
 			value = freq_table[0];
 		else
-			value = freq_table[df->profile->max_state - 1];
+			value = freq_table[stats->max_state - 1];
 	}
 
 	df->min_freq = value;
@@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
 	struct devfreq *df = to_devfreq(dev);
+	struct devfreq_stats *stats = df->profile->stats;
 	unsigned long value;
 	int ret;
 
@@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
 			goto unlock;
 		}
 	} else {
-		unsigned long *freq_table = df->profile->freq_table;
+		unsigned long *freq_table = stats->freq_table;
 
 		/* Get maximum frequency according to sorting order */
-		if (freq_table[0] < freq_table[df->profile->max_state - 1])
-			value = freq_table[df->profile->max_state - 1];
+		if (freq_table[0] < freq_table[stats->max_state - 1])
+			value = freq_table[stats->max_state - 1];
 		else
 			value = freq_table[0];
 	}
@@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
 					  char *buf)
 {
 	struct devfreq *df = to_devfreq(d);
+	struct devfreq_stats *stats = df->profile->stats;
 	ssize_t count = 0;
 	int i;
 
 	mutex_lock(&df->lock);
 
-	for (i = 0; i < df->profile->max_state; i++)
+	for (i = 0; i < stats->max_state; i++)
 		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
-				"%lu ", df->profile->freq_table[i]);
+				"%lu ", stats->freq_table[i]);
 
 	mutex_unlock(&df->lock);
 	/* Truncate the trailing space */
@@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
 {
 	struct devfreq *devfreq = to_devfreq(dev);
 	struct devfreq_dev_profile *profile = devfreq->profile;
+	struct devfreq_stats *stats = profile->stats;
+	unsigned int max_state = stats->max_state;
 	ssize_t len;
 	int i, j;
-	unsigned int max_state = profile->max_state;
 
 	if (!devfreq->stop_polling &&
 			devfreq_update_status(devfreq, devfreq->previous_freq))
@@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
 	len = sprintf(buf, "     From  :   To\n");
 	len += sprintf(buf + len, "           :");
 
-	spin_lock(&profile->stats_lock);
+	spin_lock(&stats->stats_lock);
 	for (i = 0; i < max_state; i++)
 		len += sprintf(buf + len, "%10lu",
-				profile->freq_table[i]);
+				stats->freq_table[i]);
 
 	len += sprintf(buf + len, "   time(ms)\n");
 
 	for (i = 0; i < max_state; i++) {
-		if (profile->freq_table[i] == devfreq->previous_freq)
+		if (stats->freq_table[i] == devfreq->previous_freq)
 			len += sprintf(buf + len, "*");
 		else
 			len += sprintf(buf + len, " ");
 
 		len += sprintf(buf + len, "%10lu:",
-				profile->freq_table[i]);
+				stats->freq_table[i]);
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
-				profile->trans_table[(i * max_state) + j]);
+				stats->trans_table[(i * max_state) + j]);
 		len += sprintf(buf + len, "%10llu\n", (u64)
-			jiffies64_to_msecs(profile->time_in_state[i]));
+			jiffies64_to_msecs(stats->time_in_state[i]));
 	}
 
 	len += sprintf(buf + len, "Total transition : %u\n",
-					profile->total_trans);
-	spin_unlock(&profile->stats_lock);
+					stats->total_trans);
+	spin_unlock(&stats->stats_lock);
 	return len;
 }
 static DEVICE_ATTR_RO(trans_stat);
 
-static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
+static void defvreq_stats_clear_table(struct devfreq_stats *stats)
 {
-	unsigned int count = profile->max_state;
-
-	spin_lock(&profile->stats_lock);
-	memset(profile->time_in_state, 0, count * sizeof(u64));
-	memset(profile->trans_table, 0, count * count * sizeof(int));
-	profile->last_time = get_jiffies_64();
-	profile->total_trans = 0;
-	spin_unlock(&profile->stats_lock);
+	unsigned int count = stats->max_state;
+
+	spin_lock(&stats->stats_lock);
+	memset(stats->time_in_state, 0, count * sizeof(u64));
+	memset(stats->trans_table, 0, count * count * sizeof(int));
+	stats->last_time = get_jiffies_64();
+	stats->total_trans = 0;
+	spin_unlock(&stats->stats_lock);
 }
 
 static ssize_t trans_reset_store(struct device *dev,
@@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
 {
 	struct devfreq *devfreq = to_devfreq(dev);
 
-	defvreq_stats_clear_table(devfreq->profile);
+	defvreq_stats_clear_table(devfreq->profile->stats);
 
 	return count;
 }
diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
index d9f377912c10..b212aae2bb3e 100644
--- a/drivers/devfreq/exynos-bus.c
+++ b/drivers/devfreq/exynos-bus.c
@@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
 	}
 
 out:
-	max_state = bus->devfreq->profile->max_state;
-	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
-	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
+	max_state = profile->stats->max_state;
+	min_freq = (profile->stats->freq_table[0] / 1000);
+	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
 	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
 			dev_name(dev), min_freq, max_freq);
 
diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
index 58308948b863..b2d87a88335c 100644
--- a/drivers/devfreq/governor_passive.c
+++ b/drivers/devfreq/governor_passive.c
@@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
 	struct devfreq_passive_data *p_data
 			= (struct devfreq_passive_data *)devfreq->data;
 	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
+	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
+	struct devfreq_stats *stats;
 	unsigned long child_freq = ULONG_MAX;
 	struct dev_pm_opp *opp;
 	int i, count, ret = 0;
@@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
 	 * device. And then the index is used for getting the suitable
 	 * new frequency for passive devfreq device.
 	 */
-	if (!devfreq->profile || !devfreq->profile->freq_table
-		|| devfreq->profile->max_state <= 0)
+	if (!devfreq->profile || !devfreq->profile->stats ||
+	    devfreq->profile->stats->max_state <= 0 ||
+	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
+	    parent_devfreq->profile->stats->max_state <= 0)
 		return -EINVAL;
 
+	stats = devfreq->profile->stats;
+	parent_stats = parent_devfreq->profile->stats;
 	/*
 	 * The passive governor have to get the correct frequency from OPP
 	 * list of parent device. Because in this case, *freq is temporary
@@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
 	 * Get the OPP table's index of decided freqeuncy by governor
 	 * of parent device.
 	 */
-	for (i = 0; i < parent_devfreq->profile->max_state; i++)
-		if (parent_devfreq->profile->freq_table[i] == *freq)
+	for (i = 0; i < parent_stats->max_state; i++)
+		if (parent_stats->freq_table[i] == *freq)
 			break;
 
-	if (i == parent_devfreq->profile->max_state) {
+	if (i == parent_stats->max_state) {
 		ret = -EINVAL;
 		goto out;
 	}
 
 	/* Get the suitable frequency by using index of parent device. */
-	if (i < devfreq->profile->max_state) {
-		child_freq = devfreq->profile->freq_table[i];
+	if (i < stats->max_state) {
+		child_freq = stats->freq_table[i];
 	} else {
-		count = devfreq->profile->max_state;
-		child_freq = devfreq->profile->freq_table[count - 1];
+		count = stats->max_state;
+		child_freq = stats->freq_table[count - 1];
 	}
 
 	/* Return the suitable frequency for passive device. */
@@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
 	if (ret < 0)
 		goto out;
 
-	if (devfreq->profile->freq_table
+	if (devfreq->profile->stats
 		&& (devfreq_update_status(devfreq, freq)))
 		dev_err(&devfreq->dev,
 			"Couldn't update frequency transition information.\n");
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 4ceb2a517a9c..8459af1a1583 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -64,6 +64,30 @@ struct devfreq_dev_status {
  */
 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
 
+/**
+ * struct devfreq_stats - Devfreq's transitions stats counters
+ * @freq_table:		Optional list of frequencies to support statistics
+ *			and freq_table must be generated in ascending order.
+ * @max_state:		The size of freq_table.
+ * @total_trans:	Number of devfreq transitions
+ * @trans_table:	Statistics of devfreq transitions
+ * @time_in_state:	Statistics of devfreq states
+ * @last_time:		The last time stats were updated
+ * @stats_lock:		Lock protecting trans_table, time_in_state,
+ *			last_time and total_trans used for statistics
+ */
+struct devfreq_stats {
+	unsigned long *freq_table;
+	unsigned int max_state;
+
+	/* information for device frequency transition */
+	unsigned int total_trans;
+	unsigned int *trans_table;
+	u64 *time_in_state;
+	unsigned long long last_time;
+	spinlock_t stats_lock;
+};
+
 /**
  * struct devfreq_dev_profile - Devfreq's user device profile
  * @initial_freq:	The operating frequency when devfreq_add_device() is
@@ -88,15 +112,7 @@ struct devfreq_dev_status {
  *			from devfreq_remove_device() call. If the user
  *			has registered devfreq->nb at a notifier-head,
  *			this is the time to unregister it.
- * @freq_table:		Optional list of frequencies to support statistics
- *			and freq_table must be generated in ascending order.
- * @max_state:		The size of freq_table.
- * @total_trans:	Number of devfreq transitions
- * @trans_table:	Statistics of devfreq transitions
- * @time_in_state:	Statistics of devfreq states
- * @last_time:		The last time stats were updated
- * @stats_lock:		Lock protecting trans_table, time_in_state,
- *			last_time and total_trans used for statistics
+ * @stats:		Statistics of devfreq states and state transitions
  */
 struct devfreq_dev_profile {
 	unsigned long initial_freq;
@@ -108,14 +124,7 @@ struct devfreq_dev_profile {
 	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
 	void (*exit)(struct device *dev);
 
-	unsigned long *freq_table;
-	unsigned int max_state;
-	/* information for device frequency transition */
-	unsigned int total_trans;
-	unsigned int *trans_table;
-	u64 *time_in_state;
-	unsigned long long last_time;
-	spinlock_t stats_lock;
+	struct devfreq_stats *stats;
 };
 
 /**
-- 
2.24.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Chanwoo Choi]

Hi Kamil,

The 'freq_table' and 'max_state' in the devfreq_dev_profile
were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
device driver was posted to mainline kernel, they used
them for a long time. It means that this patch break
the compatibility. The ARM Mali drivers are very
important devfreq device driver. 

[1] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
[2] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
[3] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel

Also, the devfreq device driver specifies their own
information and data into devfreq_dev_profile structure 
before registering the devfreq device with devfreq_add_device().
This patch breaks the basic usage rule of devfreq_dev_profile structure.

So, I can't agree this patch. Not ack.

Regards,
Chanwoo Choi

On 11/13/19 6:13 PM, Kamil Konieczny wrote:
> Count time and transitions between devfreq frequencies in separate struct
> for improved code readability and maintenance.
> 
> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
> ---
>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>  drivers/devfreq/exynos-bus.c       |   6 +-
>  drivers/devfreq/governor_passive.c |  26 +++--
>  include/linux/devfreq.h            |  43 ++++----
>  4 files changed, 129 insertions(+), 102 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index d79412b0de59..d85867a91230 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>   */
>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>  {
> +	struct devfreq_stats *stats = devfreq->profile->stats;
>  	int lev;
>  
> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
> -		if (freq == devfreq->profile->freq_table[lev])
> +	for (lev = 0; lev < stats->max_state; lev++)
> +		if (freq == stats->freq_table[lev])
>  			return lev;
>  
>  	return -EINVAL;
> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>  static int set_freq_table(struct devfreq *devfreq)
>  {
>  	struct devfreq_dev_profile *profile = devfreq->profile;
> +	struct devfreq_stats *stats;
>  	struct dev_pm_opp *opp;
>  	unsigned long freq;
> -	int i, count;
> +	int i, count, err = -ENOMEM;
>  
>  	/* Initialize the freq_table from OPP table */
>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>  	if (count <= 0)
>  		return -EINVAL;
>  
> -	profile->max_state = count;
> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
> -					count,
> -					sizeof(*profile->freq_table),
> -					GFP_KERNEL);
> -	if (!profile->freq_table) {
> -		profile->max_state = 0;
> +	stats = devm_kzalloc(devfreq->dev.parent,
> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
> +	if (!stats)
>  		return -ENOMEM;
> -	}
>  
> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
> +	profile->stats = stats;
> +	stats->max_state = count;
> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
> +					 count,
> +					 sizeof(*stats->freq_table),
> +					 GFP_KERNEL);
> +	if (!stats->freq_table)
> +		goto err_no_mem;
> +
> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>  		if (IS_ERR(opp)) {
> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
> -			profile->max_state = 0;
> -			return PTR_ERR(opp);
> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
> +			stats->max_state = 0;
> +			err = PTR_ERR(opp);
> +			goto err_no_mem;
>  		}
>  		dev_pm_opp_put(opp);
> -		profile->freq_table[i] = freq;
> +		stats->freq_table[i] = freq;
>  	}
>  
> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
> -					    array3_size(sizeof(unsigned int),
> -							count, count),
> -					    GFP_KERNEL);
> -	if (!profile->trans_table)
> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
> +					  array3_size(sizeof(unsigned int),
> +						      count, count),
> +					  GFP_KERNEL);
> +	if (!stats->trans_table)
>  		goto err_no_mem;
>  
> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
> -					      sizeof(*profile->time_in_state),
> -					      GFP_KERNEL);
> -	if (!profile->time_in_state)
> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
> +					    sizeof(*stats->time_in_state),
> +					    GFP_KERNEL);
> +	if (!stats->time_in_state)
>  		goto err_no_mem;
>  
> -	profile->last_time = get_jiffies_64();
> -	spin_lock_init(&profile->stats_lock);
> +	stats->last_time = get_jiffies_64();
> +	spin_lock_init(&stats->stats_lock);
>  
>  	return 0;
>  err_no_mem:
> -	profile->max_state = 0;
> -	return -ENOMEM;
> +	stats->max_state = 0;
> +	devm_kfree(devfreq->dev.parent, profile->stats);
> +	profile->stats = NULL;
> +	return err;
>  }
>  
>  /**
> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>   */
>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  {
> -	struct devfreq_dev_profile *profile = devfreq->profile;
> +	struct devfreq_stats *stats = devfreq->profile->stats;
>  	unsigned long long cur_time;
>  	int lev, prev_lev, ret = 0;
>  
> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  
>  	/* Immediately exit if previous_freq is not initialized yet. */
>  	if (!devfreq->previous_freq) {
> -		spin_lock(&profile->stats_lock);
> -		profile->last_time = cur_time;
> -		spin_unlock(&profile->stats_lock);
> +		spin_lock(&stats->stats_lock);
> +		stats->last_time = cur_time;
> +		spin_unlock(&stats->stats_lock);
>  		return 0;
>  	}
>  
>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>  
> -	spin_lock(&profile->stats_lock);
> +	spin_lock(&stats->stats_lock);
>  	if (prev_lev < 0) {
>  		ret = prev_lev;
>  		goto out;
>  	}
>  
> -	profile->time_in_state[prev_lev] +=
> -			 cur_time - profile->last_time;
> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>  	lev = devfreq_get_freq_level(devfreq, freq);
>  	if (lev < 0) {
>  		ret = lev;
> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  	}
>  
>  	if (lev != prev_lev) {
> -		profile->trans_table[(prev_lev *
> -				profile->max_state) + lev]++;
> -		profile->total_trans++;
> +		stats->trans_table[(prev_lev *
> +				stats->max_state) + lev]++;
> +		stats->total_trans++;
>  	}
>  
>  out:
> -	profile->last_time = cur_time;
> -	spin_unlock(&profile->stats_lock);
> +	stats->last_time = cur_time;
> +	spin_unlock(&stats->stats_lock);
>  	return ret;
>  }
>  EXPORT_SYMBOL(devfreq_update_status);
> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>  			msecs_to_jiffies(profile->polling_ms));
>  
> -	spin_lock(&profile->stats_lock);
> -	profile->last_time = get_jiffies_64();
> -	spin_unlock(&profile->stats_lock);
> +	spin_lock(&profile->stats->stats_lock);
> +	profile->stats->last_time = get_jiffies_64();
> +	spin_unlock(&profile->stats->stats_lock);
>  	devfreq->stop_polling = false;
>  
>  	if (profile->get_cur_freq &&
> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  	devfreq->data = data;
>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>  
> -	if (!profile->max_state && !profile->freq_table) {
> +	if (!profile->stats) {
>  		mutex_unlock(&devfreq->lock);
>  		err = set_freq_table(devfreq);
>  		if (err < 0)
> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>  			      const char *buf, size_t count)
>  {
>  	struct devfreq *df = to_devfreq(dev);
> +	struct devfreq_stats *stats = df->profile->stats;
>  	unsigned long value;
>  	int ret;
>  
> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>  			goto unlock;
>  		}
>  	} else {
> -		unsigned long *freq_table = df->profile->freq_table;
> +		unsigned long *freq_table = stats->freq_table;
>  
>  		/* Get minimum frequency according to sorting order */
> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>  			value = freq_table[0];
>  		else
> -			value = freq_table[df->profile->max_state - 1];
> +			value = freq_table[stats->max_state - 1];
>  	}
>  
>  	df->min_freq = value;
> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>  			      const char *buf, size_t count)
>  {
>  	struct devfreq *df = to_devfreq(dev);
> +	struct devfreq_stats *stats = df->profile->stats;
>  	unsigned long value;
>  	int ret;
>  
> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>  			goto unlock;
>  		}
>  	} else {
> -		unsigned long *freq_table = df->profile->freq_table;
> +		unsigned long *freq_table = stats->freq_table;
>  
>  		/* Get maximum frequency according to sorting order */
> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
> -			value = freq_table[df->profile->max_state - 1];
> +		if (freq_table[0] < freq_table[stats->max_state - 1])
> +			value = freq_table[stats->max_state - 1];
>  		else
>  			value = freq_table[0];
>  	}
> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>  					  char *buf)
>  {
>  	struct devfreq *df = to_devfreq(d);
> +	struct devfreq_stats *stats = df->profile->stats;
>  	ssize_t count = 0;
>  	int i;
>  
>  	mutex_lock(&df->lock);
>  
> -	for (i = 0; i < df->profile->max_state; i++)
> +	for (i = 0; i < stats->max_state; i++)
>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
> -				"%lu ", df->profile->freq_table[i]);
> +				"%lu ", stats->freq_table[i]);
>  
>  	mutex_unlock(&df->lock);
>  	/* Truncate the trailing space */
> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>  {
>  	struct devfreq *devfreq = to_devfreq(dev);
>  	struct devfreq_dev_profile *profile = devfreq->profile;
> +	struct devfreq_stats *stats = profile->stats;
> +	unsigned int max_state = stats->max_state;
>  	ssize_t len;
>  	int i, j;
> -	unsigned int max_state = profile->max_state;
>  
>  	if (!devfreq->stop_polling &&
>  			devfreq_update_status(devfreq, devfreq->previous_freq))
> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>  	len = sprintf(buf, "     From  :   To\n");
>  	len += sprintf(buf + len, "           :");
>  
> -	spin_lock(&profile->stats_lock);
> +	spin_lock(&stats->stats_lock);
>  	for (i = 0; i < max_state; i++)
>  		len += sprintf(buf + len, "%10lu",
> -				profile->freq_table[i]);
> +				stats->freq_table[i]);
>  
>  	len += sprintf(buf + len, "   time(ms)\n");
>  
>  	for (i = 0; i < max_state; i++) {
> -		if (profile->freq_table[i] == devfreq->previous_freq)
> +		if (stats->freq_table[i] == devfreq->previous_freq)
>  			len += sprintf(buf + len, "*");
>  		else
>  			len += sprintf(buf + len, " ");
>  
>  		len += sprintf(buf + len, "%10lu:",
> -				profile->freq_table[i]);
> +				stats->freq_table[i]);
>  		for (j = 0; j < max_state; j++)
>  			len += sprintf(buf + len, "%10u",
> -				profile->trans_table[(i * max_state) + j]);
> +				stats->trans_table[(i * max_state) + j]);
>  		len += sprintf(buf + len, "%10llu\n", (u64)
> -			jiffies64_to_msecs(profile->time_in_state[i]));
> +			jiffies64_to_msecs(stats->time_in_state[i]));
>  	}
>  
>  	len += sprintf(buf + len, "Total transition : %u\n",
> -					profile->total_trans);
> -	spin_unlock(&profile->stats_lock);
> +					stats->total_trans);
> +	spin_unlock(&stats->stats_lock);
>  	return len;
>  }
>  static DEVICE_ATTR_RO(trans_stat);
>  
> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>  {
> -	unsigned int count = profile->max_state;
> -
> -	spin_lock(&profile->stats_lock);
> -	memset(profile->time_in_state, 0, count * sizeof(u64));
> -	memset(profile->trans_table, 0, count * count * sizeof(int));
> -	profile->last_time = get_jiffies_64();
> -	profile->total_trans = 0;
> -	spin_unlock(&profile->stats_lock);
> +	unsigned int count = stats->max_state;
> +
> +	spin_lock(&stats->stats_lock);
> +	memset(stats->time_in_state, 0, count * sizeof(u64));
> +	memset(stats->trans_table, 0, count * count * sizeof(int));
> +	stats->last_time = get_jiffies_64();
> +	stats->total_trans = 0;
> +	spin_unlock(&stats->stats_lock);
>  }
>  
>  static ssize_t trans_reset_store(struct device *dev,
> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>  {
>  	struct devfreq *devfreq = to_devfreq(dev);
>  
> -	defvreq_stats_clear_table(devfreq->profile);
> +	defvreq_stats_clear_table(devfreq->profile->stats);
>  
>  	return count;
>  }
> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
> index d9f377912c10..b212aae2bb3e 100644
> --- a/drivers/devfreq/exynos-bus.c
> +++ b/drivers/devfreq/exynos-bus.c
> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>  	}
>  
>  out:
> -	max_state = bus->devfreq->profile->max_state;
> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
> +	max_state = profile->stats->max_state;
> +	min_freq = (profile->stats->freq_table[0] / 1000);
> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>  			dev_name(dev), min_freq, max_freq);
>  
> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
> index 58308948b863..b2d87a88335c 100644
> --- a/drivers/devfreq/governor_passive.c
> +++ b/drivers/devfreq/governor_passive.c
> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>  	struct devfreq_passive_data *p_data
>  			= (struct devfreq_passive_data *)devfreq->data;
>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
> +	struct devfreq_stats *stats;
>  	unsigned long child_freq = ULONG_MAX;
>  	struct dev_pm_opp *opp;
>  	int i, count, ret = 0;
> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>  	 * device. And then the index is used for getting the suitable
>  	 * new frequency for passive devfreq device.
>  	 */
> -	if (!devfreq->profile || !devfreq->profile->freq_table
> -		|| devfreq->profile->max_state <= 0)
> +	if (!devfreq->profile || !devfreq->profile->stats ||
> +	    devfreq->profile->stats->max_state <= 0 ||
> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
> +	    parent_devfreq->profile->stats->max_state <= 0)
>  		return -EINVAL;
>  
> +	stats = devfreq->profile->stats;
> +	parent_stats = parent_devfreq->profile->stats;
>  	/*
>  	 * The passive governor have to get the correct frequency from OPP
>  	 * list of parent device. Because in this case, *freq is temporary
> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>  	 * Get the OPP table's index of decided freqeuncy by governor
>  	 * of parent device.
>  	 */
> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
> -		if (parent_devfreq->profile->freq_table[i] == *freq)
> +	for (i = 0; i < parent_stats->max_state; i++)
> +		if (parent_stats->freq_table[i] == *freq)
>  			break;
>  
> -	if (i == parent_devfreq->profile->max_state) {
> +	if (i == parent_stats->max_state) {
>  		ret = -EINVAL;
>  		goto out;
>  	}
>  
>  	/* Get the suitable frequency by using index of parent device. */
> -	if (i < devfreq->profile->max_state) {
> -		child_freq = devfreq->profile->freq_table[i];
> +	if (i < stats->max_state) {
> +		child_freq = stats->freq_table[i];
>  	} else {
> -		count = devfreq->profile->max_state;
> -		child_freq = devfreq->profile->freq_table[count - 1];
> +		count = stats->max_state;
> +		child_freq = stats->freq_table[count - 1];
>  	}
>  
>  	/* Return the suitable frequency for passive device. */
> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>  	if (ret < 0)
>  		goto out;
>  
> -	if (devfreq->profile->freq_table
> +	if (devfreq->profile->stats
>  		&& (devfreq_update_status(devfreq, freq)))
>  		dev_err(&devfreq->dev,
>  			"Couldn't update frequency transition information.\n");
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 4ceb2a517a9c..8459af1a1583 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>   */
>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>  
> +/**
> + * struct devfreq_stats - Devfreq's transitions stats counters
> + * @freq_table:		Optional list of frequencies to support statistics
> + *			and freq_table must be generated in ascending order.
> + * @max_state:		The size of freq_table.
> + * @total_trans:	Number of devfreq transitions
> + * @trans_table:	Statistics of devfreq transitions
> + * @time_in_state:	Statistics of devfreq states
> + * @last_time:		The last time stats were updated
> + * @stats_lock:		Lock protecting trans_table, time_in_state,
> + *			last_time and total_trans used for statistics
> + */
> +struct devfreq_stats {
> +	unsigned long *freq_table;
> +	unsigned int max_state;
> +
> +	/* information for device frequency transition */
> +	unsigned int total_trans;
> +	unsigned int *trans_table;
> +	u64 *time_in_state;
> +	unsigned long long last_time;
> +	spinlock_t stats_lock;
> +};
> +
>  /**
>   * struct devfreq_dev_profile - Devfreq's user device profile
>   * @initial_freq:	The operating frequency when devfreq_add_device() is
> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>   *			from devfreq_remove_device() call. If the user
>   *			has registered devfreq->nb at a notifier-head,
>   *			this is the time to unregister it.
> - * @freq_table:		Optional list of frequencies to support statistics
> - *			and freq_table must be generated in ascending order.
> - * @max_state:		The size of freq_table.
> - * @total_trans:	Number of devfreq transitions
> - * @trans_table:	Statistics of devfreq transitions
> - * @time_in_state:	Statistics of devfreq states
> - * @last_time:		The last time stats were updated
> - * @stats_lock:		Lock protecting trans_table, time_in_state,
> - *			last_time and total_trans used for statistics
> + * @stats:		Statistics of devfreq states and state transitions
>   */
>  struct devfreq_dev_profile {
>  	unsigned long initial_freq;
> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>  	void (*exit)(struct device *dev);
>  
> -	unsigned long *freq_table;
> -	unsigned int max_state;
> -	/* information for device frequency transition */
> -	unsigned int total_trans;
> -	unsigned int *trans_table;
> -	u64 *time_in_state;
> -	unsigned long long last_time;
> -	spinlock_t stats_lock;
> +	struct devfreq_stats *stats;
>  };
>  
>  /**
> 

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Chanwoo Choi]

Hi Kamil,

The 'freq_table' and 'max_state' in the devfreq_dev_profile
were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
device driver was posted to mainline kernel, they used
them for a long time. It means that this patch break
the compatibility. The ARM Mali drivers are very
important devfreq device driver. 

[1] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
[2] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
[3] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel

Also, the devfreq device driver specifies their own
information and data into devfreq_dev_profile structure 
before registering the devfreq device with devfreq_add_device().
This patch breaks the basic usage rule of devfreq_dev_profile structure.

So, I can't agree this patch. Not ack.

Regards,
Chanwoo Choi

On 11/13/19 6:13 PM, Kamil Konieczny wrote:
> Count time and transitions between devfreq frequencies in separate struct
> for improved code readability and maintenance.
> 
> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
> ---
>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>  drivers/devfreq/exynos-bus.c       |   6 +-
>  drivers/devfreq/governor_passive.c |  26 +++--
>  include/linux/devfreq.h            |  43 ++++----
>  4 files changed, 129 insertions(+), 102 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index d79412b0de59..d85867a91230 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>   */
>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>  {
> +	struct devfreq_stats *stats = devfreq->profile->stats;
>  	int lev;
>  
> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
> -		if (freq == devfreq->profile->freq_table[lev])
> +	for (lev = 0; lev < stats->max_state; lev++)
> +		if (freq == stats->freq_table[lev])
>  			return lev;
>  
>  	return -EINVAL;
> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>  static int set_freq_table(struct devfreq *devfreq)
>  {
>  	struct devfreq_dev_profile *profile = devfreq->profile;
> +	struct devfreq_stats *stats;
>  	struct dev_pm_opp *opp;
>  	unsigned long freq;
> -	int i, count;
> +	int i, count, err = -ENOMEM;
>  
>  	/* Initialize the freq_table from OPP table */
>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>  	if (count <= 0)
>  		return -EINVAL;
>  
> -	profile->max_state = count;
> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
> -					count,
> -					sizeof(*profile->freq_table),
> -					GFP_KERNEL);
> -	if (!profile->freq_table) {
> -		profile->max_state = 0;
> +	stats = devm_kzalloc(devfreq->dev.parent,
> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
> +	if (!stats)
>  		return -ENOMEM;
> -	}
>  
> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
> +	profile->stats = stats;
> +	stats->max_state = count;
> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
> +					 count,
> +					 sizeof(*stats->freq_table),
> +					 GFP_KERNEL);
> +	if (!stats->freq_table)
> +		goto err_no_mem;
> +
> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>  		if (IS_ERR(opp)) {
> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
> -			profile->max_state = 0;
> -			return PTR_ERR(opp);
> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
> +			stats->max_state = 0;
> +			err = PTR_ERR(opp);
> +			goto err_no_mem;
>  		}
>  		dev_pm_opp_put(opp);
> -		profile->freq_table[i] = freq;
> +		stats->freq_table[i] = freq;
>  	}
>  
> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
> -					    array3_size(sizeof(unsigned int),
> -							count, count),
> -					    GFP_KERNEL);
> -	if (!profile->trans_table)
> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
> +					  array3_size(sizeof(unsigned int),
> +						      count, count),
> +					  GFP_KERNEL);
> +	if (!stats->trans_table)
>  		goto err_no_mem;
>  
> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
> -					      sizeof(*profile->time_in_state),
> -					      GFP_KERNEL);
> -	if (!profile->time_in_state)
> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
> +					    sizeof(*stats->time_in_state),
> +					    GFP_KERNEL);
> +	if (!stats->time_in_state)
>  		goto err_no_mem;
>  
> -	profile->last_time = get_jiffies_64();
> -	spin_lock_init(&profile->stats_lock);
> +	stats->last_time = get_jiffies_64();
> +	spin_lock_init(&stats->stats_lock);
>  
>  	return 0;
>  err_no_mem:
> -	profile->max_state = 0;
> -	return -ENOMEM;
> +	stats->max_state = 0;
> +	devm_kfree(devfreq->dev.parent, profile->stats);
> +	profile->stats = NULL;
> +	return err;
>  }
>  
>  /**
> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>   */
>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  {
> -	struct devfreq_dev_profile *profile = devfreq->profile;
> +	struct devfreq_stats *stats = devfreq->profile->stats;
>  	unsigned long long cur_time;
>  	int lev, prev_lev, ret = 0;
>  
> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  
>  	/* Immediately exit if previous_freq is not initialized yet. */
>  	if (!devfreq->previous_freq) {
> -		spin_lock(&profile->stats_lock);
> -		profile->last_time = cur_time;
> -		spin_unlock(&profile->stats_lock);
> +		spin_lock(&stats->stats_lock);
> +		stats->last_time = cur_time;
> +		spin_unlock(&stats->stats_lock);
>  		return 0;
>  	}
>  
>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>  
> -	spin_lock(&profile->stats_lock);
> +	spin_lock(&stats->stats_lock);
>  	if (prev_lev < 0) {
>  		ret = prev_lev;
>  		goto out;
>  	}
>  
> -	profile->time_in_state[prev_lev] +=
> -			 cur_time - profile->last_time;
> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>  	lev = devfreq_get_freq_level(devfreq, freq);
>  	if (lev < 0) {
>  		ret = lev;
> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  	}
>  
>  	if (lev != prev_lev) {
> -		profile->trans_table[(prev_lev *
> -				profile->max_state) + lev]++;
> -		profile->total_trans++;
> +		stats->trans_table[(prev_lev *
> +				stats->max_state) + lev]++;
> +		stats->total_trans++;
>  	}
>  
>  out:
> -	profile->last_time = cur_time;
> -	spin_unlock(&profile->stats_lock);
> +	stats->last_time = cur_time;
> +	spin_unlock(&stats->stats_lock);
>  	return ret;
>  }
>  EXPORT_SYMBOL(devfreq_update_status);
> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>  			msecs_to_jiffies(profile->polling_ms));
>  
> -	spin_lock(&profile->stats_lock);
> -	profile->last_time = get_jiffies_64();
> -	spin_unlock(&profile->stats_lock);
> +	spin_lock(&profile->stats->stats_lock);
> +	profile->stats->last_time = get_jiffies_64();
> +	spin_unlock(&profile->stats->stats_lock);
>  	devfreq->stop_polling = false;
>  
>  	if (profile->get_cur_freq &&
> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  	devfreq->data = data;
>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>  
> -	if (!profile->max_state && !profile->freq_table) {
> +	if (!profile->stats) {
>  		mutex_unlock(&devfreq->lock);
>  		err = set_freq_table(devfreq);
>  		if (err < 0)
> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>  			      const char *buf, size_t count)
>  {
>  	struct devfreq *df = to_devfreq(dev);
> +	struct devfreq_stats *stats = df->profile->stats;
>  	unsigned long value;
>  	int ret;
>  
> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>  			goto unlock;
>  		}
>  	} else {
> -		unsigned long *freq_table = df->profile->freq_table;
> +		unsigned long *freq_table = stats->freq_table;
>  
>  		/* Get minimum frequency according to sorting order */
> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>  			value = freq_table[0];
>  		else
> -			value = freq_table[df->profile->max_state - 1];
> +			value = freq_table[stats->max_state - 1];
>  	}
>  
>  	df->min_freq = value;
> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>  			      const char *buf, size_t count)
>  {
>  	struct devfreq *df = to_devfreq(dev);
> +	struct devfreq_stats *stats = df->profile->stats;
>  	unsigned long value;
>  	int ret;
>  
> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>  			goto unlock;
>  		}
>  	} else {
> -		unsigned long *freq_table = df->profile->freq_table;
> +		unsigned long *freq_table = stats->freq_table;
>  
>  		/* Get maximum frequency according to sorting order */
> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
> -			value = freq_table[df->profile->max_state - 1];
> +		if (freq_table[0] < freq_table[stats->max_state - 1])
> +			value = freq_table[stats->max_state - 1];
>  		else
>  			value = freq_table[0];
>  	}
> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>  					  char *buf)
>  {
>  	struct devfreq *df = to_devfreq(d);
> +	struct devfreq_stats *stats = df->profile->stats;
>  	ssize_t count = 0;
>  	int i;
>  
>  	mutex_lock(&df->lock);
>  
> -	for (i = 0; i < df->profile->max_state; i++)
> +	for (i = 0; i < stats->max_state; i++)
>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
> -				"%lu ", df->profile->freq_table[i]);
> +				"%lu ", stats->freq_table[i]);
>  
>  	mutex_unlock(&df->lock);
>  	/* Truncate the trailing space */
> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>  {
>  	struct devfreq *devfreq = to_devfreq(dev);
>  	struct devfreq_dev_profile *profile = devfreq->profile;
> +	struct devfreq_stats *stats = profile->stats;
> +	unsigned int max_state = stats->max_state;
>  	ssize_t len;
>  	int i, j;
> -	unsigned int max_state = profile->max_state;
>  
>  	if (!devfreq->stop_polling &&
>  			devfreq_update_status(devfreq, devfreq->previous_freq))
> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>  	len = sprintf(buf, "     From  :   To\n");
>  	len += sprintf(buf + len, "           :");
>  
> -	spin_lock(&profile->stats_lock);
> +	spin_lock(&stats->stats_lock);
>  	for (i = 0; i < max_state; i++)
>  		len += sprintf(buf + len, "%10lu",
> -				profile->freq_table[i]);
> +				stats->freq_table[i]);
>  
>  	len += sprintf(buf + len, "   time(ms)\n");
>  
>  	for (i = 0; i < max_state; i++) {
> -		if (profile->freq_table[i] == devfreq->previous_freq)
> +		if (stats->freq_table[i] == devfreq->previous_freq)
>  			len += sprintf(buf + len, "*");
>  		else
>  			len += sprintf(buf + len, " ");
>  
>  		len += sprintf(buf + len, "%10lu:",
> -				profile->freq_table[i]);
> +				stats->freq_table[i]);
>  		for (j = 0; j < max_state; j++)
>  			len += sprintf(buf + len, "%10u",
> -				profile->trans_table[(i * max_state) + j]);
> +				stats->trans_table[(i * max_state) + j]);
>  		len += sprintf(buf + len, "%10llu\n", (u64)
> -			jiffies64_to_msecs(profile->time_in_state[i]));
> +			jiffies64_to_msecs(stats->time_in_state[i]));
>  	}
>  
>  	len += sprintf(buf + len, "Total transition : %u\n",
> -					profile->total_trans);
> -	spin_unlock(&profile->stats_lock);
> +					stats->total_trans);
> +	spin_unlock(&stats->stats_lock);
>  	return len;
>  }
>  static DEVICE_ATTR_RO(trans_stat);
>  
> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>  {
> -	unsigned int count = profile->max_state;
> -
> -	spin_lock(&profile->stats_lock);
> -	memset(profile->time_in_state, 0, count * sizeof(u64));
> -	memset(profile->trans_table, 0, count * count * sizeof(int));
> -	profile->last_time = get_jiffies_64();
> -	profile->total_trans = 0;
> -	spin_unlock(&profile->stats_lock);
> +	unsigned int count = stats->max_state;
> +
> +	spin_lock(&stats->stats_lock);
> +	memset(stats->time_in_state, 0, count * sizeof(u64));
> +	memset(stats->trans_table, 0, count * count * sizeof(int));
> +	stats->last_time = get_jiffies_64();
> +	stats->total_trans = 0;
> +	spin_unlock(&stats->stats_lock);
>  }
>  
>  static ssize_t trans_reset_store(struct device *dev,
> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>  {
>  	struct devfreq *devfreq = to_devfreq(dev);
>  
> -	defvreq_stats_clear_table(devfreq->profile);
> +	defvreq_stats_clear_table(devfreq->profile->stats);
>  
>  	return count;
>  }
> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
> index d9f377912c10..b212aae2bb3e 100644
> --- a/drivers/devfreq/exynos-bus.c
> +++ b/drivers/devfreq/exynos-bus.c
> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>  	}
>  
>  out:
> -	max_state = bus->devfreq->profile->max_state;
> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
> +	max_state = profile->stats->max_state;
> +	min_freq = (profile->stats->freq_table[0] / 1000);
> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>  			dev_name(dev), min_freq, max_freq);
>  
> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
> index 58308948b863..b2d87a88335c 100644
> --- a/drivers/devfreq/governor_passive.c
> +++ b/drivers/devfreq/governor_passive.c
> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>  	struct devfreq_passive_data *p_data
>  			= (struct devfreq_passive_data *)devfreq->data;
>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
> +	struct devfreq_stats *stats;
>  	unsigned long child_freq = ULONG_MAX;
>  	struct dev_pm_opp *opp;
>  	int i, count, ret = 0;
> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>  	 * device. And then the index is used for getting the suitable
>  	 * new frequency for passive devfreq device.
>  	 */
> -	if (!devfreq->profile || !devfreq->profile->freq_table
> -		|| devfreq->profile->max_state <= 0)
> +	if (!devfreq->profile || !devfreq->profile->stats ||
> +	    devfreq->profile->stats->max_state <= 0 ||
> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
> +	    parent_devfreq->profile->stats->max_state <= 0)
>  		return -EINVAL;
>  
> +	stats = devfreq->profile->stats;
> +	parent_stats = parent_devfreq->profile->stats;
>  	/*
>  	 * The passive governor have to get the correct frequency from OPP
>  	 * list of parent device. Because in this case, *freq is temporary
> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>  	 * Get the OPP table's index of decided freqeuncy by governor
>  	 * of parent device.
>  	 */
> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
> -		if (parent_devfreq->profile->freq_table[i] == *freq)
> +	for (i = 0; i < parent_stats->max_state; i++)
> +		if (parent_stats->freq_table[i] == *freq)
>  			break;
>  
> -	if (i == parent_devfreq->profile->max_state) {
> +	if (i == parent_stats->max_state) {
>  		ret = -EINVAL;
>  		goto out;
>  	}
>  
>  	/* Get the suitable frequency by using index of parent device. */
> -	if (i < devfreq->profile->max_state) {
> -		child_freq = devfreq->profile->freq_table[i];
> +	if (i < stats->max_state) {
> +		child_freq = stats->freq_table[i];
>  	} else {
> -		count = devfreq->profile->max_state;
> -		child_freq = devfreq->profile->freq_table[count - 1];
> +		count = stats->max_state;
> +		child_freq = stats->freq_table[count - 1];
>  	}
>  
>  	/* Return the suitable frequency for passive device. */
> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>  	if (ret < 0)
>  		goto out;
>  
> -	if (devfreq->profile->freq_table
> +	if (devfreq->profile->stats
>  		&& (devfreq_update_status(devfreq, freq)))
>  		dev_err(&devfreq->dev,
>  			"Couldn't update frequency transition information.\n");
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 4ceb2a517a9c..8459af1a1583 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>   */
>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>  
> +/**
> + * struct devfreq_stats - Devfreq's transitions stats counters
> + * @freq_table:		Optional list of frequencies to support statistics
> + *			and freq_table must be generated in ascending order.
> + * @max_state:		The size of freq_table.
> + * @total_trans:	Number of devfreq transitions
> + * @trans_table:	Statistics of devfreq transitions
> + * @time_in_state:	Statistics of devfreq states
> + * @last_time:		The last time stats were updated
> + * @stats_lock:		Lock protecting trans_table, time_in_state,
> + *			last_time and total_trans used for statistics
> + */
> +struct devfreq_stats {
> +	unsigned long *freq_table;
> +	unsigned int max_state;
> +
> +	/* information for device frequency transition */
> +	unsigned int total_trans;
> +	unsigned int *trans_table;
> +	u64 *time_in_state;
> +	unsigned long long last_time;
> +	spinlock_t stats_lock;
> +};
> +
>  /**
>   * struct devfreq_dev_profile - Devfreq's user device profile
>   * @initial_freq:	The operating frequency when devfreq_add_device() is
> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>   *			from devfreq_remove_device() call. If the user
>   *			has registered devfreq->nb at a notifier-head,
>   *			this is the time to unregister it.
> - * @freq_table:		Optional list of frequencies to support statistics
> - *			and freq_table must be generated in ascending order.
> - * @max_state:		The size of freq_table.
> - * @total_trans:	Number of devfreq transitions
> - * @trans_table:	Statistics of devfreq transitions
> - * @time_in_state:	Statistics of devfreq states
> - * @last_time:		The last time stats were updated
> - * @stats_lock:		Lock protecting trans_table, time_in_state,
> - *			last_time and total_trans used for statistics
> + * @stats:		Statistics of devfreq states and state transitions
>   */
>  struct devfreq_dev_profile {
>  	unsigned long initial_freq;
> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>  	void (*exit)(struct device *dev);
>  
> -	unsigned long *freq_table;
> -	unsigned int max_state;
> -	/* information for device frequency transition */
> -	unsigned int total_trans;
> -	unsigned int *trans_table;
> -	u64 *time_in_state;
> -	unsigned long long last_time;
> -	spinlock_t stats_lock;
> +	struct devfreq_stats *stats;
>  };
>  
>  /**
> 

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Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Bartlomiej Zolnierkiewicz]

Hi Chanwoo,

On 11/14/19 2:52 AM, Chanwoo Choi wrote:
> Hi Kamil,
> 
> The 'freq_table' and 'max_state' in the devfreq_dev_profile
> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
> device driver was posted to mainline kernel, they used
> them for a long time. It means that this patch break
> the compatibility. The ARM Mali drivers are very
> important devfreq device driver. 

This argument is not a a technical one and the official upstream
kernel policy is to not depend on out-of-tree drivers.

Besides the ARM Mali drivers are full of code like:

#if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
...
#else
...
#endif

so few more instances of similar code won't do any harm.. ;-)

> [1] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
> [2] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
> [3] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel

I took a look at ARM Mali drivers source code anyway and I fail to
see a rationale behind their behavior of doing 'freq_table' and
'max_state' initialization in the driver itself (instead of leaving
it up to the devfreq core code, like all in-kernel drivers are doing
already).

Could you please explain rationale behind ARM Mali drivers' special
needs?

[ Both ARM Mali and devfreq core code are using generic PM OPP code
  these days to do 'freq_table' and 'max_state' initialization, the
  only difference seems to be that ARM Mali creates the frequency
  table in the descending order (but there also seems to be no real
  need for it). ]

Maybe this is an opportunity to simplify also the ARM Mali driver?

> Also, the devfreq device driver specifies their own
> information and data into devfreq_dev_profile structure 
> before registering the devfreq device with devfreq_add_device().
> This patch breaks the basic usage rule of devfreq_dev_profile structure.

Well, 'struct devfreq_stats *stats' can be trivially moved out of
'struct devfreq_profile' to 'struct devfreq' if you prefer it that
way..

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> So, I can't agree this patch. Not ack.
> 
> Regards,
> Chanwoo Choi
> 
> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>> Count time and transitions between devfreq frequencies in separate struct
>> for improved code readability and maintenance.
>>
>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>> ---
>>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>  drivers/devfreq/exynos-bus.c       |   6 +-
>>  drivers/devfreq/governor_passive.c |  26 +++--
>>  include/linux/devfreq.h            |  43 ++++----
>>  4 files changed, 129 insertions(+), 102 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index d79412b0de59..d85867a91230 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>   */
>>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>  {
>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>  	int lev;
>>  
>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>> -		if (freq == devfreq->profile->freq_table[lev])
>> +	for (lev = 0; lev < stats->max_state; lev++)
>> +		if (freq == stats->freq_table[lev])
>>  			return lev;
>>  
>>  	return -EINVAL;
>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>  static int set_freq_table(struct devfreq *devfreq)
>>  {
>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>> +	struct devfreq_stats *stats;
>>  	struct dev_pm_opp *opp;
>>  	unsigned long freq;
>> -	int i, count;
>> +	int i, count, err = -ENOMEM;
>>  
>>  	/* Initialize the freq_table from OPP table */
>>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>  	if (count <= 0)
>>  		return -EINVAL;
>>  
>> -	profile->max_state = count;
>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>> -					count,
>> -					sizeof(*profile->freq_table),
>> -					GFP_KERNEL);
>> -	if (!profile->freq_table) {
>> -		profile->max_state = 0;
>> +	stats = devm_kzalloc(devfreq->dev.parent,
>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>> +	if (!stats)
>>  		return -ENOMEM;
>> -	}
>>  
>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>> +	profile->stats = stats;
>> +	stats->max_state = count;
>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>> +					 count,
>> +					 sizeof(*stats->freq_table),
>> +					 GFP_KERNEL);
>> +	if (!stats->freq_table)
>> +		goto err_no_mem;
>> +
>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>  		if (IS_ERR(opp)) {
>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>> -			profile->max_state = 0;
>> -			return PTR_ERR(opp);
>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>> +			stats->max_state = 0;
>> +			err = PTR_ERR(opp);
>> +			goto err_no_mem;
>>  		}
>>  		dev_pm_opp_put(opp);
>> -		profile->freq_table[i] = freq;
>> +		stats->freq_table[i] = freq;
>>  	}
>>  
>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>> -					    array3_size(sizeof(unsigned int),
>> -							count, count),
>> -					    GFP_KERNEL);
>> -	if (!profile->trans_table)
>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>> +					  array3_size(sizeof(unsigned int),
>> +						      count, count),
>> +					  GFP_KERNEL);
>> +	if (!stats->trans_table)
>>  		goto err_no_mem;
>>  
>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>> -					      sizeof(*profile->time_in_state),
>> -					      GFP_KERNEL);
>> -	if (!profile->time_in_state)
>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>> +					    sizeof(*stats->time_in_state),
>> +					    GFP_KERNEL);
>> +	if (!stats->time_in_state)
>>  		goto err_no_mem;
>>  
>> -	profile->last_time = get_jiffies_64();
>> -	spin_lock_init(&profile->stats_lock);
>> +	stats->last_time = get_jiffies_64();
>> +	spin_lock_init(&stats->stats_lock);
>>  
>>  	return 0;
>>  err_no_mem:
>> -	profile->max_state = 0;
>> -	return -ENOMEM;
>> +	stats->max_state = 0;
>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>> +	profile->stats = NULL;
>> +	return err;
>>  }
>>  
>>  /**
>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>   */
>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  {
>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>  	unsigned long long cur_time;
>>  	int lev, prev_lev, ret = 0;
>>  
>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  
>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>  	if (!devfreq->previous_freq) {
>> -		spin_lock(&profile->stats_lock);
>> -		profile->last_time = cur_time;
>> -		spin_unlock(&profile->stats_lock);
>> +		spin_lock(&stats->stats_lock);
>> +		stats->last_time = cur_time;
>> +		spin_unlock(&stats->stats_lock);
>>  		return 0;
>>  	}
>>  
>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>  
>> -	spin_lock(&profile->stats_lock);
>> +	spin_lock(&stats->stats_lock);
>>  	if (prev_lev < 0) {
>>  		ret = prev_lev;
>>  		goto out;
>>  	}
>>  
>> -	profile->time_in_state[prev_lev] +=
>> -			 cur_time - profile->last_time;
>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>  	if (lev < 0) {
>>  		ret = lev;
>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  	}
>>  
>>  	if (lev != prev_lev) {
>> -		profile->trans_table[(prev_lev *
>> -				profile->max_state) + lev]++;
>> -		profile->total_trans++;
>> +		stats->trans_table[(prev_lev *
>> +				stats->max_state) + lev]++;
>> +		stats->total_trans++;
>>  	}
>>  
>>  out:
>> -	profile->last_time = cur_time;
>> -	spin_unlock(&profile->stats_lock);
>> +	stats->last_time = cur_time;
>> +	spin_unlock(&stats->stats_lock);
>>  	return ret;
>>  }
>>  EXPORT_SYMBOL(devfreq_update_status);
>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>  			msecs_to_jiffies(profile->polling_ms));
>>  
>> -	spin_lock(&profile->stats_lock);
>> -	profile->last_time = get_jiffies_64();
>> -	spin_unlock(&profile->stats_lock);
>> +	spin_lock(&profile->stats->stats_lock);
>> +	profile->stats->last_time = get_jiffies_64();
>> +	spin_unlock(&profile->stats->stats_lock);
>>  	devfreq->stop_polling = false;
>>  
>>  	if (profile->get_cur_freq &&
>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>  	devfreq->data = data;
>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>  
>> -	if (!profile->max_state && !profile->freq_table) {
>> +	if (!profile->stats) {
>>  		mutex_unlock(&devfreq->lock);
>>  		err = set_freq_table(devfreq);
>>  		if (err < 0)
>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>  			      const char *buf, size_t count)
>>  {
>>  	struct devfreq *df = to_devfreq(dev);
>> +	struct devfreq_stats *stats = df->profile->stats;
>>  	unsigned long value;
>>  	int ret;
>>  
>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>  			goto unlock;
>>  		}
>>  	} else {
>> -		unsigned long *freq_table = df->profile->freq_table;
>> +		unsigned long *freq_table = stats->freq_table;
>>  
>>  		/* Get minimum frequency according to sorting order */
>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>  			value = freq_table[0];
>>  		else
>> -			value = freq_table[df->profile->max_state - 1];
>> +			value = freq_table[stats->max_state - 1];
>>  	}
>>  
>>  	df->min_freq = value;
>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>  			      const char *buf, size_t count)
>>  {
>>  	struct devfreq *df = to_devfreq(dev);
>> +	struct devfreq_stats *stats = df->profile->stats;
>>  	unsigned long value;
>>  	int ret;
>>  
>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>  			goto unlock;
>>  		}
>>  	} else {
>> -		unsigned long *freq_table = df->profile->freq_table;
>> +		unsigned long *freq_table = stats->freq_table;
>>  
>>  		/* Get maximum frequency according to sorting order */
>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>> -			value = freq_table[df->profile->max_state - 1];
>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>> +			value = freq_table[stats->max_state - 1];
>>  		else
>>  			value = freq_table[0];
>>  	}
>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>  					  char *buf)
>>  {
>>  	struct devfreq *df = to_devfreq(d);
>> +	struct devfreq_stats *stats = df->profile->stats;
>>  	ssize_t count = 0;
>>  	int i;
>>  
>>  	mutex_lock(&df->lock);
>>  
>> -	for (i = 0; i < df->profile->max_state; i++)
>> +	for (i = 0; i < stats->max_state; i++)
>>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>> -				"%lu ", df->profile->freq_table[i]);
>> +				"%lu ", stats->freq_table[i]);
>>  
>>  	mutex_unlock(&df->lock);
>>  	/* Truncate the trailing space */
>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>  {
>>  	struct devfreq *devfreq = to_devfreq(dev);
>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>> +	struct devfreq_stats *stats = profile->stats;
>> +	unsigned int max_state = stats->max_state;
>>  	ssize_t len;
>>  	int i, j;
>> -	unsigned int max_state = profile->max_state;
>>  
>>  	if (!devfreq->stop_polling &&
>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>  	len = sprintf(buf, "     From  :   To\n");
>>  	len += sprintf(buf + len, "           :");
>>  
>> -	spin_lock(&profile->stats_lock);
>> +	spin_lock(&stats->stats_lock);
>>  	for (i = 0; i < max_state; i++)
>>  		len += sprintf(buf + len, "%10lu",
>> -				profile->freq_table[i]);
>> +				stats->freq_table[i]);
>>  
>>  	len += sprintf(buf + len, "   time(ms)\n");
>>  
>>  	for (i = 0; i < max_state; i++) {
>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>  			len += sprintf(buf + len, "*");
>>  		else
>>  			len += sprintf(buf + len, " ");
>>  
>>  		len += sprintf(buf + len, "%10lu:",
>> -				profile->freq_table[i]);
>> +				stats->freq_table[i]);
>>  		for (j = 0; j < max_state; j++)
>>  			len += sprintf(buf + len, "%10u",
>> -				profile->trans_table[(i * max_state) + j]);
>> +				stats->trans_table[(i * max_state) + j]);
>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>  	}
>>  
>>  	len += sprintf(buf + len, "Total transition : %u\n",
>> -					profile->total_trans);
>> -	spin_unlock(&profile->stats_lock);
>> +					stats->total_trans);
>> +	spin_unlock(&stats->stats_lock);
>>  	return len;
>>  }
>>  static DEVICE_ATTR_RO(trans_stat);
>>  
>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>  {
>> -	unsigned int count = profile->max_state;
>> -
>> -	spin_lock(&profile->stats_lock);
>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>> -	profile->last_time = get_jiffies_64();
>> -	profile->total_trans = 0;
>> -	spin_unlock(&profile->stats_lock);
>> +	unsigned int count = stats->max_state;
>> +
>> +	spin_lock(&stats->stats_lock);
>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>> +	stats->last_time = get_jiffies_64();
>> +	stats->total_trans = 0;
>> +	spin_unlock(&stats->stats_lock);
>>  }
>>  
>>  static ssize_t trans_reset_store(struct device *dev,
>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>  {
>>  	struct devfreq *devfreq = to_devfreq(dev);
>>  
>> -	defvreq_stats_clear_table(devfreq->profile);
>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>  
>>  	return count;
>>  }
>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>> index d9f377912c10..b212aae2bb3e 100644
>> --- a/drivers/devfreq/exynos-bus.c
>> +++ b/drivers/devfreq/exynos-bus.c
>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>  	}
>>  
>>  out:
>> -	max_state = bus->devfreq->profile->max_state;
>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>> +	max_state = profile->stats->max_state;
>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>  			dev_name(dev), min_freq, max_freq);
>>  
>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>> index 58308948b863..b2d87a88335c 100644
>> --- a/drivers/devfreq/governor_passive.c
>> +++ b/drivers/devfreq/governor_passive.c
>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>  	struct devfreq_passive_data *p_data
>>  			= (struct devfreq_passive_data *)devfreq->data;
>>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>> +	struct devfreq_stats *stats;
>>  	unsigned long child_freq = ULONG_MAX;
>>  	struct dev_pm_opp *opp;
>>  	int i, count, ret = 0;
>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>  	 * device. And then the index is used for getting the suitable
>>  	 * new frequency for passive devfreq device.
>>  	 */
>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>> -		|| devfreq->profile->max_state <= 0)
>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>> +	    devfreq->profile->stats->max_state <= 0 ||
>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>  		return -EINVAL;
>>  
>> +	stats = devfreq->profile->stats;
>> +	parent_stats = parent_devfreq->profile->stats;
>>  	/*
>>  	 * The passive governor have to get the correct frequency from OPP
>>  	 * list of parent device. Because in this case, *freq is temporary
>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>  	 * Get the OPP table's index of decided freqeuncy by governor
>>  	 * of parent device.
>>  	 */
>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>> +	for (i = 0; i < parent_stats->max_state; i++)
>> +		if (parent_stats->freq_table[i] == *freq)
>>  			break;
>>  
>> -	if (i == parent_devfreq->profile->max_state) {
>> +	if (i == parent_stats->max_state) {
>>  		ret = -EINVAL;
>>  		goto out;
>>  	}
>>  
>>  	/* Get the suitable frequency by using index of parent device. */
>> -	if (i < devfreq->profile->max_state) {
>> -		child_freq = devfreq->profile->freq_table[i];
>> +	if (i < stats->max_state) {
>> +		child_freq = stats->freq_table[i];
>>  	} else {
>> -		count = devfreq->profile->max_state;
>> -		child_freq = devfreq->profile->freq_table[count - 1];
>> +		count = stats->max_state;
>> +		child_freq = stats->freq_table[count - 1];
>>  	}
>>  
>>  	/* Return the suitable frequency for passive device. */
>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>  	if (ret < 0)
>>  		goto out;
>>  
>> -	if (devfreq->profile->freq_table
>> +	if (devfreq->profile->stats
>>  		&& (devfreq_update_status(devfreq, freq)))
>>  		dev_err(&devfreq->dev,
>>  			"Couldn't update frequency transition information.\n");
>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>> index 4ceb2a517a9c..8459af1a1583 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>   */
>>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>  
>> +/**
>> + * struct devfreq_stats - Devfreq's transitions stats counters
>> + * @freq_table:		Optional list of frequencies to support statistics
>> + *			and freq_table must be generated in ascending order.
>> + * @max_state:		The size of freq_table.
>> + * @total_trans:	Number of devfreq transitions
>> + * @trans_table:	Statistics of devfreq transitions
>> + * @time_in_state:	Statistics of devfreq states
>> + * @last_time:		The last time stats were updated
>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>> + *			last_time and total_trans used for statistics
>> + */
>> +struct devfreq_stats {
>> +	unsigned long *freq_table;
>> +	unsigned int max_state;
>> +
>> +	/* information for device frequency transition */
>> +	unsigned int total_trans;
>> +	unsigned int *trans_table;
>> +	u64 *time_in_state;
>> +	unsigned long long last_time;
>> +	spinlock_t stats_lock;
>> +};
>> +
>>  /**
>>   * struct devfreq_dev_profile - Devfreq's user device profile
>>   * @initial_freq:	The operating frequency when devfreq_add_device() is
>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>   *			from devfreq_remove_device() call. If the user
>>   *			has registered devfreq->nb at a notifier-head,
>>   *			this is the time to unregister it.
>> - * @freq_table:		Optional list of frequencies to support statistics
>> - *			and freq_table must be generated in ascending order.
>> - * @max_state:		The size of freq_table.
>> - * @total_trans:	Number of devfreq transitions
>> - * @trans_table:	Statistics of devfreq transitions
>> - * @time_in_state:	Statistics of devfreq states
>> - * @last_time:		The last time stats were updated
>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>> - *			last_time and total_trans used for statistics
>> + * @stats:		Statistics of devfreq states and state transitions
>>   */
>>  struct devfreq_dev_profile {
>>  	unsigned long initial_freq;
>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>  	void (*exit)(struct device *dev);
>>  
>> -	unsigned long *freq_table;
>> -	unsigned int max_state;
>> -	/* information for device frequency transition */
>> -	unsigned int total_trans;
>> -	unsigned int *trans_table;
>> -	u64 *time_in_state;
>> -	unsigned long long last_time;
>> -	spinlock_t stats_lock;
>> +	struct devfreq_stats *stats;
>>  };
>>  
>>  /**
>>

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Bartlomiej Zolnierkiewicz]

Hi Chanwoo,

On 11/14/19 2:52 AM, Chanwoo Choi wrote:
> Hi Kamil,
> 
> The 'freq_table' and 'max_state' in the devfreq_dev_profile
> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
> device driver was posted to mainline kernel, they used
> them for a long time. It means that this patch break
> the compatibility. The ARM Mali drivers are very
> important devfreq device driver. 

This argument is not a a technical one and the official upstream
kernel policy is to not depend on out-of-tree drivers.

Besides the ARM Mali drivers are full of code like:

#if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
...
#else
...
#endif

so few more instances of similar code won't do any harm.. ;-)

> [1] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
> [2] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
> [3] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel

I took a look at ARM Mali drivers source code anyway and I fail to
see a rationale behind their behavior of doing 'freq_table' and
'max_state' initialization in the driver itself (instead of leaving
it up to the devfreq core code, like all in-kernel drivers are doing
already).

Could you please explain rationale behind ARM Mali drivers' special
needs?

[ Both ARM Mali and devfreq core code are using generic PM OPP code
  these days to do 'freq_table' and 'max_state' initialization, the
  only difference seems to be that ARM Mali creates the frequency
  table in the descending order (but there also seems to be no real
  need for it). ]

Maybe this is an opportunity to simplify also the ARM Mali driver?

> Also, the devfreq device driver specifies their own
> information and data into devfreq_dev_profile structure 
> before registering the devfreq device with devfreq_add_device().
> This patch breaks the basic usage rule of devfreq_dev_profile structure.

Well, 'struct devfreq_stats *stats' can be trivially moved out of
'struct devfreq_profile' to 'struct devfreq' if you prefer it that
way..

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> So, I can't agree this patch. Not ack.
> 
> Regards,
> Chanwoo Choi
> 
> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>> Count time and transitions between devfreq frequencies in separate struct
>> for improved code readability and maintenance.
>>
>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>> ---
>>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>  drivers/devfreq/exynos-bus.c       |   6 +-
>>  drivers/devfreq/governor_passive.c |  26 +++--
>>  include/linux/devfreq.h            |  43 ++++----
>>  4 files changed, 129 insertions(+), 102 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index d79412b0de59..d85867a91230 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>   */
>>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>  {
>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>  	int lev;
>>  
>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>> -		if (freq == devfreq->profile->freq_table[lev])
>> +	for (lev = 0; lev < stats->max_state; lev++)
>> +		if (freq == stats->freq_table[lev])
>>  			return lev;
>>  
>>  	return -EINVAL;
>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>  static int set_freq_table(struct devfreq *devfreq)
>>  {
>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>> +	struct devfreq_stats *stats;
>>  	struct dev_pm_opp *opp;
>>  	unsigned long freq;
>> -	int i, count;
>> +	int i, count, err = -ENOMEM;
>>  
>>  	/* Initialize the freq_table from OPP table */
>>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>  	if (count <= 0)
>>  		return -EINVAL;
>>  
>> -	profile->max_state = count;
>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>> -					count,
>> -					sizeof(*profile->freq_table),
>> -					GFP_KERNEL);
>> -	if (!profile->freq_table) {
>> -		profile->max_state = 0;
>> +	stats = devm_kzalloc(devfreq->dev.parent,
>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>> +	if (!stats)
>>  		return -ENOMEM;
>> -	}
>>  
>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>> +	profile->stats = stats;
>> +	stats->max_state = count;
>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>> +					 count,
>> +					 sizeof(*stats->freq_table),
>> +					 GFP_KERNEL);
>> +	if (!stats->freq_table)
>> +		goto err_no_mem;
>> +
>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>  		if (IS_ERR(opp)) {
>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>> -			profile->max_state = 0;
>> -			return PTR_ERR(opp);
>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>> +			stats->max_state = 0;
>> +			err = PTR_ERR(opp);
>> +			goto err_no_mem;
>>  		}
>>  		dev_pm_opp_put(opp);
>> -		profile->freq_table[i] = freq;
>> +		stats->freq_table[i] = freq;
>>  	}
>>  
>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>> -					    array3_size(sizeof(unsigned int),
>> -							count, count),
>> -					    GFP_KERNEL);
>> -	if (!profile->trans_table)
>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>> +					  array3_size(sizeof(unsigned int),
>> +						      count, count),
>> +					  GFP_KERNEL);
>> +	if (!stats->trans_table)
>>  		goto err_no_mem;
>>  
>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>> -					      sizeof(*profile->time_in_state),
>> -					      GFP_KERNEL);
>> -	if (!profile->time_in_state)
>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>> +					    sizeof(*stats->time_in_state),
>> +					    GFP_KERNEL);
>> +	if (!stats->time_in_state)
>>  		goto err_no_mem;
>>  
>> -	profile->last_time = get_jiffies_64();
>> -	spin_lock_init(&profile->stats_lock);
>> +	stats->last_time = get_jiffies_64();
>> +	spin_lock_init(&stats->stats_lock);
>>  
>>  	return 0;
>>  err_no_mem:
>> -	profile->max_state = 0;
>> -	return -ENOMEM;
>> +	stats->max_state = 0;
>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>> +	profile->stats = NULL;
>> +	return err;
>>  }
>>  
>>  /**
>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>   */
>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  {
>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>  	unsigned long long cur_time;
>>  	int lev, prev_lev, ret = 0;
>>  
>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  
>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>  	if (!devfreq->previous_freq) {
>> -		spin_lock(&profile->stats_lock);
>> -		profile->last_time = cur_time;
>> -		spin_unlock(&profile->stats_lock);
>> +		spin_lock(&stats->stats_lock);
>> +		stats->last_time = cur_time;
>> +		spin_unlock(&stats->stats_lock);
>>  		return 0;
>>  	}
>>  
>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>  
>> -	spin_lock(&profile->stats_lock);
>> +	spin_lock(&stats->stats_lock);
>>  	if (prev_lev < 0) {
>>  		ret = prev_lev;
>>  		goto out;
>>  	}
>>  
>> -	profile->time_in_state[prev_lev] +=
>> -			 cur_time - profile->last_time;
>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>  	if (lev < 0) {
>>  		ret = lev;
>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>  	}
>>  
>>  	if (lev != prev_lev) {
>> -		profile->trans_table[(prev_lev *
>> -				profile->max_state) + lev]++;
>> -		profile->total_trans++;
>> +		stats->trans_table[(prev_lev *
>> +				stats->max_state) + lev]++;
>> +		stats->total_trans++;
>>  	}
>>  
>>  out:
>> -	profile->last_time = cur_time;
>> -	spin_unlock(&profile->stats_lock);
>> +	stats->last_time = cur_time;
>> +	spin_unlock(&stats->stats_lock);
>>  	return ret;
>>  }
>>  EXPORT_SYMBOL(devfreq_update_status);
>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>  			msecs_to_jiffies(profile->polling_ms));
>>  
>> -	spin_lock(&profile->stats_lock);
>> -	profile->last_time = get_jiffies_64();
>> -	spin_unlock(&profile->stats_lock);
>> +	spin_lock(&profile->stats->stats_lock);
>> +	profile->stats->last_time = get_jiffies_64();
>> +	spin_unlock(&profile->stats->stats_lock);
>>  	devfreq->stop_polling = false;
>>  
>>  	if (profile->get_cur_freq &&
>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>  	devfreq->data = data;
>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>  
>> -	if (!profile->max_state && !profile->freq_table) {
>> +	if (!profile->stats) {
>>  		mutex_unlock(&devfreq->lock);
>>  		err = set_freq_table(devfreq);
>>  		if (err < 0)
>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>  			      const char *buf, size_t count)
>>  {
>>  	struct devfreq *df = to_devfreq(dev);
>> +	struct devfreq_stats *stats = df->profile->stats;
>>  	unsigned long value;
>>  	int ret;
>>  
>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>  			goto unlock;
>>  		}
>>  	} else {
>> -		unsigned long *freq_table = df->profile->freq_table;
>> +		unsigned long *freq_table = stats->freq_table;
>>  
>>  		/* Get minimum frequency according to sorting order */
>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>  			value = freq_table[0];
>>  		else
>> -			value = freq_table[df->profile->max_state - 1];
>> +			value = freq_table[stats->max_state - 1];
>>  	}
>>  
>>  	df->min_freq = value;
>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>  			      const char *buf, size_t count)
>>  {
>>  	struct devfreq *df = to_devfreq(dev);
>> +	struct devfreq_stats *stats = df->profile->stats;
>>  	unsigned long value;
>>  	int ret;
>>  
>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>  			goto unlock;
>>  		}
>>  	} else {
>> -		unsigned long *freq_table = df->profile->freq_table;
>> +		unsigned long *freq_table = stats->freq_table;
>>  
>>  		/* Get maximum frequency according to sorting order */
>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>> -			value = freq_table[df->profile->max_state - 1];
>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>> +			value = freq_table[stats->max_state - 1];
>>  		else
>>  			value = freq_table[0];
>>  	}
>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>  					  char *buf)
>>  {
>>  	struct devfreq *df = to_devfreq(d);
>> +	struct devfreq_stats *stats = df->profile->stats;
>>  	ssize_t count = 0;
>>  	int i;
>>  
>>  	mutex_lock(&df->lock);
>>  
>> -	for (i = 0; i < df->profile->max_state; i++)
>> +	for (i = 0; i < stats->max_state; i++)
>>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>> -				"%lu ", df->profile->freq_table[i]);
>> +				"%lu ", stats->freq_table[i]);
>>  
>>  	mutex_unlock(&df->lock);
>>  	/* Truncate the trailing space */
>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>  {
>>  	struct devfreq *devfreq = to_devfreq(dev);
>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>> +	struct devfreq_stats *stats = profile->stats;
>> +	unsigned int max_state = stats->max_state;
>>  	ssize_t len;
>>  	int i, j;
>> -	unsigned int max_state = profile->max_state;
>>  
>>  	if (!devfreq->stop_polling &&
>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>  	len = sprintf(buf, "     From  :   To\n");
>>  	len += sprintf(buf + len, "           :");
>>  
>> -	spin_lock(&profile->stats_lock);
>> +	spin_lock(&stats->stats_lock);
>>  	for (i = 0; i < max_state; i++)
>>  		len += sprintf(buf + len, "%10lu",
>> -				profile->freq_table[i]);
>> +				stats->freq_table[i]);
>>  
>>  	len += sprintf(buf + len, "   time(ms)\n");
>>  
>>  	for (i = 0; i < max_state; i++) {
>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>  			len += sprintf(buf + len, "*");
>>  		else
>>  			len += sprintf(buf + len, " ");
>>  
>>  		len += sprintf(buf + len, "%10lu:",
>> -				profile->freq_table[i]);
>> +				stats->freq_table[i]);
>>  		for (j = 0; j < max_state; j++)
>>  			len += sprintf(buf + len, "%10u",
>> -				profile->trans_table[(i * max_state) + j]);
>> +				stats->trans_table[(i * max_state) + j]);
>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>  	}
>>  
>>  	len += sprintf(buf + len, "Total transition : %u\n",
>> -					profile->total_trans);
>> -	spin_unlock(&profile->stats_lock);
>> +					stats->total_trans);
>> +	spin_unlock(&stats->stats_lock);
>>  	return len;
>>  }
>>  static DEVICE_ATTR_RO(trans_stat);
>>  
>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>  {
>> -	unsigned int count = profile->max_state;
>> -
>> -	spin_lock(&profile->stats_lock);
>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>> -	profile->last_time = get_jiffies_64();
>> -	profile->total_trans = 0;
>> -	spin_unlock(&profile->stats_lock);
>> +	unsigned int count = stats->max_state;
>> +
>> +	spin_lock(&stats->stats_lock);
>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>> +	stats->last_time = get_jiffies_64();
>> +	stats->total_trans = 0;
>> +	spin_unlock(&stats->stats_lock);
>>  }
>>  
>>  static ssize_t trans_reset_store(struct device *dev,
>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>  {
>>  	struct devfreq *devfreq = to_devfreq(dev);
>>  
>> -	defvreq_stats_clear_table(devfreq->profile);
>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>  
>>  	return count;
>>  }
>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>> index d9f377912c10..b212aae2bb3e 100644
>> --- a/drivers/devfreq/exynos-bus.c
>> +++ b/drivers/devfreq/exynos-bus.c
>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>  	}
>>  
>>  out:
>> -	max_state = bus->devfreq->profile->max_state;
>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>> +	max_state = profile->stats->max_state;
>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>  			dev_name(dev), min_freq, max_freq);
>>  
>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>> index 58308948b863..b2d87a88335c 100644
>> --- a/drivers/devfreq/governor_passive.c
>> +++ b/drivers/devfreq/governor_passive.c
>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>  	struct devfreq_passive_data *p_data
>>  			= (struct devfreq_passive_data *)devfreq->data;
>>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>> +	struct devfreq_stats *stats;
>>  	unsigned long child_freq = ULONG_MAX;
>>  	struct dev_pm_opp *opp;
>>  	int i, count, ret = 0;
>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>  	 * device. And then the index is used for getting the suitable
>>  	 * new frequency for passive devfreq device.
>>  	 */
>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>> -		|| devfreq->profile->max_state <= 0)
>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>> +	    devfreq->profile->stats->max_state <= 0 ||
>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>  		return -EINVAL;
>>  
>> +	stats = devfreq->profile->stats;
>> +	parent_stats = parent_devfreq->profile->stats;
>>  	/*
>>  	 * The passive governor have to get the correct frequency from OPP
>>  	 * list of parent device. Because in this case, *freq is temporary
>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>  	 * Get the OPP table's index of decided freqeuncy by governor
>>  	 * of parent device.
>>  	 */
>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>> +	for (i = 0; i < parent_stats->max_state; i++)
>> +		if (parent_stats->freq_table[i] == *freq)
>>  			break;
>>  
>> -	if (i == parent_devfreq->profile->max_state) {
>> +	if (i == parent_stats->max_state) {
>>  		ret = -EINVAL;
>>  		goto out;
>>  	}
>>  
>>  	/* Get the suitable frequency by using index of parent device. */
>> -	if (i < devfreq->profile->max_state) {
>> -		child_freq = devfreq->profile->freq_table[i];
>> +	if (i < stats->max_state) {
>> +		child_freq = stats->freq_table[i];
>>  	} else {
>> -		count = devfreq->profile->max_state;
>> -		child_freq = devfreq->profile->freq_table[count - 1];
>> +		count = stats->max_state;
>> +		child_freq = stats->freq_table[count - 1];
>>  	}
>>  
>>  	/* Return the suitable frequency for passive device. */
>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>  	if (ret < 0)
>>  		goto out;
>>  
>> -	if (devfreq->profile->freq_table
>> +	if (devfreq->profile->stats
>>  		&& (devfreq_update_status(devfreq, freq)))
>>  		dev_err(&devfreq->dev,
>>  			"Couldn't update frequency transition information.\n");
>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>> index 4ceb2a517a9c..8459af1a1583 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>   */
>>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>  
>> +/**
>> + * struct devfreq_stats - Devfreq's transitions stats counters
>> + * @freq_table:		Optional list of frequencies to support statistics
>> + *			and freq_table must be generated in ascending order.
>> + * @max_state:		The size of freq_table.
>> + * @total_trans:	Number of devfreq transitions
>> + * @trans_table:	Statistics of devfreq transitions
>> + * @time_in_state:	Statistics of devfreq states
>> + * @last_time:		The last time stats were updated
>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>> + *			last_time and total_trans used for statistics
>> + */
>> +struct devfreq_stats {
>> +	unsigned long *freq_table;
>> +	unsigned int max_state;
>> +
>> +	/* information for device frequency transition */
>> +	unsigned int total_trans;
>> +	unsigned int *trans_table;
>> +	u64 *time_in_state;
>> +	unsigned long long last_time;
>> +	spinlock_t stats_lock;
>> +};
>> +
>>  /**
>>   * struct devfreq_dev_profile - Devfreq's user device profile
>>   * @initial_freq:	The operating frequency when devfreq_add_device() is
>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>   *			from devfreq_remove_device() call. If the user
>>   *			has registered devfreq->nb at a notifier-head,
>>   *			this is the time to unregister it.
>> - * @freq_table:		Optional list of frequencies to support statistics
>> - *			and freq_table must be generated in ascending order.
>> - * @max_state:		The size of freq_table.
>> - * @total_trans:	Number of devfreq transitions
>> - * @trans_table:	Statistics of devfreq transitions
>> - * @time_in_state:	Statistics of devfreq states
>> - * @last_time:		The last time stats were updated
>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>> - *			last_time and total_trans used for statistics
>> + * @stats:		Statistics of devfreq states and state transitions
>>   */
>>  struct devfreq_dev_profile {
>>  	unsigned long initial_freq;
>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>  	void (*exit)(struct device *dev);
>>  
>> -	unsigned long *freq_table;
>> -	unsigned int max_state;
>> -	/* information for device frequency transition */
>> -	unsigned int total_trans;
>> -	unsigned int *trans_table;
>> -	u64 *time_in_state;
>> -	unsigned long long last_time;
>> -	spinlock_t stats_lock;
>> +	struct devfreq_stats *stats;
>>  };
>>  
>>  /**
>>

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Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Chanwoo Choi]

Hi Bartlomiej,

On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
> 
> Hi Chanwoo,
> 
> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>> Hi Kamil,
>>
>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>> device driver was posted to mainline kernel, they used
>> them for a long time. It means that this patch break
>> the compatibility. The ARM Mali drivers are very
>> important devfreq device driver. 
> 
> This argument is not a a technical one and the official upstream
> kernel policy is to not depend on out-of-tree drivers.
> 
> Besides the ARM Mali drivers are full of code like:
> 
> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
> ...
> #else
> ...
> #endif
> 
> so few more instances of similar code won't do any harm.. ;-)
> 
>> [1] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>> [2] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>> [3] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
> 
> I took a look at ARM Mali drivers source code anyway and I fail to
> see a rationale behind their behavior of doing 'freq_table' and
> 'max_state' initialization in the driver itself (instead of leaving
> it up to the devfreq core code, like all in-kernel drivers are doing
> already).
> 
> Could you please explain rationale behind ARM Mali drivers' special
> needs?
> 
> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>   these days to do 'freq_table' and 'max_state' initialization, the
>   only difference seems to be that ARM Mali creates the frequency
>   table in the descending order (but there also seems to be no real
>   need for it). ]
> 
> Maybe this is an opportunity to simplify also the ARM Mali driver?

OK. I agree to simplify them on this time.
For touching the 'freq_table' and 'max_state', need to fix
the descending order of freq_table. 

The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
requires the descending order of freq_table. Have to change it by using
the ascending time or support both ascending and descending order for freq_table.

1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
   by using ascending order instead of descending order.

> 
>> Also, the devfreq device driver specifies their own
>> information and data into devfreq_dev_profile structure 
>> before registering the devfreq device with devfreq_add_device().
>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
> 
> Well, 'struct devfreq_stats *stats' can be trivially moved out of
> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
> way..
> 
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
> 
>> So, I can't agree this patch. Not ack.
>>
>> Regards,
>> Chanwoo Choi
>>
>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>> Count time and transitions between devfreq frequencies in separate struct
>>> for improved code readability and maintenance.
>>>
>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>> ---
>>>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>  drivers/devfreq/exynos-bus.c       |   6 +-
>>>  drivers/devfreq/governor_passive.c |  26 +++--
>>>  include/linux/devfreq.h            |  43 ++++----
>>>  4 files changed, 129 insertions(+), 102 deletions(-)
>>>
>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>> index d79412b0de59..d85867a91230 100644
>>> --- a/drivers/devfreq/devfreq.c
>>> +++ b/drivers/devfreq/devfreq.c
>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>   */
>>>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>  {
>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>  	int lev;
>>>  
>>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>> -		if (freq == devfreq->profile->freq_table[lev])
>>> +	for (lev = 0; lev < stats->max_state; lev++)
>>> +		if (freq == stats->freq_table[lev])
>>>  			return lev;
>>>  
>>>  	return -EINVAL;
>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>  static int set_freq_table(struct devfreq *devfreq)
>>>  {
>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>> +	struct devfreq_stats *stats;
>>>  	struct dev_pm_opp *opp;
>>>  	unsigned long freq;
>>> -	int i, count;
>>> +	int i, count, err = -ENOMEM;
>>>  
>>>  	/* Initialize the freq_table from OPP table */
>>>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>  	if (count <= 0)
>>>  		return -EINVAL;
>>>  
>>> -	profile->max_state = count;
>>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>> -					count,
>>> -					sizeof(*profile->freq_table),
>>> -					GFP_KERNEL);
>>> -	if (!profile->freq_table) {
>>> -		profile->max_state = 0;
>>> +	stats = devm_kzalloc(devfreq->dev.parent,
>>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>>> +	if (!stats)
>>>  		return -ENOMEM;
>>> -	}
>>>  
>>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>> +	profile->stats = stats;
>>> +	stats->max_state = count;
>>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>> +					 count,
>>> +					 sizeof(*stats->freq_table),
>>> +					 GFP_KERNEL);
>>> +	if (!stats->freq_table)
>>> +		goto err_no_mem;
>>> +
>>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>  		if (IS_ERR(opp)) {
>>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>>> -			profile->max_state = 0;
>>> -			return PTR_ERR(opp);
>>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>>> +			stats->max_state = 0;
>>> +			err = PTR_ERR(opp);
>>> +			goto err_no_mem;
>>>  		}
>>>  		dev_pm_opp_put(opp);
>>> -		profile->freq_table[i] = freq;
>>> +		stats->freq_table[i] = freq;
>>>  	}
>>>  
>>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>> -					    array3_size(sizeof(unsigned int),
>>> -							count, count),
>>> -					    GFP_KERNEL);
>>> -	if (!profile->trans_table)
>>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>> +					  array3_size(sizeof(unsigned int),
>>> +						      count, count),
>>> +					  GFP_KERNEL);
>>> +	if (!stats->trans_table)
>>>  		goto err_no_mem;
>>>  
>>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>> -					      sizeof(*profile->time_in_state),
>>> -					      GFP_KERNEL);
>>> -	if (!profile->time_in_state)
>>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>> +					    sizeof(*stats->time_in_state),
>>> +					    GFP_KERNEL);
>>> +	if (!stats->time_in_state)
>>>  		goto err_no_mem;
>>>  
>>> -	profile->last_time = get_jiffies_64();
>>> -	spin_lock_init(&profile->stats_lock);
>>> +	stats->last_time = get_jiffies_64();
>>> +	spin_lock_init(&stats->stats_lock);
>>>  
>>>  	return 0;
>>>  err_no_mem:
>>> -	profile->max_state = 0;
>>> -	return -ENOMEM;
>>> +	stats->max_state = 0;
>>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>>> +	profile->stats = NULL;
>>> +	return err;
>>>  }
>>>  
>>>  /**
>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>   */
>>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>  {
>>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>  	unsigned long long cur_time;
>>>  	int lev, prev_lev, ret = 0;
>>>  
>>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>  
>>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>>  	if (!devfreq->previous_freq) {
>>> -		spin_lock(&profile->stats_lock);
>>> -		profile->last_time = cur_time;
>>> -		spin_unlock(&profile->stats_lock);
>>> +		spin_lock(&stats->stats_lock);
>>> +		stats->last_time = cur_time;
>>> +		spin_unlock(&stats->stats_lock);
>>>  		return 0;
>>>  	}
>>>  
>>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>  
>>> -	spin_lock(&profile->stats_lock);
>>> +	spin_lock(&stats->stats_lock);
>>>  	if (prev_lev < 0) {
>>>  		ret = prev_lev;
>>>  		goto out;
>>>  	}
>>>  
>>> -	profile->time_in_state[prev_lev] +=
>>> -			 cur_time - profile->last_time;
>>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>>  	if (lev < 0) {
>>>  		ret = lev;
>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>  	}
>>>  
>>>  	if (lev != prev_lev) {
>>> -		profile->trans_table[(prev_lev *
>>> -				profile->max_state) + lev]++;
>>> -		profile->total_trans++;
>>> +		stats->trans_table[(prev_lev *
>>> +				stats->max_state) + lev]++;
>>> +		stats->total_trans++;
>>>  	}
>>>  
>>>  out:
>>> -	profile->last_time = cur_time;
>>> -	spin_unlock(&profile->stats_lock);
>>> +	stats->last_time = cur_time;
>>> +	spin_unlock(&stats->stats_lock);
>>>  	return ret;
>>>  }
>>>  EXPORT_SYMBOL(devfreq_update_status);
>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>>  			msecs_to_jiffies(profile->polling_ms));
>>>  
>>> -	spin_lock(&profile->stats_lock);
>>> -	profile->last_time = get_jiffies_64();
>>> -	spin_unlock(&profile->stats_lock);
>>> +	spin_lock(&profile->stats->stats_lock);
>>> +	profile->stats->last_time = get_jiffies_64();
>>> +	spin_unlock(&profile->stats->stats_lock);
>>>  	devfreq->stop_polling = false;
>>>  
>>>  	if (profile->get_cur_freq &&
>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>  	devfreq->data = data;
>>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>>  
>>> -	if (!profile->max_state && !profile->freq_table) {
>>> +	if (!profile->stats) {
>>>  		mutex_unlock(&devfreq->lock);
>>>  		err = set_freq_table(devfreq);
>>>  		if (err < 0)
>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>  			      const char *buf, size_t count)
>>>  {
>>>  	struct devfreq *df = to_devfreq(dev);
>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>  	unsigned long value;
>>>  	int ret;
>>>  
>>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>  			goto unlock;
>>>  		}
>>>  	} else {
>>> -		unsigned long *freq_table = df->profile->freq_table;
>>> +		unsigned long *freq_table = stats->freq_table;
>>>  
>>>  		/* Get minimum frequency according to sorting order */
>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>  			value = freq_table[0];
>>>  		else
>>> -			value = freq_table[df->profile->max_state - 1];
>>> +			value = freq_table[stats->max_state - 1];
>>>  	}
>>>  
>>>  	df->min_freq = value;
>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>  			      const char *buf, size_t count)
>>>  {
>>>  	struct devfreq *df = to_devfreq(dev);
>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>  	unsigned long value;
>>>  	int ret;
>>>  
>>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>  			goto unlock;
>>>  		}
>>>  	} else {
>>> -		unsigned long *freq_table = df->profile->freq_table;
>>> +		unsigned long *freq_table = stats->freq_table;
>>>  
>>>  		/* Get maximum frequency according to sorting order */
>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>> -			value = freq_table[df->profile->max_state - 1];
>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>> +			value = freq_table[stats->max_state - 1];
>>>  		else
>>>  			value = freq_table[0];
>>>  	}
>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>  					  char *buf)
>>>  {
>>>  	struct devfreq *df = to_devfreq(d);
>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>  	ssize_t count = 0;
>>>  	int i;
>>>  
>>>  	mutex_lock(&df->lock);
>>>  
>>> -	for (i = 0; i < df->profile->max_state; i++)
>>> +	for (i = 0; i < stats->max_state; i++)
>>>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>> -				"%lu ", df->profile->freq_table[i]);
>>> +				"%lu ", stats->freq_table[i]);
>>>  
>>>  	mutex_unlock(&df->lock);
>>>  	/* Truncate the trailing space */
>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>  {
>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>> +	struct devfreq_stats *stats = profile->stats;
>>> +	unsigned int max_state = stats->max_state;
>>>  	ssize_t len;
>>>  	int i, j;
>>> -	unsigned int max_state = profile->max_state;
>>>  
>>>  	if (!devfreq->stop_polling &&
>>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>  	len = sprintf(buf, "     From  :   To\n");
>>>  	len += sprintf(buf + len, "           :");
>>>  
>>> -	spin_lock(&profile->stats_lock);
>>> +	spin_lock(&stats->stats_lock);
>>>  	for (i = 0; i < max_state; i++)
>>>  		len += sprintf(buf + len, "%10lu",
>>> -				profile->freq_table[i]);
>>> +				stats->freq_table[i]);
>>>  
>>>  	len += sprintf(buf + len, "   time(ms)\n");
>>>  
>>>  	for (i = 0; i < max_state; i++) {
>>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>>  			len += sprintf(buf + len, "*");
>>>  		else
>>>  			len += sprintf(buf + len, " ");
>>>  
>>>  		len += sprintf(buf + len, "%10lu:",
>>> -				profile->freq_table[i]);
>>> +				stats->freq_table[i]);
>>>  		for (j = 0; j < max_state; j++)
>>>  			len += sprintf(buf + len, "%10u",
>>> -				profile->trans_table[(i * max_state) + j]);
>>> +				stats->trans_table[(i * max_state) + j]);
>>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>>  	}
>>>  
>>>  	len += sprintf(buf + len, "Total transition : %u\n",
>>> -					profile->total_trans);
>>> -	spin_unlock(&profile->stats_lock);
>>> +					stats->total_trans);
>>> +	spin_unlock(&stats->stats_lock);
>>>  	return len;
>>>  }
>>>  static DEVICE_ATTR_RO(trans_stat);
>>>  
>>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>  {
>>> -	unsigned int count = profile->max_state;
>>> -
>>> -	spin_lock(&profile->stats_lock);
>>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>>> -	profile->last_time = get_jiffies_64();
>>> -	profile->total_trans = 0;
>>> -	spin_unlock(&profile->stats_lock);
>>> +	unsigned int count = stats->max_state;
>>> +
>>> +	spin_lock(&stats->stats_lock);
>>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>>> +	stats->last_time = get_jiffies_64();
>>> +	stats->total_trans = 0;
>>> +	spin_unlock(&stats->stats_lock);
>>>  }
>>>  
>>>  static ssize_t trans_reset_store(struct device *dev,
>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>  {
>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>  
>>> -	defvreq_stats_clear_table(devfreq->profile);
>>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>>  
>>>  	return count;
>>>  }
>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>> index d9f377912c10..b212aae2bb3e 100644
>>> --- a/drivers/devfreq/exynos-bus.c
>>> +++ b/drivers/devfreq/exynos-bus.c
>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>  	}
>>>  
>>>  out:
>>> -	max_state = bus->devfreq->profile->max_state;
>>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>> +	max_state = profile->stats->max_state;
>>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>  			dev_name(dev), min_freq, max_freq);
>>>  
>>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>> index 58308948b863..b2d87a88335c 100644
>>> --- a/drivers/devfreq/governor_passive.c
>>> +++ b/drivers/devfreq/governor_passive.c
>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>  	struct devfreq_passive_data *p_data
>>>  			= (struct devfreq_passive_data *)devfreq->data;
>>>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>> +	struct devfreq_stats *stats;
>>>  	unsigned long child_freq = ULONG_MAX;
>>>  	struct dev_pm_opp *opp;
>>>  	int i, count, ret = 0;
>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>  	 * device. And then the index is used for getting the suitable
>>>  	 * new frequency for passive devfreq device.
>>>  	 */
>>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>>> -		|| devfreq->profile->max_state <= 0)
>>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>>> +	    devfreq->profile->stats->max_state <= 0 ||
>>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>>  		return -EINVAL;
>>>  
>>> +	stats = devfreq->profile->stats;
>>> +	parent_stats = parent_devfreq->profile->stats;
>>>  	/*
>>>  	 * The passive governor have to get the correct frequency from OPP
>>>  	 * list of parent device. Because in this case, *freq is temporary
>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>  	 * Get the OPP table's index of decided freqeuncy by governor
>>>  	 * of parent device.
>>>  	 */
>>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>>> +	for (i = 0; i < parent_stats->max_state; i++)
>>> +		if (parent_stats->freq_table[i] == *freq)
>>>  			break;
>>>  
>>> -	if (i == parent_devfreq->profile->max_state) {
>>> +	if (i == parent_stats->max_state) {
>>>  		ret = -EINVAL;
>>>  		goto out;
>>>  	}
>>>  
>>>  	/* Get the suitable frequency by using index of parent device. */
>>> -	if (i < devfreq->profile->max_state) {
>>> -		child_freq = devfreq->profile->freq_table[i];
>>> +	if (i < stats->max_state) {
>>> +		child_freq = stats->freq_table[i];
>>>  	} else {
>>> -		count = devfreq->profile->max_state;
>>> -		child_freq = devfreq->profile->freq_table[count - 1];
>>> +		count = stats->max_state;
>>> +		child_freq = stats->freq_table[count - 1];
>>>  	}
>>>  
>>>  	/* Return the suitable frequency for passive device. */
>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>  	if (ret < 0)
>>>  		goto out;
>>>  
>>> -	if (devfreq->profile->freq_table
>>> +	if (devfreq->profile->stats
>>>  		&& (devfreq_update_status(devfreq, freq)))
>>>  		dev_err(&devfreq->dev,
>>>  			"Couldn't update frequency transition information.\n");
>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>> index 4ceb2a517a9c..8459af1a1583 100644
>>> --- a/include/linux/devfreq.h
>>> +++ b/include/linux/devfreq.h
>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>   */
>>>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>>  
>>> +/**
>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>> + * @freq_table:		Optional list of frequencies to support statistics
>>> + *			and freq_table must be generated in ascending order.
>>> + * @max_state:		The size of freq_table.
>>> + * @total_trans:	Number of devfreq transitions
>>> + * @trans_table:	Statistics of devfreq transitions
>>> + * @time_in_state:	Statistics of devfreq states
>>> + * @last_time:		The last time stats were updated
>>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>>> + *			last_time and total_trans used for statistics
>>> + */
>>> +struct devfreq_stats {
>>> +	unsigned long *freq_table;
>>> +	unsigned int max_state;
>>> +
>>> +	/* information for device frequency transition */
>>> +	unsigned int total_trans;
>>> +	unsigned int *trans_table;
>>> +	u64 *time_in_state;
>>> +	unsigned long long last_time;
>>> +	spinlock_t stats_lock;
>>> +};
>>> +
>>>  /**
>>>   * struct devfreq_dev_profile - Devfreq's user device profile
>>>   * @initial_freq:	The operating frequency when devfreq_add_device() is
>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>   *			from devfreq_remove_device() call. If the user
>>>   *			has registered devfreq->nb at a notifier-head,
>>>   *			this is the time to unregister it.
>>> - * @freq_table:		Optional list of frequencies to support statistics
>>> - *			and freq_table must be generated in ascending order.
>>> - * @max_state:		The size of freq_table.
>>> - * @total_trans:	Number of devfreq transitions
>>> - * @trans_table:	Statistics of devfreq transitions
>>> - * @time_in_state:	Statistics of devfreq states
>>> - * @last_time:		The last time stats were updated
>>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>>> - *			last_time and total_trans used for statistics
>>> + * @stats:		Statistics of devfreq states and state transitions
>>>   */
>>>  struct devfreq_dev_profile {
>>>  	unsigned long initial_freq;
>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>  	void (*exit)(struct device *dev);
>>>  
>>> -	unsigned long *freq_table;
>>> -	unsigned int max_state;
>>> -	/* information for device frequency transition */
>>> -	unsigned int total_trans;
>>> -	unsigned int *trans_table;
>>> -	u64 *time_in_state;
>>> -	unsigned long long last_time;
>>> -	spinlock_t stats_lock;
>>> +	struct devfreq_stats *stats;
>>>  };
>>>  
>>>  /**
>>>
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Chanwoo Choi]

Hi Bartlomiej,

On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
> 
> Hi Chanwoo,
> 
> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>> Hi Kamil,
>>
>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>> device driver was posted to mainline kernel, they used
>> them for a long time. It means that this patch break
>> the compatibility. The ARM Mali drivers are very
>> important devfreq device driver. 
> 
> This argument is not a a technical one and the official upstream
> kernel policy is to not depend on out-of-tree drivers.
> 
> Besides the ARM Mali drivers are full of code like:
> 
> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
> ...
> #else
> ...
> #endif
> 
> so few more instances of similar code won't do any harm.. ;-)
> 
>> [1] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>> [2] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>> [3] https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
> 
> I took a look at ARM Mali drivers source code anyway and I fail to
> see a rationale behind their behavior of doing 'freq_table' and
> 'max_state' initialization in the driver itself (instead of leaving
> it up to the devfreq core code, like all in-kernel drivers are doing
> already).
> 
> Could you please explain rationale behind ARM Mali drivers' special
> needs?
> 
> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>   these days to do 'freq_table' and 'max_state' initialization, the
>   only difference seems to be that ARM Mali creates the frequency
>   table in the descending order (but there also seems to be no real
>   need for it). ]
> 
> Maybe this is an opportunity to simplify also the ARM Mali driver?

OK. I agree to simplify them on this time.
For touching the 'freq_table' and 'max_state', need to fix
the descending order of freq_table. 

The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
requires the descending order of freq_table. Have to change it by using
the ascending time or support both ascending and descending order for freq_table.

1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
   by using ascending order instead of descending order.

> 
>> Also, the devfreq device driver specifies their own
>> information and data into devfreq_dev_profile structure 
>> before registering the devfreq device with devfreq_add_device().
>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
> 
> Well, 'struct devfreq_stats *stats' can be trivially moved out of
> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
> way..
> 
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
> 
>> So, I can't agree this patch. Not ack.
>>
>> Regards,
>> Chanwoo Choi
>>
>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>> Count time and transitions between devfreq frequencies in separate struct
>>> for improved code readability and maintenance.
>>>
>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>> ---
>>>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>  drivers/devfreq/exynos-bus.c       |   6 +-
>>>  drivers/devfreq/governor_passive.c |  26 +++--
>>>  include/linux/devfreq.h            |  43 ++++----
>>>  4 files changed, 129 insertions(+), 102 deletions(-)
>>>
>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>> index d79412b0de59..d85867a91230 100644
>>> --- a/drivers/devfreq/devfreq.c
>>> +++ b/drivers/devfreq/devfreq.c
>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>   */
>>>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>  {
>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>  	int lev;
>>>  
>>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>> -		if (freq == devfreq->profile->freq_table[lev])
>>> +	for (lev = 0; lev < stats->max_state; lev++)
>>> +		if (freq == stats->freq_table[lev])
>>>  			return lev;
>>>  
>>>  	return -EINVAL;
>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>  static int set_freq_table(struct devfreq *devfreq)
>>>  {
>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>> +	struct devfreq_stats *stats;
>>>  	struct dev_pm_opp *opp;
>>>  	unsigned long freq;
>>> -	int i, count;
>>> +	int i, count, err = -ENOMEM;
>>>  
>>>  	/* Initialize the freq_table from OPP table */
>>>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>  	if (count <= 0)
>>>  		return -EINVAL;
>>>  
>>> -	profile->max_state = count;
>>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>> -					count,
>>> -					sizeof(*profile->freq_table),
>>> -					GFP_KERNEL);
>>> -	if (!profile->freq_table) {
>>> -		profile->max_state = 0;
>>> +	stats = devm_kzalloc(devfreq->dev.parent,
>>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>>> +	if (!stats)
>>>  		return -ENOMEM;
>>> -	}
>>>  
>>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>> +	profile->stats = stats;
>>> +	stats->max_state = count;
>>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>> +					 count,
>>> +					 sizeof(*stats->freq_table),
>>> +					 GFP_KERNEL);
>>> +	if (!stats->freq_table)
>>> +		goto err_no_mem;
>>> +
>>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>  		if (IS_ERR(opp)) {
>>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>>> -			profile->max_state = 0;
>>> -			return PTR_ERR(opp);
>>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>>> +			stats->max_state = 0;
>>> +			err = PTR_ERR(opp);
>>> +			goto err_no_mem;
>>>  		}
>>>  		dev_pm_opp_put(opp);
>>> -		profile->freq_table[i] = freq;
>>> +		stats->freq_table[i] = freq;
>>>  	}
>>>  
>>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>> -					    array3_size(sizeof(unsigned int),
>>> -							count, count),
>>> -					    GFP_KERNEL);
>>> -	if (!profile->trans_table)
>>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>> +					  array3_size(sizeof(unsigned int),
>>> +						      count, count),
>>> +					  GFP_KERNEL);
>>> +	if (!stats->trans_table)
>>>  		goto err_no_mem;
>>>  
>>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>> -					      sizeof(*profile->time_in_state),
>>> -					      GFP_KERNEL);
>>> -	if (!profile->time_in_state)
>>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>> +					    sizeof(*stats->time_in_state),
>>> +					    GFP_KERNEL);
>>> +	if (!stats->time_in_state)
>>>  		goto err_no_mem;
>>>  
>>> -	profile->last_time = get_jiffies_64();
>>> -	spin_lock_init(&profile->stats_lock);
>>> +	stats->last_time = get_jiffies_64();
>>> +	spin_lock_init(&stats->stats_lock);
>>>  
>>>  	return 0;
>>>  err_no_mem:
>>> -	profile->max_state = 0;
>>> -	return -ENOMEM;
>>> +	stats->max_state = 0;
>>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>>> +	profile->stats = NULL;
>>> +	return err;
>>>  }
>>>  
>>>  /**
>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>   */
>>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>  {
>>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>  	unsigned long long cur_time;
>>>  	int lev, prev_lev, ret = 0;
>>>  
>>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>  
>>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>>  	if (!devfreq->previous_freq) {
>>> -		spin_lock(&profile->stats_lock);
>>> -		profile->last_time = cur_time;
>>> -		spin_unlock(&profile->stats_lock);
>>> +		spin_lock(&stats->stats_lock);
>>> +		stats->last_time = cur_time;
>>> +		spin_unlock(&stats->stats_lock);
>>>  		return 0;
>>>  	}
>>>  
>>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>  
>>> -	spin_lock(&profile->stats_lock);
>>> +	spin_lock(&stats->stats_lock);
>>>  	if (prev_lev < 0) {
>>>  		ret = prev_lev;
>>>  		goto out;
>>>  	}
>>>  
>>> -	profile->time_in_state[prev_lev] +=
>>> -			 cur_time - profile->last_time;
>>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>>  	if (lev < 0) {
>>>  		ret = lev;
>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>  	}
>>>  
>>>  	if (lev != prev_lev) {
>>> -		profile->trans_table[(prev_lev *
>>> -				profile->max_state) + lev]++;
>>> -		profile->total_trans++;
>>> +		stats->trans_table[(prev_lev *
>>> +				stats->max_state) + lev]++;
>>> +		stats->total_trans++;
>>>  	}
>>>  
>>>  out:
>>> -	profile->last_time = cur_time;
>>> -	spin_unlock(&profile->stats_lock);
>>> +	stats->last_time = cur_time;
>>> +	spin_unlock(&stats->stats_lock);
>>>  	return ret;
>>>  }
>>>  EXPORT_SYMBOL(devfreq_update_status);
>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>>  			msecs_to_jiffies(profile->polling_ms));
>>>  
>>> -	spin_lock(&profile->stats_lock);
>>> -	profile->last_time = get_jiffies_64();
>>> -	spin_unlock(&profile->stats_lock);
>>> +	spin_lock(&profile->stats->stats_lock);
>>> +	profile->stats->last_time = get_jiffies_64();
>>> +	spin_unlock(&profile->stats->stats_lock);
>>>  	devfreq->stop_polling = false;
>>>  
>>>  	if (profile->get_cur_freq &&
>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>  	devfreq->data = data;
>>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>>  
>>> -	if (!profile->max_state && !profile->freq_table) {
>>> +	if (!profile->stats) {
>>>  		mutex_unlock(&devfreq->lock);
>>>  		err = set_freq_table(devfreq);
>>>  		if (err < 0)
>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>  			      const char *buf, size_t count)
>>>  {
>>>  	struct devfreq *df = to_devfreq(dev);
>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>  	unsigned long value;
>>>  	int ret;
>>>  
>>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>  			goto unlock;
>>>  		}
>>>  	} else {
>>> -		unsigned long *freq_table = df->profile->freq_table;
>>> +		unsigned long *freq_table = stats->freq_table;
>>>  
>>>  		/* Get minimum frequency according to sorting order */
>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>  			value = freq_table[0];
>>>  		else
>>> -			value = freq_table[df->profile->max_state - 1];
>>> +			value = freq_table[stats->max_state - 1];
>>>  	}
>>>  
>>>  	df->min_freq = value;
>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>  			      const char *buf, size_t count)
>>>  {
>>>  	struct devfreq *df = to_devfreq(dev);
>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>  	unsigned long value;
>>>  	int ret;
>>>  
>>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>  			goto unlock;
>>>  		}
>>>  	} else {
>>> -		unsigned long *freq_table = df->profile->freq_table;
>>> +		unsigned long *freq_table = stats->freq_table;
>>>  
>>>  		/* Get maximum frequency according to sorting order */
>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>> -			value = freq_table[df->profile->max_state - 1];
>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>> +			value = freq_table[stats->max_state - 1];
>>>  		else
>>>  			value = freq_table[0];
>>>  	}
>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>  					  char *buf)
>>>  {
>>>  	struct devfreq *df = to_devfreq(d);
>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>  	ssize_t count = 0;
>>>  	int i;
>>>  
>>>  	mutex_lock(&df->lock);
>>>  
>>> -	for (i = 0; i < df->profile->max_state; i++)
>>> +	for (i = 0; i < stats->max_state; i++)
>>>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>> -				"%lu ", df->profile->freq_table[i]);
>>> +				"%lu ", stats->freq_table[i]);
>>>  
>>>  	mutex_unlock(&df->lock);
>>>  	/* Truncate the trailing space */
>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>  {
>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>> +	struct devfreq_stats *stats = profile->stats;
>>> +	unsigned int max_state = stats->max_state;
>>>  	ssize_t len;
>>>  	int i, j;
>>> -	unsigned int max_state = profile->max_state;
>>>  
>>>  	if (!devfreq->stop_polling &&
>>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>  	len = sprintf(buf, "     From  :   To\n");
>>>  	len += sprintf(buf + len, "           :");
>>>  
>>> -	spin_lock(&profile->stats_lock);
>>> +	spin_lock(&stats->stats_lock);
>>>  	for (i = 0; i < max_state; i++)
>>>  		len += sprintf(buf + len, "%10lu",
>>> -				profile->freq_table[i]);
>>> +				stats->freq_table[i]);
>>>  
>>>  	len += sprintf(buf + len, "   time(ms)\n");
>>>  
>>>  	for (i = 0; i < max_state; i++) {
>>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>>  			len += sprintf(buf + len, "*");
>>>  		else
>>>  			len += sprintf(buf + len, " ");
>>>  
>>>  		len += sprintf(buf + len, "%10lu:",
>>> -				profile->freq_table[i]);
>>> +				stats->freq_table[i]);
>>>  		for (j = 0; j < max_state; j++)
>>>  			len += sprintf(buf + len, "%10u",
>>> -				profile->trans_table[(i * max_state) + j]);
>>> +				stats->trans_table[(i * max_state) + j]);
>>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>>  	}
>>>  
>>>  	len += sprintf(buf + len, "Total transition : %u\n",
>>> -					profile->total_trans);
>>> -	spin_unlock(&profile->stats_lock);
>>> +					stats->total_trans);
>>> +	spin_unlock(&stats->stats_lock);
>>>  	return len;
>>>  }
>>>  static DEVICE_ATTR_RO(trans_stat);
>>>  
>>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>  {
>>> -	unsigned int count = profile->max_state;
>>> -
>>> -	spin_lock(&profile->stats_lock);
>>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>>> -	profile->last_time = get_jiffies_64();
>>> -	profile->total_trans = 0;
>>> -	spin_unlock(&profile->stats_lock);
>>> +	unsigned int count = stats->max_state;
>>> +
>>> +	spin_lock(&stats->stats_lock);
>>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>>> +	stats->last_time = get_jiffies_64();
>>> +	stats->total_trans = 0;
>>> +	spin_unlock(&stats->stats_lock);
>>>  }
>>>  
>>>  static ssize_t trans_reset_store(struct device *dev,
>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>  {
>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>  
>>> -	defvreq_stats_clear_table(devfreq->profile);
>>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>>  
>>>  	return count;
>>>  }
>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>> index d9f377912c10..b212aae2bb3e 100644
>>> --- a/drivers/devfreq/exynos-bus.c
>>> +++ b/drivers/devfreq/exynos-bus.c
>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>  	}
>>>  
>>>  out:
>>> -	max_state = bus->devfreq->profile->max_state;
>>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>> +	max_state = profile->stats->max_state;
>>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>  			dev_name(dev), min_freq, max_freq);
>>>  
>>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>> index 58308948b863..b2d87a88335c 100644
>>> --- a/drivers/devfreq/governor_passive.c
>>> +++ b/drivers/devfreq/governor_passive.c
>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>  	struct devfreq_passive_data *p_data
>>>  			= (struct devfreq_passive_data *)devfreq->data;
>>>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>> +	struct devfreq_stats *stats;
>>>  	unsigned long child_freq = ULONG_MAX;
>>>  	struct dev_pm_opp *opp;
>>>  	int i, count, ret = 0;
>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>  	 * device. And then the index is used for getting the suitable
>>>  	 * new frequency for passive devfreq device.
>>>  	 */
>>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>>> -		|| devfreq->profile->max_state <= 0)
>>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>>> +	    devfreq->profile->stats->max_state <= 0 ||
>>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>>  		return -EINVAL;
>>>  
>>> +	stats = devfreq->profile->stats;
>>> +	parent_stats = parent_devfreq->profile->stats;
>>>  	/*
>>>  	 * The passive governor have to get the correct frequency from OPP
>>>  	 * list of parent device. Because in this case, *freq is temporary
>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>  	 * Get the OPP table's index of decided freqeuncy by governor
>>>  	 * of parent device.
>>>  	 */
>>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>>> +	for (i = 0; i < parent_stats->max_state; i++)
>>> +		if (parent_stats->freq_table[i] == *freq)
>>>  			break;
>>>  
>>> -	if (i == parent_devfreq->profile->max_state) {
>>> +	if (i == parent_stats->max_state) {
>>>  		ret = -EINVAL;
>>>  		goto out;
>>>  	}
>>>  
>>>  	/* Get the suitable frequency by using index of parent device. */
>>> -	if (i < devfreq->profile->max_state) {
>>> -		child_freq = devfreq->profile->freq_table[i];
>>> +	if (i < stats->max_state) {
>>> +		child_freq = stats->freq_table[i];
>>>  	} else {
>>> -		count = devfreq->profile->max_state;
>>> -		child_freq = devfreq->profile->freq_table[count - 1];
>>> +		count = stats->max_state;
>>> +		child_freq = stats->freq_table[count - 1];
>>>  	}
>>>  
>>>  	/* Return the suitable frequency for passive device. */
>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>  	if (ret < 0)
>>>  		goto out;
>>>  
>>> -	if (devfreq->profile->freq_table
>>> +	if (devfreq->profile->stats
>>>  		&& (devfreq_update_status(devfreq, freq)))
>>>  		dev_err(&devfreq->dev,
>>>  			"Couldn't update frequency transition information.\n");
>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>> index 4ceb2a517a9c..8459af1a1583 100644
>>> --- a/include/linux/devfreq.h
>>> +++ b/include/linux/devfreq.h
>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>   */
>>>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>>  
>>> +/**
>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>> + * @freq_table:		Optional list of frequencies to support statistics
>>> + *			and freq_table must be generated in ascending order.
>>> + * @max_state:		The size of freq_table.
>>> + * @total_trans:	Number of devfreq transitions
>>> + * @trans_table:	Statistics of devfreq transitions
>>> + * @time_in_state:	Statistics of devfreq states
>>> + * @last_time:		The last time stats were updated
>>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>>> + *			last_time and total_trans used for statistics
>>> + */
>>> +struct devfreq_stats {
>>> +	unsigned long *freq_table;
>>> +	unsigned int max_state;
>>> +
>>> +	/* information for device frequency transition */
>>> +	unsigned int total_trans;
>>> +	unsigned int *trans_table;
>>> +	u64 *time_in_state;
>>> +	unsigned long long last_time;
>>> +	spinlock_t stats_lock;
>>> +};
>>> +
>>>  /**
>>>   * struct devfreq_dev_profile - Devfreq's user device profile
>>>   * @initial_freq:	The operating frequency when devfreq_add_device() is
>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>   *			from devfreq_remove_device() call. If the user
>>>   *			has registered devfreq->nb at a notifier-head,
>>>   *			this is the time to unregister it.
>>> - * @freq_table:		Optional list of frequencies to support statistics
>>> - *			and freq_table must be generated in ascending order.
>>> - * @max_state:		The size of freq_table.
>>> - * @total_trans:	Number of devfreq transitions
>>> - * @trans_table:	Statistics of devfreq transitions
>>> - * @time_in_state:	Statistics of devfreq states
>>> - * @last_time:		The last time stats were updated
>>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>>> - *			last_time and total_trans used for statistics
>>> + * @stats:		Statistics of devfreq states and state transitions
>>>   */
>>>  struct devfreq_dev_profile {
>>>  	unsigned long initial_freq;
>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>  	void (*exit)(struct device *dev);
>>>  
>>> -	unsigned long *freq_table;
>>> -	unsigned int max_state;
>>> -	/* information for device frequency transition */
>>> -	unsigned int total_trans;
>>> -	unsigned int *trans_table;
>>> -	u64 *time_in_state;
>>> -	unsigned long long last_time;
>>> -	spinlock_t stats_lock;
>>> +	struct devfreq_stats *stats;
>>>  };
>>>  
>>>  /**
>>>
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

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Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Chanwoo Choi]

Hi Bartlomiej,

On 11/15/19 12:25 PM, Chanwoo Choi wrote:
> Hi Bartlomiej,
> 
> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>
>> Hi Chanwoo,
>>
>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>> Hi Kamil,
>>>
>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>> device driver was posted to mainline kernel, they used
>>> them for a long time. It means that this patch break
>>> the compatibility. The ARM Mali drivers are very
>>> important devfreq device driver. 
>>
>> This argument is not a a technical one and the official upstream
>> kernel policy is to not depend on out-of-tree drivers.
>>
>> Besides the ARM Mali drivers are full of code like:
>>
>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>> ...
>> #else
>> ...
>> #endif
>>
>> so few more instances of similar code won't do any harm.. ;-)
>>
>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>
>> I took a look at ARM Mali drivers source code anyway and I fail to
>> see a rationale behind their behavior of doing 'freq_table' and
>> 'max_state' initialization in the driver itself (instead of leaving
>> it up to the devfreq core code, like all in-kernel drivers are doing
>> already).
>>
>> Could you please explain rationale behind ARM Mali drivers' special
>> needs?
>>
>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>   these days to do 'freq_table' and 'max_state' initialization, the
>>   only difference seems to be that ARM Mali creates the frequency
>>   table in the descending order (but there also seems to be no real
>>   need for it). ]
>>
>> Maybe this is an opportunity to simplify also the ARM Mali driver?
> 
> OK. I agree to simplify them on this time.
> For touching the 'freq_table' and 'max_state', need to fix
> the descending order of freq_table. 
> 
> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
> requires the descending order of freq_table. Have to change it by using
> the ascending time or support both ascending and descending order for freq_table.
> 
> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
>    by using ascending order instead of descending order.
> 

After changed about 'freq_table' and 'max_state', the build error
will happen on ARM mail driver because the initialization code of
'freq_table' in ARM mali driver, didn't check the kernel version.

The first devfreq patch provided the 'freq_table' as optional variable
in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree, 
this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.

So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.

Frankly, I'm note sure that it is necessary. I don't want to make
the side-effect without any useful reason.

But,
Separately, have to fix the ordering issue of partition_enable_ops()
in the drivers/thermal/devfreq_cooling.c.

>>
>>> Also, the devfreq device driver specifies their own
>>> information and data into devfreq_dev_profile structure 
>>> before registering the devfreq device with devfreq_add_device().
>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>
>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>> way..
>>
>> Best regards,
>> --
>> Bartlomiej Zolnierkiewicz
>> Samsung R&D Institute Poland
>> Samsung Electronics
>>
>>> So, I can't agree this patch. Not ack.
>>>
>>> Regards,
>>> Chanwoo Choi
>>>
>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>> Count time and transitions between devfreq frequencies in separate struct
>>>> for improved code readability and maintenance.
>>>>
>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>> ---
>>>>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>  drivers/devfreq/exynos-bus.c       |   6 +-
>>>>  drivers/devfreq/governor_passive.c |  26 +++--
>>>>  include/linux/devfreq.h            |  43 ++++----
>>>>  4 files changed, 129 insertions(+), 102 deletions(-)
>>>>
>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>> index d79412b0de59..d85867a91230 100644
>>>> --- a/drivers/devfreq/devfreq.c
>>>> +++ b/drivers/devfreq/devfreq.c
>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>   */
>>>>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>  {
>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>  	int lev;
>>>>  
>>>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>> -		if (freq == devfreq->profile->freq_table[lev])
>>>> +	for (lev = 0; lev < stats->max_state; lev++)
>>>> +		if (freq == stats->freq_table[lev])
>>>>  			return lev;
>>>>  
>>>>  	return -EINVAL;
>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>  static int set_freq_table(struct devfreq *devfreq)
>>>>  {
>>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>>> +	struct devfreq_stats *stats;
>>>>  	struct dev_pm_opp *opp;
>>>>  	unsigned long freq;
>>>> -	int i, count;
>>>> +	int i, count, err = -ENOMEM;
>>>>  
>>>>  	/* Initialize the freq_table from OPP table */
>>>>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>  	if (count <= 0)
>>>>  		return -EINVAL;
>>>>  
>>>> -	profile->max_state = count;
>>>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>> -					count,
>>>> -					sizeof(*profile->freq_table),
>>>> -					GFP_KERNEL);
>>>> -	if (!profile->freq_table) {
>>>> -		profile->max_state = 0;
>>>> +	stats = devm_kzalloc(devfreq->dev.parent,
>>>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>>>> +	if (!stats)
>>>>  		return -ENOMEM;
>>>> -	}
>>>>  
>>>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>> +	profile->stats = stats;
>>>> +	stats->max_state = count;
>>>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>> +					 count,
>>>> +					 sizeof(*stats->freq_table),
>>>> +					 GFP_KERNEL);
>>>> +	if (!stats->freq_table)
>>>> +		goto err_no_mem;
>>>> +
>>>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>  		if (IS_ERR(opp)) {
>>>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>> -			profile->max_state = 0;
>>>> -			return PTR_ERR(opp);
>>>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>> +			stats->max_state = 0;
>>>> +			err = PTR_ERR(opp);
>>>> +			goto err_no_mem;
>>>>  		}
>>>>  		dev_pm_opp_put(opp);
>>>> -		profile->freq_table[i] = freq;
>>>> +		stats->freq_table[i] = freq;
>>>>  	}
>>>>  
>>>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>> -					    array3_size(sizeof(unsigned int),
>>>> -							count, count),
>>>> -					    GFP_KERNEL);
>>>> -	if (!profile->trans_table)
>>>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>> +					  array3_size(sizeof(unsigned int),
>>>> +						      count, count),
>>>> +					  GFP_KERNEL);
>>>> +	if (!stats->trans_table)
>>>>  		goto err_no_mem;
>>>>  
>>>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>> -					      sizeof(*profile->time_in_state),
>>>> -					      GFP_KERNEL);
>>>> -	if (!profile->time_in_state)
>>>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>> +					    sizeof(*stats->time_in_state),
>>>> +					    GFP_KERNEL);
>>>> +	if (!stats->time_in_state)
>>>>  		goto err_no_mem;
>>>>  
>>>> -	profile->last_time = get_jiffies_64();
>>>> -	spin_lock_init(&profile->stats_lock);
>>>> +	stats->last_time = get_jiffies_64();
>>>> +	spin_lock_init(&stats->stats_lock);
>>>>  
>>>>  	return 0;
>>>>  err_no_mem:
>>>> -	profile->max_state = 0;
>>>> -	return -ENOMEM;
>>>> +	stats->max_state = 0;
>>>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>>>> +	profile->stats = NULL;
>>>> +	return err;
>>>>  }
>>>>  
>>>>  /**
>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>   */
>>>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>  {
>>>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>  	unsigned long long cur_time;
>>>>  	int lev, prev_lev, ret = 0;
>>>>  
>>>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>  
>>>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>>>  	if (!devfreq->previous_freq) {
>>>> -		spin_lock(&profile->stats_lock);
>>>> -		profile->last_time = cur_time;
>>>> -		spin_unlock(&profile->stats_lock);
>>>> +		spin_lock(&stats->stats_lock);
>>>> +		stats->last_time = cur_time;
>>>> +		spin_unlock(&stats->stats_lock);
>>>>  		return 0;
>>>>  	}
>>>>  
>>>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>  
>>>> -	spin_lock(&profile->stats_lock);
>>>> +	spin_lock(&stats->stats_lock);
>>>>  	if (prev_lev < 0) {
>>>>  		ret = prev_lev;
>>>>  		goto out;
>>>>  	}
>>>>  
>>>> -	profile->time_in_state[prev_lev] +=
>>>> -			 cur_time - profile->last_time;
>>>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>>>  	if (lev < 0) {
>>>>  		ret = lev;
>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>  	}
>>>>  
>>>>  	if (lev != prev_lev) {
>>>> -		profile->trans_table[(prev_lev *
>>>> -				profile->max_state) + lev]++;
>>>> -		profile->total_trans++;
>>>> +		stats->trans_table[(prev_lev *
>>>> +				stats->max_state) + lev]++;
>>>> +		stats->total_trans++;
>>>>  	}
>>>>  
>>>>  out:
>>>> -	profile->last_time = cur_time;
>>>> -	spin_unlock(&profile->stats_lock);
>>>> +	stats->last_time = cur_time;
>>>> +	spin_unlock(&stats->stats_lock);
>>>>  	return ret;
>>>>  }
>>>>  EXPORT_SYMBOL(devfreq_update_status);
>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>  			msecs_to_jiffies(profile->polling_ms));
>>>>  
>>>> -	spin_lock(&profile->stats_lock);
>>>> -	profile->last_time = get_jiffies_64();
>>>> -	spin_unlock(&profile->stats_lock);
>>>> +	spin_lock(&profile->stats->stats_lock);
>>>> +	profile->stats->last_time = get_jiffies_64();
>>>> +	spin_unlock(&profile->stats->stats_lock);
>>>>  	devfreq->stop_polling = false;
>>>>  
>>>>  	if (profile->get_cur_freq &&
>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>  	devfreq->data = data;
>>>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>  
>>>> -	if (!profile->max_state && !profile->freq_table) {
>>>> +	if (!profile->stats) {
>>>>  		mutex_unlock(&devfreq->lock);
>>>>  		err = set_freq_table(devfreq);
>>>>  		if (err < 0)
>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>  			      const char *buf, size_t count)
>>>>  {
>>>>  	struct devfreq *df = to_devfreq(dev);
>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>  	unsigned long value;
>>>>  	int ret;
>>>>  
>>>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>  			goto unlock;
>>>>  		}
>>>>  	} else {
>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>  
>>>>  		/* Get minimum frequency according to sorting order */
>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>  			value = freq_table[0];
>>>>  		else
>>>> -			value = freq_table[df->profile->max_state - 1];
>>>> +			value = freq_table[stats->max_state - 1];
>>>>  	}
>>>>  
>>>>  	df->min_freq = value;
>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>  			      const char *buf, size_t count)
>>>>  {
>>>>  	struct devfreq *df = to_devfreq(dev);
>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>  	unsigned long value;
>>>>  	int ret;
>>>>  
>>>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>  			goto unlock;
>>>>  		}
>>>>  	} else {
>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>  
>>>>  		/* Get maximum frequency according to sorting order */
>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>> -			value = freq_table[df->profile->max_state - 1];
>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>> +			value = freq_table[stats->max_state - 1];
>>>>  		else
>>>>  			value = freq_table[0];
>>>>  	}
>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>  					  char *buf)
>>>>  {
>>>>  	struct devfreq *df = to_devfreq(d);
>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>  	ssize_t count = 0;
>>>>  	int i;
>>>>  
>>>>  	mutex_lock(&df->lock);
>>>>  
>>>> -	for (i = 0; i < df->profile->max_state; i++)
>>>> +	for (i = 0; i < stats->max_state; i++)
>>>>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>> -				"%lu ", df->profile->freq_table[i]);
>>>> +				"%lu ", stats->freq_table[i]);
>>>>  
>>>>  	mutex_unlock(&df->lock);
>>>>  	/* Truncate the trailing space */
>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>  {
>>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>>> +	struct devfreq_stats *stats = profile->stats;
>>>> +	unsigned int max_state = stats->max_state;
>>>>  	ssize_t len;
>>>>  	int i, j;
>>>> -	unsigned int max_state = profile->max_state;
>>>>  
>>>>  	if (!devfreq->stop_polling &&
>>>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>  	len = sprintf(buf, "     From  :   To\n");
>>>>  	len += sprintf(buf + len, "           :");
>>>>  
>>>> -	spin_lock(&profile->stats_lock);
>>>> +	spin_lock(&stats->stats_lock);
>>>>  	for (i = 0; i < max_state; i++)
>>>>  		len += sprintf(buf + len, "%10lu",
>>>> -				profile->freq_table[i]);
>>>> +				stats->freq_table[i]);
>>>>  
>>>>  	len += sprintf(buf + len, "   time(ms)\n");
>>>>  
>>>>  	for (i = 0; i < max_state; i++) {
>>>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>>>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>>>  			len += sprintf(buf + len, "*");
>>>>  		else
>>>>  			len += sprintf(buf + len, " ");
>>>>  
>>>>  		len += sprintf(buf + len, "%10lu:",
>>>> -				profile->freq_table[i]);
>>>> +				stats->freq_table[i]);
>>>>  		for (j = 0; j < max_state; j++)
>>>>  			len += sprintf(buf + len, "%10u",
>>>> -				profile->trans_table[(i * max_state) + j]);
>>>> +				stats->trans_table[(i * max_state) + j]);
>>>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>>>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>>>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>>>  	}
>>>>  
>>>>  	len += sprintf(buf + len, "Total transition : %u\n",
>>>> -					profile->total_trans);
>>>> -	spin_unlock(&profile->stats_lock);
>>>> +					stats->total_trans);
>>>> +	spin_unlock(&stats->stats_lock);
>>>>  	return len;
>>>>  }
>>>>  static DEVICE_ATTR_RO(trans_stat);
>>>>  
>>>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>  {
>>>> -	unsigned int count = profile->max_state;
>>>> -
>>>> -	spin_lock(&profile->stats_lock);
>>>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>>>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>>>> -	profile->last_time = get_jiffies_64();
>>>> -	profile->total_trans = 0;
>>>> -	spin_unlock(&profile->stats_lock);
>>>> +	unsigned int count = stats->max_state;
>>>> +
>>>> +	spin_lock(&stats->stats_lock);
>>>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>>>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>>>> +	stats->last_time = get_jiffies_64();
>>>> +	stats->total_trans = 0;
>>>> +	spin_unlock(&stats->stats_lock);
>>>>  }
>>>>  
>>>>  static ssize_t trans_reset_store(struct device *dev,
>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>  {
>>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>>  
>>>> -	defvreq_stats_clear_table(devfreq->profile);
>>>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>>>  
>>>>  	return count;
>>>>  }
>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>> index d9f377912c10..b212aae2bb3e 100644
>>>> --- a/drivers/devfreq/exynos-bus.c
>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>  	}
>>>>  
>>>>  out:
>>>> -	max_state = bus->devfreq->profile->max_state;
>>>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>> +	max_state = profile->stats->max_state;
>>>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>>>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>  			dev_name(dev), min_freq, max_freq);
>>>>  
>>>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>> index 58308948b863..b2d87a88335c 100644
>>>> --- a/drivers/devfreq/governor_passive.c
>>>> +++ b/drivers/devfreq/governor_passive.c
>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>  	struct devfreq_passive_data *p_data
>>>>  			= (struct devfreq_passive_data *)devfreq->data;
>>>>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>> +	struct devfreq_stats *stats;
>>>>  	unsigned long child_freq = ULONG_MAX;
>>>>  	struct dev_pm_opp *opp;
>>>>  	int i, count, ret = 0;
>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>  	 * device. And then the index is used for getting the suitable
>>>>  	 * new frequency for passive devfreq device.
>>>>  	 */
>>>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>>>> -		|| devfreq->profile->max_state <= 0)
>>>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>>>> +	    devfreq->profile->stats->max_state <= 0 ||
>>>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>>>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>>>  		return -EINVAL;
>>>>  
>>>> +	stats = devfreq->profile->stats;
>>>> +	parent_stats = parent_devfreq->profile->stats;
>>>>  	/*
>>>>  	 * The passive governor have to get the correct frequency from OPP
>>>>  	 * list of parent device. Because in this case, *freq is temporary
>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>  	 * Get the OPP table's index of decided freqeuncy by governor
>>>>  	 * of parent device.
>>>>  	 */
>>>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>>>> +	for (i = 0; i < parent_stats->max_state; i++)
>>>> +		if (parent_stats->freq_table[i] == *freq)
>>>>  			break;
>>>>  
>>>> -	if (i == parent_devfreq->profile->max_state) {
>>>> +	if (i == parent_stats->max_state) {
>>>>  		ret = -EINVAL;
>>>>  		goto out;
>>>>  	}
>>>>  
>>>>  	/* Get the suitable frequency by using index of parent device. */
>>>> -	if (i < devfreq->profile->max_state) {
>>>> -		child_freq = devfreq->profile->freq_table[i];
>>>> +	if (i < stats->max_state) {
>>>> +		child_freq = stats->freq_table[i];
>>>>  	} else {
>>>> -		count = devfreq->profile->max_state;
>>>> -		child_freq = devfreq->profile->freq_table[count - 1];
>>>> +		count = stats->max_state;
>>>> +		child_freq = stats->freq_table[count - 1];
>>>>  	}
>>>>  
>>>>  	/* Return the suitable frequency for passive device. */
>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>  	if (ret < 0)
>>>>  		goto out;
>>>>  
>>>> -	if (devfreq->profile->freq_table
>>>> +	if (devfreq->profile->stats
>>>>  		&& (devfreq_update_status(devfreq, freq)))
>>>>  		dev_err(&devfreq->dev,
>>>>  			"Couldn't update frequency transition information.\n");
>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>> --- a/include/linux/devfreq.h
>>>> +++ b/include/linux/devfreq.h
>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>   */
>>>>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>>>  
>>>> +/**
>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>> + * @freq_table:		Optional list of frequencies to support statistics
>>>> + *			and freq_table must be generated in ascending order.
>>>> + * @max_state:		The size of freq_table.
>>>> + * @total_trans:	Number of devfreq transitions
>>>> + * @trans_table:	Statistics of devfreq transitions
>>>> + * @time_in_state:	Statistics of devfreq states
>>>> + * @last_time:		The last time stats were updated
>>>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>> + *			last_time and total_trans used for statistics
>>>> + */
>>>> +struct devfreq_stats {
>>>> +	unsigned long *freq_table;
>>>> +	unsigned int max_state;
>>>> +
>>>> +	/* information for device frequency transition */
>>>> +	unsigned int total_trans;
>>>> +	unsigned int *trans_table;
>>>> +	u64 *time_in_state;
>>>> +	unsigned long long last_time;
>>>> +	spinlock_t stats_lock;
>>>> +};
>>>> +
>>>>  /**
>>>>   * struct devfreq_dev_profile - Devfreq's user device profile
>>>>   * @initial_freq:	The operating frequency when devfreq_add_device() is
>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>   *			from devfreq_remove_device() call. If the user
>>>>   *			has registered devfreq->nb at a notifier-head,
>>>>   *			this is the time to unregister it.
>>>> - * @freq_table:		Optional list of frequencies to support statistics
>>>> - *			and freq_table must be generated in ascending order.
>>>> - * @max_state:		The size of freq_table.
>>>> - * @total_trans:	Number of devfreq transitions
>>>> - * @trans_table:	Statistics of devfreq transitions
>>>> - * @time_in_state:	Statistics of devfreq states
>>>> - * @last_time:		The last time stats were updated
>>>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>> - *			last_time and total_trans used for statistics
>>>> + * @stats:		Statistics of devfreq states and state transitions
>>>>   */
>>>>  struct devfreq_dev_profile {
>>>>  	unsigned long initial_freq;
>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>  	void (*exit)(struct device *dev);
>>>>  
>>>> -	unsigned long *freq_table;
>>>> -	unsigned int max_state;
>>>> -	/* information for device frequency transition */
>>>> -	unsigned int total_trans;
>>>> -	unsigned int *trans_table;
>>>> -	u64 *time_in_state;
>>>> -	unsigned long long last_time;
>>>> -	spinlock_t stats_lock;
>>>> +	struct devfreq_stats *stats;
>>>>  };
>>>>  
>>>>  /**
>>>>
>>
>>
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Chanwoo Choi]

Hi Bartlomiej,

On 11/15/19 12:25 PM, Chanwoo Choi wrote:
> Hi Bartlomiej,
> 
> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>
>> Hi Chanwoo,
>>
>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>> Hi Kamil,
>>>
>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>> device driver was posted to mainline kernel, they used
>>> them for a long time. It means that this patch break
>>> the compatibility. The ARM Mali drivers are very
>>> important devfreq device driver. 
>>
>> This argument is not a a technical one and the official upstream
>> kernel policy is to not depend on out-of-tree drivers.
>>
>> Besides the ARM Mali drivers are full of code like:
>>
>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>> ...
>> #else
>> ...
>> #endif
>>
>> so few more instances of similar code won't do any harm.. ;-)
>>
>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>
>> I took a look at ARM Mali drivers source code anyway and I fail to
>> see a rationale behind their behavior of doing 'freq_table' and
>> 'max_state' initialization in the driver itself (instead of leaving
>> it up to the devfreq core code, like all in-kernel drivers are doing
>> already).
>>
>> Could you please explain rationale behind ARM Mali drivers' special
>> needs?
>>
>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>   these days to do 'freq_table' and 'max_state' initialization, the
>>   only difference seems to be that ARM Mali creates the frequency
>>   table in the descending order (but there also seems to be no real
>>   need for it). ]
>>
>> Maybe this is an opportunity to simplify also the ARM Mali driver?
> 
> OK. I agree to simplify them on this time.
> For touching the 'freq_table' and 'max_state', need to fix
> the descending order of freq_table. 
> 
> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
> requires the descending order of freq_table. Have to change it by using
> the ascending time or support both ascending and descending order for freq_table.
> 
> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
>    by using ascending order instead of descending order.
> 

After changed about 'freq_table' and 'max_state', the build error
will happen on ARM mail driver because the initialization code of
'freq_table' in ARM mali driver, didn't check the kernel version.

The first devfreq patch provided the 'freq_table' as optional variable
in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree, 
this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.

So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.

Frankly, I'm note sure that it is necessary. I don't want to make
the side-effect without any useful reason.

But,
Separately, have to fix the ordering issue of partition_enable_ops()
in the drivers/thermal/devfreq_cooling.c.

>>
>>> Also, the devfreq device driver specifies their own
>>> information and data into devfreq_dev_profile structure 
>>> before registering the devfreq device with devfreq_add_device().
>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>
>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>> way..
>>
>> Best regards,
>> --
>> Bartlomiej Zolnierkiewicz
>> Samsung R&D Institute Poland
>> Samsung Electronics
>>
>>> So, I can't agree this patch. Not ack.
>>>
>>> Regards,
>>> Chanwoo Choi
>>>
>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>> Count time and transitions between devfreq frequencies in separate struct
>>>> for improved code readability and maintenance.
>>>>
>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>> ---
>>>>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>  drivers/devfreq/exynos-bus.c       |   6 +-
>>>>  drivers/devfreq/governor_passive.c |  26 +++--
>>>>  include/linux/devfreq.h            |  43 ++++----
>>>>  4 files changed, 129 insertions(+), 102 deletions(-)
>>>>
>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>> index d79412b0de59..d85867a91230 100644
>>>> --- a/drivers/devfreq/devfreq.c
>>>> +++ b/drivers/devfreq/devfreq.c
>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>   */
>>>>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>  {
>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>  	int lev;
>>>>  
>>>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>> -		if (freq == devfreq->profile->freq_table[lev])
>>>> +	for (lev = 0; lev < stats->max_state; lev++)
>>>> +		if (freq == stats->freq_table[lev])
>>>>  			return lev;
>>>>  
>>>>  	return -EINVAL;
>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>  static int set_freq_table(struct devfreq *devfreq)
>>>>  {
>>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>>> +	struct devfreq_stats *stats;
>>>>  	struct dev_pm_opp *opp;
>>>>  	unsigned long freq;
>>>> -	int i, count;
>>>> +	int i, count, err = -ENOMEM;
>>>>  
>>>>  	/* Initialize the freq_table from OPP table */
>>>>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>  	if (count <= 0)
>>>>  		return -EINVAL;
>>>>  
>>>> -	profile->max_state = count;
>>>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>> -					count,
>>>> -					sizeof(*profile->freq_table),
>>>> -					GFP_KERNEL);
>>>> -	if (!profile->freq_table) {
>>>> -		profile->max_state = 0;
>>>> +	stats = devm_kzalloc(devfreq->dev.parent,
>>>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>>>> +	if (!stats)
>>>>  		return -ENOMEM;
>>>> -	}
>>>>  
>>>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>> +	profile->stats = stats;
>>>> +	stats->max_state = count;
>>>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>> +					 count,
>>>> +					 sizeof(*stats->freq_table),
>>>> +					 GFP_KERNEL);
>>>> +	if (!stats->freq_table)
>>>> +		goto err_no_mem;
>>>> +
>>>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>  		if (IS_ERR(opp)) {
>>>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>> -			profile->max_state = 0;
>>>> -			return PTR_ERR(opp);
>>>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>> +			stats->max_state = 0;
>>>> +			err = PTR_ERR(opp);
>>>> +			goto err_no_mem;
>>>>  		}
>>>>  		dev_pm_opp_put(opp);
>>>> -		profile->freq_table[i] = freq;
>>>> +		stats->freq_table[i] = freq;
>>>>  	}
>>>>  
>>>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>> -					    array3_size(sizeof(unsigned int),
>>>> -							count, count),
>>>> -					    GFP_KERNEL);
>>>> -	if (!profile->trans_table)
>>>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>> +					  array3_size(sizeof(unsigned int),
>>>> +						      count, count),
>>>> +					  GFP_KERNEL);
>>>> +	if (!stats->trans_table)
>>>>  		goto err_no_mem;
>>>>  
>>>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>> -					      sizeof(*profile->time_in_state),
>>>> -					      GFP_KERNEL);
>>>> -	if (!profile->time_in_state)
>>>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>> +					    sizeof(*stats->time_in_state),
>>>> +					    GFP_KERNEL);
>>>> +	if (!stats->time_in_state)
>>>>  		goto err_no_mem;
>>>>  
>>>> -	profile->last_time = get_jiffies_64();
>>>> -	spin_lock_init(&profile->stats_lock);
>>>> +	stats->last_time = get_jiffies_64();
>>>> +	spin_lock_init(&stats->stats_lock);
>>>>  
>>>>  	return 0;
>>>>  err_no_mem:
>>>> -	profile->max_state = 0;
>>>> -	return -ENOMEM;
>>>> +	stats->max_state = 0;
>>>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>>>> +	profile->stats = NULL;
>>>> +	return err;
>>>>  }
>>>>  
>>>>  /**
>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>   */
>>>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>  {
>>>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>  	unsigned long long cur_time;
>>>>  	int lev, prev_lev, ret = 0;
>>>>  
>>>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>  
>>>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>>>  	if (!devfreq->previous_freq) {
>>>> -		spin_lock(&profile->stats_lock);
>>>> -		profile->last_time = cur_time;
>>>> -		spin_unlock(&profile->stats_lock);
>>>> +		spin_lock(&stats->stats_lock);
>>>> +		stats->last_time = cur_time;
>>>> +		spin_unlock(&stats->stats_lock);
>>>>  		return 0;
>>>>  	}
>>>>  
>>>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>  
>>>> -	spin_lock(&profile->stats_lock);
>>>> +	spin_lock(&stats->stats_lock);
>>>>  	if (prev_lev < 0) {
>>>>  		ret = prev_lev;
>>>>  		goto out;
>>>>  	}
>>>>  
>>>> -	profile->time_in_state[prev_lev] +=
>>>> -			 cur_time - profile->last_time;
>>>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>>>  	if (lev < 0) {
>>>>  		ret = lev;
>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>  	}
>>>>  
>>>>  	if (lev != prev_lev) {
>>>> -		profile->trans_table[(prev_lev *
>>>> -				profile->max_state) + lev]++;
>>>> -		profile->total_trans++;
>>>> +		stats->trans_table[(prev_lev *
>>>> +				stats->max_state) + lev]++;
>>>> +		stats->total_trans++;
>>>>  	}
>>>>  
>>>>  out:
>>>> -	profile->last_time = cur_time;
>>>> -	spin_unlock(&profile->stats_lock);
>>>> +	stats->last_time = cur_time;
>>>> +	spin_unlock(&stats->stats_lock);
>>>>  	return ret;
>>>>  }
>>>>  EXPORT_SYMBOL(devfreq_update_status);
>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>  			msecs_to_jiffies(profile->polling_ms));
>>>>  
>>>> -	spin_lock(&profile->stats_lock);
>>>> -	profile->last_time = get_jiffies_64();
>>>> -	spin_unlock(&profile->stats_lock);
>>>> +	spin_lock(&profile->stats->stats_lock);
>>>> +	profile->stats->last_time = get_jiffies_64();
>>>> +	spin_unlock(&profile->stats->stats_lock);
>>>>  	devfreq->stop_polling = false;
>>>>  
>>>>  	if (profile->get_cur_freq &&
>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>  	devfreq->data = data;
>>>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>  
>>>> -	if (!profile->max_state && !profile->freq_table) {
>>>> +	if (!profile->stats) {
>>>>  		mutex_unlock(&devfreq->lock);
>>>>  		err = set_freq_table(devfreq);
>>>>  		if (err < 0)
>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>  			      const char *buf, size_t count)
>>>>  {
>>>>  	struct devfreq *df = to_devfreq(dev);
>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>  	unsigned long value;
>>>>  	int ret;
>>>>  
>>>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>  			goto unlock;
>>>>  		}
>>>>  	} else {
>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>  
>>>>  		/* Get minimum frequency according to sorting order */
>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>  			value = freq_table[0];
>>>>  		else
>>>> -			value = freq_table[df->profile->max_state - 1];
>>>> +			value = freq_table[stats->max_state - 1];
>>>>  	}
>>>>  
>>>>  	df->min_freq = value;
>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>  			      const char *buf, size_t count)
>>>>  {
>>>>  	struct devfreq *df = to_devfreq(dev);
>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>  	unsigned long value;
>>>>  	int ret;
>>>>  
>>>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>  			goto unlock;
>>>>  		}
>>>>  	} else {
>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>  
>>>>  		/* Get maximum frequency according to sorting order */
>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>> -			value = freq_table[df->profile->max_state - 1];
>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>> +			value = freq_table[stats->max_state - 1];
>>>>  		else
>>>>  			value = freq_table[0];
>>>>  	}
>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>  					  char *buf)
>>>>  {
>>>>  	struct devfreq *df = to_devfreq(d);
>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>  	ssize_t count = 0;
>>>>  	int i;
>>>>  
>>>>  	mutex_lock(&df->lock);
>>>>  
>>>> -	for (i = 0; i < df->profile->max_state; i++)
>>>> +	for (i = 0; i < stats->max_state; i++)
>>>>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>> -				"%lu ", df->profile->freq_table[i]);
>>>> +				"%lu ", stats->freq_table[i]);
>>>>  
>>>>  	mutex_unlock(&df->lock);
>>>>  	/* Truncate the trailing space */
>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>  {
>>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>>> +	struct devfreq_stats *stats = profile->stats;
>>>> +	unsigned int max_state = stats->max_state;
>>>>  	ssize_t len;
>>>>  	int i, j;
>>>> -	unsigned int max_state = profile->max_state;
>>>>  
>>>>  	if (!devfreq->stop_polling &&
>>>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>  	len = sprintf(buf, "     From  :   To\n");
>>>>  	len += sprintf(buf + len, "           :");
>>>>  
>>>> -	spin_lock(&profile->stats_lock);
>>>> +	spin_lock(&stats->stats_lock);
>>>>  	for (i = 0; i < max_state; i++)
>>>>  		len += sprintf(buf + len, "%10lu",
>>>> -				profile->freq_table[i]);
>>>> +				stats->freq_table[i]);
>>>>  
>>>>  	len += sprintf(buf + len, "   time(ms)\n");
>>>>  
>>>>  	for (i = 0; i < max_state; i++) {
>>>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>>>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>>>  			len += sprintf(buf + len, "*");
>>>>  		else
>>>>  			len += sprintf(buf + len, " ");
>>>>  
>>>>  		len += sprintf(buf + len, "%10lu:",
>>>> -				profile->freq_table[i]);
>>>> +				stats->freq_table[i]);
>>>>  		for (j = 0; j < max_state; j++)
>>>>  			len += sprintf(buf + len, "%10u",
>>>> -				profile->trans_table[(i * max_state) + j]);
>>>> +				stats->trans_table[(i * max_state) + j]);
>>>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>>>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>>>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>>>  	}
>>>>  
>>>>  	len += sprintf(buf + len, "Total transition : %u\n",
>>>> -					profile->total_trans);
>>>> -	spin_unlock(&profile->stats_lock);
>>>> +					stats->total_trans);
>>>> +	spin_unlock(&stats->stats_lock);
>>>>  	return len;
>>>>  }
>>>>  static DEVICE_ATTR_RO(trans_stat);
>>>>  
>>>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>  {
>>>> -	unsigned int count = profile->max_state;
>>>> -
>>>> -	spin_lock(&profile->stats_lock);
>>>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>>>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>>>> -	profile->last_time = get_jiffies_64();
>>>> -	profile->total_trans = 0;
>>>> -	spin_unlock(&profile->stats_lock);
>>>> +	unsigned int count = stats->max_state;
>>>> +
>>>> +	spin_lock(&stats->stats_lock);
>>>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>>>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>>>> +	stats->last_time = get_jiffies_64();
>>>> +	stats->total_trans = 0;
>>>> +	spin_unlock(&stats->stats_lock);
>>>>  }
>>>>  
>>>>  static ssize_t trans_reset_store(struct device *dev,
>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>  {
>>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>>  
>>>> -	defvreq_stats_clear_table(devfreq->profile);
>>>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>>>  
>>>>  	return count;
>>>>  }
>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>> index d9f377912c10..b212aae2bb3e 100644
>>>> --- a/drivers/devfreq/exynos-bus.c
>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>  	}
>>>>  
>>>>  out:
>>>> -	max_state = bus->devfreq->profile->max_state;
>>>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>> +	max_state = profile->stats->max_state;
>>>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>>>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>  			dev_name(dev), min_freq, max_freq);
>>>>  
>>>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>> index 58308948b863..b2d87a88335c 100644
>>>> --- a/drivers/devfreq/governor_passive.c
>>>> +++ b/drivers/devfreq/governor_passive.c
>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>  	struct devfreq_passive_data *p_data
>>>>  			= (struct devfreq_passive_data *)devfreq->data;
>>>>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>> +	struct devfreq_stats *stats;
>>>>  	unsigned long child_freq = ULONG_MAX;
>>>>  	struct dev_pm_opp *opp;
>>>>  	int i, count, ret = 0;
>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>  	 * device. And then the index is used for getting the suitable
>>>>  	 * new frequency for passive devfreq device.
>>>>  	 */
>>>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>>>> -		|| devfreq->profile->max_state <= 0)
>>>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>>>> +	    devfreq->profile->stats->max_state <= 0 ||
>>>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>>>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>>>  		return -EINVAL;
>>>>  
>>>> +	stats = devfreq->profile->stats;
>>>> +	parent_stats = parent_devfreq->profile->stats;
>>>>  	/*
>>>>  	 * The passive governor have to get the correct frequency from OPP
>>>>  	 * list of parent device. Because in this case, *freq is temporary
>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>  	 * Get the OPP table's index of decided freqeuncy by governor
>>>>  	 * of parent device.
>>>>  	 */
>>>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>>>> +	for (i = 0; i < parent_stats->max_state; i++)
>>>> +		if (parent_stats->freq_table[i] == *freq)
>>>>  			break;
>>>>  
>>>> -	if (i == parent_devfreq->profile->max_state) {
>>>> +	if (i == parent_stats->max_state) {
>>>>  		ret = -EINVAL;
>>>>  		goto out;
>>>>  	}
>>>>  
>>>>  	/* Get the suitable frequency by using index of parent device. */
>>>> -	if (i < devfreq->profile->max_state) {
>>>> -		child_freq = devfreq->profile->freq_table[i];
>>>> +	if (i < stats->max_state) {
>>>> +		child_freq = stats->freq_table[i];
>>>>  	} else {
>>>> -		count = devfreq->profile->max_state;
>>>> -		child_freq = devfreq->profile->freq_table[count - 1];
>>>> +		count = stats->max_state;
>>>> +		child_freq = stats->freq_table[count - 1];
>>>>  	}
>>>>  
>>>>  	/* Return the suitable frequency for passive device. */
>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>  	if (ret < 0)
>>>>  		goto out;
>>>>  
>>>> -	if (devfreq->profile->freq_table
>>>> +	if (devfreq->profile->stats
>>>>  		&& (devfreq_update_status(devfreq, freq)))
>>>>  		dev_err(&devfreq->dev,
>>>>  			"Couldn't update frequency transition information.\n");
>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>> --- a/include/linux/devfreq.h
>>>> +++ b/include/linux/devfreq.h
>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>   */
>>>>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>>>  
>>>> +/**
>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>> + * @freq_table:		Optional list of frequencies to support statistics
>>>> + *			and freq_table must be generated in ascending order.
>>>> + * @max_state:		The size of freq_table.
>>>> + * @total_trans:	Number of devfreq transitions
>>>> + * @trans_table:	Statistics of devfreq transitions
>>>> + * @time_in_state:	Statistics of devfreq states
>>>> + * @last_time:		The last time stats were updated
>>>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>> + *			last_time and total_trans used for statistics
>>>> + */
>>>> +struct devfreq_stats {
>>>> +	unsigned long *freq_table;
>>>> +	unsigned int max_state;
>>>> +
>>>> +	/* information for device frequency transition */
>>>> +	unsigned int total_trans;
>>>> +	unsigned int *trans_table;
>>>> +	u64 *time_in_state;
>>>> +	unsigned long long last_time;
>>>> +	spinlock_t stats_lock;
>>>> +};
>>>> +
>>>>  /**
>>>>   * struct devfreq_dev_profile - Devfreq's user device profile
>>>>   * @initial_freq:	The operating frequency when devfreq_add_device() is
>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>   *			from devfreq_remove_device() call. If the user
>>>>   *			has registered devfreq->nb at a notifier-head,
>>>>   *			this is the time to unregister it.
>>>> - * @freq_table:		Optional list of frequencies to support statistics
>>>> - *			and freq_table must be generated in ascending order.
>>>> - * @max_state:		The size of freq_table.
>>>> - * @total_trans:	Number of devfreq transitions
>>>> - * @trans_table:	Statistics of devfreq transitions
>>>> - * @time_in_state:	Statistics of devfreq states
>>>> - * @last_time:		The last time stats were updated
>>>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>> - *			last_time and total_trans used for statistics
>>>> + * @stats:		Statistics of devfreq states and state transitions
>>>>   */
>>>>  struct devfreq_dev_profile {
>>>>  	unsigned long initial_freq;
>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>  	void (*exit)(struct device *dev);
>>>>  
>>>> -	unsigned long *freq_table;
>>>> -	unsigned int max_state;
>>>> -	/* information for device frequency transition */
>>>> -	unsigned int total_trans;
>>>> -	unsigned int *trans_table;
>>>> -	u64 *time_in_state;
>>>> -	unsigned long long last_time;
>>>> -	spinlock_t stats_lock;
>>>> +	struct devfreq_stats *stats;
>>>>  };
>>>>  
>>>>  /**
>>>>
>>
>>
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

_______________________________________________
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linux-arm-kernel@lists.infradead.org
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Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Bartlomiej Zolnierkiewicz]

[ added Zhang, Eduardo, Ørjan and Javi to Cc: ]

On 11/15/19 7:21 AM, Chanwoo Choi wrote:
> Hi Bartlomiej,
> 
> On 11/15/19 12:25 PM, Chanwoo Choi wrote:
>> Hi Bartlomiej,
>>
>> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>>
>>> Hi Chanwoo,
>>>
>>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>>> Hi Kamil,
>>>>
>>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>>> device driver was posted to mainline kernel, they used
>>>> them for a long time. It means that this patch break
>>>> the compatibility. The ARM Mali drivers are very
>>>> important devfreq device driver. 
>>>
>>> This argument is not a a technical one and the official upstream
>>> kernel policy is to not depend on out-of-tree drivers.
>>>
>>> Besides the ARM Mali drivers are full of code like:
>>>
>>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>>> ...
>>> #else
>>> ...
>>> #endif
>>>
>>> so few more instances of similar code won't do any harm.. ;-)
>>>
>>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>>
>>> I took a look at ARM Mali drivers source code anyway and I fail to
>>> see a rationale behind their behavior of doing 'freq_table' and
>>> 'max_state' initialization in the driver itself (instead of leaving
>>> it up to the devfreq core code, like all in-kernel drivers are doing
>>> already).
>>>
>>> Could you please explain rationale behind ARM Mali drivers' special
>>> needs?
>>>
>>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>>   these days to do 'freq_table' and 'max_state' initialization, the
>>>   only difference seems to be that ARM Mali creates the frequency
>>>   table in the descending order (but there also seems to be no real
>>>   need for it). ]
>>>
>>> Maybe this is an opportunity to simplify also the ARM Mali driver?
>>
>> OK. I agree to simplify them on this time.
>> For touching the 'freq_table' and 'max_state', need to fix
>> the descending order of freq_table. 
>>
>> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
>> requires the descending order of freq_table. Have to change it by using
>> the ascending time or support both ascending and descending order for freq_table.
>>
>> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
>> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
>>    by using ascending order instead of descending order.
>>
> 
> After changed about 'freq_table' and 'max_state', the build error
> will happen on ARM mail driver because the initialization code of
> 'freq_table' in ARM mali driver, didn't check the kernel version.
> 
> The first devfreq patch provided the 'freq_table' as optional variable
> in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree, 
> this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
> 
> So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
> in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
> 
> Frankly, I'm note sure that it is necessary. I don't want to make
> the side-effect without any useful reason.
> 
> But,
> Separately, have to fix the ordering issue of partition_enable_ops()
> in the drivers/thermal/devfreq_cooling.c.

Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
why we are carrying devfreq_cooling.c code in upstream kernel at all?

It has been merged in the following commit:

commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
Author: Ørjan Eide <orjan.eide@arm.com>
Date:   Thu Sep 10 18:09:30 2015 +0100

    thermal: Add devfreq cooling
    
    Add a generic thermal cooling device for devfreq, that is similar to
    cpu_cooling.
    
    The device must use devfreq.  In order to use the power extension of the
    cooling device, it must have registered its OPPs using the OPP library.
    
    Cc: Zhang Rui <rui.zhang@intel.com>
    Cc: Eduardo Valentin <edubezval@gmail.com>
    Signed-off-by: Javi Merino <javi.merino@arm.com>
    Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
    Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
...

but 4 years later there is still no single in-kernel user for this code?

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

>>>
>>>> Also, the devfreq device driver specifies their own
>>>> information and data into devfreq_dev_profile structure 
>>>> before registering the devfreq device with devfreq_add_device().
>>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>>
>>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>>> way..
>>>
>>> Best regards,
>>> --
>>> Bartlomiej Zolnierkiewicz
>>> Samsung R&D Institute Poland
>>> Samsung Electronics
>>>
>>>> So, I can't agree this patch. Not ack.
>>>>
>>>> Regards,
>>>> Chanwoo Choi
>>>>
>>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>>> Count time and transitions between devfreq frequencies in separate struct
>>>>> for improved code readability and maintenance.
>>>>>
>>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>>> ---
>>>>>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>>  drivers/devfreq/exynos-bus.c       |   6 +-
>>>>>  drivers/devfreq/governor_passive.c |  26 +++--
>>>>>  include/linux/devfreq.h            |  43 ++++----
>>>>>  4 files changed, 129 insertions(+), 102 deletions(-)
>>>>>
>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>> index d79412b0de59..d85867a91230 100644
>>>>> --- a/drivers/devfreq/devfreq.c
>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>>   */
>>>>>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>  {
>>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>  	int lev;
>>>>>  
>>>>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>>> -		if (freq == devfreq->profile->freq_table[lev])
>>>>> +	for (lev = 0; lev < stats->max_state; lev++)
>>>>> +		if (freq == stats->freq_table[lev])
>>>>>  			return lev;
>>>>>  
>>>>>  	return -EINVAL;
>>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>  static int set_freq_table(struct devfreq *devfreq)
>>>>>  {
>>>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>> +	struct devfreq_stats *stats;
>>>>>  	struct dev_pm_opp *opp;
>>>>>  	unsigned long freq;
>>>>> -	int i, count;
>>>>> +	int i, count, err = -ENOMEM;
>>>>>  
>>>>>  	/* Initialize the freq_table from OPP table */
>>>>>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>>  	if (count <= 0)
>>>>>  		return -EINVAL;
>>>>>  
>>>>> -	profile->max_state = count;
>>>>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>> -					count,
>>>>> -					sizeof(*profile->freq_table),
>>>>> -					GFP_KERNEL);
>>>>> -	if (!profile->freq_table) {
>>>>> -		profile->max_state = 0;
>>>>> +	stats = devm_kzalloc(devfreq->dev.parent,
>>>>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>>>>> +	if (!stats)
>>>>>  		return -ENOMEM;
>>>>> -	}
>>>>>  
>>>>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>>> +	profile->stats = stats;
>>>>> +	stats->max_state = count;
>>>>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>> +					 count,
>>>>> +					 sizeof(*stats->freq_table),
>>>>> +					 GFP_KERNEL);
>>>>> +	if (!stats->freq_table)
>>>>> +		goto err_no_mem;
>>>>> +
>>>>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>>  		if (IS_ERR(opp)) {
>>>>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>>> -			profile->max_state = 0;
>>>>> -			return PTR_ERR(opp);
>>>>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>>> +			stats->max_state = 0;
>>>>> +			err = PTR_ERR(opp);
>>>>> +			goto err_no_mem;
>>>>>  		}
>>>>>  		dev_pm_opp_put(opp);
>>>>> -		profile->freq_table[i] = freq;
>>>>> +		stats->freq_table[i] = freq;
>>>>>  	}
>>>>>  
>>>>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>> -					    array3_size(sizeof(unsigned int),
>>>>> -							count, count),
>>>>> -					    GFP_KERNEL);
>>>>> -	if (!profile->trans_table)
>>>>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>> +					  array3_size(sizeof(unsigned int),
>>>>> +						      count, count),
>>>>> +					  GFP_KERNEL);
>>>>> +	if (!stats->trans_table)
>>>>>  		goto err_no_mem;
>>>>>  
>>>>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>> -					      sizeof(*profile->time_in_state),
>>>>> -					      GFP_KERNEL);
>>>>> -	if (!profile->time_in_state)
>>>>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>> +					    sizeof(*stats->time_in_state),
>>>>> +					    GFP_KERNEL);
>>>>> +	if (!stats->time_in_state)
>>>>>  		goto err_no_mem;
>>>>>  
>>>>> -	profile->last_time = get_jiffies_64();
>>>>> -	spin_lock_init(&profile->stats_lock);
>>>>> +	stats->last_time = get_jiffies_64();
>>>>> +	spin_lock_init(&stats->stats_lock);
>>>>>  
>>>>>  	return 0;
>>>>>  err_no_mem:
>>>>> -	profile->max_state = 0;
>>>>> -	return -ENOMEM;
>>>>> +	stats->max_state = 0;
>>>>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>>>>> +	profile->stats = NULL;
>>>>> +	return err;
>>>>>  }
>>>>>  
>>>>>  /**
>>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>>   */
>>>>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>  {
>>>>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>  	unsigned long long cur_time;
>>>>>  	int lev, prev_lev, ret = 0;
>>>>>  
>>>>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>  
>>>>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>>>>  	if (!devfreq->previous_freq) {
>>>>> -		spin_lock(&profile->stats_lock);
>>>>> -		profile->last_time = cur_time;
>>>>> -		spin_unlock(&profile->stats_lock);
>>>>> +		spin_lock(&stats->stats_lock);
>>>>> +		stats->last_time = cur_time;
>>>>> +		spin_unlock(&stats->stats_lock);
>>>>>  		return 0;
>>>>>  	}
>>>>>  
>>>>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>>  
>>>>> -	spin_lock(&profile->stats_lock);
>>>>> +	spin_lock(&stats->stats_lock);
>>>>>  	if (prev_lev < 0) {
>>>>>  		ret = prev_lev;
>>>>>  		goto out;
>>>>>  	}
>>>>>  
>>>>> -	profile->time_in_state[prev_lev] +=
>>>>> -			 cur_time - profile->last_time;
>>>>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>>>>  	if (lev < 0) {
>>>>>  		ret = lev;
>>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>  	}
>>>>>  
>>>>>  	if (lev != prev_lev) {
>>>>> -		profile->trans_table[(prev_lev *
>>>>> -				profile->max_state) + lev]++;
>>>>> -		profile->total_trans++;
>>>>> +		stats->trans_table[(prev_lev *
>>>>> +				stats->max_state) + lev]++;
>>>>> +		stats->total_trans++;
>>>>>  	}
>>>>>  
>>>>>  out:
>>>>> -	profile->last_time = cur_time;
>>>>> -	spin_unlock(&profile->stats_lock);
>>>>> +	stats->last_time = cur_time;
>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>  	return ret;
>>>>>  }
>>>>>  EXPORT_SYMBOL(devfreq_update_status);
>>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>>  			msecs_to_jiffies(profile->polling_ms));
>>>>>  
>>>>> -	spin_lock(&profile->stats_lock);
>>>>> -	profile->last_time = get_jiffies_64();
>>>>> -	spin_unlock(&profile->stats_lock);
>>>>> +	spin_lock(&profile->stats->stats_lock);
>>>>> +	profile->stats->last_time = get_jiffies_64();
>>>>> +	spin_unlock(&profile->stats->stats_lock);
>>>>>  	devfreq->stop_polling = false;
>>>>>  
>>>>>  	if (profile->get_cur_freq &&
>>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>>  	devfreq->data = data;
>>>>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>>  
>>>>> -	if (!profile->max_state && !profile->freq_table) {
>>>>> +	if (!profile->stats) {
>>>>>  		mutex_unlock(&devfreq->lock);
>>>>>  		err = set_freq_table(devfreq);
>>>>>  		if (err < 0)
>>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>  			      const char *buf, size_t count)
>>>>>  {
>>>>>  	struct devfreq *df = to_devfreq(dev);
>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>  	unsigned long value;
>>>>>  	int ret;
>>>>>  
>>>>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>  			goto unlock;
>>>>>  		}
>>>>>  	} else {
>>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>>  
>>>>>  		/* Get minimum frequency according to sorting order */
>>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>  			value = freq_table[0];
>>>>>  		else
>>>>> -			value = freq_table[df->profile->max_state - 1];
>>>>> +			value = freq_table[stats->max_state - 1];
>>>>>  	}
>>>>>  
>>>>>  	df->min_freq = value;
>>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>  			      const char *buf, size_t count)
>>>>>  {
>>>>>  	struct devfreq *df = to_devfreq(dev);
>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>  	unsigned long value;
>>>>>  	int ret;
>>>>>  
>>>>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>  			goto unlock;
>>>>>  		}
>>>>>  	} else {
>>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>>  
>>>>>  		/* Get maximum frequency according to sorting order */
>>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>> -			value = freq_table[df->profile->max_state - 1];
>>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>> +			value = freq_table[stats->max_state - 1];
>>>>>  		else
>>>>>  			value = freq_table[0];
>>>>>  	}
>>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>>  					  char *buf)
>>>>>  {
>>>>>  	struct devfreq *df = to_devfreq(d);
>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>  	ssize_t count = 0;
>>>>>  	int i;
>>>>>  
>>>>>  	mutex_lock(&df->lock);
>>>>>  
>>>>> -	for (i = 0; i < df->profile->max_state; i++)
>>>>> +	for (i = 0; i < stats->max_state; i++)
>>>>>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>>> -				"%lu ", df->profile->freq_table[i]);
>>>>> +				"%lu ", stats->freq_table[i]);
>>>>>  
>>>>>  	mutex_unlock(&df->lock);
>>>>>  	/* Truncate the trailing space */
>>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>  {
>>>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>> +	struct devfreq_stats *stats = profile->stats;
>>>>> +	unsigned int max_state = stats->max_state;
>>>>>  	ssize_t len;
>>>>>  	int i, j;
>>>>> -	unsigned int max_state = profile->max_state;
>>>>>  
>>>>>  	if (!devfreq->stop_polling &&
>>>>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>  	len = sprintf(buf, "     From  :   To\n");
>>>>>  	len += sprintf(buf + len, "           :");
>>>>>  
>>>>> -	spin_lock(&profile->stats_lock);
>>>>> +	spin_lock(&stats->stats_lock);
>>>>>  	for (i = 0; i < max_state; i++)
>>>>>  		len += sprintf(buf + len, "%10lu",
>>>>> -				profile->freq_table[i]);
>>>>> +				stats->freq_table[i]);
>>>>>  
>>>>>  	len += sprintf(buf + len, "   time(ms)\n");
>>>>>  
>>>>>  	for (i = 0; i < max_state; i++) {
>>>>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>>>>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>>>>  			len += sprintf(buf + len, "*");
>>>>>  		else
>>>>>  			len += sprintf(buf + len, " ");
>>>>>  
>>>>>  		len += sprintf(buf + len, "%10lu:",
>>>>> -				profile->freq_table[i]);
>>>>> +				stats->freq_table[i]);
>>>>>  		for (j = 0; j < max_state; j++)
>>>>>  			len += sprintf(buf + len, "%10u",
>>>>> -				profile->trans_table[(i * max_state) + j]);
>>>>> +				stats->trans_table[(i * max_state) + j]);
>>>>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>>>>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>>>>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>>>>  	}
>>>>>  
>>>>>  	len += sprintf(buf + len, "Total transition : %u\n",
>>>>> -					profile->total_trans);
>>>>> -	spin_unlock(&profile->stats_lock);
>>>>> +					stats->total_trans);
>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>  	return len;
>>>>>  }
>>>>>  static DEVICE_ATTR_RO(trans_stat);
>>>>>  
>>>>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>>  {
>>>>> -	unsigned int count = profile->max_state;
>>>>> -
>>>>> -	spin_lock(&profile->stats_lock);
>>>>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>>>>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>>>>> -	profile->last_time = get_jiffies_64();
>>>>> -	profile->total_trans = 0;
>>>>> -	spin_unlock(&profile->stats_lock);
>>>>> +	unsigned int count = stats->max_state;
>>>>> +
>>>>> +	spin_lock(&stats->stats_lock);
>>>>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>>>>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>>>>> +	stats->last_time = get_jiffies_64();
>>>>> +	stats->total_trans = 0;
>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>  }
>>>>>  
>>>>>  static ssize_t trans_reset_store(struct device *dev,
>>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>>  {
>>>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>>>  
>>>>> -	defvreq_stats_clear_table(devfreq->profile);
>>>>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>>>>  
>>>>>  	return count;
>>>>>  }
>>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>>> index d9f377912c10..b212aae2bb3e 100644
>>>>> --- a/drivers/devfreq/exynos-bus.c
>>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>>  	}
>>>>>  
>>>>>  out:
>>>>> -	max_state = bus->devfreq->profile->max_state;
>>>>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>>> +	max_state = profile->stats->max_state;
>>>>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>>>>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>>  			dev_name(dev), min_freq, max_freq);
>>>>>  
>>>>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>>> index 58308948b863..b2d87a88335c 100644
>>>>> --- a/drivers/devfreq/governor_passive.c
>>>>> +++ b/drivers/devfreq/governor_passive.c
>>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>  	struct devfreq_passive_data *p_data
>>>>>  			= (struct devfreq_passive_data *)devfreq->data;
>>>>>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>>> +	struct devfreq_stats *stats;
>>>>>  	unsigned long child_freq = ULONG_MAX;
>>>>>  	struct dev_pm_opp *opp;
>>>>>  	int i, count, ret = 0;
>>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>  	 * device. And then the index is used for getting the suitable
>>>>>  	 * new frequency for passive devfreq device.
>>>>>  	 */
>>>>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>>>>> -		|| devfreq->profile->max_state <= 0)
>>>>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>>>>> +	    devfreq->profile->stats->max_state <= 0 ||
>>>>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>>>>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>>>>  		return -EINVAL;
>>>>>  
>>>>> +	stats = devfreq->profile->stats;
>>>>> +	parent_stats = parent_devfreq->profile->stats;
>>>>>  	/*
>>>>>  	 * The passive governor have to get the correct frequency from OPP
>>>>>  	 * list of parent device. Because in this case, *freq is temporary
>>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>  	 * Get the OPP table's index of decided freqeuncy by governor
>>>>>  	 * of parent device.
>>>>>  	 */
>>>>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>>>>> +	for (i = 0; i < parent_stats->max_state; i++)
>>>>> +		if (parent_stats->freq_table[i] == *freq)
>>>>>  			break;
>>>>>  
>>>>> -	if (i == parent_devfreq->profile->max_state) {
>>>>> +	if (i == parent_stats->max_state) {
>>>>>  		ret = -EINVAL;
>>>>>  		goto out;
>>>>>  	}
>>>>>  
>>>>>  	/* Get the suitable frequency by using index of parent device. */
>>>>> -	if (i < devfreq->profile->max_state) {
>>>>> -		child_freq = devfreq->profile->freq_table[i];
>>>>> +	if (i < stats->max_state) {
>>>>> +		child_freq = stats->freq_table[i];
>>>>>  	} else {
>>>>> -		count = devfreq->profile->max_state;
>>>>> -		child_freq = devfreq->profile->freq_table[count - 1];
>>>>> +		count = stats->max_state;
>>>>> +		child_freq = stats->freq_table[count - 1];
>>>>>  	}
>>>>>  
>>>>>  	/* Return the suitable frequency for passive device. */
>>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>>  	if (ret < 0)
>>>>>  		goto out;
>>>>>  
>>>>> -	if (devfreq->profile->freq_table
>>>>> +	if (devfreq->profile->stats
>>>>>  		&& (devfreq_update_status(devfreq, freq)))
>>>>>  		dev_err(&devfreq->dev,
>>>>>  			"Couldn't update frequency transition information.\n");
>>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>>> --- a/include/linux/devfreq.h
>>>>> +++ b/include/linux/devfreq.h
>>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>>   */
>>>>>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>>>>  
>>>>> +/**
>>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>>> + * @freq_table:		Optional list of frequencies to support statistics
>>>>> + *			and freq_table must be generated in ascending order.
>>>>> + * @max_state:		The size of freq_table.
>>>>> + * @total_trans:	Number of devfreq transitions
>>>>> + * @trans_table:	Statistics of devfreq transitions
>>>>> + * @time_in_state:	Statistics of devfreq states
>>>>> + * @last_time:		The last time stats were updated
>>>>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>>> + *			last_time and total_trans used for statistics
>>>>> + */
>>>>> +struct devfreq_stats {
>>>>> +	unsigned long *freq_table;
>>>>> +	unsigned int max_state;
>>>>> +
>>>>> +	/* information for device frequency transition */
>>>>> +	unsigned int total_trans;
>>>>> +	unsigned int *trans_table;
>>>>> +	u64 *time_in_state;
>>>>> +	unsigned long long last_time;
>>>>> +	spinlock_t stats_lock;
>>>>> +};
>>>>> +
>>>>>  /**
>>>>>   * struct devfreq_dev_profile - Devfreq's user device profile
>>>>>   * @initial_freq:	The operating frequency when devfreq_add_device() is
>>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>>   *			from devfreq_remove_device() call. If the user
>>>>>   *			has registered devfreq->nb at a notifier-head,
>>>>>   *			this is the time to unregister it.
>>>>> - * @freq_table:		Optional list of frequencies to support statistics
>>>>> - *			and freq_table must be generated in ascending order.
>>>>> - * @max_state:		The size of freq_table.
>>>>> - * @total_trans:	Number of devfreq transitions
>>>>> - * @trans_table:	Statistics of devfreq transitions
>>>>> - * @time_in_state:	Statistics of devfreq states
>>>>> - * @last_time:		The last time stats were updated
>>>>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>>> - *			last_time and total_trans used for statistics
>>>>> + * @stats:		Statistics of devfreq states and state transitions
>>>>>   */
>>>>>  struct devfreq_dev_profile {
>>>>>  	unsigned long initial_freq;
>>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>>  	void (*exit)(struct device *dev);
>>>>>  
>>>>> -	unsigned long *freq_table;
>>>>> -	unsigned int max_state;
>>>>> -	/* information for device frequency transition */
>>>>> -	unsigned int total_trans;
>>>>> -	unsigned int *trans_table;
>>>>> -	u64 *time_in_state;
>>>>> -	unsigned long long last_time;
>>>>> -	spinlock_t stats_lock;
>>>>> +	struct devfreq_stats *stats;
>>>>>  };
>>>>>  
>>>>>  /**
>>>>>

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Bartlomiej Zolnierkiewicz]

[ added Zhang, Eduardo, Ørjan and Javi to Cc: ]

On 11/15/19 7:21 AM, Chanwoo Choi wrote:
> Hi Bartlomiej,
> 
> On 11/15/19 12:25 PM, Chanwoo Choi wrote:
>> Hi Bartlomiej,
>>
>> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>>
>>> Hi Chanwoo,
>>>
>>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>>> Hi Kamil,
>>>>
>>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>>> device driver was posted to mainline kernel, they used
>>>> them for a long time. It means that this patch break
>>>> the compatibility. The ARM Mali drivers are very
>>>> important devfreq device driver. 
>>>
>>> This argument is not a a technical one and the official upstream
>>> kernel policy is to not depend on out-of-tree drivers.
>>>
>>> Besides the ARM Mali drivers are full of code like:
>>>
>>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>>> ...
>>> #else
>>> ...
>>> #endif
>>>
>>> so few more instances of similar code won't do any harm.. ;-)
>>>
>>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>>
>>> I took a look at ARM Mali drivers source code anyway and I fail to
>>> see a rationale behind their behavior of doing 'freq_table' and
>>> 'max_state' initialization in the driver itself (instead of leaving
>>> it up to the devfreq core code, like all in-kernel drivers are doing
>>> already).
>>>
>>> Could you please explain rationale behind ARM Mali drivers' special
>>> needs?
>>>
>>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>>   these days to do 'freq_table' and 'max_state' initialization, the
>>>   only difference seems to be that ARM Mali creates the frequency
>>>   table in the descending order (but there also seems to be no real
>>>   need for it). ]
>>>
>>> Maybe this is an opportunity to simplify also the ARM Mali driver?
>>
>> OK. I agree to simplify them on this time.
>> For touching the 'freq_table' and 'max_state', need to fix
>> the descending order of freq_table. 
>>
>> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
>> requires the descending order of freq_table. Have to change it by using
>> the ascending time or support both ascending and descending order for freq_table.
>>
>> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
>> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c 
>>    by using ascending order instead of descending order.
>>
> 
> After changed about 'freq_table' and 'max_state', the build error
> will happen on ARM mail driver because the initialization code of
> 'freq_table' in ARM mali driver, didn't check the kernel version.
> 
> The first devfreq patch provided the 'freq_table' as optional variable
> in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree, 
> this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
> 
> So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
> in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
> 
> Frankly, I'm note sure that it is necessary. I don't want to make
> the side-effect without any useful reason.
> 
> But,
> Separately, have to fix the ordering issue of partition_enable_ops()
> in the drivers/thermal/devfreq_cooling.c.

Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
why we are carrying devfreq_cooling.c code in upstream kernel at all?

It has been merged in the following commit:

commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
Author: Ørjan Eide <orjan.eide@arm.com>
Date:   Thu Sep 10 18:09:30 2015 +0100

    thermal: Add devfreq cooling
    
    Add a generic thermal cooling device for devfreq, that is similar to
    cpu_cooling.
    
    The device must use devfreq.  In order to use the power extension of the
    cooling device, it must have registered its OPPs using the OPP library.
    
    Cc: Zhang Rui <rui.zhang@intel.com>
    Cc: Eduardo Valentin <edubezval@gmail.com>
    Signed-off-by: Javi Merino <javi.merino@arm.com>
    Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
    Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
...

but 4 years later there is still no single in-kernel user for this code?

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

>>>
>>>> Also, the devfreq device driver specifies their own
>>>> information and data into devfreq_dev_profile structure 
>>>> before registering the devfreq device with devfreq_add_device().
>>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>>
>>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>>> way..
>>>
>>> Best regards,
>>> --
>>> Bartlomiej Zolnierkiewicz
>>> Samsung R&D Institute Poland
>>> Samsung Electronics
>>>
>>>> So, I can't agree this patch. Not ack.
>>>>
>>>> Regards,
>>>> Chanwoo Choi
>>>>
>>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>>> Count time and transitions between devfreq frequencies in separate struct
>>>>> for improved code readability and maintenance.
>>>>>
>>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>>> ---
>>>>>  drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>>  drivers/devfreq/exynos-bus.c       |   6 +-
>>>>>  drivers/devfreq/governor_passive.c |  26 +++--
>>>>>  include/linux/devfreq.h            |  43 ++++----
>>>>>  4 files changed, 129 insertions(+), 102 deletions(-)
>>>>>
>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>> index d79412b0de59..d85867a91230 100644
>>>>> --- a/drivers/devfreq/devfreq.c
>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>>   */
>>>>>  static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>  {
>>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>  	int lev;
>>>>>  
>>>>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>>> -		if (freq == devfreq->profile->freq_table[lev])
>>>>> +	for (lev = 0; lev < stats->max_state; lev++)
>>>>> +		if (freq == stats->freq_table[lev])
>>>>>  			return lev;
>>>>>  
>>>>>  	return -EINVAL;
>>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>  static int set_freq_table(struct devfreq *devfreq)
>>>>>  {
>>>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>> +	struct devfreq_stats *stats;
>>>>>  	struct dev_pm_opp *opp;
>>>>>  	unsigned long freq;
>>>>> -	int i, count;
>>>>> +	int i, count, err = -ENOMEM;
>>>>>  
>>>>>  	/* Initialize the freq_table from OPP table */
>>>>>  	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>>  	if (count <= 0)
>>>>>  		return -EINVAL;
>>>>>  
>>>>> -	profile->max_state = count;
>>>>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>> -					count,
>>>>> -					sizeof(*profile->freq_table),
>>>>> -					GFP_KERNEL);
>>>>> -	if (!profile->freq_table) {
>>>>> -		profile->max_state = 0;
>>>>> +	stats = devm_kzalloc(devfreq->dev.parent,
>>>>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>>>>> +	if (!stats)
>>>>>  		return -ENOMEM;
>>>>> -	}
>>>>>  
>>>>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>>> +	profile->stats = stats;
>>>>> +	stats->max_state = count;
>>>>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>> +					 count,
>>>>> +					 sizeof(*stats->freq_table),
>>>>> +					 GFP_KERNEL);
>>>>> +	if (!stats->freq_table)
>>>>> +		goto err_no_mem;
>>>>> +
>>>>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>>  		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>>  		if (IS_ERR(opp)) {
>>>>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>>> -			profile->max_state = 0;
>>>>> -			return PTR_ERR(opp);
>>>>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>>> +			stats->max_state = 0;
>>>>> +			err = PTR_ERR(opp);
>>>>> +			goto err_no_mem;
>>>>>  		}
>>>>>  		dev_pm_opp_put(opp);
>>>>> -		profile->freq_table[i] = freq;
>>>>> +		stats->freq_table[i] = freq;
>>>>>  	}
>>>>>  
>>>>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>> -					    array3_size(sizeof(unsigned int),
>>>>> -							count, count),
>>>>> -					    GFP_KERNEL);
>>>>> -	if (!profile->trans_table)
>>>>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>> +					  array3_size(sizeof(unsigned int),
>>>>> +						      count, count),
>>>>> +					  GFP_KERNEL);
>>>>> +	if (!stats->trans_table)
>>>>>  		goto err_no_mem;
>>>>>  
>>>>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>> -					      sizeof(*profile->time_in_state),
>>>>> -					      GFP_KERNEL);
>>>>> -	if (!profile->time_in_state)
>>>>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>> +					    sizeof(*stats->time_in_state),
>>>>> +					    GFP_KERNEL);
>>>>> +	if (!stats->time_in_state)
>>>>>  		goto err_no_mem;
>>>>>  
>>>>> -	profile->last_time = get_jiffies_64();
>>>>> -	spin_lock_init(&profile->stats_lock);
>>>>> +	stats->last_time = get_jiffies_64();
>>>>> +	spin_lock_init(&stats->stats_lock);
>>>>>  
>>>>>  	return 0;
>>>>>  err_no_mem:
>>>>> -	profile->max_state = 0;
>>>>> -	return -ENOMEM;
>>>>> +	stats->max_state = 0;
>>>>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>>>>> +	profile->stats = NULL;
>>>>> +	return err;
>>>>>  }
>>>>>  
>>>>>  /**
>>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>>   */
>>>>>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>  {
>>>>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>  	unsigned long long cur_time;
>>>>>  	int lev, prev_lev, ret = 0;
>>>>>  
>>>>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>  
>>>>>  	/* Immediately exit if previous_freq is not initialized yet. */
>>>>>  	if (!devfreq->previous_freq) {
>>>>> -		spin_lock(&profile->stats_lock);
>>>>> -		profile->last_time = cur_time;
>>>>> -		spin_unlock(&profile->stats_lock);
>>>>> +		spin_lock(&stats->stats_lock);
>>>>> +		stats->last_time = cur_time;
>>>>> +		spin_unlock(&stats->stats_lock);
>>>>>  		return 0;
>>>>>  	}
>>>>>  
>>>>>  	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>>  
>>>>> -	spin_lock(&profile->stats_lock);
>>>>> +	spin_lock(&stats->stats_lock);
>>>>>  	if (prev_lev < 0) {
>>>>>  		ret = prev_lev;
>>>>>  		goto out;
>>>>>  	}
>>>>>  
>>>>> -	profile->time_in_state[prev_lev] +=
>>>>> -			 cur_time - profile->last_time;
>>>>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>>  	lev = devfreq_get_freq_level(devfreq, freq);
>>>>>  	if (lev < 0) {
>>>>>  		ret = lev;
>>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>  	}
>>>>>  
>>>>>  	if (lev != prev_lev) {
>>>>> -		profile->trans_table[(prev_lev *
>>>>> -				profile->max_state) + lev]++;
>>>>> -		profile->total_trans++;
>>>>> +		stats->trans_table[(prev_lev *
>>>>> +				stats->max_state) + lev]++;
>>>>> +		stats->total_trans++;
>>>>>  	}
>>>>>  
>>>>>  out:
>>>>> -	profile->last_time = cur_time;
>>>>> -	spin_unlock(&profile->stats_lock);
>>>>> +	stats->last_time = cur_time;
>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>  	return ret;
>>>>>  }
>>>>>  EXPORT_SYMBOL(devfreq_update_status);
>>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>>  			msecs_to_jiffies(profile->polling_ms));
>>>>>  
>>>>> -	spin_lock(&profile->stats_lock);
>>>>> -	profile->last_time = get_jiffies_64();
>>>>> -	spin_unlock(&profile->stats_lock);
>>>>> +	spin_lock(&profile->stats->stats_lock);
>>>>> +	profile->stats->last_time = get_jiffies_64();
>>>>> +	spin_unlock(&profile->stats->stats_lock);
>>>>>  	devfreq->stop_polling = false;
>>>>>  
>>>>>  	if (profile->get_cur_freq &&
>>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>>  	devfreq->data = data;
>>>>>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>>  
>>>>> -	if (!profile->max_state && !profile->freq_table) {
>>>>> +	if (!profile->stats) {
>>>>>  		mutex_unlock(&devfreq->lock);
>>>>>  		err = set_freq_table(devfreq);
>>>>>  		if (err < 0)
>>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>  			      const char *buf, size_t count)
>>>>>  {
>>>>>  	struct devfreq *df = to_devfreq(dev);
>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>  	unsigned long value;
>>>>>  	int ret;
>>>>>  
>>>>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>  			goto unlock;
>>>>>  		}
>>>>>  	} else {
>>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>>  
>>>>>  		/* Get minimum frequency according to sorting order */
>>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>  			value = freq_table[0];
>>>>>  		else
>>>>> -			value = freq_table[df->profile->max_state - 1];
>>>>> +			value = freq_table[stats->max_state - 1];
>>>>>  	}
>>>>>  
>>>>>  	df->min_freq = value;
>>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>  			      const char *buf, size_t count)
>>>>>  {
>>>>>  	struct devfreq *df = to_devfreq(dev);
>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>  	unsigned long value;
>>>>>  	int ret;
>>>>>  
>>>>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>  			goto unlock;
>>>>>  		}
>>>>>  	} else {
>>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>>  
>>>>>  		/* Get maximum frequency according to sorting order */
>>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>> -			value = freq_table[df->profile->max_state - 1];
>>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>> +			value = freq_table[stats->max_state - 1];
>>>>>  		else
>>>>>  			value = freq_table[0];
>>>>>  	}
>>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>>  					  char *buf)
>>>>>  {
>>>>>  	struct devfreq *df = to_devfreq(d);
>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>  	ssize_t count = 0;
>>>>>  	int i;
>>>>>  
>>>>>  	mutex_lock(&df->lock);
>>>>>  
>>>>> -	for (i = 0; i < df->profile->max_state; i++)
>>>>> +	for (i = 0; i < stats->max_state; i++)
>>>>>  		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>>> -				"%lu ", df->profile->freq_table[i]);
>>>>> +				"%lu ", stats->freq_table[i]);
>>>>>  
>>>>>  	mutex_unlock(&df->lock);
>>>>>  	/* Truncate the trailing space */
>>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>  {
>>>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>>>  	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>> +	struct devfreq_stats *stats = profile->stats;
>>>>> +	unsigned int max_state = stats->max_state;
>>>>>  	ssize_t len;
>>>>>  	int i, j;
>>>>> -	unsigned int max_state = profile->max_state;
>>>>>  
>>>>>  	if (!devfreq->stop_polling &&
>>>>>  			devfreq_update_status(devfreq, devfreq->previous_freq))
>>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>  	len = sprintf(buf, "     From  :   To\n");
>>>>>  	len += sprintf(buf + len, "           :");
>>>>>  
>>>>> -	spin_lock(&profile->stats_lock);
>>>>> +	spin_lock(&stats->stats_lock);
>>>>>  	for (i = 0; i < max_state; i++)
>>>>>  		len += sprintf(buf + len, "%10lu",
>>>>> -				profile->freq_table[i]);
>>>>> +				stats->freq_table[i]);
>>>>>  
>>>>>  	len += sprintf(buf + len, "   time(ms)\n");
>>>>>  
>>>>>  	for (i = 0; i < max_state; i++) {
>>>>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>>>>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>>>>  			len += sprintf(buf + len, "*");
>>>>>  		else
>>>>>  			len += sprintf(buf + len, " ");
>>>>>  
>>>>>  		len += sprintf(buf + len, "%10lu:",
>>>>> -				profile->freq_table[i]);
>>>>> +				stats->freq_table[i]);
>>>>>  		for (j = 0; j < max_state; j++)
>>>>>  			len += sprintf(buf + len, "%10u",
>>>>> -				profile->trans_table[(i * max_state) + j]);
>>>>> +				stats->trans_table[(i * max_state) + j]);
>>>>>  		len += sprintf(buf + len, "%10llu\n", (u64)
>>>>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>>>>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>>>>  	}
>>>>>  
>>>>>  	len += sprintf(buf + len, "Total transition : %u\n",
>>>>> -					profile->total_trans);
>>>>> -	spin_unlock(&profile->stats_lock);
>>>>> +					stats->total_trans);
>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>  	return len;
>>>>>  }
>>>>>  static DEVICE_ATTR_RO(trans_stat);
>>>>>  
>>>>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>>  {
>>>>> -	unsigned int count = profile->max_state;
>>>>> -
>>>>> -	spin_lock(&profile->stats_lock);
>>>>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>>>>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>>>>> -	profile->last_time = get_jiffies_64();
>>>>> -	profile->total_trans = 0;
>>>>> -	spin_unlock(&profile->stats_lock);
>>>>> +	unsigned int count = stats->max_state;
>>>>> +
>>>>> +	spin_lock(&stats->stats_lock);
>>>>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>>>>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>>>>> +	stats->last_time = get_jiffies_64();
>>>>> +	stats->total_trans = 0;
>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>  }
>>>>>  
>>>>>  static ssize_t trans_reset_store(struct device *dev,
>>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>>  {
>>>>>  	struct devfreq *devfreq = to_devfreq(dev);
>>>>>  
>>>>> -	defvreq_stats_clear_table(devfreq->profile);
>>>>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>>>>  
>>>>>  	return count;
>>>>>  }
>>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>>> index d9f377912c10..b212aae2bb3e 100644
>>>>> --- a/drivers/devfreq/exynos-bus.c
>>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>>  	}
>>>>>  
>>>>>  out:
>>>>> -	max_state = bus->devfreq->profile->max_state;
>>>>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>>> +	max_state = profile->stats->max_state;
>>>>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>>>>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>>  	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>>  			dev_name(dev), min_freq, max_freq);
>>>>>  
>>>>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>>> index 58308948b863..b2d87a88335c 100644
>>>>> --- a/drivers/devfreq/governor_passive.c
>>>>> +++ b/drivers/devfreq/governor_passive.c
>>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>  	struct devfreq_passive_data *p_data
>>>>>  			= (struct devfreq_passive_data *)devfreq->data;
>>>>>  	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>>> +	struct devfreq_stats *stats;
>>>>>  	unsigned long child_freq = ULONG_MAX;
>>>>>  	struct dev_pm_opp *opp;
>>>>>  	int i, count, ret = 0;
>>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>  	 * device. And then the index is used for getting the suitable
>>>>>  	 * new frequency for passive devfreq device.
>>>>>  	 */
>>>>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>>>>> -		|| devfreq->profile->max_state <= 0)
>>>>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>>>>> +	    devfreq->profile->stats->max_state <= 0 ||
>>>>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>>>>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>>>>  		return -EINVAL;
>>>>>  
>>>>> +	stats = devfreq->profile->stats;
>>>>> +	parent_stats = parent_devfreq->profile->stats;
>>>>>  	/*
>>>>>  	 * The passive governor have to get the correct frequency from OPP
>>>>>  	 * list of parent device. Because in this case, *freq is temporary
>>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>  	 * Get the OPP table's index of decided freqeuncy by governor
>>>>>  	 * of parent device.
>>>>>  	 */
>>>>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>>>>> +	for (i = 0; i < parent_stats->max_state; i++)
>>>>> +		if (parent_stats->freq_table[i] == *freq)
>>>>>  			break;
>>>>>  
>>>>> -	if (i == parent_devfreq->profile->max_state) {
>>>>> +	if (i == parent_stats->max_state) {
>>>>>  		ret = -EINVAL;
>>>>>  		goto out;
>>>>>  	}
>>>>>  
>>>>>  	/* Get the suitable frequency by using index of parent device. */
>>>>> -	if (i < devfreq->profile->max_state) {
>>>>> -		child_freq = devfreq->profile->freq_table[i];
>>>>> +	if (i < stats->max_state) {
>>>>> +		child_freq = stats->freq_table[i];
>>>>>  	} else {
>>>>> -		count = devfreq->profile->max_state;
>>>>> -		child_freq = devfreq->profile->freq_table[count - 1];
>>>>> +		count = stats->max_state;
>>>>> +		child_freq = stats->freq_table[count - 1];
>>>>>  	}
>>>>>  
>>>>>  	/* Return the suitable frequency for passive device. */
>>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>>  	if (ret < 0)
>>>>>  		goto out;
>>>>>  
>>>>> -	if (devfreq->profile->freq_table
>>>>> +	if (devfreq->profile->stats
>>>>>  		&& (devfreq_update_status(devfreq, freq)))
>>>>>  		dev_err(&devfreq->dev,
>>>>>  			"Couldn't update frequency transition information.\n");
>>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>>> --- a/include/linux/devfreq.h
>>>>> +++ b/include/linux/devfreq.h
>>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>>   */
>>>>>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>>>>  
>>>>> +/**
>>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>>> + * @freq_table:		Optional list of frequencies to support statistics
>>>>> + *			and freq_table must be generated in ascending order.
>>>>> + * @max_state:		The size of freq_table.
>>>>> + * @total_trans:	Number of devfreq transitions
>>>>> + * @trans_table:	Statistics of devfreq transitions
>>>>> + * @time_in_state:	Statistics of devfreq states
>>>>> + * @last_time:		The last time stats were updated
>>>>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>>> + *			last_time and total_trans used for statistics
>>>>> + */
>>>>> +struct devfreq_stats {
>>>>> +	unsigned long *freq_table;
>>>>> +	unsigned int max_state;
>>>>> +
>>>>> +	/* information for device frequency transition */
>>>>> +	unsigned int total_trans;
>>>>> +	unsigned int *trans_table;
>>>>> +	u64 *time_in_state;
>>>>> +	unsigned long long last_time;
>>>>> +	spinlock_t stats_lock;
>>>>> +};
>>>>> +
>>>>>  /**
>>>>>   * struct devfreq_dev_profile - Devfreq's user device profile
>>>>>   * @initial_freq:	The operating frequency when devfreq_add_device() is
>>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>>   *			from devfreq_remove_device() call. If the user
>>>>>   *			has registered devfreq->nb at a notifier-head,
>>>>>   *			this is the time to unregister it.
>>>>> - * @freq_table:		Optional list of frequencies to support statistics
>>>>> - *			and freq_table must be generated in ascending order.
>>>>> - * @max_state:		The size of freq_table.
>>>>> - * @total_trans:	Number of devfreq transitions
>>>>> - * @trans_table:	Statistics of devfreq transitions
>>>>> - * @time_in_state:	Statistics of devfreq states
>>>>> - * @last_time:		The last time stats were updated
>>>>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>>> - *			last_time and total_trans used for statistics
>>>>> + * @stats:		Statistics of devfreq states and state transitions
>>>>>   */
>>>>>  struct devfreq_dev_profile {
>>>>>  	unsigned long initial_freq;
>>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>>  	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>>  	void (*exit)(struct device *dev);
>>>>>  
>>>>> -	unsigned long *freq_table;
>>>>> -	unsigned int max_state;
>>>>> -	/* information for device frequency transition */
>>>>> -	unsigned int total_trans;
>>>>> -	unsigned int *trans_table;
>>>>> -	u64 *time_in_state;
>>>>> -	unsigned long long last_time;
>>>>> -	spinlock_t stats_lock;
>>>>> +	struct devfreq_stats *stats;
>>>>>  };
>>>>>  
>>>>>  /**
>>>>>

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Re: Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Lukasz Luba]

Hi Bartek,

[added Dietmar, Robin, Andrzej (for upcoming DRM drm-misc-next)]

On 11/15/19 12:40 PM, Bartlomiej Zolnierkiewicz wrote:
> 
> [ added Zhang, Eduardo, Ørjan and Javi to Cc: ]
> 
> On 11/15/19 7:21 AM, Chanwoo Choi wrote:
>> Hi Bartlomiej,
>>
>> On 11/15/19 12:25 PM, Chanwoo Choi wrote:
>>> Hi Bartlomiej,
>>>
>>> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>>>
>>>> Hi Chanwoo,
>>>>
>>>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>>>> Hi Kamil,
>>>>>
>>>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>>>> device driver was posted to mainline kernel, they used
>>>>> them for a long time. It means that this patch break
>>>>> the compatibility. The ARM Mali drivers are very
>>>>> important devfreq device driver.
>>>>
>>>> This argument is not a a technical one and the official upstream
>>>> kernel policy is to not depend on out-of-tree drivers.
>>>>
>>>> Besides the ARM Mali drivers are full of code like:
>>>>
>>>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>>>> ...
>>>> #else
>>>> ...
>>>> #endif
>>>>
>>>> so few more instances of similar code won't do any harm.. ;-)
>>>>
>>>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>>>
>>>> I took a look at ARM Mali drivers source code anyway and I fail to
>>>> see a rationale behind their behavior of doing 'freq_table' and
>>>> 'max_state' initialization in the driver itself (instead of leaving
>>>> it up to the devfreq core code, like all in-kernel drivers are doing
>>>> already).
>>>>
>>>> Could you please explain rationale behind ARM Mali drivers' special
>>>> needs?
>>>>
>>>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>>>    these days to do 'freq_table' and 'max_state' initialization, the
>>>>    only difference seems to be that ARM Mali creates the frequency
>>>>    table in the descending order (but there also seems to be no real
>>>>    need for it). ]
>>>>
>>>> Maybe this is an opportunity to simplify also the ARM Mali driver?
>>>
>>> OK. I agree to simplify them on this time.
>>> For touching the 'freq_table' and 'max_state', need to fix
>>> the descending order of freq_table.
>>>
>>> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>> requires the descending order of freq_table. Have to change it by using
>>> the ascending time or support both ascending and descending order for freq_table.
>>>
>>> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
>>> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>     by using ascending order instead of descending order.
>>>
>>
>> After changed about 'freq_table' and 'max_state', the build error
>> will happen on ARM mail driver because the initialization code of
>> 'freq_table' in ARM mali driver, didn't check the kernel version.
>>
>> The first devfreq patch provided the 'freq_table' as optional variable
>> in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree,
>> this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>
>> So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
>> in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>
>> Frankly, I'm note sure that it is necessary. I don't want to make
>> the side-effect without any useful reason.
>>
>> But,
>> Separately, have to fix the ordering issue of partition_enable_ops()
>> in the drivers/thermal/devfreq_cooling.c.
> 
> Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
> why we are carrying devfreq_cooling.c code in upstream kernel at all?

Well, the devfreq_cooling.c is going to have a client in mainline:
the GPU driver - Panfrost.

It is already in DRM branch 'drm-misc-next':
https://patchwork.freedesktop.org/patch/342848/

Regarding the devfreq_cooling.c code structure.
I am currently working on cleaning up the devfreq cooling code and
adding Energy Model instead for private freq, power tables. It will be
in similar fashion as it is done in cpufreq_cooling. The model will
be also simplified so hopefully more clients would come.
It is under internal review and will be posted shortly.

> 
> It has been merged in the following commit:
> 
> commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
> Author: Ørjan Eide <orjan.eide@arm.com>
> Date:   Thu Sep 10 18:09:30 2015 +0100
> 
>      thermal: Add devfreq cooling
>      
>      Add a generic thermal cooling device for devfreq, that is similar to
>      cpu_cooling.
>      
>      The device must use devfreq.  In order to use the power extension of the
>      cooling device, it must have registered its OPPs using the OPP library.
>      
>      Cc: Zhang Rui <rui.zhang@intel.com>
>      Cc: Eduardo Valentin <edubezval@gmail.com>
>      Signed-off-by: Javi Merino <javi.merino@arm.com>
>      Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
>      Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
> ...
> 
> but 4 years later there is still no single in-kernel user for this code?

There will be, via DRM tree.

Regards,
Lukasz

> 
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
> 
>>>>
>>>>> Also, the devfreq device driver specifies their own
>>>>> information and data into devfreq_dev_profile structure
>>>>> before registering the devfreq device with devfreq_add_device().
>>>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>>>
>>>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>>>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>>>> way..
>>>>
>>>> Best regards,
>>>> --
>>>> Bartlomiej Zolnierkiewicz
>>>> Samsung R&D Institute Poland
>>>> Samsung Electronics
>>>>
>>>>> So, I can't agree this patch. Not ack.
>>>>>
>>>>> Regards,
>>>>> Chanwoo Choi
>>>>>
>>>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>>>> Count time and transitions between devfreq frequencies in separate struct
>>>>>> for improved code readability and maintenance.
>>>>>>
>>>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>>>> ---
>>>>>>   drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>>>   drivers/devfreq/exynos-bus.c       |   6 +-
>>>>>>   drivers/devfreq/governor_passive.c |  26 +++--
>>>>>>   include/linux/devfreq.h            |  43 ++++----
>>>>>>   4 files changed, 129 insertions(+), 102 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>>> index d79412b0de59..d85867a91230 100644
>>>>>> --- a/drivers/devfreq/devfreq.c
>>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>>>    */
>>>>>>   static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>   {
>>>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>   	int lev;
>>>>>>   
>>>>>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>>>> -		if (freq == devfreq->profile->freq_table[lev])
>>>>>> +	for (lev = 0; lev < stats->max_state; lev++)
>>>>>> +		if (freq == stats->freq_table[lev])
>>>>>>   			return lev;
>>>>>>   
>>>>>>   	return -EINVAL;
>>>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>   static int set_freq_table(struct devfreq *devfreq)
>>>>>>   {
>>>>>>   	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>> +	struct devfreq_stats *stats;
>>>>>>   	struct dev_pm_opp *opp;
>>>>>>   	unsigned long freq;
>>>>>> -	int i, count;
>>>>>> +	int i, count, err = -ENOMEM;
>>>>>>   
>>>>>>   	/* Initialize the freq_table from OPP table */
>>>>>>   	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>>>   	if (count <= 0)
>>>>>>   		return -EINVAL;
>>>>>>   
>>>>>> -	profile->max_state = count;
>>>>>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>> -					count,
>>>>>> -					sizeof(*profile->freq_table),
>>>>>> -					GFP_KERNEL);
>>>>>> -	if (!profile->freq_table) {
>>>>>> -		profile->max_state = 0;
>>>>>> +	stats = devm_kzalloc(devfreq->dev.parent,
>>>>>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>>>>>> +	if (!stats)
>>>>>>   		return -ENOMEM;
>>>>>> -	}
>>>>>>   
>>>>>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>>>> +	profile->stats = stats;
>>>>>> +	stats->max_state = count;
>>>>>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>> +					 count,
>>>>>> +					 sizeof(*stats->freq_table),
>>>>>> +					 GFP_KERNEL);
>>>>>> +	if (!stats->freq_table)
>>>>>> +		goto err_no_mem;
>>>>>> +
>>>>>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>>>   		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>>>   		if (IS_ERR(opp)) {
>>>>>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>>>> -			profile->max_state = 0;
>>>>>> -			return PTR_ERR(opp);
>>>>>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>>>> +			stats->max_state = 0;
>>>>>> +			err = PTR_ERR(opp);
>>>>>> +			goto err_no_mem;
>>>>>>   		}
>>>>>>   		dev_pm_opp_put(opp);
>>>>>> -		profile->freq_table[i] = freq;
>>>>>> +		stats->freq_table[i] = freq;
>>>>>>   	}
>>>>>>   
>>>>>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>> -					    array3_size(sizeof(unsigned int),
>>>>>> -							count, count),
>>>>>> -					    GFP_KERNEL);
>>>>>> -	if (!profile->trans_table)
>>>>>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>> +					  array3_size(sizeof(unsigned int),
>>>>>> +						      count, count),
>>>>>> +					  GFP_KERNEL);
>>>>>> +	if (!stats->trans_table)
>>>>>>   		goto err_no_mem;
>>>>>>   
>>>>>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>> -					      sizeof(*profile->time_in_state),
>>>>>> -					      GFP_KERNEL);
>>>>>> -	if (!profile->time_in_state)
>>>>>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>> +					    sizeof(*stats->time_in_state),
>>>>>> +					    GFP_KERNEL);
>>>>>> +	if (!stats->time_in_state)
>>>>>>   		goto err_no_mem;
>>>>>>   
>>>>>> -	profile->last_time = get_jiffies_64();
>>>>>> -	spin_lock_init(&profile->stats_lock);
>>>>>> +	stats->last_time = get_jiffies_64();
>>>>>> +	spin_lock_init(&stats->stats_lock);
>>>>>>   
>>>>>>   	return 0;
>>>>>>   err_no_mem:
>>>>>> -	profile->max_state = 0;
>>>>>> -	return -ENOMEM;
>>>>>> +	stats->max_state = 0;
>>>>>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>>>>>> +	profile->stats = NULL;
>>>>>> +	return err;
>>>>>>   }
>>>>>>   
>>>>>>   /**
>>>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>>>    */
>>>>>>   int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>   {
>>>>>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>   	unsigned long long cur_time;
>>>>>>   	int lev, prev_lev, ret = 0;
>>>>>>   
>>>>>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>   
>>>>>>   	/* Immediately exit if previous_freq is not initialized yet. */
>>>>>>   	if (!devfreq->previous_freq) {
>>>>>> -		spin_lock(&profile->stats_lock);
>>>>>> -		profile->last_time = cur_time;
>>>>>> -		spin_unlock(&profile->stats_lock);
>>>>>> +		spin_lock(&stats->stats_lock);
>>>>>> +		stats->last_time = cur_time;
>>>>>> +		spin_unlock(&stats->stats_lock);
>>>>>>   		return 0;
>>>>>>   	}
>>>>>>   
>>>>>>   	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>>>   
>>>>>> -	spin_lock(&profile->stats_lock);
>>>>>> +	spin_lock(&stats->stats_lock);
>>>>>>   	if (prev_lev < 0) {
>>>>>>   		ret = prev_lev;
>>>>>>   		goto out;
>>>>>>   	}
>>>>>>   
>>>>>> -	profile->time_in_state[prev_lev] +=
>>>>>> -			 cur_time - profile->last_time;
>>>>>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>>>   	lev = devfreq_get_freq_level(devfreq, freq);
>>>>>>   	if (lev < 0) {
>>>>>>   		ret = lev;
>>>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>   	}
>>>>>>   
>>>>>>   	if (lev != prev_lev) {
>>>>>> -		profile->trans_table[(prev_lev *
>>>>>> -				profile->max_state) + lev]++;
>>>>>> -		profile->total_trans++;
>>>>>> +		stats->trans_table[(prev_lev *
>>>>>> +				stats->max_state) + lev]++;
>>>>>> +		stats->total_trans++;
>>>>>>   	}
>>>>>>   
>>>>>>   out:
>>>>>> -	profile->last_time = cur_time;
>>>>>> -	spin_unlock(&profile->stats_lock);
>>>>>> +	stats->last_time = cur_time;
>>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>>   	return ret;
>>>>>>   }
>>>>>>   EXPORT_SYMBOL(devfreq_update_status);
>>>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>>>   		queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>>>   			msecs_to_jiffies(profile->polling_ms));
>>>>>>   
>>>>>> -	spin_lock(&profile->stats_lock);
>>>>>> -	profile->last_time = get_jiffies_64();
>>>>>> -	spin_unlock(&profile->stats_lock);
>>>>>> +	spin_lock(&profile->stats->stats_lock);
>>>>>> +	profile->stats->last_time = get_jiffies_64();
>>>>>> +	spin_unlock(&profile->stats->stats_lock);
>>>>>>   	devfreq->stop_polling = false;
>>>>>>   
>>>>>>   	if (profile->get_cur_freq &&
>>>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>>>   	devfreq->data = data;
>>>>>>   	devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>>>   
>>>>>> -	if (!profile->max_state && !profile->freq_table) {
>>>>>> +	if (!profile->stats) {
>>>>>>   		mutex_unlock(&devfreq->lock);
>>>>>>   		err = set_freq_table(devfreq);
>>>>>>   		if (err < 0)
>>>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>   			      const char *buf, size_t count)
>>>>>>   {
>>>>>>   	struct devfreq *df = to_devfreq(dev);
>>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>>   	unsigned long value;
>>>>>>   	int ret;
>>>>>>   
>>>>>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>   			goto unlock;
>>>>>>   		}
>>>>>>   	} else {
>>>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>>>   
>>>>>>   		/* Get minimum frequency according to sorting order */
>>>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>   			value = freq_table[0];
>>>>>>   		else
>>>>>> -			value = freq_table[df->profile->max_state - 1];
>>>>>> +			value = freq_table[stats->max_state - 1];
>>>>>>   	}
>>>>>>   
>>>>>>   	df->min_freq = value;
>>>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>   			      const char *buf, size_t count)
>>>>>>   {
>>>>>>   	struct devfreq *df = to_devfreq(dev);
>>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>>   	unsigned long value;
>>>>>>   	int ret;
>>>>>>   
>>>>>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>   			goto unlock;
>>>>>>   		}
>>>>>>   	} else {
>>>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>>>   
>>>>>>   		/* Get maximum frequency according to sorting order */
>>>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>> -			value = freq_table[df->profile->max_state - 1];
>>>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>> +			value = freq_table[stats->max_state - 1];
>>>>>>   		else
>>>>>>   			value = freq_table[0];
>>>>>>   	}
>>>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>>>   					  char *buf)
>>>>>>   {
>>>>>>   	struct devfreq *df = to_devfreq(d);
>>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>>   	ssize_t count = 0;
>>>>>>   	int i;
>>>>>>   
>>>>>>   	mutex_lock(&df->lock);
>>>>>>   
>>>>>> -	for (i = 0; i < df->profile->max_state; i++)
>>>>>> +	for (i = 0; i < stats->max_state; i++)
>>>>>>   		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>>>> -				"%lu ", df->profile->freq_table[i]);
>>>>>> +				"%lu ", stats->freq_table[i]);
>>>>>>   
>>>>>>   	mutex_unlock(&df->lock);
>>>>>>   	/* Truncate the trailing space */
>>>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>   {
>>>>>>   	struct devfreq *devfreq = to_devfreq(dev);
>>>>>>   	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>> +	struct devfreq_stats *stats = profile->stats;
>>>>>> +	unsigned int max_state = stats->max_state;
>>>>>>   	ssize_t len;
>>>>>>   	int i, j;
>>>>>> -	unsigned int max_state = profile->max_state;
>>>>>>   
>>>>>>   	if (!devfreq->stop_polling &&
>>>>>>   			devfreq_update_status(devfreq, devfreq->previous_freq))
>>>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>   	len = sprintf(buf, "     From  :   To\n");
>>>>>>   	len += sprintf(buf + len, "           :");
>>>>>>   
>>>>>> -	spin_lock(&profile->stats_lock);
>>>>>> +	spin_lock(&stats->stats_lock);
>>>>>>   	for (i = 0; i < max_state; i++)
>>>>>>   		len += sprintf(buf + len, "%10lu",
>>>>>> -				profile->freq_table[i]);
>>>>>> +				stats->freq_table[i]);
>>>>>>   
>>>>>>   	len += sprintf(buf + len, "   time(ms)\n");
>>>>>>   
>>>>>>   	for (i = 0; i < max_state; i++) {
>>>>>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>>>>>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>>>>>   			len += sprintf(buf + len, "*");
>>>>>>   		else
>>>>>>   			len += sprintf(buf + len, " ");
>>>>>>   
>>>>>>   		len += sprintf(buf + len, "%10lu:",
>>>>>> -				profile->freq_table[i]);
>>>>>> +				stats->freq_table[i]);
>>>>>>   		for (j = 0; j < max_state; j++)
>>>>>>   			len += sprintf(buf + len, "%10u",
>>>>>> -				profile->trans_table[(i * max_state) + j]);
>>>>>> +				stats->trans_table[(i * max_state) + j]);
>>>>>>   		len += sprintf(buf + len, "%10llu\n", (u64)
>>>>>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>>>>>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>>>>>   	}
>>>>>>   
>>>>>>   	len += sprintf(buf + len, "Total transition : %u\n",
>>>>>> -					profile->total_trans);
>>>>>> -	spin_unlock(&profile->stats_lock);
>>>>>> +					stats->total_trans);
>>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>>   	return len;
>>>>>>   }
>>>>>>   static DEVICE_ATTR_RO(trans_stat);
>>>>>>   
>>>>>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>>>   {
>>>>>> -	unsigned int count = profile->max_state;
>>>>>> -
>>>>>> -	spin_lock(&profile->stats_lock);
>>>>>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>>>>>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>>>>>> -	profile->last_time = get_jiffies_64();
>>>>>> -	profile->total_trans = 0;
>>>>>> -	spin_unlock(&profile->stats_lock);
>>>>>> +	unsigned int count = stats->max_state;
>>>>>> +
>>>>>> +	spin_lock(&stats->stats_lock);
>>>>>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>>>>>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>>>>>> +	stats->last_time = get_jiffies_64();
>>>>>> +	stats->total_trans = 0;
>>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>>   }
>>>>>>   
>>>>>>   static ssize_t trans_reset_store(struct device *dev,
>>>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>>>   {
>>>>>>   	struct devfreq *devfreq = to_devfreq(dev);
>>>>>>   
>>>>>> -	defvreq_stats_clear_table(devfreq->profile);
>>>>>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>>>>>   
>>>>>>   	return count;
>>>>>>   }
>>>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>>>> index d9f377912c10..b212aae2bb3e 100644
>>>>>> --- a/drivers/devfreq/exynos-bus.c
>>>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>>>   	}
>>>>>>   
>>>>>>   out:
>>>>>> -	max_state = bus->devfreq->profile->max_state;
>>>>>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>>>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>>>> +	max_state = profile->stats->max_state;
>>>>>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>>>>>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>>>   	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>>>   			dev_name(dev), min_freq, max_freq);
>>>>>>   
>>>>>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>>>> index 58308948b863..b2d87a88335c 100644
>>>>>> --- a/drivers/devfreq/governor_passive.c
>>>>>> +++ b/drivers/devfreq/governor_passive.c
>>>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>   	struct devfreq_passive_data *p_data
>>>>>>   			= (struct devfreq_passive_data *)devfreq->data;
>>>>>>   	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>>>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>>>> +	struct devfreq_stats *stats;
>>>>>>   	unsigned long child_freq = ULONG_MAX;
>>>>>>   	struct dev_pm_opp *opp;
>>>>>>   	int i, count, ret = 0;
>>>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>   	 * device. And then the index is used for getting the suitable
>>>>>>   	 * new frequency for passive devfreq device.
>>>>>>   	 */
>>>>>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>>>>>> -		|| devfreq->profile->max_state <= 0)
>>>>>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>>>>>> +	    devfreq->profile->stats->max_state <= 0 ||
>>>>>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>>>>>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>>>>>   		return -EINVAL;
>>>>>>   
>>>>>> +	stats = devfreq->profile->stats;
>>>>>> +	parent_stats = parent_devfreq->profile->stats;
>>>>>>   	/*
>>>>>>   	 * The passive governor have to get the correct frequency from OPP
>>>>>>   	 * list of parent device. Because in this case, *freq is temporary
>>>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>   	 * Get the OPP table's index of decided freqeuncy by governor
>>>>>>   	 * of parent device.
>>>>>>   	 */
>>>>>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>>>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>>>>>> +	for (i = 0; i < parent_stats->max_state; i++)
>>>>>> +		if (parent_stats->freq_table[i] == *freq)
>>>>>>   			break;
>>>>>>   
>>>>>> -	if (i == parent_devfreq->profile->max_state) {
>>>>>> +	if (i == parent_stats->max_state) {
>>>>>>   		ret = -EINVAL;
>>>>>>   		goto out;
>>>>>>   	}
>>>>>>   
>>>>>>   	/* Get the suitable frequency by using index of parent device. */
>>>>>> -	if (i < devfreq->profile->max_state) {
>>>>>> -		child_freq = devfreq->profile->freq_table[i];
>>>>>> +	if (i < stats->max_state) {
>>>>>> +		child_freq = stats->freq_table[i];
>>>>>>   	} else {
>>>>>> -		count = devfreq->profile->max_state;
>>>>>> -		child_freq = devfreq->profile->freq_table[count - 1];
>>>>>> +		count = stats->max_state;
>>>>>> +		child_freq = stats->freq_table[count - 1];
>>>>>>   	}
>>>>>>   
>>>>>>   	/* Return the suitable frequency for passive device. */
>>>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>>>   	if (ret < 0)
>>>>>>   		goto out;
>>>>>>   
>>>>>> -	if (devfreq->profile->freq_table
>>>>>> +	if (devfreq->profile->stats
>>>>>>   		&& (devfreq_update_status(devfreq, freq)))
>>>>>>   		dev_err(&devfreq->dev,
>>>>>>   			"Couldn't update frequency transition information.\n");
>>>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>>>> --- a/include/linux/devfreq.h
>>>>>> +++ b/include/linux/devfreq.h
>>>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>>>    */
>>>>>>   #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>>>>>   
>>>>>> +/**
>>>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>>>> + * @freq_table:		Optional list of frequencies to support statistics
>>>>>> + *			and freq_table must be generated in ascending order.
>>>>>> + * @max_state:		The size of freq_table.
>>>>>> + * @total_trans:	Number of devfreq transitions
>>>>>> + * @trans_table:	Statistics of devfreq transitions
>>>>>> + * @time_in_state:	Statistics of devfreq states
>>>>>> + * @last_time:		The last time stats were updated
>>>>>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>>>> + *			last_time and total_trans used for statistics
>>>>>> + */
>>>>>> +struct devfreq_stats {
>>>>>> +	unsigned long *freq_table;
>>>>>> +	unsigned int max_state;
>>>>>> +
>>>>>> +	/* information for device frequency transition */
>>>>>> +	unsigned int total_trans;
>>>>>> +	unsigned int *trans_table;
>>>>>> +	u64 *time_in_state;
>>>>>> +	unsigned long long last_time;
>>>>>> +	spinlock_t stats_lock;
>>>>>> +};
>>>>>> +
>>>>>>   /**
>>>>>>    * struct devfreq_dev_profile - Devfreq's user device profile
>>>>>>    * @initial_freq:	The operating frequency when devfreq_add_device() is
>>>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>>>    *			from devfreq_remove_device() call. If the user
>>>>>>    *			has registered devfreq->nb at a notifier-head,
>>>>>>    *			this is the time to unregister it.
>>>>>> - * @freq_table:		Optional list of frequencies to support statistics
>>>>>> - *			and freq_table must be generated in ascending order.
>>>>>> - * @max_state:		The size of freq_table.
>>>>>> - * @total_trans:	Number of devfreq transitions
>>>>>> - * @trans_table:	Statistics of devfreq transitions
>>>>>> - * @time_in_state:	Statistics of devfreq states
>>>>>> - * @last_time:		The last time stats were updated
>>>>>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>>>> - *			last_time and total_trans used for statistics
>>>>>> + * @stats:		Statistics of devfreq states and state transitions
>>>>>>    */
>>>>>>   struct devfreq_dev_profile {
>>>>>>   	unsigned long initial_freq;
>>>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>>>   	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>>>   	void (*exit)(struct device *dev);
>>>>>>   
>>>>>> -	unsigned long *freq_table;
>>>>>> -	unsigned int max_state;
>>>>>> -	/* information for device frequency transition */
>>>>>> -	unsigned int total_trans;
>>>>>> -	unsigned int *trans_table;
>>>>>> -	u64 *time_in_state;
>>>>>> -	unsigned long long last_time;
>>>>>> -	spinlock_t stats_lock;
>>>>>> +	struct devfreq_stats *stats;
>>>>>>   };
>>>>>>   
>>>>>>   /**
>>>>>>
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

Re: Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Lukasz Luba]

Hi Bartek,

[added Dietmar, Robin, Andrzej (for upcoming DRM drm-misc-next)]

On 11/15/19 12:40 PM, Bartlomiej Zolnierkiewicz wrote:
> 
> [ added Zhang, Eduardo, Ørjan and Javi to Cc: ]
> 
> On 11/15/19 7:21 AM, Chanwoo Choi wrote:
>> Hi Bartlomiej,
>>
>> On 11/15/19 12:25 PM, Chanwoo Choi wrote:
>>> Hi Bartlomiej,
>>>
>>> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>>>
>>>> Hi Chanwoo,
>>>>
>>>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>>>> Hi Kamil,
>>>>>
>>>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>>>> device driver was posted to mainline kernel, they used
>>>>> them for a long time. It means that this patch break
>>>>> the compatibility. The ARM Mali drivers are very
>>>>> important devfreq device driver.
>>>>
>>>> This argument is not a a technical one and the official upstream
>>>> kernel policy is to not depend on out-of-tree drivers.
>>>>
>>>> Besides the ARM Mali drivers are full of code like:
>>>>
>>>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>>>> ...
>>>> #else
>>>> ...
>>>> #endif
>>>>
>>>> so few more instances of similar code won't do any harm.. ;-)
>>>>
>>>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>>>
>>>> I took a look at ARM Mali drivers source code anyway and I fail to
>>>> see a rationale behind their behavior of doing 'freq_table' and
>>>> 'max_state' initialization in the driver itself (instead of leaving
>>>> it up to the devfreq core code, like all in-kernel drivers are doing
>>>> already).
>>>>
>>>> Could you please explain rationale behind ARM Mali drivers' special
>>>> needs?
>>>>
>>>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>>>    these days to do 'freq_table' and 'max_state' initialization, the
>>>>    only difference seems to be that ARM Mali creates the frequency
>>>>    table in the descending order (but there also seems to be no real
>>>>    need for it). ]
>>>>
>>>> Maybe this is an opportunity to simplify also the ARM Mali driver?
>>>
>>> OK. I agree to simplify them on this time.
>>> For touching the 'freq_table' and 'max_state', need to fix
>>> the descending order of freq_table.
>>>
>>> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>> requires the descending order of freq_table. Have to change it by using
>>> the ascending time or support both ascending and descending order for freq_table.
>>>
>>> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
>>> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>     by using ascending order instead of descending order.
>>>
>>
>> After changed about 'freq_table' and 'max_state', the build error
>> will happen on ARM mail driver because the initialization code of
>> 'freq_table' in ARM mali driver, didn't check the kernel version.
>>
>> The first devfreq patch provided the 'freq_table' as optional variable
>> in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree,
>> this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>
>> So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
>> in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>
>> Frankly, I'm note sure that it is necessary. I don't want to make
>> the side-effect without any useful reason.
>>
>> But,
>> Separately, have to fix the ordering issue of partition_enable_ops()
>> in the drivers/thermal/devfreq_cooling.c.
> 
> Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
> why we are carrying devfreq_cooling.c code in upstream kernel at all?

Well, the devfreq_cooling.c is going to have a client in mainline:
the GPU driver - Panfrost.

It is already in DRM branch 'drm-misc-next':
https://patchwork.freedesktop.org/patch/342848/

Regarding the devfreq_cooling.c code structure.
I am currently working on cleaning up the devfreq cooling code and
adding Energy Model instead for private freq, power tables. It will be
in similar fashion as it is done in cpufreq_cooling. The model will
be also simplified so hopefully more clients would come.
It is under internal review and will be posted shortly.

> 
> It has been merged in the following commit:
> 
> commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
> Author: Ørjan Eide <orjan.eide@arm.com>
> Date:   Thu Sep 10 18:09:30 2015 +0100
> 
>      thermal: Add devfreq cooling
>      
>      Add a generic thermal cooling device for devfreq, that is similar to
>      cpu_cooling.
>      
>      The device must use devfreq.  In order to use the power extension of the
>      cooling device, it must have registered its OPPs using the OPP library.
>      
>      Cc: Zhang Rui <rui.zhang@intel.com>
>      Cc: Eduardo Valentin <edubezval@gmail.com>
>      Signed-off-by: Javi Merino <javi.merino@arm.com>
>      Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
>      Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
> ...
> 
> but 4 years later there is still no single in-kernel user for this code?

There will be, via DRM tree.

Regards,
Lukasz

> 
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
> 
>>>>
>>>>> Also, the devfreq device driver specifies their own
>>>>> information and data into devfreq_dev_profile structure
>>>>> before registering the devfreq device with devfreq_add_device().
>>>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>>>
>>>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>>>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>>>> way..
>>>>
>>>> Best regards,
>>>> --
>>>> Bartlomiej Zolnierkiewicz
>>>> Samsung R&D Institute Poland
>>>> Samsung Electronics
>>>>
>>>>> So, I can't agree this patch. Not ack.
>>>>>
>>>>> Regards,
>>>>> Chanwoo Choi
>>>>>
>>>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>>>> Count time and transitions between devfreq frequencies in separate struct
>>>>>> for improved code readability and maintenance.
>>>>>>
>>>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>>>> ---
>>>>>>   drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>>>   drivers/devfreq/exynos-bus.c       |   6 +-
>>>>>>   drivers/devfreq/governor_passive.c |  26 +++--
>>>>>>   include/linux/devfreq.h            |  43 ++++----
>>>>>>   4 files changed, 129 insertions(+), 102 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>>> index d79412b0de59..d85867a91230 100644
>>>>>> --- a/drivers/devfreq/devfreq.c
>>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>>>    */
>>>>>>   static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>   {
>>>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>   	int lev;
>>>>>>   
>>>>>> -	for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>>>> -		if (freq == devfreq->profile->freq_table[lev])
>>>>>> +	for (lev = 0; lev < stats->max_state; lev++)
>>>>>> +		if (freq == stats->freq_table[lev])
>>>>>>   			return lev;
>>>>>>   
>>>>>>   	return -EINVAL;
>>>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>   static int set_freq_table(struct devfreq *devfreq)
>>>>>>   {
>>>>>>   	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>> +	struct devfreq_stats *stats;
>>>>>>   	struct dev_pm_opp *opp;
>>>>>>   	unsigned long freq;
>>>>>> -	int i, count;
>>>>>> +	int i, count, err = -ENOMEM;
>>>>>>   
>>>>>>   	/* Initialize the freq_table from OPP table */
>>>>>>   	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>>>   	if (count <= 0)
>>>>>>   		return -EINVAL;
>>>>>>   
>>>>>> -	profile->max_state = count;
>>>>>> -	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>> -					count,
>>>>>> -					sizeof(*profile->freq_table),
>>>>>> -					GFP_KERNEL);
>>>>>> -	if (!profile->freq_table) {
>>>>>> -		profile->max_state = 0;
>>>>>> +	stats = devm_kzalloc(devfreq->dev.parent,
>>>>>> +			     sizeof(struct devfreq_stats), GFP_KERNEL);
>>>>>> +	if (!stats)
>>>>>>   		return -ENOMEM;
>>>>>> -	}
>>>>>>   
>>>>>> -	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>>>> +	profile->stats = stats;
>>>>>> +	stats->max_state = count;
>>>>>> +	stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>> +					 count,
>>>>>> +					 sizeof(*stats->freq_table),
>>>>>> +					 GFP_KERNEL);
>>>>>> +	if (!stats->freq_table)
>>>>>> +		goto err_no_mem;
>>>>>> +
>>>>>> +	for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>>>   		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>>>   		if (IS_ERR(opp)) {
>>>>>> -			devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>>>> -			profile->max_state = 0;
>>>>>> -			return PTR_ERR(opp);
>>>>>> +			devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>>>> +			stats->max_state = 0;
>>>>>> +			err = PTR_ERR(opp);
>>>>>> +			goto err_no_mem;
>>>>>>   		}
>>>>>>   		dev_pm_opp_put(opp);
>>>>>> -		profile->freq_table[i] = freq;
>>>>>> +		stats->freq_table[i] = freq;
>>>>>>   	}
>>>>>>   
>>>>>> -	profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>> -					    array3_size(sizeof(unsigned int),
>>>>>> -							count, count),
>>>>>> -					    GFP_KERNEL);
>>>>>> -	if (!profile->trans_table)
>>>>>> +	stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>> +					  array3_size(sizeof(unsigned int),
>>>>>> +						      count, count),
>>>>>> +					  GFP_KERNEL);
>>>>>> +	if (!stats->trans_table)
>>>>>>   		goto err_no_mem;
>>>>>>   
>>>>>> -	profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>> -					      sizeof(*profile->time_in_state),
>>>>>> -					      GFP_KERNEL);
>>>>>> -	if (!profile->time_in_state)
>>>>>> +	stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>> +					    sizeof(*stats->time_in_state),
>>>>>> +					    GFP_KERNEL);
>>>>>> +	if (!stats->time_in_state)
>>>>>>   		goto err_no_mem;
>>>>>>   
>>>>>> -	profile->last_time = get_jiffies_64();
>>>>>> -	spin_lock_init(&profile->stats_lock);
>>>>>> +	stats->last_time = get_jiffies_64();
>>>>>> +	spin_lock_init(&stats->stats_lock);
>>>>>>   
>>>>>>   	return 0;
>>>>>>   err_no_mem:
>>>>>> -	profile->max_state = 0;
>>>>>> -	return -ENOMEM;
>>>>>> +	stats->max_state = 0;
>>>>>> +	devm_kfree(devfreq->dev.parent, profile->stats);
>>>>>> +	profile->stats = NULL;
>>>>>> +	return err;
>>>>>>   }
>>>>>>   
>>>>>>   /**
>>>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>>>    */
>>>>>>   int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>   {
>>>>>> -	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>> +	struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>   	unsigned long long cur_time;
>>>>>>   	int lev, prev_lev, ret = 0;
>>>>>>   
>>>>>> @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>   
>>>>>>   	/* Immediately exit if previous_freq is not initialized yet. */
>>>>>>   	if (!devfreq->previous_freq) {
>>>>>> -		spin_lock(&profile->stats_lock);
>>>>>> -		profile->last_time = cur_time;
>>>>>> -		spin_unlock(&profile->stats_lock);
>>>>>> +		spin_lock(&stats->stats_lock);
>>>>>> +		stats->last_time = cur_time;
>>>>>> +		spin_unlock(&stats->stats_lock);
>>>>>>   		return 0;
>>>>>>   	}
>>>>>>   
>>>>>>   	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>>>   
>>>>>> -	spin_lock(&profile->stats_lock);
>>>>>> +	spin_lock(&stats->stats_lock);
>>>>>>   	if (prev_lev < 0) {
>>>>>>   		ret = prev_lev;
>>>>>>   		goto out;
>>>>>>   	}
>>>>>>   
>>>>>> -	profile->time_in_state[prev_lev] +=
>>>>>> -			 cur_time - profile->last_time;
>>>>>> +	stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>>>   	lev = devfreq_get_freq_level(devfreq, freq);
>>>>>>   	if (lev < 0) {
>>>>>>   		ret = lev;
>>>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>   	}
>>>>>>   
>>>>>>   	if (lev != prev_lev) {
>>>>>> -		profile->trans_table[(prev_lev *
>>>>>> -				profile->max_state) + lev]++;
>>>>>> -		profile->total_trans++;
>>>>>> +		stats->trans_table[(prev_lev *
>>>>>> +				stats->max_state) + lev]++;
>>>>>> +		stats->total_trans++;
>>>>>>   	}
>>>>>>   
>>>>>>   out:
>>>>>> -	profile->last_time = cur_time;
>>>>>> -	spin_unlock(&profile->stats_lock);
>>>>>> +	stats->last_time = cur_time;
>>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>>   	return ret;
>>>>>>   }
>>>>>>   EXPORT_SYMBOL(devfreq_update_status);
>>>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>>>   		queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>>>   			msecs_to_jiffies(profile->polling_ms));
>>>>>>   
>>>>>> -	spin_lock(&profile->stats_lock);
>>>>>> -	profile->last_time = get_jiffies_64();
>>>>>> -	spin_unlock(&profile->stats_lock);
>>>>>> +	spin_lock(&profile->stats->stats_lock);
>>>>>> +	profile->stats->last_time = get_jiffies_64();
>>>>>> +	spin_unlock(&profile->stats->stats_lock);
>>>>>>   	devfreq->stop_polling = false;
>>>>>>   
>>>>>>   	if (profile->get_cur_freq &&
>>>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>>>   	devfreq->data = data;
>>>>>>   	devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>>>   
>>>>>> -	if (!profile->max_state && !profile->freq_table) {
>>>>>> +	if (!profile->stats) {
>>>>>>   		mutex_unlock(&devfreq->lock);
>>>>>>   		err = set_freq_table(devfreq);
>>>>>>   		if (err < 0)
>>>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>   			      const char *buf, size_t count)
>>>>>>   {
>>>>>>   	struct devfreq *df = to_devfreq(dev);
>>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>>   	unsigned long value;
>>>>>>   	int ret;
>>>>>>   
>>>>>> @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>   			goto unlock;
>>>>>>   		}
>>>>>>   	} else {
>>>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>>>   
>>>>>>   		/* Get minimum frequency according to sorting order */
>>>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>   			value = freq_table[0];
>>>>>>   		else
>>>>>> -			value = freq_table[df->profile->max_state - 1];
>>>>>> +			value = freq_table[stats->max_state - 1];
>>>>>>   	}
>>>>>>   
>>>>>>   	df->min_freq = value;
>>>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>   			      const char *buf, size_t count)
>>>>>>   {
>>>>>>   	struct devfreq *df = to_devfreq(dev);
>>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>>   	unsigned long value;
>>>>>>   	int ret;
>>>>>>   
>>>>>> @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>   			goto unlock;
>>>>>>   		}
>>>>>>   	} else {
>>>>>> -		unsigned long *freq_table = df->profile->freq_table;
>>>>>> +		unsigned long *freq_table = stats->freq_table;
>>>>>>   
>>>>>>   		/* Get maximum frequency according to sorting order */
>>>>>> -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>> -			value = freq_table[df->profile->max_state - 1];
>>>>>> +		if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>> +			value = freq_table[stats->max_state - 1];
>>>>>>   		else
>>>>>>   			value = freq_table[0];
>>>>>>   	}
>>>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>>>   					  char *buf)
>>>>>>   {
>>>>>>   	struct devfreq *df = to_devfreq(d);
>>>>>> +	struct devfreq_stats *stats = df->profile->stats;
>>>>>>   	ssize_t count = 0;
>>>>>>   	int i;
>>>>>>   
>>>>>>   	mutex_lock(&df->lock);
>>>>>>   
>>>>>> -	for (i = 0; i < df->profile->max_state; i++)
>>>>>> +	for (i = 0; i < stats->max_state; i++)
>>>>>>   		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>>>> -				"%lu ", df->profile->freq_table[i]);
>>>>>> +				"%lu ", stats->freq_table[i]);
>>>>>>   
>>>>>>   	mutex_unlock(&df->lock);
>>>>>>   	/* Truncate the trailing space */
>>>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>   {
>>>>>>   	struct devfreq *devfreq = to_devfreq(dev);
>>>>>>   	struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>> +	struct devfreq_stats *stats = profile->stats;
>>>>>> +	unsigned int max_state = stats->max_state;
>>>>>>   	ssize_t len;
>>>>>>   	int i, j;
>>>>>> -	unsigned int max_state = profile->max_state;
>>>>>>   
>>>>>>   	if (!devfreq->stop_polling &&
>>>>>>   			devfreq_update_status(devfreq, devfreq->previous_freq))
>>>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>   	len = sprintf(buf, "     From  :   To\n");
>>>>>>   	len += sprintf(buf + len, "           :");
>>>>>>   
>>>>>> -	spin_lock(&profile->stats_lock);
>>>>>> +	spin_lock(&stats->stats_lock);
>>>>>>   	for (i = 0; i < max_state; i++)
>>>>>>   		len += sprintf(buf + len, "%10lu",
>>>>>> -				profile->freq_table[i]);
>>>>>> +				stats->freq_table[i]);
>>>>>>   
>>>>>>   	len += sprintf(buf + len, "   time(ms)\n");
>>>>>>   
>>>>>>   	for (i = 0; i < max_state; i++) {
>>>>>> -		if (profile->freq_table[i] == devfreq->previous_freq)
>>>>>> +		if (stats->freq_table[i] == devfreq->previous_freq)
>>>>>>   			len += sprintf(buf + len, "*");
>>>>>>   		else
>>>>>>   			len += sprintf(buf + len, " ");
>>>>>>   
>>>>>>   		len += sprintf(buf + len, "%10lu:",
>>>>>> -				profile->freq_table[i]);
>>>>>> +				stats->freq_table[i]);
>>>>>>   		for (j = 0; j < max_state; j++)
>>>>>>   			len += sprintf(buf + len, "%10u",
>>>>>> -				profile->trans_table[(i * max_state) + j]);
>>>>>> +				stats->trans_table[(i * max_state) + j]);
>>>>>>   		len += sprintf(buf + len, "%10llu\n", (u64)
>>>>>> -			jiffies64_to_msecs(profile->time_in_state[i]));
>>>>>> +			jiffies64_to_msecs(stats->time_in_state[i]));
>>>>>>   	}
>>>>>>   
>>>>>>   	len += sprintf(buf + len, "Total transition : %u\n",
>>>>>> -					profile->total_trans);
>>>>>> -	spin_unlock(&profile->stats_lock);
>>>>>> +					stats->total_trans);
>>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>>   	return len;
>>>>>>   }
>>>>>>   static DEVICE_ATTR_RO(trans_stat);
>>>>>>   
>>>>>> -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>>>   {
>>>>>> -	unsigned int count = profile->max_state;
>>>>>> -
>>>>>> -	spin_lock(&profile->stats_lock);
>>>>>> -	memset(profile->time_in_state, 0, count * sizeof(u64));
>>>>>> -	memset(profile->trans_table, 0, count * count * sizeof(int));
>>>>>> -	profile->last_time = get_jiffies_64();
>>>>>> -	profile->total_trans = 0;
>>>>>> -	spin_unlock(&profile->stats_lock);
>>>>>> +	unsigned int count = stats->max_state;
>>>>>> +
>>>>>> +	spin_lock(&stats->stats_lock);
>>>>>> +	memset(stats->time_in_state, 0, count * sizeof(u64));
>>>>>> +	memset(stats->trans_table, 0, count * count * sizeof(int));
>>>>>> +	stats->last_time = get_jiffies_64();
>>>>>> +	stats->total_trans = 0;
>>>>>> +	spin_unlock(&stats->stats_lock);
>>>>>>   }
>>>>>>   
>>>>>>   static ssize_t trans_reset_store(struct device *dev,
>>>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>>>   {
>>>>>>   	struct devfreq *devfreq = to_devfreq(dev);
>>>>>>   
>>>>>> -	defvreq_stats_clear_table(devfreq->profile);
>>>>>> +	defvreq_stats_clear_table(devfreq->profile->stats);
>>>>>>   
>>>>>>   	return count;
>>>>>>   }
>>>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>>>> index d9f377912c10..b212aae2bb3e 100644
>>>>>> --- a/drivers/devfreq/exynos-bus.c
>>>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>>>   	}
>>>>>>   
>>>>>>   out:
>>>>>> -	max_state = bus->devfreq->profile->max_state;
>>>>>> -	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>>>> -	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>>>> +	max_state = profile->stats->max_state;
>>>>>> +	min_freq = (profile->stats->freq_table[0] / 1000);
>>>>>> +	max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>>>   	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>>>   			dev_name(dev), min_freq, max_freq);
>>>>>>   
>>>>>> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>>>> index 58308948b863..b2d87a88335c 100644
>>>>>> --- a/drivers/devfreq/governor_passive.c
>>>>>> +++ b/drivers/devfreq/governor_passive.c
>>>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>   	struct devfreq_passive_data *p_data
>>>>>>   			= (struct devfreq_passive_data *)devfreq->data;
>>>>>>   	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>>>> +	struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>>>> +	struct devfreq_stats *stats;
>>>>>>   	unsigned long child_freq = ULONG_MAX;
>>>>>>   	struct dev_pm_opp *opp;
>>>>>>   	int i, count, ret = 0;
>>>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>   	 * device. And then the index is used for getting the suitable
>>>>>>   	 * new frequency for passive devfreq device.
>>>>>>   	 */
>>>>>> -	if (!devfreq->profile || !devfreq->profile->freq_table
>>>>>> -		|| devfreq->profile->max_state <= 0)
>>>>>> +	if (!devfreq->profile || !devfreq->profile->stats ||
>>>>>> +	    devfreq->profile->stats->max_state <= 0 ||
>>>>>> +	    !parent_devfreq->profile ||	!parent_devfreq->profile->stats ||
>>>>>> +	    parent_devfreq->profile->stats->max_state <= 0)
>>>>>>   		return -EINVAL;
>>>>>>   
>>>>>> +	stats = devfreq->profile->stats;
>>>>>> +	parent_stats = parent_devfreq->profile->stats;
>>>>>>   	/*
>>>>>>   	 * The passive governor have to get the correct frequency from OPP
>>>>>>   	 * list of parent device. Because in this case, *freq is temporary
>>>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>   	 * Get the OPP table's index of decided freqeuncy by governor
>>>>>>   	 * of parent device.
>>>>>>   	 */
>>>>>> -	for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>>>> -		if (parent_devfreq->profile->freq_table[i] == *freq)
>>>>>> +	for (i = 0; i < parent_stats->max_state; i++)
>>>>>> +		if (parent_stats->freq_table[i] == *freq)
>>>>>>   			break;
>>>>>>   
>>>>>> -	if (i == parent_devfreq->profile->max_state) {
>>>>>> +	if (i == parent_stats->max_state) {
>>>>>>   		ret = -EINVAL;
>>>>>>   		goto out;
>>>>>>   	}
>>>>>>   
>>>>>>   	/* Get the suitable frequency by using index of parent device. */
>>>>>> -	if (i < devfreq->profile->max_state) {
>>>>>> -		child_freq = devfreq->profile->freq_table[i];
>>>>>> +	if (i < stats->max_state) {
>>>>>> +		child_freq = stats->freq_table[i];
>>>>>>   	} else {
>>>>>> -		count = devfreq->profile->max_state;
>>>>>> -		child_freq = devfreq->profile->freq_table[count - 1];
>>>>>> +		count = stats->max_state;
>>>>>> +		child_freq = stats->freq_table[count - 1];
>>>>>>   	}
>>>>>>   
>>>>>>   	/* Return the suitable frequency for passive device. */
>>>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>>>   	if (ret < 0)
>>>>>>   		goto out;
>>>>>>   
>>>>>> -	if (devfreq->profile->freq_table
>>>>>> +	if (devfreq->profile->stats
>>>>>>   		&& (devfreq_update_status(devfreq, freq)))
>>>>>>   		dev_err(&devfreq->dev,
>>>>>>   			"Couldn't update frequency transition information.\n");
>>>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>>>> --- a/include/linux/devfreq.h
>>>>>> +++ b/include/linux/devfreq.h
>>>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>>>    */
>>>>>>   #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>>>>>>   
>>>>>> +/**
>>>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>>>> + * @freq_table:		Optional list of frequencies to support statistics
>>>>>> + *			and freq_table must be generated in ascending order.
>>>>>> + * @max_state:		The size of freq_table.
>>>>>> + * @total_trans:	Number of devfreq transitions
>>>>>> + * @trans_table:	Statistics of devfreq transitions
>>>>>> + * @time_in_state:	Statistics of devfreq states
>>>>>> + * @last_time:		The last time stats were updated
>>>>>> + * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>>>> + *			last_time and total_trans used for statistics
>>>>>> + */
>>>>>> +struct devfreq_stats {
>>>>>> +	unsigned long *freq_table;
>>>>>> +	unsigned int max_state;
>>>>>> +
>>>>>> +	/* information for device frequency transition */
>>>>>> +	unsigned int total_trans;
>>>>>> +	unsigned int *trans_table;
>>>>>> +	u64 *time_in_state;
>>>>>> +	unsigned long long last_time;
>>>>>> +	spinlock_t stats_lock;
>>>>>> +};
>>>>>> +
>>>>>>   /**
>>>>>>    * struct devfreq_dev_profile - Devfreq's user device profile
>>>>>>    * @initial_freq:	The operating frequency when devfreq_add_device() is
>>>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>>>    *			from devfreq_remove_device() call. If the user
>>>>>>    *			has registered devfreq->nb at a notifier-head,
>>>>>>    *			this is the time to unregister it.
>>>>>> - * @freq_table:		Optional list of frequencies to support statistics
>>>>>> - *			and freq_table must be generated in ascending order.
>>>>>> - * @max_state:		The size of freq_table.
>>>>>> - * @total_trans:	Number of devfreq transitions
>>>>>> - * @trans_table:	Statistics of devfreq transitions
>>>>>> - * @time_in_state:	Statistics of devfreq states
>>>>>> - * @last_time:		The last time stats were updated
>>>>>> - * @stats_lock:		Lock protecting trans_table, time_in_state,
>>>>>> - *			last_time and total_trans used for statistics
>>>>>> + * @stats:		Statistics of devfreq states and state transitions
>>>>>>    */
>>>>>>   struct devfreq_dev_profile {
>>>>>>   	unsigned long initial_freq;
>>>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>>>   	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>>>   	void (*exit)(struct device *dev);
>>>>>>   
>>>>>> -	unsigned long *freq_table;
>>>>>> -	unsigned int max_state;
>>>>>> -	/* information for device frequency transition */
>>>>>> -	unsigned int total_trans;
>>>>>> -	unsigned int *trans_table;
>>>>>> -	u64 *time_in_state;
>>>>>> -	unsigned long long last_time;
>>>>>> -	spinlock_t stats_lock;
>>>>>> +	struct devfreq_stats *stats;
>>>>>>   };
>>>>>>   
>>>>>>   /**
>>>>>>
> 
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> 

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Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Chanwoo Choi]

Hi Lukaz,

On 12/16/19 10:01 PM, Lukasz Luba wrote:
> Hi Bartek,
> 
> [added Dietmar, Robin, Andrzej (for upcoming DRM drm-misc-next)]
> 
> On 11/15/19 12:40 PM, Bartlomiej Zolnierkiewicz wrote:
>>
>> [ added Zhang, Eduardo, Ørjan and Javi to Cc: ]
>>
>> On 11/15/19 7:21 AM, Chanwoo Choi wrote:
>>> Hi Bartlomiej,
>>>
>>> On 11/15/19 12:25 PM, Chanwoo Choi wrote:
>>>> Hi Bartlomiej,
>>>>
>>>> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>>>>
>>>>> Hi Chanwoo,
>>>>>
>>>>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>>>>> Hi Kamil,
>>>>>>
>>>>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>>>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>>>>> device driver was posted to mainline kernel, they used
>>>>>> them for a long time. It means that this patch break
>>>>>> the compatibility. The ARM Mali drivers are very
>>>>>> important devfreq device driver.
>>>>>
>>>>> This argument is not a a technical one and the official upstream
>>>>> kernel policy is to not depend on out-of-tree drivers.
>>>>>
>>>>> Besides the ARM Mali drivers are full of code like:
>>>>>
>>>>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>>>>> ...
>>>>> #else
>>>>> ...
>>>>> #endif
>>>>>
>>>>> so few more instances of similar code won't do any harm.. ;-)
>>>>>
>>>>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>>>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>>>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>>>>
>>>>> I took a look at ARM Mali drivers source code anyway and I fail to
>>>>> see a rationale behind their behavior of doing 'freq_table' and
>>>>> 'max_state' initialization in the driver itself (instead of leaving
>>>>> it up to the devfreq core code, like all in-kernel drivers are doing
>>>>> already).
>>>>>
>>>>> Could you please explain rationale behind ARM Mali drivers' special
>>>>> needs?
>>>>>
>>>>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>>>>    these days to do 'freq_table' and 'max_state' initialization, the
>>>>>    only difference seems to be that ARM Mali creates the frequency
>>>>>    table in the descending order (but there also seems to be no real
>>>>>    need for it). ]
>>>>>
>>>>> Maybe this is an opportunity to simplify also the ARM Mali driver?
>>>>
>>>> OK. I agree to simplify them on this time.
>>>> For touching the 'freq_table' and 'max_state', need to fix
>>>> the descending order of freq_table.
>>>>
>>>> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>> requires the descending order of freq_table. Have to change it by using
>>>> the ascending time or support both ascending and descending order for freq_table.
>>>>
>>>> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
>>>> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>>     by using ascending order instead of descending order.
>>>>
>>>
>>> After changed about 'freq_table' and 'max_state', the build error
>>> will happen on ARM mail driver because the initialization code of
>>> 'freq_table' in ARM mali driver, didn't check the kernel version.
>>>
>>> The first devfreq patch provided the 'freq_table' as optional variable
>>> in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree,
>>> this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>
>>> So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
>>> in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>
>>> Frankly, I'm note sure that it is necessary. I don't want to make
>>> the side-effect without any useful reason.
>>>
>>> But,
>>> Separately, have to fix the ordering issue of partition_enable_ops()
>>> in the drivers/thermal/devfreq_cooling.c.
>>
>> Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
>> why we are carrying devfreq_cooling.c code in upstream kernel at all?
> 
> Well, the devfreq_cooling.c is going to have a client in mainline:
> the GPU driver - Panfrost.
> 
> It is already in DRM branch 'drm-misc-next':
> https://protect2.fireeye.com/url?k=75a0e087-283b1ce4-75a16bc8-0cc47a31cdbc-4953aa9e0574f6dc&u=https://patchwork.freedesktop.org/patch/342848/
> 
> Regarding the devfreq_cooling.c code structure.
> I am currently working on cleaning up the devfreq cooling code and
> adding Energy Model instead for private freq, power tables. It will be
> in similar fashion as it is done in cpufreq_cooling. The model will
> be also simplified so hopefully more clients would come.
> It is under internal review and will be posted shortly.

Good news about Energy Model. When you send the patch related to Energy model,
please add me to Cc list.

> 
>>
>> It has been merged in the following commit:
>>
>> commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
>> Author: Ørjan Eide <orjan.eide@arm.com>
>> Date:   Thu Sep 10 18:09:30 2015 +0100
>>
>>      thermal: Add devfreq cooling
>>           Add a generic thermal cooling device for devfreq, that is similar to
>>      cpu_cooling.
>>           The device must use devfreq.  In order to use the power extension of the
>>      cooling device, it must have registered its OPPs using the OPP library.
>>           Cc: Zhang Rui <rui.zhang@intel.com>
>>      Cc: Eduardo Valentin <edubezval@gmail.com>
>>      Signed-off-by: Javi Merino <javi.merino@arm.com>
>>      Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
>>      Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
>> ...
>>
>> but 4 years later there is still no single in-kernel user for this code?
> 
> There will be, via DRM tree.
> 
> Regards,
> Lukasz
> 
>>
>> Best regards,
>> -- 
>> Bartlomiej Zolnierkiewicz
>> Samsung R&D Institute Poland
>> Samsung Electronics
>>
>>>>>
>>>>>> Also, the devfreq device driver specifies their own
>>>>>> information and data into devfreq_dev_profile structure
>>>>>> before registering the devfreq device with devfreq_add_device().
>>>>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>>>>
>>>>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>>>>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>>>>> way..
>>>>>
>>>>> Best regards,
>>>>> -- 
>>>>> Bartlomiej Zolnierkiewicz
>>>>> Samsung R&D Institute Poland
>>>>> Samsung Electronics
>>>>>
>>>>>> So, I can't agree this patch. Not ack.
>>>>>>
>>>>>> Regards,
>>>>>> Chanwoo Choi
>>>>>>
>>>>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>>>>> Count time and transitions between devfreq frequencies in separate struct
>>>>>>> for improved code readability and maintenance.
>>>>>>>
>>>>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>>>>> ---
>>>>>>>   drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>>>>   drivers/devfreq/exynos-bus.c       |   6 +-
>>>>>>>   drivers/devfreq/governor_passive.c |  26 +++--
>>>>>>>   include/linux/devfreq.h            |  43 ++++----
>>>>>>>   4 files changed, 129 insertions(+), 102 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>>>> index d79412b0de59..d85867a91230 100644
>>>>>>> --- a/drivers/devfreq/devfreq.c
>>>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>>>>    */
>>>>>>>   static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>   {
>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>       int lev;
>>>>>>>   -    for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>>>>> -        if (freq == devfreq->profile->freq_table[lev])
>>>>>>> +    for (lev = 0; lev < stats->max_state; lev++)
>>>>>>> +        if (freq == stats->freq_table[lev])
>>>>>>>               return lev;
>>>>>>>         return -EINVAL;
>>>>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>   static int set_freq_table(struct devfreq *devfreq)
>>>>>>>   {
>>>>>>>       struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>       struct dev_pm_opp *opp;
>>>>>>>       unsigned long freq;
>>>>>>> -    int i, count;
>>>>>>> +    int i, count, err = -ENOMEM;
>>>>>>>         /* Initialize the freq_table from OPP table */
>>>>>>>       count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>>>>       if (count <= 0)
>>>>>>>           return -EINVAL;
>>>>>>>   -    profile->max_state = count;
>>>>>>> -    profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>> -                    count,
>>>>>>> -                    sizeof(*profile->freq_table),
>>>>>>> -                    GFP_KERNEL);
>>>>>>> -    if (!profile->freq_table) {
>>>>>>> -        profile->max_state = 0;
>>>>>>> +    stats = devm_kzalloc(devfreq->dev.parent,
>>>>>>> +                 sizeof(struct devfreq_stats), GFP_KERNEL);
>>>>>>> +    if (!stats)
>>>>>>>           return -ENOMEM;
>>>>>>> -    }
>>>>>>>   -    for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>>>>> +    profile->stats = stats;
>>>>>>> +    stats->max_state = count;
>>>>>>> +    stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>> +                     count,
>>>>>>> +                     sizeof(*stats->freq_table),
>>>>>>> +                     GFP_KERNEL);
>>>>>>> +    if (!stats->freq_table)
>>>>>>> +        goto err_no_mem;
>>>>>>> +
>>>>>>> +    for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>>>>           opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>>>>           if (IS_ERR(opp)) {
>>>>>>> -            devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>>>>> -            profile->max_state = 0;
>>>>>>> -            return PTR_ERR(opp);
>>>>>>> +            devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>>>>> +            stats->max_state = 0;
>>>>>>> +            err = PTR_ERR(opp);
>>>>>>> +            goto err_no_mem;
>>>>>>>           }
>>>>>>>           dev_pm_opp_put(opp);
>>>>>>> -        profile->freq_table[i] = freq;
>>>>>>> +        stats->freq_table[i] = freq;
>>>>>>>       }
>>>>>>>   -    profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>> -                        array3_size(sizeof(unsigned int),
>>>>>>> -                            count, count),
>>>>>>> -                        GFP_KERNEL);
>>>>>>> -    if (!profile->trans_table)
>>>>>>> +    stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>> +                      array3_size(sizeof(unsigned int),
>>>>>>> +                              count, count),
>>>>>>> +                      GFP_KERNEL);
>>>>>>> +    if (!stats->trans_table)
>>>>>>>           goto err_no_mem;
>>>>>>>   -    profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>> -                          sizeof(*profile->time_in_state),
>>>>>>> -                          GFP_KERNEL);
>>>>>>> -    if (!profile->time_in_state)
>>>>>>> +    stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>> +                        sizeof(*stats->time_in_state),
>>>>>>> +                        GFP_KERNEL);
>>>>>>> +    if (!stats->time_in_state)
>>>>>>>           goto err_no_mem;
>>>>>>>   -    profile->last_time = get_jiffies_64();
>>>>>>> -    spin_lock_init(&profile->stats_lock);
>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>> +    spin_lock_init(&stats->stats_lock);
>>>>>>>         return 0;
>>>>>>>   err_no_mem:
>>>>>>> -    profile->max_state = 0;
>>>>>>> -    return -ENOMEM;
>>>>>>> +    stats->max_state = 0;
>>>>>>> +    devm_kfree(devfreq->dev.parent, profile->stats);
>>>>>>> +    profile->stats = NULL;
>>>>>>> +    return err;
>>>>>>>   }
>>>>>>>     /**
>>>>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>>>>    */
>>>>>>>   int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>   {
>>>>>>> -    struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>       unsigned long long cur_time;
>>>>>>>       int lev, prev_lev, ret = 0;
>>>>>>>   @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>         /* Immediately exit if previous_freq is not initialized yet. */
>>>>>>>       if (!devfreq->previous_freq) {
>>>>>>> -        spin_lock(&profile->stats_lock);
>>>>>>> -        profile->last_time = cur_time;
>>>>>>> -        spin_unlock(&profile->stats_lock);
>>>>>>> +        spin_lock(&stats->stats_lock);
>>>>>>> +        stats->last_time = cur_time;
>>>>>>> +        spin_unlock(&stats->stats_lock);
>>>>>>>           return 0;
>>>>>>>       }
>>>>>>>         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>>>>   -    spin_lock(&profile->stats_lock);
>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>       if (prev_lev < 0) {
>>>>>>>           ret = prev_lev;
>>>>>>>           goto out;
>>>>>>>       }
>>>>>>>   -    profile->time_in_state[prev_lev] +=
>>>>>>> -             cur_time - profile->last_time;
>>>>>>> +    stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>>>>       lev = devfreq_get_freq_level(devfreq, freq);
>>>>>>>       if (lev < 0) {
>>>>>>>           ret = lev;
>>>>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>       }
>>>>>>>         if (lev != prev_lev) {
>>>>>>> -        profile->trans_table[(prev_lev *
>>>>>>> -                profile->max_state) + lev]++;
>>>>>>> -        profile->total_trans++;
>>>>>>> +        stats->trans_table[(prev_lev *
>>>>>>> +                stats->max_state) + lev]++;
>>>>>>> +        stats->total_trans++;
>>>>>>>       }
>>>>>>>     out:
>>>>>>> -    profile->last_time = cur_time;
>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>> +    stats->last_time = cur_time;
>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>       return ret;
>>>>>>>   }
>>>>>>>   EXPORT_SYMBOL(devfreq_update_status);
>>>>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>>>>           queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>>>>               msecs_to_jiffies(profile->polling_ms));
>>>>>>>   -    spin_lock(&profile->stats_lock);
>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>> +    spin_lock(&profile->stats->stats_lock);
>>>>>>> +    profile->stats->last_time = get_jiffies_64();
>>>>>>> +    spin_unlock(&profile->stats->stats_lock);
>>>>>>>       devfreq->stop_polling = false;
>>>>>>>         if (profile->get_cur_freq &&
>>>>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>>>>       devfreq->data = data;
>>>>>>>       devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>>>>   -    if (!profile->max_state && !profile->freq_table) {
>>>>>>> +    if (!profile->stats) {
>>>>>>>           mutex_unlock(&devfreq->lock);
>>>>>>>           err = set_freq_table(devfreq);
>>>>>>>           if (err < 0)
>>>>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>                     const char *buf, size_t count)
>>>>>>>   {
>>>>>>>       struct devfreq *df = to_devfreq(dev);
>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>       unsigned long value;
>>>>>>>       int ret;
>>>>>>>   @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>               goto unlock;
>>>>>>>           }
>>>>>>>       } else {
>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>             /* Get minimum frequency according to sorting order */
>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>>               value = freq_table[0];
>>>>>>>           else
>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>       }
>>>>>>>         df->min_freq = value;
>>>>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>                     const char *buf, size_t count)
>>>>>>>   {
>>>>>>>       struct devfreq *df = to_devfreq(dev);
>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>       unsigned long value;
>>>>>>>       int ret;
>>>>>>>   @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>               goto unlock;
>>>>>>>           }
>>>>>>>       } else {
>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>             /* Get maximum frequency according to sorting order */
>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>           else
>>>>>>>               value = freq_table[0];
>>>>>>>       }
>>>>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>>>>                         char *buf)
>>>>>>>   {
>>>>>>>       struct devfreq *df = to_devfreq(d);
>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>       ssize_t count = 0;
>>>>>>>       int i;
>>>>>>>         mutex_lock(&df->lock);
>>>>>>>   -    for (i = 0; i < df->profile->max_state; i++)
>>>>>>> +    for (i = 0; i < stats->max_state; i++)
>>>>>>>           count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>>>>> -                "%lu ", df->profile->freq_table[i]);
>>>>>>> +                "%lu ", stats->freq_table[i]);
>>>>>>>         mutex_unlock(&df->lock);
>>>>>>>       /* Truncate the trailing space */
>>>>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>   {
>>>>>>>       struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>       struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>> +    struct devfreq_stats *stats = profile->stats;
>>>>>>> +    unsigned int max_state = stats->max_state;
>>>>>>>       ssize_t len;
>>>>>>>       int i, j;
>>>>>>> -    unsigned int max_state = profile->max_state;
>>>>>>>         if (!devfreq->stop_polling &&
>>>>>>>               devfreq_update_status(devfreq, devfreq->previous_freq))
>>>>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>       len = sprintf(buf, "     From  :   To\n");
>>>>>>>       len += sprintf(buf + len, "           :");
>>>>>>>   -    spin_lock(&profile->stats_lock);
>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>       for (i = 0; i < max_state; i++)
>>>>>>>           len += sprintf(buf + len, "%10lu",
>>>>>>> -                profile->freq_table[i]);
>>>>>>> +                stats->freq_table[i]);
>>>>>>>         len += sprintf(buf + len, "   time(ms)\n");
>>>>>>>         for (i = 0; i < max_state; i++) {
>>>>>>> -        if (profile->freq_table[i] == devfreq->previous_freq)
>>>>>>> +        if (stats->freq_table[i] == devfreq->previous_freq)
>>>>>>>               len += sprintf(buf + len, "*");
>>>>>>>           else
>>>>>>>               len += sprintf(buf + len, " ");
>>>>>>>             len += sprintf(buf + len, "%10lu:",
>>>>>>> -                profile->freq_table[i]);
>>>>>>> +                stats->freq_table[i]);
>>>>>>>           for (j = 0; j < max_state; j++)
>>>>>>>               len += sprintf(buf + len, "%10u",
>>>>>>> -                profile->trans_table[(i * max_state) + j]);
>>>>>>> +                stats->trans_table[(i * max_state) + j]);
>>>>>>>           len += sprintf(buf + len, "%10llu\n", (u64)
>>>>>>> -            jiffies64_to_msecs(profile->time_in_state[i]));
>>>>>>> +            jiffies64_to_msecs(stats->time_in_state[i]));
>>>>>>>       }
>>>>>>>         len += sprintf(buf + len, "Total transition : %u\n",
>>>>>>> -                    profile->total_trans);
>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>> +                    stats->total_trans);
>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>       return len;
>>>>>>>   }
>>>>>>>   static DEVICE_ATTR_RO(trans_stat);
>>>>>>>   -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>>>>   {
>>>>>>> -    unsigned int count = profile->max_state;
>>>>>>> -
>>>>>>> -    spin_lock(&profile->stats_lock);
>>>>>>> -    memset(profile->time_in_state, 0, count * sizeof(u64));
>>>>>>> -    memset(profile->trans_table, 0, count * count * sizeof(int));
>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>> -    profile->total_trans = 0;
>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>> +    unsigned int count = stats->max_state;
>>>>>>> +
>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>> +    memset(stats->time_in_state, 0, count * sizeof(u64));
>>>>>>> +    memset(stats->trans_table, 0, count * count * sizeof(int));
>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>> +    stats->total_trans = 0;
>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>   }
>>>>>>>     static ssize_t trans_reset_store(struct device *dev,
>>>>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>>>>   {
>>>>>>>       struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>   -    defvreq_stats_clear_table(devfreq->profile);
>>>>>>> +    defvreq_stats_clear_table(devfreq->profile->stats);
>>>>>>>         return count;
>>>>>>>   }
>>>>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>>>>> index d9f377912c10..b212aae2bb3e 100644
>>>>>>> --- a/drivers/devfreq/exynos-bus.c
>>>>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>>>>       }
>>>>>>>     out:
>>>>>>> -    max_state = bus->devfreq->profile->max_state;
>>>>>>> -    min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>>>>> -    max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>>>>> +    max_state = profile->stats->max_state;
>>>>>>> +    min_freq = (profile->stats->freq_table[0] / 1000);
>>>>>>> +    max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>>>>       pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>>>>               dev_name(dev), min_freq, max_freq);
>>>>>>>   diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>>>>> index 58308948b863..b2d87a88335c 100644
>>>>>>> --- a/drivers/devfreq/governor_passive.c
>>>>>>> +++ b/drivers/devfreq/governor_passive.c
>>>>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>       struct devfreq_passive_data *p_data
>>>>>>>               = (struct devfreq_passive_data *)devfreq->data;
>>>>>>>       struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>>>>> +    struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>       unsigned long child_freq = ULONG_MAX;
>>>>>>>       struct dev_pm_opp *opp;
>>>>>>>       int i, count, ret = 0;
>>>>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>        * device. And then the index is used for getting the suitable
>>>>>>>        * new frequency for passive devfreq device.
>>>>>>>        */
>>>>>>> -    if (!devfreq->profile || !devfreq->profile->freq_table
>>>>>>> -        || devfreq->profile->max_state <= 0)
>>>>>>> +    if (!devfreq->profile || !devfreq->profile->stats ||
>>>>>>> +        devfreq->profile->stats->max_state <= 0 ||
>>>>>>> +        !parent_devfreq->profile ||    !parent_devfreq->profile->stats ||
>>>>>>> +        parent_devfreq->profile->stats->max_state <= 0)
>>>>>>>           return -EINVAL;
>>>>>>>   +    stats = devfreq->profile->stats;
>>>>>>> +    parent_stats = parent_devfreq->profile->stats;
>>>>>>>       /*
>>>>>>>        * The passive governor have to get the correct frequency from OPP
>>>>>>>        * list of parent device. Because in this case, *freq is temporary
>>>>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>        * Get the OPP table's index of decided freqeuncy by governor
>>>>>>>        * of parent device.
>>>>>>>        */
>>>>>>> -    for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>>>>> -        if (parent_devfreq->profile->freq_table[i] == *freq)
>>>>>>> +    for (i = 0; i < parent_stats->max_state; i++)
>>>>>>> +        if (parent_stats->freq_table[i] == *freq)
>>>>>>>               break;
>>>>>>>   -    if (i == parent_devfreq->profile->max_state) {
>>>>>>> +    if (i == parent_stats->max_state) {
>>>>>>>           ret = -EINVAL;
>>>>>>>           goto out;
>>>>>>>       }
>>>>>>>         /* Get the suitable frequency by using index of parent device. */
>>>>>>> -    if (i < devfreq->profile->max_state) {
>>>>>>> -        child_freq = devfreq->profile->freq_table[i];
>>>>>>> +    if (i < stats->max_state) {
>>>>>>> +        child_freq = stats->freq_table[i];
>>>>>>>       } else {
>>>>>>> -        count = devfreq->profile->max_state;
>>>>>>> -        child_freq = devfreq->profile->freq_table[count - 1];
>>>>>>> +        count = stats->max_state;
>>>>>>> +        child_freq = stats->freq_table[count - 1];
>>>>>>>       }
>>>>>>>         /* Return the suitable frequency for passive device. */
>>>>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>>>>       if (ret < 0)
>>>>>>>           goto out;
>>>>>>>   -    if (devfreq->profile->freq_table
>>>>>>> +    if (devfreq->profile->stats
>>>>>>>           && (devfreq_update_status(devfreq, freq)))
>>>>>>>           dev_err(&devfreq->dev,
>>>>>>>               "Couldn't update frequency transition information.\n");
>>>>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>>>>> --- a/include/linux/devfreq.h
>>>>>>> +++ b/include/linux/devfreq.h
>>>>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>>>>    */
>>>>>>>   #define DEVFREQ_FLAG_LEAST_UPPER_BOUND        0x1
>>>>>>>   +/**
>>>>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>>>>> + * @freq_table:        Optional list of frequencies to support statistics
>>>>>>> + *            and freq_table must be generated in ascending order.
>>>>>>> + * @max_state:        The size of freq_table.
>>>>>>> + * @total_trans:    Number of devfreq transitions
>>>>>>> + * @trans_table:    Statistics of devfreq transitions
>>>>>>> + * @time_in_state:    Statistics of devfreq states
>>>>>>> + * @last_time:        The last time stats were updated
>>>>>>> + * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>> + *            last_time and total_trans used for statistics
>>>>>>> + */
>>>>>>> +struct devfreq_stats {
>>>>>>> +    unsigned long *freq_table;
>>>>>>> +    unsigned int max_state;
>>>>>>> +
>>>>>>> +    /* information for device frequency transition */
>>>>>>> +    unsigned int total_trans;
>>>>>>> +    unsigned int *trans_table;
>>>>>>> +    u64 *time_in_state;
>>>>>>> +    unsigned long long last_time;
>>>>>>> +    spinlock_t stats_lock;
>>>>>>> +};
>>>>>>> +
>>>>>>>   /**
>>>>>>>    * struct devfreq_dev_profile - Devfreq's user device profile
>>>>>>>    * @initial_freq:    The operating frequency when devfreq_add_device() is
>>>>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>>>>    *            from devfreq_remove_device() call. If the user
>>>>>>>    *            has registered devfreq->nb at a notifier-head,
>>>>>>>    *            this is the time to unregister it.
>>>>>>> - * @freq_table:        Optional list of frequencies to support statistics
>>>>>>> - *            and freq_table must be generated in ascending order.
>>>>>>> - * @max_state:        The size of freq_table.
>>>>>>> - * @total_trans:    Number of devfreq transitions
>>>>>>> - * @trans_table:    Statistics of devfreq transitions
>>>>>>> - * @time_in_state:    Statistics of devfreq states
>>>>>>> - * @last_time:        The last time stats were updated
>>>>>>> - * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>> - *            last_time and total_trans used for statistics
>>>>>>> + * @stats:        Statistics of devfreq states and state transitions
>>>>>>>    */
>>>>>>>   struct devfreq_dev_profile {
>>>>>>>       unsigned long initial_freq;
>>>>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>>>>       int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>>>>       void (*exit)(struct device *dev);
>>>>>>>   -    unsigned long *freq_table;
>>>>>>> -    unsigned int max_state;
>>>>>>> -    /* information for device frequency transition */
>>>>>>> -    unsigned int total_trans;
>>>>>>> -    unsigned int *trans_table;
>>>>>>> -    u64 *time_in_state;
>>>>>>> -    unsigned long long last_time;
>>>>>>> -    spinlock_t stats_lock;
>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>   };
>>>>>>>     /**
>>>>>>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> https://protect2.fireeye.com/url?k=856913bb-d8f2efd8-856898f4-0cc47a31cdbc-5cb40ce5f31ed8ed&u=http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Chanwoo Choi]

Hi Lukaz,

On 12/16/19 10:01 PM, Lukasz Luba wrote:
> Hi Bartek,
> 
> [added Dietmar, Robin, Andrzej (for upcoming DRM drm-misc-next)]
> 
> On 11/15/19 12:40 PM, Bartlomiej Zolnierkiewicz wrote:
>>
>> [ added Zhang, Eduardo, Ørjan and Javi to Cc: ]
>>
>> On 11/15/19 7:21 AM, Chanwoo Choi wrote:
>>> Hi Bartlomiej,
>>>
>>> On 11/15/19 12:25 PM, Chanwoo Choi wrote:
>>>> Hi Bartlomiej,
>>>>
>>>> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>>>>
>>>>> Hi Chanwoo,
>>>>>
>>>>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>>>>> Hi Kamil,
>>>>>>
>>>>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>>>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>>>>> device driver was posted to mainline kernel, they used
>>>>>> them for a long time. It means that this patch break
>>>>>> the compatibility. The ARM Mali drivers are very
>>>>>> important devfreq device driver.
>>>>>
>>>>> This argument is not a a technical one and the official upstream
>>>>> kernel policy is to not depend on out-of-tree drivers.
>>>>>
>>>>> Besides the ARM Mali drivers are full of code like:
>>>>>
>>>>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>>>>> ...
>>>>> #else
>>>>> ...
>>>>> #endif
>>>>>
>>>>> so few more instances of similar code won't do any harm.. ;-)
>>>>>
>>>>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>>>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>>>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>>>>
>>>>> I took a look at ARM Mali drivers source code anyway and I fail to
>>>>> see a rationale behind their behavior of doing 'freq_table' and
>>>>> 'max_state' initialization in the driver itself (instead of leaving
>>>>> it up to the devfreq core code, like all in-kernel drivers are doing
>>>>> already).
>>>>>
>>>>> Could you please explain rationale behind ARM Mali drivers' special
>>>>> needs?
>>>>>
>>>>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>>>>    these days to do 'freq_table' and 'max_state' initialization, the
>>>>>    only difference seems to be that ARM Mali creates the frequency
>>>>>    table in the descending order (but there also seems to be no real
>>>>>    need for it). ]
>>>>>
>>>>> Maybe this is an opportunity to simplify also the ARM Mali driver?
>>>>
>>>> OK. I agree to simplify them on this time.
>>>> For touching the 'freq_table' and 'max_state', need to fix
>>>> the descending order of freq_table.
>>>>
>>>> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>> requires the descending order of freq_table. Have to change it by using
>>>> the ascending time or support both ascending and descending order for freq_table.
>>>>
>>>> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
>>>> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>>     by using ascending order instead of descending order.
>>>>
>>>
>>> After changed about 'freq_table' and 'max_state', the build error
>>> will happen on ARM mail driver because the initialization code of
>>> 'freq_table' in ARM mali driver, didn't check the kernel version.
>>>
>>> The first devfreq patch provided the 'freq_table' as optional variable
>>> in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree,
>>> this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>
>>> So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
>>> in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>
>>> Frankly, I'm note sure that it is necessary. I don't want to make
>>> the side-effect without any useful reason.
>>>
>>> But,
>>> Separately, have to fix the ordering issue of partition_enable_ops()
>>> in the drivers/thermal/devfreq_cooling.c.
>>
>> Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
>> why we are carrying devfreq_cooling.c code in upstream kernel at all?
> 
> Well, the devfreq_cooling.c is going to have a client in mainline:
> the GPU driver - Panfrost.
> 
> It is already in DRM branch 'drm-misc-next':
> https://protect2.fireeye.com/url?k=75a0e087-283b1ce4-75a16bc8-0cc47a31cdbc-4953aa9e0574f6dc&u=https://patchwork.freedesktop.org/patch/342848/
> 
> Regarding the devfreq_cooling.c code structure.
> I am currently working on cleaning up the devfreq cooling code and
> adding Energy Model instead for private freq, power tables. It will be
> in similar fashion as it is done in cpufreq_cooling. The model will
> be also simplified so hopefully more clients would come.
> It is under internal review and will be posted shortly.

Good news about Energy Model. When you send the patch related to Energy model,
please add me to Cc list.

> 
>>
>> It has been merged in the following commit:
>>
>> commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
>> Author: Ørjan Eide <orjan.eide@arm.com>
>> Date:   Thu Sep 10 18:09:30 2015 +0100
>>
>>      thermal: Add devfreq cooling
>>           Add a generic thermal cooling device for devfreq, that is similar to
>>      cpu_cooling.
>>           The device must use devfreq.  In order to use the power extension of the
>>      cooling device, it must have registered its OPPs using the OPP library.
>>           Cc: Zhang Rui <rui.zhang@intel.com>
>>      Cc: Eduardo Valentin <edubezval@gmail.com>
>>      Signed-off-by: Javi Merino <javi.merino@arm.com>
>>      Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
>>      Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
>> ...
>>
>> but 4 years later there is still no single in-kernel user for this code?
> 
> There will be, via DRM tree.
> 
> Regards,
> Lukasz
> 
>>
>> Best regards,
>> -- 
>> Bartlomiej Zolnierkiewicz
>> Samsung R&D Institute Poland
>> Samsung Electronics
>>
>>>>>
>>>>>> Also, the devfreq device driver specifies their own
>>>>>> information and data into devfreq_dev_profile structure
>>>>>> before registering the devfreq device with devfreq_add_device().
>>>>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>>>>
>>>>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>>>>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>>>>> way..
>>>>>
>>>>> Best regards,
>>>>> -- 
>>>>> Bartlomiej Zolnierkiewicz
>>>>> Samsung R&D Institute Poland
>>>>> Samsung Electronics
>>>>>
>>>>>> So, I can't agree this patch. Not ack.
>>>>>>
>>>>>> Regards,
>>>>>> Chanwoo Choi
>>>>>>
>>>>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>>>>> Count time and transitions between devfreq frequencies in separate struct
>>>>>>> for improved code readability and maintenance.
>>>>>>>
>>>>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>>>>> ---
>>>>>>>   drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>>>>   drivers/devfreq/exynos-bus.c       |   6 +-
>>>>>>>   drivers/devfreq/governor_passive.c |  26 +++--
>>>>>>>   include/linux/devfreq.h            |  43 ++++----
>>>>>>>   4 files changed, 129 insertions(+), 102 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>>>> index d79412b0de59..d85867a91230 100644
>>>>>>> --- a/drivers/devfreq/devfreq.c
>>>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>>>>    */
>>>>>>>   static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>   {
>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>       int lev;
>>>>>>>   -    for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>>>>> -        if (freq == devfreq->profile->freq_table[lev])
>>>>>>> +    for (lev = 0; lev < stats->max_state; lev++)
>>>>>>> +        if (freq == stats->freq_table[lev])
>>>>>>>               return lev;
>>>>>>>         return -EINVAL;
>>>>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>   static int set_freq_table(struct devfreq *devfreq)
>>>>>>>   {
>>>>>>>       struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>       struct dev_pm_opp *opp;
>>>>>>>       unsigned long freq;
>>>>>>> -    int i, count;
>>>>>>> +    int i, count, err = -ENOMEM;
>>>>>>>         /* Initialize the freq_table from OPP table */
>>>>>>>       count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>>>>       if (count <= 0)
>>>>>>>           return -EINVAL;
>>>>>>>   -    profile->max_state = count;
>>>>>>> -    profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>> -                    count,
>>>>>>> -                    sizeof(*profile->freq_table),
>>>>>>> -                    GFP_KERNEL);
>>>>>>> -    if (!profile->freq_table) {
>>>>>>> -        profile->max_state = 0;
>>>>>>> +    stats = devm_kzalloc(devfreq->dev.parent,
>>>>>>> +                 sizeof(struct devfreq_stats), GFP_KERNEL);
>>>>>>> +    if (!stats)
>>>>>>>           return -ENOMEM;
>>>>>>> -    }
>>>>>>>   -    for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>>>>> +    profile->stats = stats;
>>>>>>> +    stats->max_state = count;
>>>>>>> +    stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>> +                     count,
>>>>>>> +                     sizeof(*stats->freq_table),
>>>>>>> +                     GFP_KERNEL);
>>>>>>> +    if (!stats->freq_table)
>>>>>>> +        goto err_no_mem;
>>>>>>> +
>>>>>>> +    for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>>>>           opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>>>>           if (IS_ERR(opp)) {
>>>>>>> -            devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>>>>> -            profile->max_state = 0;
>>>>>>> -            return PTR_ERR(opp);
>>>>>>> +            devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>>>>> +            stats->max_state = 0;
>>>>>>> +            err = PTR_ERR(opp);
>>>>>>> +            goto err_no_mem;
>>>>>>>           }
>>>>>>>           dev_pm_opp_put(opp);
>>>>>>> -        profile->freq_table[i] = freq;
>>>>>>> +        stats->freq_table[i] = freq;
>>>>>>>       }
>>>>>>>   -    profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>> -                        array3_size(sizeof(unsigned int),
>>>>>>> -                            count, count),
>>>>>>> -                        GFP_KERNEL);
>>>>>>> -    if (!profile->trans_table)
>>>>>>> +    stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>> +                      array3_size(sizeof(unsigned int),
>>>>>>> +                              count, count),
>>>>>>> +                      GFP_KERNEL);
>>>>>>> +    if (!stats->trans_table)
>>>>>>>           goto err_no_mem;
>>>>>>>   -    profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>> -                          sizeof(*profile->time_in_state),
>>>>>>> -                          GFP_KERNEL);
>>>>>>> -    if (!profile->time_in_state)
>>>>>>> +    stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>> +                        sizeof(*stats->time_in_state),
>>>>>>> +                        GFP_KERNEL);
>>>>>>> +    if (!stats->time_in_state)
>>>>>>>           goto err_no_mem;
>>>>>>>   -    profile->last_time = get_jiffies_64();
>>>>>>> -    spin_lock_init(&profile->stats_lock);
>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>> +    spin_lock_init(&stats->stats_lock);
>>>>>>>         return 0;
>>>>>>>   err_no_mem:
>>>>>>> -    profile->max_state = 0;
>>>>>>> -    return -ENOMEM;
>>>>>>> +    stats->max_state = 0;
>>>>>>> +    devm_kfree(devfreq->dev.parent, profile->stats);
>>>>>>> +    profile->stats = NULL;
>>>>>>> +    return err;
>>>>>>>   }
>>>>>>>     /**
>>>>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>>>>    */
>>>>>>>   int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>   {
>>>>>>> -    struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>       unsigned long long cur_time;
>>>>>>>       int lev, prev_lev, ret = 0;
>>>>>>>   @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>         /* Immediately exit if previous_freq is not initialized yet. */
>>>>>>>       if (!devfreq->previous_freq) {
>>>>>>> -        spin_lock(&profile->stats_lock);
>>>>>>> -        profile->last_time = cur_time;
>>>>>>> -        spin_unlock(&profile->stats_lock);
>>>>>>> +        spin_lock(&stats->stats_lock);
>>>>>>> +        stats->last_time = cur_time;
>>>>>>> +        spin_unlock(&stats->stats_lock);
>>>>>>>           return 0;
>>>>>>>       }
>>>>>>>         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>>>>   -    spin_lock(&profile->stats_lock);
>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>       if (prev_lev < 0) {
>>>>>>>           ret = prev_lev;
>>>>>>>           goto out;
>>>>>>>       }
>>>>>>>   -    profile->time_in_state[prev_lev] +=
>>>>>>> -             cur_time - profile->last_time;
>>>>>>> +    stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>>>>       lev = devfreq_get_freq_level(devfreq, freq);
>>>>>>>       if (lev < 0) {
>>>>>>>           ret = lev;
>>>>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>       }
>>>>>>>         if (lev != prev_lev) {
>>>>>>> -        profile->trans_table[(prev_lev *
>>>>>>> -                profile->max_state) + lev]++;
>>>>>>> -        profile->total_trans++;
>>>>>>> +        stats->trans_table[(prev_lev *
>>>>>>> +                stats->max_state) + lev]++;
>>>>>>> +        stats->total_trans++;
>>>>>>>       }
>>>>>>>     out:
>>>>>>> -    profile->last_time = cur_time;
>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>> +    stats->last_time = cur_time;
>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>       return ret;
>>>>>>>   }
>>>>>>>   EXPORT_SYMBOL(devfreq_update_status);
>>>>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>>>>           queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>>>>               msecs_to_jiffies(profile->polling_ms));
>>>>>>>   -    spin_lock(&profile->stats_lock);
>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>> +    spin_lock(&profile->stats->stats_lock);
>>>>>>> +    profile->stats->last_time = get_jiffies_64();
>>>>>>> +    spin_unlock(&profile->stats->stats_lock);
>>>>>>>       devfreq->stop_polling = false;
>>>>>>>         if (profile->get_cur_freq &&
>>>>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>>>>       devfreq->data = data;
>>>>>>>       devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>>>>   -    if (!profile->max_state && !profile->freq_table) {
>>>>>>> +    if (!profile->stats) {
>>>>>>>           mutex_unlock(&devfreq->lock);
>>>>>>>           err = set_freq_table(devfreq);
>>>>>>>           if (err < 0)
>>>>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>                     const char *buf, size_t count)
>>>>>>>   {
>>>>>>>       struct devfreq *df = to_devfreq(dev);
>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>       unsigned long value;
>>>>>>>       int ret;
>>>>>>>   @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>               goto unlock;
>>>>>>>           }
>>>>>>>       } else {
>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>             /* Get minimum frequency according to sorting order */
>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>>               value = freq_table[0];
>>>>>>>           else
>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>       }
>>>>>>>         df->min_freq = value;
>>>>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>                     const char *buf, size_t count)
>>>>>>>   {
>>>>>>>       struct devfreq *df = to_devfreq(dev);
>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>       unsigned long value;
>>>>>>>       int ret;
>>>>>>>   @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>               goto unlock;
>>>>>>>           }
>>>>>>>       } else {
>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>             /* Get maximum frequency according to sorting order */
>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>           else
>>>>>>>               value = freq_table[0];
>>>>>>>       }
>>>>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>>>>                         char *buf)
>>>>>>>   {
>>>>>>>       struct devfreq *df = to_devfreq(d);
>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>       ssize_t count = 0;
>>>>>>>       int i;
>>>>>>>         mutex_lock(&df->lock);
>>>>>>>   -    for (i = 0; i < df->profile->max_state; i++)
>>>>>>> +    for (i = 0; i < stats->max_state; i++)
>>>>>>>           count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>>>>> -                "%lu ", df->profile->freq_table[i]);
>>>>>>> +                "%lu ", stats->freq_table[i]);
>>>>>>>         mutex_unlock(&df->lock);
>>>>>>>       /* Truncate the trailing space */
>>>>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>   {
>>>>>>>       struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>       struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>> +    struct devfreq_stats *stats = profile->stats;
>>>>>>> +    unsigned int max_state = stats->max_state;
>>>>>>>       ssize_t len;
>>>>>>>       int i, j;
>>>>>>> -    unsigned int max_state = profile->max_state;
>>>>>>>         if (!devfreq->stop_polling &&
>>>>>>>               devfreq_update_status(devfreq, devfreq->previous_freq))
>>>>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>       len = sprintf(buf, "     From  :   To\n");
>>>>>>>       len += sprintf(buf + len, "           :");
>>>>>>>   -    spin_lock(&profile->stats_lock);
>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>       for (i = 0; i < max_state; i++)
>>>>>>>           len += sprintf(buf + len, "%10lu",
>>>>>>> -                profile->freq_table[i]);
>>>>>>> +                stats->freq_table[i]);
>>>>>>>         len += sprintf(buf + len, "   time(ms)\n");
>>>>>>>         for (i = 0; i < max_state; i++) {
>>>>>>> -        if (profile->freq_table[i] == devfreq->previous_freq)
>>>>>>> +        if (stats->freq_table[i] == devfreq->previous_freq)
>>>>>>>               len += sprintf(buf + len, "*");
>>>>>>>           else
>>>>>>>               len += sprintf(buf + len, " ");
>>>>>>>             len += sprintf(buf + len, "%10lu:",
>>>>>>> -                profile->freq_table[i]);
>>>>>>> +                stats->freq_table[i]);
>>>>>>>           for (j = 0; j < max_state; j++)
>>>>>>>               len += sprintf(buf + len, "%10u",
>>>>>>> -                profile->trans_table[(i * max_state) + j]);
>>>>>>> +                stats->trans_table[(i * max_state) + j]);
>>>>>>>           len += sprintf(buf + len, "%10llu\n", (u64)
>>>>>>> -            jiffies64_to_msecs(profile->time_in_state[i]));
>>>>>>> +            jiffies64_to_msecs(stats->time_in_state[i]));
>>>>>>>       }
>>>>>>>         len += sprintf(buf + len, "Total transition : %u\n",
>>>>>>> -                    profile->total_trans);
>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>> +                    stats->total_trans);
>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>       return len;
>>>>>>>   }
>>>>>>>   static DEVICE_ATTR_RO(trans_stat);
>>>>>>>   -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>>>>   {
>>>>>>> -    unsigned int count = profile->max_state;
>>>>>>> -
>>>>>>> -    spin_lock(&profile->stats_lock);
>>>>>>> -    memset(profile->time_in_state, 0, count * sizeof(u64));
>>>>>>> -    memset(profile->trans_table, 0, count * count * sizeof(int));
>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>> -    profile->total_trans = 0;
>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>> +    unsigned int count = stats->max_state;
>>>>>>> +
>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>> +    memset(stats->time_in_state, 0, count * sizeof(u64));
>>>>>>> +    memset(stats->trans_table, 0, count * count * sizeof(int));
>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>> +    stats->total_trans = 0;
>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>   }
>>>>>>>     static ssize_t trans_reset_store(struct device *dev,
>>>>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>>>>   {
>>>>>>>       struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>   -    defvreq_stats_clear_table(devfreq->profile);
>>>>>>> +    defvreq_stats_clear_table(devfreq->profile->stats);
>>>>>>>         return count;
>>>>>>>   }
>>>>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>>>>> index d9f377912c10..b212aae2bb3e 100644
>>>>>>> --- a/drivers/devfreq/exynos-bus.c
>>>>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>>>>       }
>>>>>>>     out:
>>>>>>> -    max_state = bus->devfreq->profile->max_state;
>>>>>>> -    min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>>>>> -    max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>>>>> +    max_state = profile->stats->max_state;
>>>>>>> +    min_freq = (profile->stats->freq_table[0] / 1000);
>>>>>>> +    max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>>>>       pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>>>>               dev_name(dev), min_freq, max_freq);
>>>>>>>   diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>>>>> index 58308948b863..b2d87a88335c 100644
>>>>>>> --- a/drivers/devfreq/governor_passive.c
>>>>>>> +++ b/drivers/devfreq/governor_passive.c
>>>>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>       struct devfreq_passive_data *p_data
>>>>>>>               = (struct devfreq_passive_data *)devfreq->data;
>>>>>>>       struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>>>>> +    struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>       unsigned long child_freq = ULONG_MAX;
>>>>>>>       struct dev_pm_opp *opp;
>>>>>>>       int i, count, ret = 0;
>>>>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>        * device. And then the index is used for getting the suitable
>>>>>>>        * new frequency for passive devfreq device.
>>>>>>>        */
>>>>>>> -    if (!devfreq->profile || !devfreq->profile->freq_table
>>>>>>> -        || devfreq->profile->max_state <= 0)
>>>>>>> +    if (!devfreq->profile || !devfreq->profile->stats ||
>>>>>>> +        devfreq->profile->stats->max_state <= 0 ||
>>>>>>> +        !parent_devfreq->profile ||    !parent_devfreq->profile->stats ||
>>>>>>> +        parent_devfreq->profile->stats->max_state <= 0)
>>>>>>>           return -EINVAL;
>>>>>>>   +    stats = devfreq->profile->stats;
>>>>>>> +    parent_stats = parent_devfreq->profile->stats;
>>>>>>>       /*
>>>>>>>        * The passive governor have to get the correct frequency from OPP
>>>>>>>        * list of parent device. Because in this case, *freq is temporary
>>>>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>        * Get the OPP table's index of decided freqeuncy by governor
>>>>>>>        * of parent device.
>>>>>>>        */
>>>>>>> -    for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>>>>> -        if (parent_devfreq->profile->freq_table[i] == *freq)
>>>>>>> +    for (i = 0; i < parent_stats->max_state; i++)
>>>>>>> +        if (parent_stats->freq_table[i] == *freq)
>>>>>>>               break;
>>>>>>>   -    if (i == parent_devfreq->profile->max_state) {
>>>>>>> +    if (i == parent_stats->max_state) {
>>>>>>>           ret = -EINVAL;
>>>>>>>           goto out;
>>>>>>>       }
>>>>>>>         /* Get the suitable frequency by using index of parent device. */
>>>>>>> -    if (i < devfreq->profile->max_state) {
>>>>>>> -        child_freq = devfreq->profile->freq_table[i];
>>>>>>> +    if (i < stats->max_state) {
>>>>>>> +        child_freq = stats->freq_table[i];
>>>>>>>       } else {
>>>>>>> -        count = devfreq->profile->max_state;
>>>>>>> -        child_freq = devfreq->profile->freq_table[count - 1];
>>>>>>> +        count = stats->max_state;
>>>>>>> +        child_freq = stats->freq_table[count - 1];
>>>>>>>       }
>>>>>>>         /* Return the suitable frequency for passive device. */
>>>>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>>>>       if (ret < 0)
>>>>>>>           goto out;
>>>>>>>   -    if (devfreq->profile->freq_table
>>>>>>> +    if (devfreq->profile->stats
>>>>>>>           && (devfreq_update_status(devfreq, freq)))
>>>>>>>           dev_err(&devfreq->dev,
>>>>>>>               "Couldn't update frequency transition information.\n");
>>>>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>>>>> --- a/include/linux/devfreq.h
>>>>>>> +++ b/include/linux/devfreq.h
>>>>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>>>>    */
>>>>>>>   #define DEVFREQ_FLAG_LEAST_UPPER_BOUND        0x1
>>>>>>>   +/**
>>>>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>>>>> + * @freq_table:        Optional list of frequencies to support statistics
>>>>>>> + *            and freq_table must be generated in ascending order.
>>>>>>> + * @max_state:        The size of freq_table.
>>>>>>> + * @total_trans:    Number of devfreq transitions
>>>>>>> + * @trans_table:    Statistics of devfreq transitions
>>>>>>> + * @time_in_state:    Statistics of devfreq states
>>>>>>> + * @last_time:        The last time stats were updated
>>>>>>> + * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>> + *            last_time and total_trans used for statistics
>>>>>>> + */
>>>>>>> +struct devfreq_stats {
>>>>>>> +    unsigned long *freq_table;
>>>>>>> +    unsigned int max_state;
>>>>>>> +
>>>>>>> +    /* information for device frequency transition */
>>>>>>> +    unsigned int total_trans;
>>>>>>> +    unsigned int *trans_table;
>>>>>>> +    u64 *time_in_state;
>>>>>>> +    unsigned long long last_time;
>>>>>>> +    spinlock_t stats_lock;
>>>>>>> +};
>>>>>>> +
>>>>>>>   /**
>>>>>>>    * struct devfreq_dev_profile - Devfreq's user device profile
>>>>>>>    * @initial_freq:    The operating frequency when devfreq_add_device() is
>>>>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>>>>    *            from devfreq_remove_device() call. If the user
>>>>>>>    *            has registered devfreq->nb at a notifier-head,
>>>>>>>    *            this is the time to unregister it.
>>>>>>> - * @freq_table:        Optional list of frequencies to support statistics
>>>>>>> - *            and freq_table must be generated in ascending order.
>>>>>>> - * @max_state:        The size of freq_table.
>>>>>>> - * @total_trans:    Number of devfreq transitions
>>>>>>> - * @trans_table:    Statistics of devfreq transitions
>>>>>>> - * @time_in_state:    Statistics of devfreq states
>>>>>>> - * @last_time:        The last time stats were updated
>>>>>>> - * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>> - *            last_time and total_trans used for statistics
>>>>>>> + * @stats:        Statistics of devfreq states and state transitions
>>>>>>>    */
>>>>>>>   struct devfreq_dev_profile {
>>>>>>>       unsigned long initial_freq;
>>>>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>>>>       int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>>>>       void (*exit)(struct device *dev);
>>>>>>>   -    unsigned long *freq_table;
>>>>>>> -    unsigned int max_state;
>>>>>>> -    /* information for device frequency transition */
>>>>>>> -    unsigned int total_trans;
>>>>>>> -    unsigned int *trans_table;
>>>>>>> -    u64 *time_in_state;
>>>>>>> -    unsigned long long last_time;
>>>>>>> -    spinlock_t stats_lock;
>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>   };
>>>>>>>     /**
>>>>>>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> https://protect2.fireeye.com/url?k=856913bb-d8f2efd8-856898f4-0cc47a31cdbc-5cb40ce5f31ed8ed&u=http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

_______________________________________________
linux-arm-kernel mailing list
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Lukasz Luba]

Hi Chanwoo,

On 12/17/19 12:07 AM, Chanwoo Choi wrote:
> Hi Lukaz,
> 
> On 12/16/19 10:01 PM, Lukasz Luba wrote:
>> Hi Bartek,
>>
>> [added Dietmar, Robin, Andrzej (for upcoming DRM drm-misc-next)]
>>
>> On 11/15/19 12:40 PM, Bartlomiej Zolnierkiewicz wrote:
>>>
>>> [ added Zhang, Eduardo, Ørjan and Javi to Cc: ]
>>>
>>> On 11/15/19 7:21 AM, Chanwoo Choi wrote:
>>>> Hi Bartlomiej,
>>>>
>>>> On 11/15/19 12:25 PM, Chanwoo Choi wrote:
>>>>> Hi Bartlomiej,
>>>>>
>>>>> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>>>>>
>>>>>> Hi Chanwoo,
>>>>>>
>>>>>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>>>>>> Hi Kamil,
>>>>>>>
>>>>>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>>>>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>>>>>> device driver was posted to mainline kernel, they used
>>>>>>> them for a long time. It means that this patch break
>>>>>>> the compatibility. The ARM Mali drivers are very
>>>>>>> important devfreq device driver.
>>>>>>
>>>>>> This argument is not a a technical one and the official upstream
>>>>>> kernel policy is to not depend on out-of-tree drivers.
>>>>>>
>>>>>> Besides the ARM Mali drivers are full of code like:
>>>>>>
>>>>>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>>>>>> ...
>>>>>> #else
>>>>>> ...
>>>>>> #endif
>>>>>>
>>>>>> so few more instances of similar code won't do any harm.. ;-)
>>>>>>
>>>>>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>>>>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>>>>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>>>>>
>>>>>> I took a look at ARM Mali drivers source code anyway and I fail to
>>>>>> see a rationale behind their behavior of doing 'freq_table' and
>>>>>> 'max_state' initialization in the driver itself (instead of leaving
>>>>>> it up to the devfreq core code, like all in-kernel drivers are doing
>>>>>> already).
>>>>>>
>>>>>> Could you please explain rationale behind ARM Mali drivers' special
>>>>>> needs?
>>>>>>
>>>>>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>>>>>     these days to do 'freq_table' and 'max_state' initialization, the
>>>>>>     only difference seems to be that ARM Mali creates the frequency
>>>>>>     table in the descending order (but there also seems to be no real
>>>>>>     need for it). ]
>>>>>>
>>>>>> Maybe this is an opportunity to simplify also the ARM Mali driver?
>>>>>
>>>>> OK. I agree to simplify them on this time.
>>>>> For touching the 'freq_table' and 'max_state', need to fix
>>>>> the descending order of freq_table.
>>>>>
>>>>> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>>> requires the descending order of freq_table. Have to change it by using
>>>>> the ascending time or support both ascending and descending order for freq_table.
>>>>>
>>>>> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
>>>>> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>>>      by using ascending order instead of descending order.
>>>>>
>>>>
>>>> After changed about 'freq_table' and 'max_state', the build error
>>>> will happen on ARM mail driver because the initialization code of
>>>> 'freq_table' in ARM mali driver, didn't check the kernel version.
>>>>
>>>> The first devfreq patch provided the 'freq_table' as optional variable
>>>> in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree,
>>>> this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>>
>>>> So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
>>>> in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>>
>>>> Frankly, I'm note sure that it is necessary. I don't want to make
>>>> the side-effect without any useful reason.
>>>>
>>>> But,
>>>> Separately, have to fix the ordering issue of partition_enable_ops()
>>>> in the drivers/thermal/devfreq_cooling.c.
>>>
>>> Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
>>> why we are carrying devfreq_cooling.c code in upstream kernel at all?
>>
>> Well, the devfreq_cooling.c is going to have a client in mainline:
>> the GPU driver - Panfrost.
>>
>> It is already in DRM branch 'drm-misc-next':
>> https://protect2.fireeye.com/url?k=75a0e087-283b1ce4-75a16bc8-0cc47a31cdbc-4953aa9e0574f6dc&u=https://patchwork.freedesktop.org/patch/342848/
>>
>> Regarding the devfreq_cooling.c code structure.
>> I am currently working on cleaning up the devfreq cooling code and
>> adding Energy Model instead for private freq, power tables. It will be
>> in similar fashion as it is done in cpufreq_cooling. The model will
>> be also simplified so hopefully more clients would come.
>> It is under internal review and will be posted shortly.
> 
> Good news about Energy Model. When you send the patch related to Energy model,
> please add me to Cc list.

I will add you, thanks. More eyeballs in capturing bugs are more than
welcome.

Regards,
Lukasz

> 
>>
>>>
>>> It has been merged in the following commit:
>>>
>>> commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
>>> Author: Ørjan Eide <orjan.eide@arm.com>
>>> Date:   Thu Sep 10 18:09:30 2015 +0100
>>>
>>>       thermal: Add devfreq cooling
>>>            Add a generic thermal cooling device for devfreq, that is similar to
>>>       cpu_cooling.
>>>            The device must use devfreq.  In order to use the power extension of the
>>>       cooling device, it must have registered its OPPs using the OPP library.
>>>            Cc: Zhang Rui <rui.zhang@intel.com>
>>>       Cc: Eduardo Valentin <edubezval@gmail.com>
>>>       Signed-off-by: Javi Merino <javi.merino@arm.com>
>>>       Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
>>>       Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
>>> ...
>>>
>>> but 4 years later there is still no single in-kernel user for this code?
>>
>> There will be, via DRM tree.
>>
>> Regards,
>> Lukasz
>>
>>>
>>> Best regards,
>>> -- 
>>> Bartlomiej Zolnierkiewicz
>>> Samsung R&D Institute Poland
>>> Samsung Electronics
>>>
>>>>>>
>>>>>>> Also, the devfreq device driver specifies their own
>>>>>>> information and data into devfreq_dev_profile structure
>>>>>>> before registering the devfreq device with devfreq_add_device().
>>>>>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>>>>>
>>>>>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>>>>>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>>>>>> way..
>>>>>>
>>>>>> Best regards,
>>>>>> -- 
>>>>>> Bartlomiej Zolnierkiewicz
>>>>>> Samsung R&D Institute Poland
>>>>>> Samsung Electronics
>>>>>>
>>>>>>> So, I can't agree this patch. Not ack.
>>>>>>>
>>>>>>> Regards,
>>>>>>> Chanwoo Choi
>>>>>>>
>>>>>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>>>>>> Count time and transitions between devfreq frequencies in separate struct
>>>>>>>> for improved code readability and maintenance.
>>>>>>>>
>>>>>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>>>>>> ---
>>>>>>>>    drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>>>>>    drivers/devfreq/exynos-bus.c       |   6 +-
>>>>>>>>    drivers/devfreq/governor_passive.c |  26 +++--
>>>>>>>>    include/linux/devfreq.h            |  43 ++++----
>>>>>>>>    4 files changed, 129 insertions(+), 102 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>>>>> index d79412b0de59..d85867a91230 100644
>>>>>>>> --- a/drivers/devfreq/devfreq.c
>>>>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>>>>>     */
>>>>>>>>    static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>    {
>>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>>        int lev;
>>>>>>>>    -    for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>>>>>> -        if (freq == devfreq->profile->freq_table[lev])
>>>>>>>> +    for (lev = 0; lev < stats->max_state; lev++)
>>>>>>>> +        if (freq == stats->freq_table[lev])
>>>>>>>>                return lev;
>>>>>>>>          return -EINVAL;
>>>>>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>    static int set_freq_table(struct devfreq *devfreq)
>>>>>>>>    {
>>>>>>>>        struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>>        struct dev_pm_opp *opp;
>>>>>>>>        unsigned long freq;
>>>>>>>> -    int i, count;
>>>>>>>> +    int i, count, err = -ENOMEM;
>>>>>>>>          /* Initialize the freq_table from OPP table */
>>>>>>>>        count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>>>>>        if (count <= 0)
>>>>>>>>            return -EINVAL;
>>>>>>>>    -    profile->max_state = count;
>>>>>>>> -    profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>>> -                    count,
>>>>>>>> -                    sizeof(*profile->freq_table),
>>>>>>>> -                    GFP_KERNEL);
>>>>>>>> -    if (!profile->freq_table) {
>>>>>>>> -        profile->max_state = 0;
>>>>>>>> +    stats = devm_kzalloc(devfreq->dev.parent,
>>>>>>>> +                 sizeof(struct devfreq_stats), GFP_KERNEL);
>>>>>>>> +    if (!stats)
>>>>>>>>            return -ENOMEM;
>>>>>>>> -    }
>>>>>>>>    -    for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>>>>>> +    profile->stats = stats;
>>>>>>>> +    stats->max_state = count;
>>>>>>>> +    stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>>> +                     count,
>>>>>>>> +                     sizeof(*stats->freq_table),
>>>>>>>> +                     GFP_KERNEL);
>>>>>>>> +    if (!stats->freq_table)
>>>>>>>> +        goto err_no_mem;
>>>>>>>> +
>>>>>>>> +    for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>>>>>            opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>>>>>            if (IS_ERR(opp)) {
>>>>>>>> -            devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>>>>>> -            profile->max_state = 0;
>>>>>>>> -            return PTR_ERR(opp);
>>>>>>>> +            devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>>>>>> +            stats->max_state = 0;
>>>>>>>> +            err = PTR_ERR(opp);
>>>>>>>> +            goto err_no_mem;
>>>>>>>>            }
>>>>>>>>            dev_pm_opp_put(opp);
>>>>>>>> -        profile->freq_table[i] = freq;
>>>>>>>> +        stats->freq_table[i] = freq;
>>>>>>>>        }
>>>>>>>>    -    profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>>> -                        array3_size(sizeof(unsigned int),
>>>>>>>> -                            count, count),
>>>>>>>> -                        GFP_KERNEL);
>>>>>>>> -    if (!profile->trans_table)
>>>>>>>> +    stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>>> +                      array3_size(sizeof(unsigned int),
>>>>>>>> +                              count, count),
>>>>>>>> +                      GFP_KERNEL);
>>>>>>>> +    if (!stats->trans_table)
>>>>>>>>            goto err_no_mem;
>>>>>>>>    -    profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>>> -                          sizeof(*profile->time_in_state),
>>>>>>>> -                          GFP_KERNEL);
>>>>>>>> -    if (!profile->time_in_state)
>>>>>>>> +    stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>>> +                        sizeof(*stats->time_in_state),
>>>>>>>> +                        GFP_KERNEL);
>>>>>>>> +    if (!stats->time_in_state)
>>>>>>>>            goto err_no_mem;
>>>>>>>>    -    profile->last_time = get_jiffies_64();
>>>>>>>> -    spin_lock_init(&profile->stats_lock);
>>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>>> +    spin_lock_init(&stats->stats_lock);
>>>>>>>>          return 0;
>>>>>>>>    err_no_mem:
>>>>>>>> -    profile->max_state = 0;
>>>>>>>> -    return -ENOMEM;
>>>>>>>> +    stats->max_state = 0;
>>>>>>>> +    devm_kfree(devfreq->dev.parent, profile->stats);
>>>>>>>> +    profile->stats = NULL;
>>>>>>>> +    return err;
>>>>>>>>    }
>>>>>>>>      /**
>>>>>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>>>>>     */
>>>>>>>>    int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>    {
>>>>>>>> -    struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>>        unsigned long long cur_time;
>>>>>>>>        int lev, prev_lev, ret = 0;
>>>>>>>>    @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>          /* Immediately exit if previous_freq is not initialized yet. */
>>>>>>>>        if (!devfreq->previous_freq) {
>>>>>>>> -        spin_lock(&profile->stats_lock);
>>>>>>>> -        profile->last_time = cur_time;
>>>>>>>> -        spin_unlock(&profile->stats_lock);
>>>>>>>> +        spin_lock(&stats->stats_lock);
>>>>>>>> +        stats->last_time = cur_time;
>>>>>>>> +        spin_unlock(&stats->stats_lock);
>>>>>>>>            return 0;
>>>>>>>>        }
>>>>>>>>          prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>>>>>    -    spin_lock(&profile->stats_lock);
>>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>>        if (prev_lev < 0) {
>>>>>>>>            ret = prev_lev;
>>>>>>>>            goto out;
>>>>>>>>        }
>>>>>>>>    -    profile->time_in_state[prev_lev] +=
>>>>>>>> -             cur_time - profile->last_time;
>>>>>>>> +    stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>>>>>        lev = devfreq_get_freq_level(devfreq, freq);
>>>>>>>>        if (lev < 0) {
>>>>>>>>            ret = lev;
>>>>>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>        }
>>>>>>>>          if (lev != prev_lev) {
>>>>>>>> -        profile->trans_table[(prev_lev *
>>>>>>>> -                profile->max_state) + lev]++;
>>>>>>>> -        profile->total_trans++;
>>>>>>>> +        stats->trans_table[(prev_lev *
>>>>>>>> +                stats->max_state) + lev]++;
>>>>>>>> +        stats->total_trans++;
>>>>>>>>        }
>>>>>>>>      out:
>>>>>>>> -    profile->last_time = cur_time;
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +    stats->last_time = cur_time;
>>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>>        return ret;
>>>>>>>>    }
>>>>>>>>    EXPORT_SYMBOL(devfreq_update_status);
>>>>>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>>>>>            queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>>>>>                msecs_to_jiffies(profile->polling_ms));
>>>>>>>>    -    spin_lock(&profile->stats_lock);
>>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +    spin_lock(&profile->stats->stats_lock);
>>>>>>>> +    profile->stats->last_time = get_jiffies_64();
>>>>>>>> +    spin_unlock(&profile->stats->stats_lock);
>>>>>>>>        devfreq->stop_polling = false;
>>>>>>>>          if (profile->get_cur_freq &&
>>>>>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>>>>>        devfreq->data = data;
>>>>>>>>        devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>>>>>    -    if (!profile->max_state && !profile->freq_table) {
>>>>>>>> +    if (!profile->stats) {
>>>>>>>>            mutex_unlock(&devfreq->lock);
>>>>>>>>            err = set_freq_table(devfreq);
>>>>>>>>            if (err < 0)
>>>>>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                      const char *buf, size_t count)
>>>>>>>>    {
>>>>>>>>        struct devfreq *df = to_devfreq(dev);
>>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>>        unsigned long value;
>>>>>>>>        int ret;
>>>>>>>>    @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                goto unlock;
>>>>>>>>            }
>>>>>>>>        } else {
>>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>>              /* Get minimum frequency according to sorting order */
>>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>>>                value = freq_table[0];
>>>>>>>>            else
>>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>>        }
>>>>>>>>          df->min_freq = value;
>>>>>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                      const char *buf, size_t count)
>>>>>>>>    {
>>>>>>>>        struct devfreq *df = to_devfreq(dev);
>>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>>        unsigned long value;
>>>>>>>>        int ret;
>>>>>>>>    @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                goto unlock;
>>>>>>>>            }
>>>>>>>>        } else {
>>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>>              /* Get maximum frequency according to sorting order */
>>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>>            else
>>>>>>>>                value = freq_table[0];
>>>>>>>>        }
>>>>>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>>>>>                          char *buf)
>>>>>>>>    {
>>>>>>>>        struct devfreq *df = to_devfreq(d);
>>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>>        ssize_t count = 0;
>>>>>>>>        int i;
>>>>>>>>          mutex_lock(&df->lock);
>>>>>>>>    -    for (i = 0; i < df->profile->max_state; i++)
>>>>>>>> +    for (i = 0; i < stats->max_state; i++)
>>>>>>>>            count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>>>>>> -                "%lu ", df->profile->freq_table[i]);
>>>>>>>> +                "%lu ", stats->freq_table[i]);
>>>>>>>>          mutex_unlock(&df->lock);
>>>>>>>>        /* Truncate the trailing space */
>>>>>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>>    {
>>>>>>>>        struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>>        struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>>> +    struct devfreq_stats *stats = profile->stats;
>>>>>>>> +    unsigned int max_state = stats->max_state;
>>>>>>>>        ssize_t len;
>>>>>>>>        int i, j;
>>>>>>>> -    unsigned int max_state = profile->max_state;
>>>>>>>>          if (!devfreq->stop_polling &&
>>>>>>>>                devfreq_update_status(devfreq, devfreq->previous_freq))
>>>>>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>>        len = sprintf(buf, "     From  :   To\n");
>>>>>>>>        len += sprintf(buf + len, "           :");
>>>>>>>>    -    spin_lock(&profile->stats_lock);
>>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>>        for (i = 0; i < max_state; i++)
>>>>>>>>            len += sprintf(buf + len, "%10lu",
>>>>>>>> -                profile->freq_table[i]);
>>>>>>>> +                stats->freq_table[i]);
>>>>>>>>          len += sprintf(buf + len, "   time(ms)\n");
>>>>>>>>          for (i = 0; i < max_state; i++) {
>>>>>>>> -        if (profile->freq_table[i] == devfreq->previous_freq)
>>>>>>>> +        if (stats->freq_table[i] == devfreq->previous_freq)
>>>>>>>>                len += sprintf(buf + len, "*");
>>>>>>>>            else
>>>>>>>>                len += sprintf(buf + len, " ");
>>>>>>>>              len += sprintf(buf + len, "%10lu:",
>>>>>>>> -                profile->freq_table[i]);
>>>>>>>> +                stats->freq_table[i]);
>>>>>>>>            for (j = 0; j < max_state; j++)
>>>>>>>>                len += sprintf(buf + len, "%10u",
>>>>>>>> -                profile->trans_table[(i * max_state) + j]);
>>>>>>>> +                stats->trans_table[(i * max_state) + j]);
>>>>>>>>            len += sprintf(buf + len, "%10llu\n", (u64)
>>>>>>>> -            jiffies64_to_msecs(profile->time_in_state[i]));
>>>>>>>> +            jiffies64_to_msecs(stats->time_in_state[i]));
>>>>>>>>        }
>>>>>>>>          len += sprintf(buf + len, "Total transition : %u\n",
>>>>>>>> -                    profile->total_trans);
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +                    stats->total_trans);
>>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>>        return len;
>>>>>>>>    }
>>>>>>>>    static DEVICE_ATTR_RO(trans_stat);
>>>>>>>>    -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>>>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>>>>>    {
>>>>>>>> -    unsigned int count = profile->max_state;
>>>>>>>> -
>>>>>>>> -    spin_lock(&profile->stats_lock);
>>>>>>>> -    memset(profile->time_in_state, 0, count * sizeof(u64));
>>>>>>>> -    memset(profile->trans_table, 0, count * count * sizeof(int));
>>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>>> -    profile->total_trans = 0;
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +    unsigned int count = stats->max_state;
>>>>>>>> +
>>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>> +    memset(stats->time_in_state, 0, count * sizeof(u64));
>>>>>>>> +    memset(stats->trans_table, 0, count * count * sizeof(int));
>>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>>> +    stats->total_trans = 0;
>>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>>    }
>>>>>>>>      static ssize_t trans_reset_store(struct device *dev,
>>>>>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>>>>>    {
>>>>>>>>        struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>>    -    defvreq_stats_clear_table(devfreq->profile);
>>>>>>>> +    defvreq_stats_clear_table(devfreq->profile->stats);
>>>>>>>>          return count;
>>>>>>>>    }
>>>>>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>>>>>> index d9f377912c10..b212aae2bb3e 100644
>>>>>>>> --- a/drivers/devfreq/exynos-bus.c
>>>>>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>>>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>>>>>        }
>>>>>>>>      out:
>>>>>>>> -    max_state = bus->devfreq->profile->max_state;
>>>>>>>> -    min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>>>>>> -    max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>>>>>> +    max_state = profile->stats->max_state;
>>>>>>>> +    min_freq = (profile->stats->freq_table[0] / 1000);
>>>>>>>> +    max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>>>>>        pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>>>>>                dev_name(dev), min_freq, max_freq);
>>>>>>>>    diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>>>>>> index 58308948b863..b2d87a88335c 100644
>>>>>>>> --- a/drivers/devfreq/governor_passive.c
>>>>>>>> +++ b/drivers/devfreq/governor_passive.c
>>>>>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>>        struct devfreq_passive_data *p_data
>>>>>>>>                = (struct devfreq_passive_data *)devfreq->data;
>>>>>>>>        struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>>>>>> +    struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>>        unsigned long child_freq = ULONG_MAX;
>>>>>>>>        struct dev_pm_opp *opp;
>>>>>>>>        int i, count, ret = 0;
>>>>>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>>         * device. And then the index is used for getting the suitable
>>>>>>>>         * new frequency for passive devfreq device.
>>>>>>>>         */
>>>>>>>> -    if (!devfreq->profile || !devfreq->profile->freq_table
>>>>>>>> -        || devfreq->profile->max_state <= 0)
>>>>>>>> +    if (!devfreq->profile || !devfreq->profile->stats ||
>>>>>>>> +        devfreq->profile->stats->max_state <= 0 ||
>>>>>>>> +        !parent_devfreq->profile ||    !parent_devfreq->profile->stats ||
>>>>>>>> +        parent_devfreq->profile->stats->max_state <= 0)
>>>>>>>>            return -EINVAL;
>>>>>>>>    +    stats = devfreq->profile->stats;
>>>>>>>> +    parent_stats = parent_devfreq->profile->stats;
>>>>>>>>        /*
>>>>>>>>         * The passive governor have to get the correct frequency from OPP
>>>>>>>>         * list of parent device. Because in this case, *freq is temporary
>>>>>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>>         * Get the OPP table's index of decided freqeuncy by governor
>>>>>>>>         * of parent device.
>>>>>>>>         */
>>>>>>>> -    for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>>>>>> -        if (parent_devfreq->profile->freq_table[i] == *freq)
>>>>>>>> +    for (i = 0; i < parent_stats->max_state; i++)
>>>>>>>> +        if (parent_stats->freq_table[i] == *freq)
>>>>>>>>                break;
>>>>>>>>    -    if (i == parent_devfreq->profile->max_state) {
>>>>>>>> +    if (i == parent_stats->max_state) {
>>>>>>>>            ret = -EINVAL;
>>>>>>>>            goto out;
>>>>>>>>        }
>>>>>>>>          /* Get the suitable frequency by using index of parent device. */
>>>>>>>> -    if (i < devfreq->profile->max_state) {
>>>>>>>> -        child_freq = devfreq->profile->freq_table[i];
>>>>>>>> +    if (i < stats->max_state) {
>>>>>>>> +        child_freq = stats->freq_table[i];
>>>>>>>>        } else {
>>>>>>>> -        count = devfreq->profile->max_state;
>>>>>>>> -        child_freq = devfreq->profile->freq_table[count - 1];
>>>>>>>> +        count = stats->max_state;
>>>>>>>> +        child_freq = stats->freq_table[count - 1];
>>>>>>>>        }
>>>>>>>>          /* Return the suitable frequency for passive device. */
>>>>>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>        if (ret < 0)
>>>>>>>>            goto out;
>>>>>>>>    -    if (devfreq->profile->freq_table
>>>>>>>> +    if (devfreq->profile->stats
>>>>>>>>            && (devfreq_update_status(devfreq, freq)))
>>>>>>>>            dev_err(&devfreq->dev,
>>>>>>>>                "Couldn't update frequency transition information.\n");
>>>>>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>>>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>>>>>> --- a/include/linux/devfreq.h
>>>>>>>> +++ b/include/linux/devfreq.h
>>>>>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>>>>>     */
>>>>>>>>    #define DEVFREQ_FLAG_LEAST_UPPER_BOUND        0x1
>>>>>>>>    +/**
>>>>>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>>>>>> + * @freq_table:        Optional list of frequencies to support statistics
>>>>>>>> + *            and freq_table must be generated in ascending order.
>>>>>>>> + * @max_state:        The size of freq_table.
>>>>>>>> + * @total_trans:    Number of devfreq transitions
>>>>>>>> + * @trans_table:    Statistics of devfreq transitions
>>>>>>>> + * @time_in_state:    Statistics of devfreq states
>>>>>>>> + * @last_time:        The last time stats were updated
>>>>>>>> + * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>>> + *            last_time and total_trans used for statistics
>>>>>>>> + */
>>>>>>>> +struct devfreq_stats {
>>>>>>>> +    unsigned long *freq_table;
>>>>>>>> +    unsigned int max_state;
>>>>>>>> +
>>>>>>>> +    /* information for device frequency transition */
>>>>>>>> +    unsigned int total_trans;
>>>>>>>> +    unsigned int *trans_table;
>>>>>>>> +    u64 *time_in_state;
>>>>>>>> +    unsigned long long last_time;
>>>>>>>> +    spinlock_t stats_lock;
>>>>>>>> +};
>>>>>>>> +
>>>>>>>>    /**
>>>>>>>>     * struct devfreq_dev_profile - Devfreq's user device profile
>>>>>>>>     * @initial_freq:    The operating frequency when devfreq_add_device() is
>>>>>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>>>>>     *            from devfreq_remove_device() call. If the user
>>>>>>>>     *            has registered devfreq->nb at a notifier-head,
>>>>>>>>     *            this is the time to unregister it.
>>>>>>>> - * @freq_table:        Optional list of frequencies to support statistics
>>>>>>>> - *            and freq_table must be generated in ascending order.
>>>>>>>> - * @max_state:        The size of freq_table.
>>>>>>>> - * @total_trans:    Number of devfreq transitions
>>>>>>>> - * @trans_table:    Statistics of devfreq transitions
>>>>>>>> - * @time_in_state:    Statistics of devfreq states
>>>>>>>> - * @last_time:        The last time stats were updated
>>>>>>>> - * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>>> - *            last_time and total_trans used for statistics
>>>>>>>> + * @stats:        Statistics of devfreq states and state transitions
>>>>>>>>     */
>>>>>>>>    struct devfreq_dev_profile {
>>>>>>>>        unsigned long initial_freq;
>>>>>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>>>>>        int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>>>>>        void (*exit)(struct device *dev);
>>>>>>>>    -    unsigned long *freq_table;
>>>>>>>> -    unsigned int max_state;
>>>>>>>> -    /* information for device frequency transition */
>>>>>>>> -    unsigned int total_trans;
>>>>>>>> -    unsigned int *trans_table;
>>>>>>>> -    u64 *time_in_state;
>>>>>>>> -    unsigned long long last_time;
>>>>>>>> -    spinlock_t stats_lock;
>>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>>    };
>>>>>>>>      /**
>>>>>>>>
>>>
>>> _______________________________________________
>>> linux-arm-kernel mailing list
>>> linux-arm-kernel@lists.infradead.org
>>> https://protect2.fireeye.com/url?k=856913bb-d8f2efd8-856898f4-0cc47a31cdbc-5cb40ce5f31ed8ed&u=http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>>
>>
>>
> 
> 

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Lukasz Luba]

Hi Chanwoo,

On 12/17/19 12:07 AM, Chanwoo Choi wrote:
> Hi Lukaz,
> 
> On 12/16/19 10:01 PM, Lukasz Luba wrote:
>> Hi Bartek,
>>
>> [added Dietmar, Robin, Andrzej (for upcoming DRM drm-misc-next)]
>>
>> On 11/15/19 12:40 PM, Bartlomiej Zolnierkiewicz wrote:
>>>
>>> [ added Zhang, Eduardo, Ørjan and Javi to Cc: ]
>>>
>>> On 11/15/19 7:21 AM, Chanwoo Choi wrote:
>>>> Hi Bartlomiej,
>>>>
>>>> On 11/15/19 12:25 PM, Chanwoo Choi wrote:
>>>>> Hi Bartlomiej,
>>>>>
>>>>> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>>>>>
>>>>>> Hi Chanwoo,
>>>>>>
>>>>>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>>>>>> Hi Kamil,
>>>>>>>
>>>>>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>>>>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>>>>>> device driver was posted to mainline kernel, they used
>>>>>>> them for a long time. It means that this patch break
>>>>>>> the compatibility. The ARM Mali drivers are very
>>>>>>> important devfreq device driver.
>>>>>>
>>>>>> This argument is not a a technical one and the official upstream
>>>>>> kernel policy is to not depend on out-of-tree drivers.
>>>>>>
>>>>>> Besides the ARM Mali drivers are full of code like:
>>>>>>
>>>>>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>>>>>> ...
>>>>>> #else
>>>>>> ...
>>>>>> #endif
>>>>>>
>>>>>> so few more instances of similar code won't do any harm.. ;-)
>>>>>>
>>>>>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>>>>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>>>>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>>>>>
>>>>>> I took a look at ARM Mali drivers source code anyway and I fail to
>>>>>> see a rationale behind their behavior of doing 'freq_table' and
>>>>>> 'max_state' initialization in the driver itself (instead of leaving
>>>>>> it up to the devfreq core code, like all in-kernel drivers are doing
>>>>>> already).
>>>>>>
>>>>>> Could you please explain rationale behind ARM Mali drivers' special
>>>>>> needs?
>>>>>>
>>>>>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>>>>>     these days to do 'freq_table' and 'max_state' initialization, the
>>>>>>     only difference seems to be that ARM Mali creates the frequency
>>>>>>     table in the descending order (but there also seems to be no real
>>>>>>     need for it). ]
>>>>>>
>>>>>> Maybe this is an opportunity to simplify also the ARM Mali driver?
>>>>>
>>>>> OK. I agree to simplify them on this time.
>>>>> For touching the 'freq_table' and 'max_state', need to fix
>>>>> the descending order of freq_table.
>>>>>
>>>>> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>>> requires the descending order of freq_table. Have to change it by using
>>>>> the ascending time or support both ascending and descending order for freq_table.
>>>>>
>>>>> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
>>>>> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>>>      by using ascending order instead of descending order.
>>>>>
>>>>
>>>> After changed about 'freq_table' and 'max_state', the build error
>>>> will happen on ARM mail driver because the initialization code of
>>>> 'freq_table' in ARM mali driver, didn't check the kernel version.
>>>>
>>>> The first devfreq patch provided the 'freq_table' as optional variable
>>>> in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree,
>>>> this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>>
>>>> So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
>>>> in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>>
>>>> Frankly, I'm note sure that it is necessary. I don't want to make
>>>> the side-effect without any useful reason.
>>>>
>>>> But,
>>>> Separately, have to fix the ordering issue of partition_enable_ops()
>>>> in the drivers/thermal/devfreq_cooling.c.
>>>
>>> Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
>>> why we are carrying devfreq_cooling.c code in upstream kernel at all?
>>
>> Well, the devfreq_cooling.c is going to have a client in mainline:
>> the GPU driver - Panfrost.
>>
>> It is already in DRM branch 'drm-misc-next':
>> https://protect2.fireeye.com/url?k=75a0e087-283b1ce4-75a16bc8-0cc47a31cdbc-4953aa9e0574f6dc&u=https://patchwork.freedesktop.org/patch/342848/
>>
>> Regarding the devfreq_cooling.c code structure.
>> I am currently working on cleaning up the devfreq cooling code and
>> adding Energy Model instead for private freq, power tables. It will be
>> in similar fashion as it is done in cpufreq_cooling. The model will
>> be also simplified so hopefully more clients would come.
>> It is under internal review and will be posted shortly.
> 
> Good news about Energy Model. When you send the patch related to Energy model,
> please add me to Cc list.

I will add you, thanks. More eyeballs in capturing bugs are more than
welcome.

Regards,
Lukasz

> 
>>
>>>
>>> It has been merged in the following commit:
>>>
>>> commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
>>> Author: Ørjan Eide <orjan.eide@arm.com>
>>> Date:   Thu Sep 10 18:09:30 2015 +0100
>>>
>>>       thermal: Add devfreq cooling
>>>            Add a generic thermal cooling device for devfreq, that is similar to
>>>       cpu_cooling.
>>>            The device must use devfreq.  In order to use the power extension of the
>>>       cooling device, it must have registered its OPPs using the OPP library.
>>>            Cc: Zhang Rui <rui.zhang@intel.com>
>>>       Cc: Eduardo Valentin <edubezval@gmail.com>
>>>       Signed-off-by: Javi Merino <javi.merino@arm.com>
>>>       Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
>>>       Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
>>> ...
>>>
>>> but 4 years later there is still no single in-kernel user for this code?
>>
>> There will be, via DRM tree.
>>
>> Regards,
>> Lukasz
>>
>>>
>>> Best regards,
>>> -- 
>>> Bartlomiej Zolnierkiewicz
>>> Samsung R&D Institute Poland
>>> Samsung Electronics
>>>
>>>>>>
>>>>>>> Also, the devfreq device driver specifies their own
>>>>>>> information and data into devfreq_dev_profile structure
>>>>>>> before registering the devfreq device with devfreq_add_device().
>>>>>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>>>>>
>>>>>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>>>>>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>>>>>> way..
>>>>>>
>>>>>> Best regards,
>>>>>> -- 
>>>>>> Bartlomiej Zolnierkiewicz
>>>>>> Samsung R&D Institute Poland
>>>>>> Samsung Electronics
>>>>>>
>>>>>>> So, I can't agree this patch. Not ack.
>>>>>>>
>>>>>>> Regards,
>>>>>>> Chanwoo Choi
>>>>>>>
>>>>>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>>>>>> Count time and transitions between devfreq frequencies in separate struct
>>>>>>>> for improved code readability and maintenance.
>>>>>>>>
>>>>>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>>>>>> ---
>>>>>>>>    drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>>>>>    drivers/devfreq/exynos-bus.c       |   6 +-
>>>>>>>>    drivers/devfreq/governor_passive.c |  26 +++--
>>>>>>>>    include/linux/devfreq.h            |  43 ++++----
>>>>>>>>    4 files changed, 129 insertions(+), 102 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>>>>> index d79412b0de59..d85867a91230 100644
>>>>>>>> --- a/drivers/devfreq/devfreq.c
>>>>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>>>>>     */
>>>>>>>>    static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>    {
>>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>>        int lev;
>>>>>>>>    -    for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>>>>>> -        if (freq == devfreq->profile->freq_table[lev])
>>>>>>>> +    for (lev = 0; lev < stats->max_state; lev++)
>>>>>>>> +        if (freq == stats->freq_table[lev])
>>>>>>>>                return lev;
>>>>>>>>          return -EINVAL;
>>>>>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>    static int set_freq_table(struct devfreq *devfreq)
>>>>>>>>    {
>>>>>>>>        struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>>        struct dev_pm_opp *opp;
>>>>>>>>        unsigned long freq;
>>>>>>>> -    int i, count;
>>>>>>>> +    int i, count, err = -ENOMEM;
>>>>>>>>          /* Initialize the freq_table from OPP table */
>>>>>>>>        count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>>>>>        if (count <= 0)
>>>>>>>>            return -EINVAL;
>>>>>>>>    -    profile->max_state = count;
>>>>>>>> -    profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>>> -                    count,
>>>>>>>> -                    sizeof(*profile->freq_table),
>>>>>>>> -                    GFP_KERNEL);
>>>>>>>> -    if (!profile->freq_table) {
>>>>>>>> -        profile->max_state = 0;
>>>>>>>> +    stats = devm_kzalloc(devfreq->dev.parent,
>>>>>>>> +                 sizeof(struct devfreq_stats), GFP_KERNEL);
>>>>>>>> +    if (!stats)
>>>>>>>>            return -ENOMEM;
>>>>>>>> -    }
>>>>>>>>    -    for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>>>>>> +    profile->stats = stats;
>>>>>>>> +    stats->max_state = count;
>>>>>>>> +    stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>>> +                     count,
>>>>>>>> +                     sizeof(*stats->freq_table),
>>>>>>>> +                     GFP_KERNEL);
>>>>>>>> +    if (!stats->freq_table)
>>>>>>>> +        goto err_no_mem;
>>>>>>>> +
>>>>>>>> +    for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>>>>>            opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>>>>>            if (IS_ERR(opp)) {
>>>>>>>> -            devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>>>>>> -            profile->max_state = 0;
>>>>>>>> -            return PTR_ERR(opp);
>>>>>>>> +            devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>>>>>> +            stats->max_state = 0;
>>>>>>>> +            err = PTR_ERR(opp);
>>>>>>>> +            goto err_no_mem;
>>>>>>>>            }
>>>>>>>>            dev_pm_opp_put(opp);
>>>>>>>> -        profile->freq_table[i] = freq;
>>>>>>>> +        stats->freq_table[i] = freq;
>>>>>>>>        }
>>>>>>>>    -    profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>>> -                        array3_size(sizeof(unsigned int),
>>>>>>>> -                            count, count),
>>>>>>>> -                        GFP_KERNEL);
>>>>>>>> -    if (!profile->trans_table)
>>>>>>>> +    stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>>> +                      array3_size(sizeof(unsigned int),
>>>>>>>> +                              count, count),
>>>>>>>> +                      GFP_KERNEL);
>>>>>>>> +    if (!stats->trans_table)
>>>>>>>>            goto err_no_mem;
>>>>>>>>    -    profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>>> -                          sizeof(*profile->time_in_state),
>>>>>>>> -                          GFP_KERNEL);
>>>>>>>> -    if (!profile->time_in_state)
>>>>>>>> +    stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>>> +                        sizeof(*stats->time_in_state),
>>>>>>>> +                        GFP_KERNEL);
>>>>>>>> +    if (!stats->time_in_state)
>>>>>>>>            goto err_no_mem;
>>>>>>>>    -    profile->last_time = get_jiffies_64();
>>>>>>>> -    spin_lock_init(&profile->stats_lock);
>>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>>> +    spin_lock_init(&stats->stats_lock);
>>>>>>>>          return 0;
>>>>>>>>    err_no_mem:
>>>>>>>> -    profile->max_state = 0;
>>>>>>>> -    return -ENOMEM;
>>>>>>>> +    stats->max_state = 0;
>>>>>>>> +    devm_kfree(devfreq->dev.parent, profile->stats);
>>>>>>>> +    profile->stats = NULL;
>>>>>>>> +    return err;
>>>>>>>>    }
>>>>>>>>      /**
>>>>>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>>>>>     */
>>>>>>>>    int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>    {
>>>>>>>> -    struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>>        unsigned long long cur_time;
>>>>>>>>        int lev, prev_lev, ret = 0;
>>>>>>>>    @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>          /* Immediately exit if previous_freq is not initialized yet. */
>>>>>>>>        if (!devfreq->previous_freq) {
>>>>>>>> -        spin_lock(&profile->stats_lock);
>>>>>>>> -        profile->last_time = cur_time;
>>>>>>>> -        spin_unlock(&profile->stats_lock);
>>>>>>>> +        spin_lock(&stats->stats_lock);
>>>>>>>> +        stats->last_time = cur_time;
>>>>>>>> +        spin_unlock(&stats->stats_lock);
>>>>>>>>            return 0;
>>>>>>>>        }
>>>>>>>>          prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>>>>>    -    spin_lock(&profile->stats_lock);
>>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>>        if (prev_lev < 0) {
>>>>>>>>            ret = prev_lev;
>>>>>>>>            goto out;
>>>>>>>>        }
>>>>>>>>    -    profile->time_in_state[prev_lev] +=
>>>>>>>> -             cur_time - profile->last_time;
>>>>>>>> +    stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>>>>>        lev = devfreq_get_freq_level(devfreq, freq);
>>>>>>>>        if (lev < 0) {
>>>>>>>>            ret = lev;
>>>>>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>        }
>>>>>>>>          if (lev != prev_lev) {
>>>>>>>> -        profile->trans_table[(prev_lev *
>>>>>>>> -                profile->max_state) + lev]++;
>>>>>>>> -        profile->total_trans++;
>>>>>>>> +        stats->trans_table[(prev_lev *
>>>>>>>> +                stats->max_state) + lev]++;
>>>>>>>> +        stats->total_trans++;
>>>>>>>>        }
>>>>>>>>      out:
>>>>>>>> -    profile->last_time = cur_time;
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +    stats->last_time = cur_time;
>>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>>        return ret;
>>>>>>>>    }
>>>>>>>>    EXPORT_SYMBOL(devfreq_update_status);
>>>>>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>>>>>            queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>>>>>                msecs_to_jiffies(profile->polling_ms));
>>>>>>>>    -    spin_lock(&profile->stats_lock);
>>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +    spin_lock(&profile->stats->stats_lock);
>>>>>>>> +    profile->stats->last_time = get_jiffies_64();
>>>>>>>> +    spin_unlock(&profile->stats->stats_lock);
>>>>>>>>        devfreq->stop_polling = false;
>>>>>>>>          if (profile->get_cur_freq &&
>>>>>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>>>>>        devfreq->data = data;
>>>>>>>>        devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>>>>>    -    if (!profile->max_state && !profile->freq_table) {
>>>>>>>> +    if (!profile->stats) {
>>>>>>>>            mutex_unlock(&devfreq->lock);
>>>>>>>>            err = set_freq_table(devfreq);
>>>>>>>>            if (err < 0)
>>>>>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                      const char *buf, size_t count)
>>>>>>>>    {
>>>>>>>>        struct devfreq *df = to_devfreq(dev);
>>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>>        unsigned long value;
>>>>>>>>        int ret;
>>>>>>>>    @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                goto unlock;
>>>>>>>>            }
>>>>>>>>        } else {
>>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>>              /* Get minimum frequency according to sorting order */
>>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>>>                value = freq_table[0];
>>>>>>>>            else
>>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>>        }
>>>>>>>>          df->min_freq = value;
>>>>>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                      const char *buf, size_t count)
>>>>>>>>    {
>>>>>>>>        struct devfreq *df = to_devfreq(dev);
>>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>>        unsigned long value;
>>>>>>>>        int ret;
>>>>>>>>    @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                goto unlock;
>>>>>>>>            }
>>>>>>>>        } else {
>>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>>              /* Get maximum frequency according to sorting order */
>>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>>            else
>>>>>>>>                value = freq_table[0];
>>>>>>>>        }
>>>>>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>>>>>                          char *buf)
>>>>>>>>    {
>>>>>>>>        struct devfreq *df = to_devfreq(d);
>>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>>        ssize_t count = 0;
>>>>>>>>        int i;
>>>>>>>>          mutex_lock(&df->lock);
>>>>>>>>    -    for (i = 0; i < df->profile->max_state; i++)
>>>>>>>> +    for (i = 0; i < stats->max_state; i++)
>>>>>>>>            count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>>>>>> -                "%lu ", df->profile->freq_table[i]);
>>>>>>>> +                "%lu ", stats->freq_table[i]);
>>>>>>>>          mutex_unlock(&df->lock);
>>>>>>>>        /* Truncate the trailing space */
>>>>>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>>    {
>>>>>>>>        struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>>        struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>>> +    struct devfreq_stats *stats = profile->stats;
>>>>>>>> +    unsigned int max_state = stats->max_state;
>>>>>>>>        ssize_t len;
>>>>>>>>        int i, j;
>>>>>>>> -    unsigned int max_state = profile->max_state;
>>>>>>>>          if (!devfreq->stop_polling &&
>>>>>>>>                devfreq_update_status(devfreq, devfreq->previous_freq))
>>>>>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>>        len = sprintf(buf, "     From  :   To\n");
>>>>>>>>        len += sprintf(buf + len, "           :");
>>>>>>>>    -    spin_lock(&profile->stats_lock);
>>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>>        for (i = 0; i < max_state; i++)
>>>>>>>>            len += sprintf(buf + len, "%10lu",
>>>>>>>> -                profile->freq_table[i]);
>>>>>>>> +                stats->freq_table[i]);
>>>>>>>>          len += sprintf(buf + len, "   time(ms)\n");
>>>>>>>>          for (i = 0; i < max_state; i++) {
>>>>>>>> -        if (profile->freq_table[i] == devfreq->previous_freq)
>>>>>>>> +        if (stats->freq_table[i] == devfreq->previous_freq)
>>>>>>>>                len += sprintf(buf + len, "*");
>>>>>>>>            else
>>>>>>>>                len += sprintf(buf + len, " ");
>>>>>>>>              len += sprintf(buf + len, "%10lu:",
>>>>>>>> -                profile->freq_table[i]);
>>>>>>>> +                stats->freq_table[i]);
>>>>>>>>            for (j = 0; j < max_state; j++)
>>>>>>>>                len += sprintf(buf + len, "%10u",
>>>>>>>> -                profile->trans_table[(i * max_state) + j]);
>>>>>>>> +                stats->trans_table[(i * max_state) + j]);
>>>>>>>>            len += sprintf(buf + len, "%10llu\n", (u64)
>>>>>>>> -            jiffies64_to_msecs(profile->time_in_state[i]));
>>>>>>>> +            jiffies64_to_msecs(stats->time_in_state[i]));
>>>>>>>>        }
>>>>>>>>          len += sprintf(buf + len, "Total transition : %u\n",
>>>>>>>> -                    profile->total_trans);
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +                    stats->total_trans);
>>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>>        return len;
>>>>>>>>    }
>>>>>>>>    static DEVICE_ATTR_RO(trans_stat);
>>>>>>>>    -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>>>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>>>>>    {
>>>>>>>> -    unsigned int count = profile->max_state;
>>>>>>>> -
>>>>>>>> -    spin_lock(&profile->stats_lock);
>>>>>>>> -    memset(profile->time_in_state, 0, count * sizeof(u64));
>>>>>>>> -    memset(profile->trans_table, 0, count * count * sizeof(int));
>>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>>> -    profile->total_trans = 0;
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +    unsigned int count = stats->max_state;
>>>>>>>> +
>>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>> +    memset(stats->time_in_state, 0, count * sizeof(u64));
>>>>>>>> +    memset(stats->trans_table, 0, count * count * sizeof(int));
>>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>>> +    stats->total_trans = 0;
>>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>>    }
>>>>>>>>      static ssize_t trans_reset_store(struct device *dev,
>>>>>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>>>>>    {
>>>>>>>>        struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>>    -    defvreq_stats_clear_table(devfreq->profile);
>>>>>>>> +    defvreq_stats_clear_table(devfreq->profile->stats);
>>>>>>>>          return count;
>>>>>>>>    }
>>>>>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>>>>>> index d9f377912c10..b212aae2bb3e 100644
>>>>>>>> --- a/drivers/devfreq/exynos-bus.c
>>>>>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>>>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>>>>>        }
>>>>>>>>      out:
>>>>>>>> -    max_state = bus->devfreq->profile->max_state;
>>>>>>>> -    min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>>>>>> -    max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>>>>>> +    max_state = profile->stats->max_state;
>>>>>>>> +    min_freq = (profile->stats->freq_table[0] / 1000);
>>>>>>>> +    max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>>>>>        pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>>>>>                dev_name(dev), min_freq, max_freq);
>>>>>>>>    diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>>>>>> index 58308948b863..b2d87a88335c 100644
>>>>>>>> --- a/drivers/devfreq/governor_passive.c
>>>>>>>> +++ b/drivers/devfreq/governor_passive.c
>>>>>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>>        struct devfreq_passive_data *p_data
>>>>>>>>                = (struct devfreq_passive_data *)devfreq->data;
>>>>>>>>        struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>>>>>> +    struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>>        unsigned long child_freq = ULONG_MAX;
>>>>>>>>        struct dev_pm_opp *opp;
>>>>>>>>        int i, count, ret = 0;
>>>>>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>>         * device. And then the index is used for getting the suitable
>>>>>>>>         * new frequency for passive devfreq device.
>>>>>>>>         */
>>>>>>>> -    if (!devfreq->profile || !devfreq->profile->freq_table
>>>>>>>> -        || devfreq->profile->max_state <= 0)
>>>>>>>> +    if (!devfreq->profile || !devfreq->profile->stats ||
>>>>>>>> +        devfreq->profile->stats->max_state <= 0 ||
>>>>>>>> +        !parent_devfreq->profile ||    !parent_devfreq->profile->stats ||
>>>>>>>> +        parent_devfreq->profile->stats->max_state <= 0)
>>>>>>>>            return -EINVAL;
>>>>>>>>    +    stats = devfreq->profile->stats;
>>>>>>>> +    parent_stats = parent_devfreq->profile->stats;
>>>>>>>>        /*
>>>>>>>>         * The passive governor have to get the correct frequency from OPP
>>>>>>>>         * list of parent device. Because in this case, *freq is temporary
>>>>>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>>         * Get the OPP table's index of decided freqeuncy by governor
>>>>>>>>         * of parent device.
>>>>>>>>         */
>>>>>>>> -    for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>>>>>> -        if (parent_devfreq->profile->freq_table[i] == *freq)
>>>>>>>> +    for (i = 0; i < parent_stats->max_state; i++)
>>>>>>>> +        if (parent_stats->freq_table[i] == *freq)
>>>>>>>>                break;
>>>>>>>>    -    if (i == parent_devfreq->profile->max_state) {
>>>>>>>> +    if (i == parent_stats->max_state) {
>>>>>>>>            ret = -EINVAL;
>>>>>>>>            goto out;
>>>>>>>>        }
>>>>>>>>          /* Get the suitable frequency by using index of parent device. */
>>>>>>>> -    if (i < devfreq->profile->max_state) {
>>>>>>>> -        child_freq = devfreq->profile->freq_table[i];
>>>>>>>> +    if (i < stats->max_state) {
>>>>>>>> +        child_freq = stats->freq_table[i];
>>>>>>>>        } else {
>>>>>>>> -        count = devfreq->profile->max_state;
>>>>>>>> -        child_freq = devfreq->profile->freq_table[count - 1];
>>>>>>>> +        count = stats->max_state;
>>>>>>>> +        child_freq = stats->freq_table[count - 1];
>>>>>>>>        }
>>>>>>>>          /* Return the suitable frequency for passive device. */
>>>>>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>        if (ret < 0)
>>>>>>>>            goto out;
>>>>>>>>    -    if (devfreq->profile->freq_table
>>>>>>>> +    if (devfreq->profile->stats
>>>>>>>>            && (devfreq_update_status(devfreq, freq)))
>>>>>>>>            dev_err(&devfreq->dev,
>>>>>>>>                "Couldn't update frequency transition information.\n");
>>>>>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>>>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>>>>>> --- a/include/linux/devfreq.h
>>>>>>>> +++ b/include/linux/devfreq.h
>>>>>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>>>>>     */
>>>>>>>>    #define DEVFREQ_FLAG_LEAST_UPPER_BOUND        0x1
>>>>>>>>    +/**
>>>>>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>>>>>> + * @freq_table:        Optional list of frequencies to support statistics
>>>>>>>> + *            and freq_table must be generated in ascending order.
>>>>>>>> + * @max_state:        The size of freq_table.
>>>>>>>> + * @total_trans:    Number of devfreq transitions
>>>>>>>> + * @trans_table:    Statistics of devfreq transitions
>>>>>>>> + * @time_in_state:    Statistics of devfreq states
>>>>>>>> + * @last_time:        The last time stats were updated
>>>>>>>> + * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>>> + *            last_time and total_trans used for statistics
>>>>>>>> + */
>>>>>>>> +struct devfreq_stats {
>>>>>>>> +    unsigned long *freq_table;
>>>>>>>> +    unsigned int max_state;
>>>>>>>> +
>>>>>>>> +    /* information for device frequency transition */
>>>>>>>> +    unsigned int total_trans;
>>>>>>>> +    unsigned int *trans_table;
>>>>>>>> +    u64 *time_in_state;
>>>>>>>> +    unsigned long long last_time;
>>>>>>>> +    spinlock_t stats_lock;
>>>>>>>> +};
>>>>>>>> +
>>>>>>>>    /**
>>>>>>>>     * struct devfreq_dev_profile - Devfreq's user device profile
>>>>>>>>     * @initial_freq:    The operating frequency when devfreq_add_device() is
>>>>>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>>>>>     *            from devfreq_remove_device() call. If the user
>>>>>>>>     *            has registered devfreq->nb at a notifier-head,
>>>>>>>>     *            this is the time to unregister it.
>>>>>>>> - * @freq_table:        Optional list of frequencies to support statistics
>>>>>>>> - *            and freq_table must be generated in ascending order.
>>>>>>>> - * @max_state:        The size of freq_table.
>>>>>>>> - * @total_trans:    Number of devfreq transitions
>>>>>>>> - * @trans_table:    Statistics of devfreq transitions
>>>>>>>> - * @time_in_state:    Statistics of devfreq states
>>>>>>>> - * @last_time:        The last time stats were updated
>>>>>>>> - * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>>> - *            last_time and total_trans used for statistics
>>>>>>>> + * @stats:        Statistics of devfreq states and state transitions
>>>>>>>>     */
>>>>>>>>    struct devfreq_dev_profile {
>>>>>>>>        unsigned long initial_freq;
>>>>>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>>>>>        int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>>>>>        void (*exit)(struct device *dev);
>>>>>>>>    -    unsigned long *freq_table;
>>>>>>>> -    unsigned int max_state;
>>>>>>>> -    /* information for device frequency transition */
>>>>>>>> -    unsigned int total_trans;
>>>>>>>> -    unsigned int *trans_table;
>>>>>>>> -    u64 *time_in_state;
>>>>>>>> -    unsigned long long last_time;
>>>>>>>> -    spinlock_t stats_lock;
>>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>>    };
>>>>>>>>      /**
>>>>>>>>
>>>
>>> _______________________________________________
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>>> linux-arm-kernel@lists.infradead.org
>>> https://protect2.fireeye.com/url?k=856913bb-d8f2efd8-856898f4-0cc47a31cdbc-5cb40ce5f31ed8ed&u=http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>>
>>
>>
> 
> 

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Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Bartlomiej Zolnierkiewicz]

On 12/16/19 2:01 PM, Lukasz Luba wrote:
> Hi Bartek,
> 
> [added Dietmar, Robin, Andrzej (for upcoming DRM drm-misc-next)]
> 
> On 11/15/19 12:40 PM, Bartlomiej Zolnierkiewicz wrote:

[...]

>> Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
>> why we are carrying devfreq_cooling.c code in upstream kernel at all?
> 
> Well, the devfreq_cooling.c is going to have a client in mainline:
> the GPU driver - Panfrost.
> 
> It is already in DRM branch 'drm-misc-next':
> https://patchwork.freedesktop.org/patch/342848/

OK, thanks for explaining this.

> Regarding the devfreq_cooling.c code structure.
> I am currently working on cleaning up the devfreq cooling code and
> adding Energy Model instead for private freq, power tables. It will be
> in similar fashion as it is done in cpufreq_cooling. The model will
> be also simplified so hopefully more clients would come.
> It is under internal review and will be posted shortly.

Great to hear this and thank you for working on it.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Bartlomiej Zolnierkiewicz]

On 12/16/19 2:01 PM, Lukasz Luba wrote:
> Hi Bartek,
> 
> [added Dietmar, Robin, Andrzej (for upcoming DRM drm-misc-next)]
> 
> On 11/15/19 12:40 PM, Bartlomiej Zolnierkiewicz wrote:

[...]

>> Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
>> why we are carrying devfreq_cooling.c code in upstream kernel at all?
> 
> Well, the devfreq_cooling.c is going to have a client in mainline:
> the GPU driver - Panfrost.
> 
> It is already in DRM branch 'drm-misc-next':
> https://patchwork.freedesktop.org/patch/342848/

OK, thanks for explaining this.

> Regarding the devfreq_cooling.c code structure.
> I am currently working on cleaning up the devfreq cooling code and
> adding Energy Model instead for private freq, power tables. It will be
> in similar fashion as it is done in cpufreq_cooling. The model will
> be also simplified so hopefully more clients would come.
> It is under internal review and will be posted shortly.

Great to hear this and thank you for working on it.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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