Re: [PATCH v3 3/3] devfreq: move statistics to separate struct

[Chanwoo Choi]

Hi,

Looks good. But, it include the some clean-up code
regardless of 'struct stats'. So, I modified them as following by myself:

- Remove the code touched the 'devfreq->profile' in this patch
- Use 'devfreq->stats.*' style instead of 'stats->*' in order to
 keep the consistent coding style.

On 12/5/19 11:55 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@xxxxxxxxxxx>
> Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> ---
> Changes in v3:
> - removed freq_table and max_state from struct devfreq_stats as they are
>   already present in struct devfreq_dev_profile
> - renamed last_stat_updated to last_update, as 'stat' is already present
>   in struct devfreq_stats
> - define struct devfreq_stats stats; in devfreq as there is only one
>   stats per devfreq
> - improve descriptions of devfreq_stats and stats
> - use profile instead of devfreq->profile in devfreq_add_device, as this
>   var is already parameter
> - added Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> 
> Changes in v2:
> - squash three patches into one, do not modify devfreq_profile and separate stats
>   into devfreq_stats
> ---
>  drivers/devfreq/devfreq.c | 67 ++++++++++++++++++++-------------------
>  include/linux/devfreq.h   | 26 +++++++++------
>  2 files changed, 51 insertions(+), 42 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 218eb64d7f28..bcd7e92d2cf3 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -198,6 +198,7 @@ static int set_freq_table(struct devfreq *devfreq)
>   */
>  int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  {
> +	struct devfreq_stats *stats = &devfreq->stats;
>  	int lev, prev_lev, ret = 0;
>  	u64 cur_time;
>  
> @@ -214,9 +215,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>  		goto out;
>  	}
>  
> -	devfreq->time_in_state[prev_lev] +=
> -			 cur_time - devfreq->last_stat_updated;
> -
> +	stats->time_in_state[prev_lev] += cur_time - stats->last_update;
>  	lev = devfreq_get_freq_level(devfreq, freq);
>  	if (lev < 0) {
>  		ret = lev;
> @@ -224,13 +223,13 @@ 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++;
> +		stats->trans_table[(prev_lev * devfreq->profile->max_state) +
> +				   lev]++;
> +		stats->total_trans++;
>  	}
>  
>  out:
> -	devfreq->last_stat_updated = cur_time;
> +	stats->last_update = cur_time;
>  	return ret;
>  }
>  EXPORT_SYMBOL(devfreq_update_status);
> @@ -525,7 +524,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>  			msecs_to_jiffies(devfreq->profile->polling_ms));
>  
>  out_update:
> -	devfreq->last_stat_updated = get_jiffies_64();
> +	devfreq->stats.last_update = get_jiffies_64();
>  	devfreq->stop_polling = false;
>  
>  	if (devfreq->profile->get_cur_freq &&
> @@ -735,28 +734,29 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  		goto err_out;
>  	}
>  
> -	devfreq->trans_table = devm_kzalloc(&devfreq->dev,
> +	devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
>  			array3_size(sizeof(unsigned int),
> -				    devfreq->profile->max_state,
> -				    devfreq->profile->max_state),

It is not good touching the 'devfreq->profile' variable
that is not related to 'struct devfreq_stats'. Just keep the previous code.


> +				    profile->max_state,
> +				    profile->max_state),
>  			GFP_KERNEL);
> -	if (!devfreq->trans_table) {
> +	if (!devfreq->stats.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),
> +	devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
> +			profile->max_state,

ditto. Just keep the previous code.

> +			sizeof(*devfreq->stats.time_in_state),
>  			GFP_KERNEL);
> -	if (!devfreq->time_in_state) {
> +	if (!devfreq->stats.time_in_state) {
>  		mutex_unlock(&devfreq->lock);
>  		err = -ENOMEM;
>  		goto err_devfreq;
>  	}
>  
> -	devfreq->last_stat_updated = get_jiffies_64();
> +	devfreq->stats.last_update = get_jiffies_64();
> +	devfreq->stats.total_trans = 0;
>  
>  	srcu_init_notifier_head(&devfreq->transition_notifier_list);
>  
> @@ -1435,9 +1435,11 @@ static ssize_t trans_stat_show(struct device *dev,
>  			       struct device_attribute *attr, char *buf)
>  {
>  	struct devfreq *devfreq = to_devfreq(dev);
> +	struct devfreq_stats *stats = &devfreq->stats;
> +	unsigned int max_state = devfreq->profile->max_state;
> +	unsigned long *freq_table = devfreq->profile->freq_table;
>  	ssize_t len;
>  	int i, j;
> -	unsigned int max_state = devfreq->profile->max_state;

It is not good touching the 'devfreq->profile' variable
that is not related to 'struct devfreq_stats'.

>  
>  	if (max_state == 0)
>  		return sprintf(buf, "Not Supported.\n");
> @@ -1453,29 +1455,27 @@ static ssize_t trans_stat_show(struct device *dev,
>  	len = sprintf(buf, "     From  :   To\n");
>  	len += sprintf(buf + len, "           :");
>  	for (i = 0; i < max_state; i++)
> -		len += sprintf(buf + len, "%10lu",
> -				devfreq->profile->freq_table[i]);
> +		len += sprintf(buf + len, "%10lu", freq_table[i]);

It is not good touching the 'devfreq->profile' variable
that is not related to 'struct devfreq_stats'.

>  
>  	len += sprintf(buf + len, "   time(ms)\n");
>  
>  	for (i = 0; i < max_state; i++) {
> -		if (devfreq->profile->freq_table[i]
> -					== devfreq->previous_freq) {
> +		if (freq_table[i] == devfreq->previous_freq)

ditto.

>  			len += sprintf(buf + len, "*");
> -		} else {

Don't touch the something if it is not related to 'struct devfreq_stats'

> +		else
>  			len += sprintf(buf + len, " ");
> -		}

ditto.

> -		len += sprintf(buf + len, "%10lu:",
> -				devfreq->profile->freq_table[i]);
> +
> +		len += sprintf(buf + len, "%10lu:", freq_table[i]);

ditto.

>  		for (j = 0; j < max_state; j++)
>  			len += sprintf(buf + len, "%10u",
> -				devfreq->trans_table[(i * max_state) + j]);
> +				stats->trans_table[(i * max_state) + j]);
> +
>  		len += sprintf(buf + len, "%10llu\n", (u64)
> -			jiffies64_to_msecs(devfreq->time_in_state[i]));
> +			jiffies64_to_msecs(stats->time_in_state[i]));
>  	}
>  
>  	len += sprintf(buf + len, "Total transition : %u\n",
> -					devfreq->total_trans);
> +					stats->total_trans);
>  	return len;
>  }
>  
> @@ -1484,6 +1484,7 @@ static ssize_t trans_stat_store(struct device *dev,
>  				const char *buf, size_t count)
>  {
>  	struct devfreq *df = to_devfreq(dev);
> +	struct devfreq_stats *stats = &df->stats;
>  	unsigned int cnt = df->profile->max_state;
>  	int err, value;
>  
> @@ -1495,10 +1496,10 @@ static ssize_t trans_stat_store(struct device *dev,
>  		return count;
>  
>  	mutex_lock(&df->lock);
> -	memset(df->time_in_state, 0, cnt * sizeof(u64));
> -	memset(df->trans_table, 0, cnt * cnt * sizeof(int));
> -	df->last_stat_updated = get_jiffies_64();
> -	df->total_trans = 0;
> +	memset(stats->time_in_state, 0, cnt * sizeof(u64));
> +	memset(stats->trans_table, 0, cnt * cnt * sizeof(int));
> +	stats->last_update = get_jiffies_64();
> +	stats->total_trans = 0;
>  	mutex_unlock(&df->lock);
>  
>  	return count;
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 41f15e7a22b8..de2fdc56aa5b 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -106,6 +106,20 @@ struct devfreq_dev_profile {
>  	unsigned int max_state;
>  };
>  
> +/**
> + * struct devfreq_stats - Statistics of devfreq device behavior
> + * @total_trans:	Number of devfreq transitions.
> + * @trans_table:	Statistics of devfreq transitions.
> + * @time_in_state:	Statistics of devfreq states.
> + * @last_update:	The last time stats were updated.
> + */
> +struct devfreq_stats {
> +	unsigned int total_trans;
> +	unsigned int *trans_table;
> +	u64 *time_in_state;
> +	u64 last_update;
> +};
> +
>  /**
>   * struct devfreq - Device devfreq structure
>   * @node:	list node - contains the devices with devfreq that have been
> @@ -131,10 +145,7 @@ 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_stat_updated:	The last time stat updated
> + * @stats:	Statistics of devfreq device behavior
>   * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
>   *
>   * This structure stores the devfreq information for a give device.
> @@ -171,11 +182,8 @@ 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;
> -	u64 last_stat_updated;
> +	/* information for device frequency transitions */
> +	struct devfreq_stats stats;
>  
>  	struct srcu_notifier_head transition_notifier_list;
>  };
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics