Re: [PATCH v7 16/19] PM / devfreq: Add new interrupt_driven flag for governors

[Dmitry Osipenko]

01.11.2019 10:32, Chanwoo Choi ÐÐÑÐÑ:
> Hi,
> 
> On 19. 10. 30. ìì 7:00, Dmitry Osipenko wrote:
>> Currently interrupt-driven governors (like NVIDIA Tegra30 ACTMON governor)
>> are used to set polling_ms=0 in order to avoid periodic polling of device
>> status by devfreq core. This means that polling interval can't be changed
>> by userspace for such governors.
>>
>> The new governor flag allows interrupt-driven governors to convey that
>> devfreq core shouldn't perform polling of device status and thus generic
>> devfreq polling interval could be supported by these governors now.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>> ---
>>  drivers/devfreq/devfreq.c  | 14 +++++++++-----
>>  drivers/devfreq/governor.h |  3 +++
>>  2 files changed, 12 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index b905963cea7d..0ef972264841 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -410,7 +410,8 @@ static void devfreq_monitor(struct work_struct *work)
>>  void devfreq_monitor_start(struct devfreq *devfreq)
>>  {
>>  	INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
>> -	if (devfreq->profile->polling_ms)
>> +	if (devfreq->profile->polling_ms &&
>> +	    !devfreq->governor->interrupt_driven)
>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>  			msecs_to_jiffies(devfreq->profile->polling_ms));
>>  }
>> @@ -474,7 +475,8 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>  		goto out;
>>  
>>  	if (!delayed_work_pending(&devfreq->work) &&
>> -			devfreq->profile->polling_ms)
>> +			devfreq->profile->polling_ms &&
>> +				!devfreq->governor->interrupt_driven)
> 
> Better to edit it as following for the indentation.
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index cea05b43225f..60c5540b2a55 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -477,7 +477,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>  
>         if (!delayed_work_pending(&devfreq->work) &&
>                         devfreq->profile->polling_ms &&
> -                               !devfreq->governor->interrupt_driven)
> +                       !devfreq->governor->interrupt_driven)
> 
> 
> 
>>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>>  			msecs_to_jiffies(devfreq->profile->polling_ms));
>>  
>> @@ -518,8 +520,9 @@ void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
>>  
>>  	/* if current delay is zero, start polling with new delay */
>>  	if (!cur_delay) {
>> -		queue_delayed_work(devfreq_wq, &devfreq->work,
>> -			msecs_to_jiffies(devfreq->profile->polling_ms));
>> +		if (!devfreq->governor->interrupt_driven)
>> +			queue_delayed_work(devfreq_wq, &devfreq->work,
>> +				msecs_to_jiffies(devfreq->profile->polling_ms));
>>  		goto out;
>>  	}
>>  
>> @@ -528,7 +531,8 @@ void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
>>  		mutex_unlock(&devfreq->lock);
>>  		cancel_delayed_work_sync(&devfreq->work);
>>  		mutex_lock(&devfreq->lock);
>> -		if (!devfreq->stop_polling)
>> +		if (!devfreq->stop_polling &&
>> +		    !devfreq->governor->interrupt_driven)
>>  			queue_delayed_work(devfreq_wq, &devfreq->work,
>>  				msecs_to_jiffies(devfreq->profile->polling_ms));
>>  	}
> 
> In the devfreq_interval_update(), you better to modify this function as following:
> It is more simple.
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index d3d12ed0ed29..80acb55d1686 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -510,6 +510,9 @@ void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
>         if (devfreq->stop_polling)
>                 goto out;
>  
> +       if (!devfreq->governor->interrupt_driven)
> +               goto out;
> +
>         /* if new delay is zero, stop polling */
>         if (!new_delay) {
>                 mutex_unlock(&devfreq->lock);
> 
> 
> 
>> diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
>> index bbe5ff9fcecf..dc7533ccc3db 100644
>> --- a/drivers/devfreq/governor.h
>> +++ b/drivers/devfreq/governor.h
>> @@ -31,6 +31,8 @@
>>   * @name:		Governor's name
>>   * @immutable:		Immutable flag for governor. If the value is 1,
>>   *			this govenror is never changeable to other governor.
>> + * @interrupt_driven:	Devfreq core won't schedule polling work for this
>> + *			governor if value is set to 1.
>>   * @get_target_freq:	Returns desired operating frequency for the device.
>>   *			Basically, get_target_freq will run
>>   *			devfreq_dev_profile.get_dev_status() to get the
>> @@ -49,6 +51,7 @@ struct devfreq_governor {
>>  
>>  	const char name[DEVFREQ_NAME_LEN];
>>  	const unsigned int immutable;
>> +	const unsigned int interrupt_driven;
>>  	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
>>  	int (*event_handler)(struct devfreq *devfreq,
>>  				unsigned int event, void *data);
>>
> 
> 

Okay, I'll update this patch.