linux-kernel - Re: [PATCH 3/3] powercap/drivers/idle_inject: Specify the idle state to inject

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Date:   Wed, 18 Sep 2019 13:35:54 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     rafael@...nel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Rafael J. Wysocki" <rjw@...ysocki.net>
Subject: Re: [PATCH 3/3] powercap/drivers/idle_inject: Specify the idle state
 to inject

On Mon, Sep 09, 2019 at 04:50:15PM +0200, Daniel Lezcano wrote:
> Currently the idle injection framework only allows to inject the
> deepest idle state available on the system.
> 
> Give the opportunity to specify which idle state we want to inject by
> adding a new function helper to set the state and use it when calling
> play_idle().
> 
> There is no functional changes, the cpuidle state is the deepest one.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
> ---
>  drivers/powercap/idle_inject.c | 15 ++++++++++++++-
>  include/linux/idle_inject.h    |  3 +++
>  2 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c
> index 9b18667b9f26..a612c425d74c 100644
> --- a/drivers/powercap/idle_inject.c
> +++ b/drivers/powercap/idle_inject.c
> @@ -38,6 +38,7 @@
>  #define pr_fmt(fmt) "ii_dev: " fmt
>  
>  #include <linux/cpu.h>
> +#include <linux/cpuidle.h>
>  #include <linux/hrtimer.h>
>  #include <linux/kthread.h>
>  #include <linux/sched.h>
> @@ -65,6 +66,7 @@ struct idle_inject_thread {
>   */
>  struct idle_inject_device {
>  	struct hrtimer timer;
> +	int state;
>  	unsigned int idle_duration_us;
>  	unsigned int run_duration_us;
>  	unsigned long int cpumask[0];
> @@ -139,7 +141,7 @@ static void idle_inject_fn(unsigned int cpu)
>  	iit->should_run = 0;
>  
>  	play_idle(READ_ONCE(ii_dev->idle_duration_us),
> -		  cpuidle_find_deepest_state());
> +		  READ_ONCE(ii_dev->state));
>  }
>  
>  /**
> @@ -170,6 +172,16 @@ void idle_inject_get_duration(struct idle_inject_device *ii_dev,
>  	*idle_duration_us = READ_ONCE(ii_dev->idle_duration_us);
>  }
>  
> +/**
> + * idle_inject_set_state - set the idle state to inject
> + * @state: an integer for the idle state to inject
> + */
> +void idle_inject_set_state(struct idle_inject_device *ii_dev, int state)
> +{
> +	if (state >= CPUIDLE_STATE_NOUSE && state < CPUIDLE_STATE_MAX)
> +		WRITE_ONCE(ii_dev->state, state);
> +}
> +
>  /**
>   * idle_inject_start - start idle injections
>   * @ii_dev: idle injection control device structure
> @@ -298,6 +310,7 @@ struct idle_inject_device *idle_inject_register(struct cpumask *cpumask)
>  	cpumask_copy(to_cpumask(ii_dev->cpumask), cpumask);
>  	hrtimer_init(&ii_dev->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
>  	ii_dev->timer.function = idle_inject_timer_fn;
> +	ii_dev->state = cpuidle_find_deepest_state();
>  
>  	for_each_cpu(cpu, to_cpumask(ii_dev->cpumask)) {
>  
> diff --git a/include/linux/idle_inject.h b/include/linux/idle_inject.h
> index a445cd1a36c5..e2b26b9ccd34 100644
> --- a/include/linux/idle_inject.h
> +++ b/include/linux/idle_inject.h
> @@ -26,4 +26,7 @@ void idle_inject_set_duration(struct idle_inject_device *ii_dev,
>  void idle_inject_get_duration(struct idle_inject_device *ii_dev,
>  				 unsigned int *run_duration_us,
>  				 unsigned int *idle_duration_us);
> +
> +void idle_inject_set_state(struct idle_inject_device *ii_dev, int state);
> +

The above function is not used in this patch and as such should be introduce as
part of future work.  Otherwise I agree that this patch does not carry any
functional changes.

Without function idle_inject_set_state():

Acked-by: Mathieu Poirier <mathieu.poirier@...aro.org> 

>  #endif /* __IDLE_INJECT_H__ */
> -- 
> 2.17.1
>