linux-kernel - Re: [RFC PATCH 2/3] cpuidle: move the cpuidle_idle

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Message-ID: <alpine.LFD.2.11.1401301442240.1652@knanqh.ubzr>
Date:	Thu, 30 Jan 2014 14:42:57 -0500 (EST)
From:	Nicolas Pitre <nicolas.pitre@...aro.org>
To:	Daniel Lezcano <daniel.lezcano@...aro.org>
cc:	peterz@...radead.org, mingo@...hat.com, tglx@...utronix.de,
	rjw@...ysocki.net, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org, linaro-kernel@...ts.linaro.org
Subject: Re: [RFC PATCH 2/3] cpuidle: move the cpuidle_idle_call function to
 idle.c

On Thu, 30 Jan 2014, Daniel Lezcano wrote:

> Now the cpuidle_idle_call does nothing more than calling the three individuals
> function, we can move this function into the idle task code to ensure better
> proximity to the scheduler code.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>

Acked-by: Nicolas Pitre <nico@...aro.org>

> ---
>  drivers/cpuidle/cpuidle.c |   37 -------------------------------------
>  include/linux/cpuidle.h   |    2 --
>  kernel/sched/idle.c       |   44 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 44 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index a8fbb28..a039344 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -176,43 +176,6 @@ void cpuidle_reflect(struct cpuidle_device *dev, int index)
>  EXPORT_SYMBOL(cpuidle_reflect);
>  
>  /**
> - * cpuidle_idle_call - the main idle loop
> - *
> - * NOTE: no locks or semaphores should be used here
> - * return non-zero on failure
> - */
> -int cpuidle_idle_call(void)
> -{
> -	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
> -	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
> -	int next_state, entered_state;
> -
> -	/* ask the governor for the next state */
> -	next_state = cpuidle_select(drv, dev);
> -	if (next_state < 0)
> -		return next_state;
> -
> -	if (need_resched()) {
> -		dev->last_residency = 0;
> -		/* give the governor an opportunity to reflect on the outcome */
> -		cpuidle_reflect(dev, next_state);
> -		local_irq_enable();
> -		return 0;
> -	}
> -
> -	trace_cpu_idle_rcuidle(next_state, dev->cpu);
> -
> -	entered_state = cpuidle_enter(drv, dev, next_state);
> -
> -	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
> -
> -	/* give the governor an opportunity to reflect on the outcome */
> -	cpuidle_reflect(dev, entered_state);
> -
> -	return 0;
> -}
> -
> -/**
>   * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
>   */
>  void cpuidle_install_idle_handler(void)
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index 1ebe9ff..74cdfc9 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -126,7 +126,6 @@ extern int cpuidle_enter(struct cpuidle_driver *drv,
>  			 struct cpuidle_device *dev, int index);
>  extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
>  
> -extern int cpuidle_idle_call(void);
>  extern int cpuidle_register_driver(struct cpuidle_driver *drv);
>  extern struct cpuidle_driver *cpuidle_get_driver(void);
>  extern struct cpuidle_driver *cpuidle_driver_ref(void);
> @@ -148,7 +147,6 @@ extern int cpuidle_play_dead(void);
>  extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
>  #else
>  static inline void disable_cpuidle(void) { }
> -static inline int cpuidle_idle_call(void) { return -ENODEV; }
>  static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
>  {return -ENODEV; }
>  static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> index 65d0427..3e85d38 100644
> --- a/kernel/sched/idle.c
> +++ b/kernel/sched/idle.c
> @@ -62,6 +62,50 @@ void __weak arch_cpu_idle(void)
>  	local_irq_enable();
>  }
>  
> +#ifdef CONFIG_CPU_IDLE
> +/**
> + * cpuidle_idle_call - the main idle function
> + *
> + * NOTE: no locks or semaphores should be used here
> + * return non-zero on failure
> + */
> +static int cpuidle_idle_call(void)
> +{
> +	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
> +	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
> +	int next_state, entered_state;
> +
> +	/* ask the governor for the next state */
> +	next_state = cpuidle_select(drv, dev);
> +	if (next_state < 0)
> +		return next_state;
> +
> +	if (need_resched()) {
> +		dev->last_residency = 0;
> +		/* give the governor an opportunity to reflect on the outcome */
> +		cpuidle_reflect(dev, next_state);
> +		local_irq_enable();
> +		return 0;
> +	}
> +
> +	trace_cpu_idle_rcuidle(next_state, dev->cpu);
> +
> +	entered_state = cpuidle_enter(drv, dev, next_state);
> +
> +	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
> +
> +	/* give the governor an opportunity to reflect on the outcome */
> +	cpuidle_reflect(dev, entered_state);
> +
> +	return 0;
> +}
> +#else
> +static inline int cpuidle_idle_call(void)
> +{
> +	return -ENODEV;
> +}
> +#endif
> +
>  /*
>   * Generic idle loop implementation
>   */
> -- 
> 1.7.9.5
> 
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