linux-kernel - Re: [PATCH V3 4/6] cpuidle: idle: menu: Don't reflect when a state selection failed

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Date:	Sat, 08 Nov 2014 16:11:55 +0530
From:	Preeti U Murthy <preeti@...ux.vnet.ibm.com>
To:	Daniel Lezcano <daniel.lezcano@...aro.org>, rjw@...ysocki.net
CC:	nicolas.pitre@...aro.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, peterz@...radead.org,
	linaro-kernel@...ts.linaro.org, patches@...aro.org, lenb@...nel.org
Subject: Re: [PATCH V3 4/6] cpuidle: idle: menu: Don't reflect when a state
 selection failed

On 11/07/2014 08:01 PM, Daniel Lezcano wrote:
> In the current code, the check to reflect or not the outcoming state is done
> against the idle state which has been chosen and its value.
> 
> Instead of doing a check in each of the reflect functions, just don't call reflect
> if something went wrong in the idle path.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
> Acked-by: Nicolas Pitre <nico@...aro.org>
> ---
>  drivers/cpuidle/governors/ladder.c | 3 +--
>  drivers/cpuidle/governors/menu.c   | 3 +--
>  kernel/sched/idle.c                | 3 ++-
>  3 files changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
> index 51c9ccd..86e4d49 100644
> --- a/drivers/cpuidle/governors/ladder.c
> +++ b/drivers/cpuidle/governors/ladder.c
> @@ -165,8 +165,7 @@ static int ladder_enable_device(struct cpuidle_driver *drv,
>  static void ladder_reflect(struct cpuidle_device *dev, int index)
>  {
>  	struct ladder_device *ldev = this_cpu_ptr(&ladder_devices);
> -	if (index > 0)
> -		ldev->last_state_idx = index;
> +	ldev->last_state_idx = index;
>  }
> 
>  static struct cpuidle_governor ladder_governor = {
> diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
> index 91b3000..2e4a315 100644
> --- a/drivers/cpuidle/governors/menu.c
> +++ b/drivers/cpuidle/governors/menu.c
> @@ -366,8 +366,7 @@ static void menu_reflect(struct cpuidle_device *dev, int index)
>  {
>  	struct menu_device *data = this_cpu_ptr(&menu_devices);
>  	data->last_state_idx = index;
> -	if (index >= 0)
> -		data->needs_update = 1;
> +	data->needs_update = 1;
>  }
> 
>  /**
> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> index 0a7a1d1..0ae1cc8 100644
> --- a/kernel/sched/idle.c
> +++ b/kernel/sched/idle.c
> @@ -173,7 +173,8 @@ use_default:
>  	/*
>  	 * Give the governor an opportunity to reflect on the outcome
>  	 */
> -	cpuidle_reflect(dev, entered_state);
> +	if (entered_state >= 0)
> +		cpuidle_reflect(dev, entered_state);
> 
>  exit_idle:
>  	__current_set_polling();
> 
Reviewed-by: Preeti U. Murthy <preeti@...ux.vnet.ibm.com>

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