linux-kernel - Re: [PATCH 14/21] cpuidle: coupled: don't compare cpu masks unnecessarily

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Date:	Thu, 26 Sep 2013 00:06:39 +0200
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Viresh Kumar <viresh.kumar@...aro.org>, rjw@...k.pl
CC:	linaro-kernel@...ts.linaro.org, patches@...aro.org,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	Colin Cross <ccross@...gle.com>
Subject: Re: [PATCH 14/21] cpuidle: coupled: don't compare cpu masks unnecessarily

On 09/22/2013 03:21 AM, Viresh Kumar wrote:
> In cpuidle_coupled_register_device() we do following:
> 	if (WARN_ON(!cpumask_equal(&dev->coupled_cpus, &coupled->coupled_cpus)))
> 		coupled->prevent++;
> 
> This is only required to be done when we are using 'coupled' from an existing
> cpuidle_device and not when we have just done this:
> 
> 	coupled->coupled_cpus = dev->coupled_cpus
> 
> So, move this compare statement to the right place.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>

Cc'ed Colin Cross.

> ---
>  drivers/cpuidle/coupled.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
> index e952936..19a89eb 100644
> --- a/drivers/cpuidle/coupled.c
> +++ b/drivers/cpuidle/coupled.c
> @@ -642,6 +642,10 @@ int cpuidle_coupled_register_device(struct cpuidle_device *dev)
>  		other_dev = per_cpu(cpuidle_devices, cpu);
>  		if (other_dev && other_dev->coupled) {
>  			coupled = other_dev->coupled;
> +
> +			if (WARN_ON(!cpumask_equal(&dev->coupled_cpus,
> +						&coupled->coupled_cpus)))
> +				coupled->prevent++;
>  			goto have_coupled;
>  		}
>  	}
> @@ -655,9 +659,6 @@ int cpuidle_coupled_register_device(struct cpuidle_device *dev)
>  
>  have_coupled:
>  	dev->coupled = coupled;
> -	if (WARN_ON(!cpumask_equal(&dev->coupled_cpus, &coupled->coupled_cpus)))
> -		coupled->prevent++;
> -
>  	cpuidle_coupled_update_online_cpus(coupled);
>  
>  	coupled->refcnt++;
> 


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