linux-kernel - Re: [PATCH 10/21] cpuidle: reduce code duplication inside cpuidle_idle

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Message-ID: <52435D2A.1000907@linaro.org>
Date:	Thu, 26 Sep 2013 00:01:14 +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
Subject: Re: [PATCH 10/21] cpuidle: reduce code duplication inside cpuidle_idle_call()

On 09/22/2013 03:21 AM, Viresh Kumar wrote:
> We are doing this twice in cpuidle_idle_call() routine:
> 	drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP
> 
> Would be better if we actually store this in a local variable and use that. That
> would remove code duplication as well as make this piece of code run fast (in
> case compiler wasn't able to optimize it earlier)
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>

Acked-by: Daniel Lezcano <daniel.lezcano@...aro.org>

> ---
>  drivers/cpuidle/cpuidle.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index b8c63cb..ed67e3c 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -118,6 +118,7 @@ int cpuidle_idle_call(void)
>  	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
>  	struct cpuidle_driver *drv;
>  	int next_state, entered_state;
> +	bool broadcast;
>  
>  	if (cpuidle_disabled() || !initialized)
>  		return -ENODEV;
> @@ -141,7 +142,9 @@ int cpuidle_idle_call(void)
>  
>  	trace_cpu_idle_rcuidle(next_state, dev->cpu);
>  
> -	if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
> +	broadcast = drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP;
> +
> +	if (broadcast)
>  		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
>  				   &dev->cpu);
>  
> @@ -151,7 +154,7 @@ int cpuidle_idle_call(void)
>  	else
>  		entered_state = cpuidle_enter_state(dev, drv, next_state);
>  
> -	if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
> +	if (broadcast)
>  		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
>  				   &dev->cpu);
>  
> 


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