linux-kernel - Re: [PATCH V2 4/5] idle: Move idle conditions in cpuidle

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Date:	Mon, 24 Feb 2014 16:39:08 +0100
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	mingo@...nel.org, tglx@...utronix.de, rjw@...ysocki.net,
	nicolas.pitre@...aro.org, preeti@...ux.vnet.ibm.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 4/5] idle: Move idle conditions in cpuidle_idle main
 function

On 02/24/2014 03:59 PM, Peter Zijlstra wrote:
> On Mon, Feb 24, 2014 at 02:55:50PM +0100, Daniel Lezcano wrote:
>> @@ -136,25 +155,8 @@ static void cpu_idle_loop(void)
>>   			local_irq_disable();
>>   			arch_cpu_idle_enter();
>>
>> -			/*
>> -			 * In poll mode we reenable interrupts and spin.
>> -			 *
>> -			 * Also if we detected in the wakeup from idle
>> -			 * path that the tick broadcast device expired
>> -			 * for us, we don't want to go deep idle as we
>> -			 * know that the IPI is going to arrive right
>> -			 * away
>> -			 */
>> -			if (cpu_idle_force_poll || tick_check_broadcast_expired()) {
>> -				cpu_idle_poll();
>> -			} else {
>> -				if (!current_clr_polling_and_test()) {
>> -					cpuidle_idle_call();
>> -				} else {
>> -					local_irq_enable();
>> -				}
>> -				__current_set_polling();
>> -			}
>> +			cpuidle_idle_call();
>> +
>
> Yeah, not liking that much; you can make it look like:
>
> 	if (cpu_idle_force_poll || tick_check_broadcast_expired())
> 		cpu_idle_poll();
> 	else
> 		cpu_idle_call();
>
> Though. That keeps the polling case separate from the actual idle
> function.

Yes, you are right, it looks better.

> And when you do that; you can also push down the
> current_clr_polling_and_test() muck so it doesn't cover the actual
> cpuidle policy code.

I am not getting it. Where do you suggest to move it ?

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