linux-kernel - Re: [PATCH 01/10] cpumask: Introduce cpumask_any_online

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Message-ID: <alpine.DEB.2.10.1506161129140.32420@vshiva-Udesk>
Date:	Tue, 16 Jun 2015 12:00:46 -0700 (PDT)
From:	Vikas Shivappa <vikas.shivappa@...el.com>
To:	Thomas Gleixner <tglx@...utronix.de>
cc:	Vikas Shivappa <vikas.shivappa@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Vikas Shivappa <vikas.shivappa@...ux.intel.com>,
	linux-kernel@...r.kernel.org, x86@...nel.org, hpa@...or.com,
	mingo@...nel.org, Matt Fleming <matt.fleming@...el.com>,
	"Juvva, Kanaka D" <kanaka.d.juvva@...el.com>,
	"Williamson, Glenn P" <glenn.p.williamson@...el.com>,
	"Auld, Will" <will.auld@...el.com>
Subject: Re: [PATCH 01/10] cpumask: Introduce cpumask_any_online_but



On Tue, 16 Jun 2015, Thomas Gleixner wrote:

> On Mon, 15 Jun 2015, Vikas Shivappa wrote:
>> On Mon, 15 Jun 2015, Peter Zijlstra wrote:
>>> On Fri, Jun 12, 2015 at 11:17:08AM -0700, Vikas Shivappa wrote:
>>>> +	cpumask_and(&tmp, cpu_online_mask, mask);
>>>> +	cpumask_clear_cpu(cpu, &tmp);
>>>> +	return cpumask_any(&tmp);
>>>> +}
>>>
>>> You had a good example in cpumask_any_but() copy that.
>>
>> I saw the cpumask_any_but but wanted to avoid the for loop in the
>> cpumask_any_but , but now i see why from your previous comment. Without the
>> cpumask_t I will have to use the cpumask_any_but .. the two were related.
>
> It can be done w/o a loop. Hint, you need a static cpumask in your
> code anyway.

Ah thats right, I always need the tmp mask. Confused this with 
avoiding the cpumask_clear_cpu line in the code vs. using cpumask_any_but.

something like this just making it static then ?

 	static cpumask_t tmp;

 	cpumask_and(&tmp, cpu_online_mask, mask);
 	cpumask_clear_cpu(cpu, &tmp);
 	return cpumask_any(&tmp);

Thanks,
Vikas

>
> Thanks
>
> 	tglx
>
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