Re: [PATCH 01/10] cpumask: Introduce cpumask_any_online_but

From: Vikas Shivappa <vikas.shivappa@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Vikas Shivappa <vikas.shivappa@linux.intel.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com,
	mingo@kernel.org, Matt Fleming <matt.fleming@intel.com>,
	"Juvva, Kanaka D" <kanaka.d.juvva@intel.com>,
	"Williamson, Glenn P" <glenn.p.williamson@intel.com>,
	"Auld, Will" <will.auld@intel.com>
Subject: Re: [PATCH 01/10] cpumask: Introduce cpumask_any_online_but
Date: Tue, 16 Jun 2015 12:00:46 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.10.1506161129140.32420@vshiva-Udesk> (raw)
In-Reply-To: <alpine.DEB.2.11.1506161018210.4120@nanos>

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
>