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Date: Tue, 03 Mar 2009 16:54:33 +0800
From: Li Zefan <lizf@cn.fujitsu.com>
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To: Paul Menage <menage@google.com>
CC: Linux Containers <containers@lists.linux-foundation.org>,
       Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Andrew Morton <akpm@linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Allow cpusets to be configured/built on non-SMP systems
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Li Zefan wrote:
> Paul Menage wrote:
>> On Mon, Mar 2, 2009 at 10:01 PM, Paul Menage <menage@google.com> wrote:
>>> On Mon, Mar 2, 2009 at 7:17 PM, Li Zefan <lizf@cn.fujitsu.com> wrote:
>>>>> +static int generate_sched_domains(struct cpumask **domains,
>>>>> +                     struct sched_domain_attr **attributes)
>>>>> +{
>>>> Except here should "return 0;", otherwise emit a compile warining.
>>>>
>>> Good catch - the weird thing is that (in my UML build) it doesn't
>>> actually generate that warning. Mysterious.
>>>
>>> I'll resend with the extra return.
>> After looking at the sched domains code it's not clear to me that
>> returning 0 is necessarily the right thing to do -
>> partition_sched_domains() says that 0 is a special case used for
>> destroying existing domains? Would returning 1 and setting up a single
>> dummy domain be better?
>>
> 

partition_sched_domains() says (0, NULL, ...) is used for destroying existing
domains, (1, NULL, ...) will fallback to the single default domain.

But partition_sched_domains() is a stub if !CONFIG_SMP

> Yes, return 1 seems more reasonable. And if we do this, should we also set
> *domains to NULL like this?
> 
> static int generate_sched_domains(struct cpumask **domains,
>                      struct sched_domain_attr **attributes)
> {
> 	*domains = NULL;
> 	return 1;
> }
>