Re: [PATCH 2/4] sched: implement __set_cpus_allowed()

[Tejun Heo]

On 05/31/2010 12:02 PM, Peter Zijlstra wrote:
> On Mon, 2010-05-31 at 12:01 +0200, Peter Zijlstra wrote:
>>>  but we can update cpu_active mask before other
>>> CPU_UP_PREPARE notifiers are executed so that it's symmetrical to cpu
>>> down path and then this problem goes away the exact same way, right?
>>
>> Ah, no, we cannot mark it active before its actually up, because at that
>> time we'll actually try and run stuff on it, which clearly won't work
>> when its not there to run stuff. 
> 
> So we should clear it _before_ we go down, and set it _after_ we're up.
> 

Yeah, sure, I misspoke.  I meant CPU_ONLINE not CPU_UP_PREPARE.  So,
we can mark a cpu active before other CPU_ONLINE callbacks are run.

Thanks.

-- 
tejun
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