Re: [RFC PATCH v3 7/9] yield_to(), cpu-hotplug: Prevent offliningof other CPUs properly

From: Srivatsa S. Bhat
Date: Sun Dec 09 2012 - 23:06:45 EST


On 12/10/2012 02:10 AM, Oleg Nesterov wrote:
> On 12/10, Srivatsa S. Bhat wrote:
>>
>> On 12/10/2012 01:18 AM, Oleg Nesterov wrote:
>>>> - if (preempt && rq != p_rq)
>>>> + if (preempt && rq != p_rq && cpu_online(task_cpu(p)))
>>>
>>> Why do we need this change?
>>>
>>> Afaics, you could add BUG_ON(!cpu_online(...)) instead?
>>>
>>> I am just curious.
>>>
>>
>> Oh, I think that's a remnant of v1 (which needed readers to use
>> cpu_online_stable()). You're right, we don't need it.
>
> Ah OK, thanks.
>
>> Or we could put a
>> BUG_ON instead, like you suggested.
>
> IMHO it would be better to simply drop this chunk.
>

Sure, will drop it. Its distracting, if nothing else ;-)

Regards,
Srivatsa S. Bhat

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