Re: Overview of concurrency managed workqueue

From: Tejun Heo
Date: Sat Jun 19 2010 - 04:41:28 EST


On 06/19/2010 10:38 AM, Andi Kleen wrote:
> Andy Walls <awalls@xxxxxxxxxxxxxxxx> writes:
>>
>> I'm going to agree with Tejun, that tweaking worker thread priorities
>> seems like an odd thing, since they are meant to handle deferable
>> actions - things that can be put off until later.
>
>> If one needs to support Real Time deadlines on deferable actions,
>> wouldn't using dedicated kernel threads be more deterministic?
>> Would the user ever up the priority for a workqueue other than a
>> single-threaded workqueue?
>
> One exceptional case here are things like high priority error handling
> which is rare.
>
> For example you get an MCE that tells you some of your
> memory got corrupted and you should handle it ASAP.
> Better give it high priority then.
>
> But it's still a rare event so you don't want dedicated
> threads hanging around for it all time
> (that's what we currently have and it causes all sorts
> of problems)
>
> So yes I think having a priority mechanism for work items
> is useful.

Wouldn't that be better served by cpu_stop?

Thanks.

--
tejun
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