Re: um: this_cpu_cmpxchg16b_emu

From: Pekka Enberg
Date: Tue Apr 12 2011 - 15:22:52 EST


On Tue, Apr 12, 2011 at 08:41:11PM +0200, Richard Weinberger wrote:
>> Am Dienstag 12 April 2011, 20:10:37 schrieb Christoph Lameter:
>> > On Tue, 12 Apr 2011, Richard Weinberger wrote:
>> > > This patch implements this_cpu_cmpxchg16b_emu() for UML.
>> >
>> > Is this really necessary? Just undefine CONFIG_CMPXCHG_LOCAL for UML and
>> > the asm code will not be used.
>>
>> UML includes arch/x86/Kconfig.cpu which defines CONFIG_CMPXCHG_LOCAL automatically.
>> Just disabling CONFIG_CMPXCHG_LOCAL for UML is IMHO not very nice.
>> When chpxchg is available also UML should use it...

On Tue, Apr 12, 2011 at 10:20 PM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Ugh... I'd really like to avoid things like this for UML.  Is there
> any SLUB performance sensitive workload running on UML?  I've never
> seen any UML in production environment.  Wouldn't it be better to keep
> things simple?

Yes, it would be. :-)
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