Re: um: this_cpu_cmpxchg16b_emu

From: Tejun Heo
Date: Tue Apr 12 2011 - 15:20:28 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...

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?


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at