Re: [patch 2/5] mutex subsystem: add architecture specific mutexprimitives

[Nick Piggin]

Nick Piggin wrote:

> I think ARMv6 has a decent atomic_cmpxchg implementation but does
> not define __HAVE_ARCH_CMPXCHG. It might be useful to try to use this
> for ARMv6 SMP for a slightly better trylock.

And on UP builds, it may simply be best to open code an interrupt unsafe
cmpxchg and use atomic_cmpxchg unconditionally on SMP builds (which I
think generates half decent code on all SMP architectures).

Just something to think about. Of course this will require the dreaded
preempt_disable() which might make it a showstopper.

--
SUSE Labs, Novell Inc.

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