Re: [PATCH 2/5] atomic: introduce atomic_inc_not_zero

[Nick Piggin]

Nick Piggin wrote:
> Roman Zippel wrote:
>
> > Hi,
> >
> > On Thu, 15 Sep 2005, Nick Piggin wrote:
> >
> >
> > > Also needs work on those same architectures. Other architectures
> > > might want to look at providing a more optimal implementation.
> >
> >
> >
> > IMO a rather pointless primitive, unless there is a cpu architecture 
> > which has a inc_not_zero instruction, otherwise it will always be the 
> > same as using cmpxchg.

[snip]

But even supposing the cmpxchg variant was the highest
performing implementation available on any architecture, I
would still consider exporting the inc_not_zero instruction.

The reason is that cmpxchg is not nearly so readable as
inc_not_zero when used inline in the code.

--
SUSE Labs, Novell Inc.

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