Re: Synchronizing Bit operations V2

From: Andi Kleen
Date: Fri Mar 31 2006 - 12:46:09 EST


On Friday 31 March 2006 19:45, Christoph Lameter wrote:
> On Fri, 31 Mar 2006, Andi Kleen wrote:
>
> > Christoph Lameter <clameter@xxxxxxx> writes:
> > > MODE_BARRIER
> > > An atomic operation that is guaranteed to occur between
> > > previous and later memory operations.
> > I think it's a bad idea to create such an complicated interface.
> > The chances that an average kernel coder will get these right are
> > quite small. And it will be 100% untested outside IA64 I guess
> > and thus likely be always slightly buggy as kernel code continues
> > to change.
>
> Powerpc can do similar things AFAIK. Not sure what other arches have
> finer grained control over barriers but it could cover a lot of special
> cases for other processors as well.

Yes, but I don't think the goal of a portable atomic operations API
in Linux is it to cover everybody's special case in every possible
combination. The goal is to have an abstraction that will lead to
portable code. I don't think your proposal will do this.

-Andi
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