Re: [PATCH] Document Linux's memory barriers

Jesse Barnes
2006-03-07T20:01:37Z

On Tuesday, March 7, 2006 3:57 am, Andi Kleen wrote:
> On Tuesday 07 March 2006 20:23, Bryan O'Sullivan wrote:
> > On Tue, 2006-03-07 at 18:30 +0000, David Howells wrote:
> > > True, I suppose. I should make it clear that these accessor
> > > functions imply memory barriers, if indeed they do,
> >
> > They don't, but according to Documentation/DocBook/deviceiobook.tmpl
> > they are performed by the compiler in the order specified.
>
> I don't think that's correct. Probably the documentation should
> be fixed.

On ia64 I'm pretty sure it's true, and it seems like it should be in the
general case too. The compiler shouldn't reorder uncached memory
accesses with volatile semantics...

Jesse