On Fri, 3 Mar 2006, David Howells wrote: > > I suspect, then, that x86_64 should not have an SFENCE for smp_wmb(), and that > only io_wmb() should have that. Indeed. I think smp_wmb() should be a compiler fence only on x86(-64), ie just compile to a "barrier()" (and not even that on UP, of course). Linus