Re: [patch 134/149] x86, paravirt: Add a global synchronization point for pvclock

Jeremy Fitzhardinge
2010-07-14T18:15:50Z

On 07/14/2010 11:08 AM, H. Peter Anvin wrote:
> Noone has talked about strict ordering between volatiles and
> (non-volatile) memory ops in general. I have been talking about
> volatile to volatile ordering, and I thought I'd been very clear about that.
>

OK.

> H.J., we're having a debate about the actual semantics of "volatile",
> especially "asm volatile" in gcc. In particular, I believe that
> volatile operations should not be possible to reorder with regards to
> each other, and the kernel depends on that fact.
>

I think we should consider that deprecated and rely on dependencies and
clobbers.

J