Re: [PATCH v2] tools/memory-model: Add extra ordering for locks and remove it for ordinary release/acquire

Andrea Parri
2018-07-12T21:13:59Z

On Thu, Jul 12, 2018 at 04:43:46PM -0400, Alan Stern wrote:
> On Thu, 12 Jul 2018, Andrea Parri wrote:
>
> > > It seems reasonable to ask people to learn that locks have stronger
> > > ordering guarantees than RMW atomics do. Maybe not the greatest
> > > situation in the world, but one I think we could live with.
> >
> > Yeah, this was one of my main objections.
>
> Does this mean you don't think you could live with it?

Well, I *could* leave with it and with RCtso locks, ;-) but I'd rather not.

Assuming that I will not be able to resist this RCtso trend, ;-) would the
below (completely untested) work?

let rmw = rmw | lk-rmw (* from lock.cat *)
let po-unlock-rf-lock-po = po ; [Release] ; rf ; [domain(rmw)] ; po
[the rest of your patch + the updates to the doc. I suggested in v2 ;-)]

Andrea