Re: [PATCH 2/3] tools/memory-model: Refactor some RCU relations

[Alan Stern]

On Fri, 16 Nov 2018, Boqun Feng wrote:

> > -let rcu-rscsi = po ; rcu-rscs^-1 ; po?
> > +let rcu-gp = [Sync-rcu]		(* Compare with gp *)
> > +let rcu-rscsi = rcu-rscs^-1
> 
> Isn't it more straight-forward to use "rcu-rscs^-1" other than
> "rcu-rscsi" in the definition of "rcu-fence", is it?

It's a matter of personal preference.  I prefer to store the inverse
relation in a separate variable rather than recomputing it multiple
times.  (Maybe OCaml is smart enough to recognize when a value has 
already been computed and avoid computing it again; I don't know.)

> The introduction of "rcu-rscsi" makes sense in the first patch, but with
> this refactoring, I think it's better we just don't use it.

In the end this probably doesn't make much difference.

Alan