Re: fix more casting away of qualifiers

On 19.10.26 13:55, Andres Freund wrote:
> I don't think the volatiles moved into PMSignalData are particularly
> useful. They're precisely one of the cases where volatile is just pretending
> to do things correctly.

> Tom, is there any reason this doesn't use barriers? I assume it's just
> because the code is "too old"?

I played around with this a little bit. Using memory barriers here
makes for very difficult to follow code, because the interacting parts
are spread over a bunch of different functions, and so you don't get the
idiomatic

do one thing
barrier
do another thing

code.

If we're going to touch it, would it better to try to write this with
atomics (with barrier semantics, as appropriate)? What is the current
thinking on whether the barrier macros or atomics should be used?