Re: Spinlocks and semaphores in 9.2 and 9.3

I wrote:
> So at this point I'm not sure what to do. I could back out the back-patch
> of 44cd47c1d49655c5, which would mean accepting that 9.2/9.3 are broken
> and will never be fixed for HPPA, as well as any other architectures that
> use the same fallback memory barrier implementation. The lack of
> complaints from the field suggests that nobody would care. Or I could
> push forward by back-patching daa7527afc227443 (and a couple of minor
> follow-on cleanups). That doesn't seem particularly risky, now that
> 9.4's been out for awhile, but it's kind of a large back-patch to benefit
> architectures that apparently no actual users care about.

I went ahead and prepared and tested such a patch; the version for 9.3
is attached. (9.2 is identical modulo some pgindent-induced whitespace
difference.) This doesn't look too hazardous to me, so I'm thinking
we should apply it.

regards, tom lane