Re: BUG #15844: MIPS: remove .set mips2 in s_lock.h to fix r6 build

Andres Freund <andres(at)anarazel(dot)de> writes:
> I think we're pretty much at the point where we should just rip out all
> of our own spinlock implementations for non-common platforms, and solely
> rely on compiler intrinsics... The open coded ASM really doesn't age
> very well, and there's very little chance of us actually testing them
> properly.

It's completely not true that this code isn't tested; we have two
different MIPS buildfarm machines that surely exercise spinlocks plenty.

(There's a separate argument to be had about whether we should drop
source-code support for platforms that aren't represented in the
buildfarm. I'm not inclined to, but you could tenably hold that
position.)

As for compiler intrinsics, I dunno. I don't have very much faith in
the quality of those for non-mainstream platforms, either --- see
https://www.postgresql.org/message-id/flat/25414.1483076673%40sss.pgh.pa.us
for a not-too-old example. And a lot of platforms like this are running
pretty old compilers, so even if the problems have been fixed it'll be a
long time before we can depend on that.

regards, tom lane