Andres Freund <andres@anarazel.de> writes:
> On 2023-10-20 15:59:42 -0400, Tom Lane wrote:
>> Hmm, are you saying there's more of port/atomics/ that could be
>> removed? What exactly?
> I was thinking we could remove the whole fallback path for atomic operations,
> but it's a bit less, because we likely don't want to mandate support for 64bit
> atomics yet.
Yeah. That'd be tantamount to desupporting 32-bit arches altogether,
I think. I'm not ready to go there yet.
> That'd still allow removing more than half of
> src/include/port/atomics/fallback.h and src/backend/port/atomics.c - and more
> if we finally decided to require a spinlock implementation.
In the wake of 1c72d82c2, it seems likely that requiring some kind of
spinlock implementation is not such a big lift. Certainly, a machine
without that hasn't been a fit target for production in a very long
time, so maybe we should just drop that semaphore-based emulation.
>> Do we really want to assume that all future architectures will have atomic
>> operations?
> Yes. Outside of the tiny microcontrollers, which obviously won't run postgres,
> I cannot see any future architecture not having support for atomic operations.
I'd like to refine what that means a bit more. Are we assuming that
a machine providing any of the gcc atomic intrinsics (of a given
width) will provide all of them? Or is there a specific subset that
we can emulate the rest on top of?
regards, tom lane