Re: [PATCH] Fix ARM64/MSVC atomic memory ordering issues on Win11 by adding explicit DMB ?barriers

Nathan Bossart <nathandbossart@gmail.com>

From: Nathan Bossart <nathandbossart@gmail.com>

To: Greg Burd <greg@burd.me>

Cc: Andres Freund <andres@anarazel.de>, Thomas Munro <thomas.munro@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Peter Eisentraut <peter@eisentraut.org>, Dave Cramer <davecramer@gmail.com>

Date: 2025-12-16T21:40:45Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

MSVC: Support building for AArch64.
- a516b3f00d74 19 (unreleased) landed

Attachments

v13-0001-Add-support-for-building-with-MSVC-for-AArch64.patch (text/plain)

Sorry for the noise.

I discovered that this patch originated in another thread [0], so I spent
some time updating the attributions.  Please let me know if there are any
inaccuracies.

On Tue, Dec 16, 2025 at 12:07:34PM -0600, Nathan Bossart wrote:
> Here's what I have staged for commit.  I searched around for anything else
> that might be missing, and I only found a couple of small things.  First,
> there are some optional AArch64 optimizations (simd.h and popcount) that
> likely need more work, but those can wait for now.

Hm.  I think the USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER thing might need
work, too.  We don't have any Windows buildfarm machines with LLVM enabled,
but IIUC it should be possible.  Perhaps we can add that to unicorn.

> Also, while the patch
> is targeting Windows 11 (IIUC), there are some notes in the docs that give
> the impression Windows 10 is supported, too [0].  I could easily change it
> to say that AArch64 requires Windows 11, but I don't know what to do with
> the references to specific versions of Visual Studio and the Windows SDK.

Actually, I'm not sure there's anything specific to Windows 11 in this
patch, besides perhaps the choice to set USE_ARMV8_CRC32C unconditionally.
I don't know how likely it is that someone will try to run Postgres on
Windows on an AArch64 machine without CRC extension support, though.

[0] https://postgr.es/m/CAFPTBD-74%2BAEuN9n7caJ0YUnW5A0r-KBX8rYoEJWqFPgLKpzdg%40mail.gmail.com

-- 
nathan