Re: BUG #17448: In Windows 10, version 1703 and later, huge_pages doesn't work.

On Sun, Mar 27, 2022 at 12:07:57AM +1300, Thomas Munro wrote:
> Some question I have: is FILE_MAP_LARGE PAGES a macro?  We claim to
> support all those ancient zombie OSes like Windows 7, or maybe it's
> even XP for 11, and this has to be back-patched to 11, so we might
> need to make it conditional.  But conditional on what?  For example,
> does something like the attached work (untested)?  What happens if a <
> 1703 kernel sees this flag, does it reject it or ignore it?

Good question.  I would choose a soft approach here and not insist if
the flag was not known at compilation time, but we could also take a
more aggressive approach and hardcode a value.  Anyway, it seems to me
that the correct solution here would be to compile the code with a
PG_FILE_MAP_LARGE_PAGES that checks if the flag exists at compile
time, and we would set it at run time if we know that we are on a
version of Windows that supports it.  IsWindowsVersionOrGreater()
should be able to do the job.
--
Michael