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help / color / mirror / Atom feedFrom: Julien Rouhaud <[email protected]>
To: Michael Paquier <[email protected]>
Cc: Thomas Munro <[email protected]>
Cc: [email protected]
Cc: PostgreSQL mailing lists <[email protected]>
Subject: Re: BUG #17448: In Windows 10, version 1703 and later, huge_pages doesn't work.
Date: Thu, 31 Mar 2022 18:46:59 +0800
Message-ID: <20220331104659.ol6pqe7s3tpkymuk@jrouhaud> (raw)
In-Reply-To: <20220331080055.hjrrsrd4lxwlt7f5@jrouhaud>
References: <[email protected]>
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On Thu, Mar 31, 2022 at 04:00:55PM +0800, Julien Rouhaud wrote:
> > Okano-san has mentioned VMMap upthread:
> > https://docs.microsoft.com/en-us/sysinternals/downloads/vmmap
>
> Yes, I totally missed that. Thomas Munro also mentioned it off-list, and
> also found some reference [1] indicating that large pages should show up as
> "Locked WS". I tested with and without the patch and in both case I don't see
> any "Locked WS" usage. I also get the same Page Table size, which seems
> consistent with large pages not being used. Now, this is a vm running with
> virtualbox and we're not entirely sure that huge pages can be allocated with
> it. I wish I could test on my windows 10 machine as it's not virtualized, but
> I can't give the required privileges.
>
> [1] https://aloiskraus.wordpress.com/2016/10/03/windows-10-memory-compression-and-more/
So, after more digging it turns out that the patch is supposed to work. If I
force using the PG_FILE_MAP_LARGE_PAGES, postgres starts and I do see "Locked
WS" usage with VMMap, with a size in the order of magnitude of my
shared_buffers.
What is apparently not working on my VM is IsWindowsVersionOrGreater(10, 0,
1703). I added some debug around to check what GetVersionEx() [2] is saying,
and I get:
dwMajorVersion == 6
dwMinorVersion == 2
dwBuildNumber == 9200
While winver.exe on the same vm says windows 11, version 21H2, build 22000.493.
I'm therefore extremely confused. The documentation of
IsWindowsVersionOrGreater() at [3] is also highly confusing:
> TRUE if the specified version matches, or is greater than, the version of the
> current Windows OS; otherwise, FALSE.
Isn't that supposed to be the opposite?
[2] https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getversionexa
https://docs.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-osversioninfoexa
[3] https://docs.microsoft.com/en-us/windows/win32/api/versionhelpers/nf-versionhelpers-iswindowsversion...
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To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected]
Subject: Re: BUG #17448: In Windows 10, version 1703 and later, huge_pages doesn't work.
In-Reply-To: <20220331104659.ol6pqe7s3tpkymuk@jrouhaud>
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