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Fix huge_pages on Windows

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Since Windows 10 1703, it is additionally necessary to pass a flag
called FILE_MAP_LARGE_PAGES to MapViewOfFile() to enable large pages at
map time.  This flag is ignored on older versions of Windows, where
large pages should still be able to work properly without setting it.
Note that the flag would be set only for binaries that knew about it at
compile-time, which should be more or less all the Windows environments
these days.

Since 495ed0e, Windows 10 is the minimum version of Windows supported by
Postgres, making this change easy to reason about on HEAD.  Per
discussion, no backpatch is done for the moment.

Reported-by: Okano Naoki
Author: Thomas Munro
Reviewed-by: Tom Lane, Michael Paquier, Julien Rouhaud
Discussion: https://postgr.es/m/17448-0a96583a67edb1f7@postgresql.org
This commit is contained in:
Michael Paquier 2022-09-17 15:39:55 +09:00
parent a0b65155d0
commit fdd8937c07
1 changed files with 9 additions and 1 deletions
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10
src/backend/port/win32_shmem.c
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@ -218,6 +218,7 @@ PGSharedMemoryCreate(Size size,
SIZE_T largePageSize = 0;
Size orig_size = size;
DWORD flProtect = PAGE_READWRITE;
DWORD desiredAccess;
ShmemProtectiveRegion = VirtualAlloc(NULL, PROTECTIVE_REGION_SIZE,
MEM_RESERVE, PAGE_NOACCESS);
@ -355,12 +356,19 @@ retry:
if (!CloseHandle(hmap))
elog(LOG, "could not close handle to shared memory: error code %lu", GetLastError());
desiredAccess = FILE_MAP_WRITE | FILE_MAP_READ;
#ifdef FILE_MAP_LARGE_PAGES
/* Set large pages if wanted. */
if ((flProtect & SEC_LARGE_PAGES) != 0)
desiredAccess |= FILE_MAP_LARGE_PAGES;
#endif
/*
* Get a pointer to the new shared memory segment. Map the whole segment
* at once, and let the system decide on the initial address.
*/
memAddress = MapViewOfFileEx(hmap2, FILE_MAP_WRITE | FILE_MAP_READ, 0, 0, 0, NULL);
memAddress = MapViewOfFileEx(hmap2, desiredAccess, 0, 0, 0, NULL);
if (!memAddress)
ereport(FATAL,
(errmsg("could not create shared memory segment: error code %lu", GetLastError()),