Remove PG_MMAP_FLAGS

Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>

From: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>

To: pgsql-hackers <pgsql-hackers@postgresql.org>, Peter Eisentraut <peter@eisentraut.org>

Date: 2026-01-22T17:22:08Z

Lists: pgsql-hackers

Attachments

v20260112-0001-Fix-PGShmemType-and-HugePagesType-typedefs.patch (text/x-patch) patch v20260112-0001

Hi,
Over [1] Peter mentioned that PG_MMAP_FLAGS is not used for
portability even though it's placed in portability/mem.h. That might
have been the intention when it was added in
b0fc0df9364d2d2d17c0162cf3b8b59f6cb09f67. But history does not show it
being used that way at any point in time. Per suggestion removing that
macro and instead using the flags directly in CreateAnonymousSegment()
which is the only place where it's used.

PFA patch for the same.

-- 
Best Wishes,
Ashutosh Bapat

Commits

Remove PG_MMAP_FLAGS from mem.h
- c100340729b6 19 (unreleased) landed
Dramatically reduce System V shared memory consumption.
- b0fc0df9364d 9.3.0 cited