Remove PG_MMAP_FLAGS from mem.h

Based on name of the macro, it was implied that it could be used for all
mmap() calls on portability grounds.  However, its use is limited to
sysv_shmem.c, for CreateAnonymousSegment().  This commit removes the
declaration, reducing the confusion around it as a portability tweak,
being limited to SysV-style shared memory.

This macro has been introduced in b0fc0df9364d for sysv_shmem.c,
originally.  It has been moved to mem.h in 0ac5e5a7e152 a bit later.

Suggested by: Peter Eisentraut <peter@eisentraut.org>
Author: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://postgr.es/m/CAExHW5vTWABxuM5fbQcFkGuTLwaxuZDEE2vtx2WuMUWk6JnF4g@mail.gmail.com
Discussion: https://postgr.es/m/12add41a-7625-4639-a394-a5563e349322@eisentraut.org

diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c
index 5239b6acbbc9f90a05b9d395fadfaa65783121a4..3cd3544fa2bb1254601d59f6984ebc1d2fb80d78 100644 (file)
--- a/src/backend/port/sysv_shmem.c
+++ b/src/backend/port/sysv_shmem.c
@@ -602,6 +602,7 @@ CreateAnonymousSegment(Size *size)
        Size            allocsize = *size;
        void       *ptr = MAP_FAILED;
        int                     mmap_errno = 0;
+       int                     mmap_flags = MAP_SHARED | MAP_ANONYMOUS | MAP_HASSEMAPHORE;
 
 #ifndef MAP_HUGETLB
        /* PGSharedMemoryCreate should have dealt with this case */
@@ -613,15 +614,15 @@ CreateAnonymousSegment(Size *size)
                 * Round up the request size to a suitable large value.
                 */
                Size            hugepagesize;
-               int                     mmap_flags;
+               int                     huge_mmap_flags;
 
-               GetHugePageSize(&hugepagesize, &mmap_flags);
+               GetHugePageSize(&hugepagesize, &huge_mmap_flags);
 
                if (allocsize % hugepagesize != 0)
                        allocsize = add_size(allocsize, hugepagesize - (allocsize % hugepagesize));
 
                ptr = mmap(NULL, allocsize, PROT_READ | PROT_WRITE,
-                                  PG_MMAP_FLAGS | mmap_flags, -1, 0);
+                                  mmap_flags | huge_mmap_flags, -1, 0);
                mmap_errno = errno;
                if (huge_pages == HUGE_PAGES_TRY && ptr == MAP_FAILED)
                        elog(DEBUG1, "mmap(%zu) with MAP_HUGETLB failed, huge pages disabled: %m",
@@ -645,7 +646,7 @@ CreateAnonymousSegment(Size *size)
                 */
                allocsize = *size;
                ptr = mmap(NULL, allocsize, PROT_READ | PROT_WRITE,
-                                  PG_MMAP_FLAGS, -1, 0);
+                                  mmap_flags, -1, 0);
                mmap_errno = errno;
        }
 

diff --git a/src/include/portability/mem.h b/src/include/portability/mem.h
index 091328f680da5fa3bed98e975bb3c6da193aea92..c048e8836c514d67cd1c3c308c6f835d585f8c75 100644 (file)
--- a/src/include/portability/mem.h
+++ b/src/include/portability/mem.h
@@ -38,8 +38,6 @@
 #define MAP_NOSYNC                     0
 #endif
 
-#define PG_MMAP_FLAGS                  (MAP_SHARED|MAP_ANONYMOUS|MAP_HASSEMAPHORE)
-
 /* Some really old systems don't define MAP_FAILED. */
 #ifndef MAP_FAILED
 #define MAP_FAILED ((void *) -1)