Re: Reducing the chunk header sizes on all memory context types

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>

To: Tom Lane <tgl@sss.pgh.pa.us>

Cc: Amit Kapila <amit.kapila16@gmail.com>, David Rowley <dgrowleyml@gmail.com>, Andres Freund <andres@anarazel.de>, Yura Sokolov <y.sokolov@postgrespro.ru>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>

Date: 2022-08-29T15:15:52Z

Lists: pgsql-hackers

Hi,

I've got another problem with this patch here on macOS:

ccache clang -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Werror=vla
-Werror=unguarded-availability-new -Wendif-labels
-Wmissing-format-attribute -Wformat-security -fno-strict-aliasing
-fwrapv -Wno-unused-command-line-argument -g -O2 -Wall -Werror
-Wno-unknown-warning-option -fno-omit-frame-pointer
-I../../../../src/include  -isysroot
/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk
-I/opt/local/include/libxml2 -I/opt/local/include -I/opt/local/include
 -I/opt/local/include  -c -o aset.o aset.c -MMD -MP -MF .deps/aset.Po
In file included from aset.c:52:
../../../../src/include/utils/memutils_memorychunk.h:170:18: error:
comparison of constant 7 with expression of type
'MemoryContextMethodID' (aka 'enum MemoryContextMethodID') is always
true [-Werror,-Wtautological-constant-out-of-range-compare]
        Assert(methodid <= MEMORY_CONTEXT_METHODID_MASK);
        ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../../../src/include/c.h:827:9: note: expanded from macro 'Assert'
                if (!(condition)) \
                      ^~~~~~~~~
In file included from aset.c:52:
../../../../src/include/utils/memutils_memorychunk.h:186:18: error:
comparison of constant 7 with expression of type
'MemoryContextMethodID' (aka 'enum MemoryContextMethodID') is always
true [-Werror,-Wtautological-constant-out-of-range-compare]
        Assert(methodid <= MEMORY_CONTEXT_METHODID_MASK);
        ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../../../src/include/c.h:827:9: note: expanded from macro 'Assert'
                if (!(condition)) \
                      ^~~~~~~~~

I'm not sure what to do about that, but every file that includes
memutils_memorychunk.h produces those warnings (which become errors
due to -Werror).

...Robert

Commits

Harden memory context allocators against bogus chunk pointers.
- 0e87dfe46443 16.0 landed
Improve our ability to detect bogus pointers passed to pfree et al.
- 80ef92675823 16.0 landed
Remove MemoryContextContains().
- 9543eff5e015 16.0 landed
Remove uses of MemoryContextContains in nodeAgg.c and nodeWindowAgg.c.
- 42b746d4c982 16.0 landed
Temporarily make MemoryContextContains return false
- b76fb6c2a99e 16.0 landed
Make MemoryContextContains work correctly again
- 5265e91fd10d 16.0 landed
Make more effort to put a sentinel at the end of allocated memory
- 0e480385ec59 16.0 landed
Fix some possibly latent bugs in slab.c
- 258b0411b243 10.23 landed
- 1b1154396798 11.18 landed
- f249f1026f71 12.13 landed
- 210bece161b0 13.9 landed
- 6ec896109254 14.6 landed
- c4e861b7bba3 15.0 landed
Various cleanups of the new memory context header code
- 05f908423695 16.0 landed
Revert "Add missing padding from MemoryChunk struct"
- 5495796ad12a 16.0 landed
Use MAXALIGN() in calculations using sizeof(SlabBlock)
- d5ee4db0eaf6 16.0 landed
Add missing padding from MemoryChunk struct
- df0f4feef8de 16.0 landed
Improve performance of and reduce overheads of memory management
- c6e0fe1f2a08 16.0 landed