Horton

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

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Tomas Vondra <tomas.vondra@enterprisedb.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Amit Kapila <amit.kapila16@gmail.com>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Yura Sokolov <y.sokolov@postgrespro.ru>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2022-08-30T02:42:09Z
Lists: pgsql-hackers 
On Tue, 30 Aug 2022 at 13:58, Tomas Vondra
<tomas.vondra@enterprisedb.com> wrote:
>
> On 8/30/22 03:16, David Rowley wrote:
> > Any chance you could run make check-world on your 32-bit Raspberry PI?
> >
>
> Will do, but I think the sentinel fix should be

Thank you.  I think Tom is also running make check-world.  I now have
an old RPI3 setup with a 32-bit OS, which is currently busy compiling
Postgres. I'll kick off a make check-world run once that's done.

>    if (!sentinel_ok(chunk, Slab_CHUNKHDRSZ + slab->chunkSize))

Agreed. I've changed the patch to do it that way.  Since the 32-bit
ARM animals are already broken and per what Tom mentioned in [1], I've
pushed the patch.

Thanks again for taking the time to look at this.

David

[1] https://www.postgresql.org/message-id/3455754.1661823905@sss.pgh.pa.us

Commits

  1. Harden memory context allocators against bogus chunk pointers.

  2. Improve our ability to detect bogus pointers passed to pfree et al.

  3. Remove MemoryContextContains().

  4. Remove uses of MemoryContextContains in nodeAgg.c and nodeWindowAgg.c.

  5. Temporarily make MemoryContextContains return false

  6. Make MemoryContextContains work correctly again

  7. Make more effort to put a sentinel at the end of allocated memory

  8. Fix some possibly latent bugs in slab.c

  9. Various cleanups of the new memory context header code

  10. Revert "Add missing padding from MemoryChunk struct"

  11. Use MAXALIGN() in calculations using sizeof(SlabBlock)

  12. Add missing padding from MemoryChunk struct

  13. Improve performance of and reduce overheads of memory management