Horton

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

Julien Rouhaud <rjuju123@gmail.com>

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From: Julien Rouhaud <rjuju123@gmail.com>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Yura Sokolov <y.sokolov@postgrespro.ru>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2022-09-07T13:05:52Z
Lists: pgsql-hackers 
Hi,

On Thu, Sep 08, 2022 at 12:29:22AM +1200, David Rowley wrote:
>
> I spent some time looking at our existing usages of
> MemoryContextContains() to satisfy myself that we'll only ever pass in
> a pointer to memory allocated by a MemoryContext and pushed this
> patch.

FYI lapwing isn't happy with this patch:
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=lapwing&dt=2022-09-07%2012%3A40%3A16.

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