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

On Tue, Oct 11, 2022 at 5:31 AM David Rowley <dgrowleyml@gmail.com> wrote:
>
> The proposed patches in [1] do aim to make additional usages of the
> slab allocator, and I have a feeling that we'll want to fix the
> performance of slab.c before those. Perhaps the Asserts are a better
> option if we're to get the proposed radix tree implementation.

Going by [1], that use case is not actually a natural fit for slab because of memory fragmentation. The motivation to use slab there was that the allocation sizes are just over a power of two, leading to a lot of wasted space for aset. FWIW, I have proposed in that thread a scheme to squeeze things into power-of-two sizes without wasting quite as much space. That's not a done deal, of course, but it could work today without adding memory management code.

[1] https://www.postgresql.org/message-id/20220704220038.at2ane5xkymzzssb%40awork3.anarazel.de

--
John Naylor
EDB: http://www.enterprisedb.com