Hi, On 2022-11-08 14:57:35 +1300, David Rowley wrote: > On Tue, 8 Nov 2022 at 05:24, Andres Freund <and...@anarazel.de> wrote: > > Should we handle the case where we get a suitably aligned pointer from > > MemoryContextAllocExtended() differently? > > Maybe it would be worth the extra check. I'm trying to imagine future > use cases. Maybe if someone wanted to ensure that we're aligned to > CPU cache line boundaries then the chances of the pointer already > being aligned to 64 bytes is decent enough. The problem is it that > it's too late to save any memory, it just saves a bit of boxing and > unboxing of the redirect headers.
Couldn't we reduce the amount of over-allocation by a small amount by special casing the already-aligned case? That's not going to be relevant for page size aligne allocations, but for smaller alignment values it could matter. Greetings, Andres Freund
