On Wed, 13 Jul 2022 at 05:42, Andres Freund <and...@anarazel.de> wrote: > > There is at least one. It might be major; to reduce the AllocSet chunk > > header from 16 bytes down to 8 bytes I had to get rid of the freelist > > pointer that was reusing the "aset" field in the chunk header struct. > > This works now by storing that pointer in the actual palloc'd memory. > > This could lead to pretty hard-to-trace bugs if we have any code that > > accidentally writes to memory after pfree. > > Can't we use the same trick for allcations in the freelist as we do for the > header in a live allocation? I.e. split the 8 byte header into two and use > part of it to point to the next element in the list using the offset from the > start of the block, and part of it to indicate the size?
That can't work as the next freelist item might be on some other block. David
