On Thu, Jan 1, 2015 at 11:59 AM, Andres Freund <andres@2ndquadrant.com> wrote:
> The problem is that just aligning the main allocation to some boundary
> doesn't mean the hot part of the allocation is properly aligned. shmem.c
> in fact can't really do much about that - so fully moving the
> responsibility seems more likely to ensure that future code thinks about
> alignment.
That's true, but if you don't align the beginnings of the allocations,
then it's a lot more complicated for the code to properly align stuff
within the allocation. It's got to insert a variable amount of
padding based on the alignment it happens to get.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company