Re: Solaris ISM Testing

Bruce Momjian <pgman@candle.pha.pa.us> writes:
> The attached email shows that Solaris benefits from the ISM or Intimate
> Shared Memory setting during shmat() shared memory creation.  It causes
> processes mapping the same shared memory to shared mapping pages _and_
> locks the pages in RAM.

Huh?  I understand "locks the pages in RAM" but I don't understand the
first part of that.  ISTM shared memory is shared memory; if we didn't
share it without this flag, we'd not be working at all on Solaris.

> I know many OS's lock shared memory in RAM anyway, or have OS parameters
> that control this (FreeBSD), but it seems Solaris does this on a per
> shmat() basis.  Should we add this flag to shmat() calls for Solaris?

Certainly on any OS where we can request pinning our shmem in RAM, we
should do so --- I've pointed out before that allowing our disk buffers
to be swapped out can't be anything but counterproductive.  Not sure
that this should be thought of as an "#ifdef SOLARIS" kind of change;
do any other Unixen share this aspect of the API?
        regards, tom lane