Re: Memory reporting on CentOS Linux

Jeremy Carroll <jeremy.carroll@networkedinsights.com> writes:
> I am thoroughly confused that TOP is reporting that I have 99% of my
> physical RAM free, while the process list suggests that some are
> taking ~8Gb of Resident (Physical) Memory. Any explanation as to why
> TOP is reporting this? I have a PostgreSQL 8.3 server with 48Gb of RAM
> on a Dell R610 server that is reporting that 46.5GB of RAM is free.

Exactly where do you draw that conclusion from?  I see "free 138M".

It does look like there's something funny about top's accounting for
shared memory --- maybe it's counting it as "cached"?  It's hardly
unusual for top to give bogus numbers in the presence of shared memory,
of course, but this seems odd :-(.  With such large amounts of RAM
involved I wonder if there could be an overflow problem.  You might file
a bug against top in whatever distro you are using.

            regards, tom lane