Memory limit on Linux?

From: Jack Challen [mailto:jack.challen at ocsl.co.uk] 
Sent: Wednesday, August 14, 2013 10:45 AM
Subject: RE: Memory limit on Linux?

(I'm replying from a horrific WebMail UI. I've attempted to maintain
what I think is sensible quoting. Hopefully it reads ok).

If all users are able to allocate that much RAM in a single process
(e.g. "top" shows the process taking 20 GBytes) then it's very unlikely
to be an OS- or user-specific restriction (there are exceptions to that if
 e.g. the R job is submitted in a different shell environment [e.g. batch
 queuing]). Your ulimits look sensible to me.

The only differences I have found between the two boxes that really 
stands out is that the system that works runs RHEL proper and has R 
compiled but the one that doesn't allocate all of the memory was installed
via EPEL RPM on CentOS. Compiling R on the CentOS system is on the
try-this list, but before I spend that time trying to compile I thought I
would ask a few questions.

I would look there first. It seems (from the first quoted bit) that your
problem is specific to that version of R on that machine as Matlab can
gobble up RAM happily (I do have a very simple bit of C kicking about
here which is specifically for testing the memory allocation limit of a
system which you could have if you really wanted).

2) When I compile from source to test this, is there a specific option I should pass to ensure max usage?

Absolutely no idea, I'm afraid. There is an --enable-memory-profiling
option, but I doubt that''ll solve your problem and it'll probably just
slow R down. I'd simply give compiling it a go.