2GB swap partition limit?

[Bruno Wolff III]

On Thu, Mar 16, 2006 at 09:20:54 +1100,
  Russell Coker <russell at coker.com.au> wrote:
> 
> In most cases your machine will become totally unusable long before the 4G 
> space is used, and often it would be more desirable to have the OOM killer 
> kill something before it gets to that stage.  When configuring machines with 
> more than about 512M of RAM I never use 2*RAM for swap size for this reason.

If you want a reliable system you don't want to turn on the oom killer.
When you do this you need to have swap space available for all allocated
memory even if it isn't being used. In this case you can have swap space
much larger than will actually be used in practice. Note that there are
cases where processes don't have there own copy of memory they have allocated
to them. A common case is memory in use when a fork is done that hasn't been
modified.