Illogical usage of swap

Jerry McAllister jerrymc at
Wed Mar 16 06:48:05 PST 2005

> "Colin J. Raven" <colin at> writes:
> > On Mar 16 at 07:29, Lowell Gilbert launched this into the bitstream:
> > >
> > 
> > Hmm, yeah I should have included what I've actually read in the
> > handbook and elsewhere. In fact I did read that exerpt you quoted the
> > URL for  above sometime previously, when it was quoted in another
> > thread on the list.
> > 
> > Free memory (or the lack thereof) isn't the issue though.
> > 
> > The issue is this:
> > Swap: 8192M Total, 116K Used, 8192M Free
> > and that's the piece of the puzzle that has us all utterly baffled.
> The same logic applies to some extent, though.
> > No way in creation this box should be swapping.
> I have noticed that FreeBSD 5.x is swapping out small amounts of
> memory in situations (as near I can tell; it is quite hard to be sure
> that the situation is really identical) where 4.x was not.  I haven't
> really tried to track down exactly what's going on, but it's always
> been less than the text segment of any task in the system, so I was
> pretty sure I wasn't seeing a problem.

Swap space is also used for paging.   If you are running through some 
big file or have processes that are live but not active, they can
use up some page space.   That space just stays there until it is
needed otherwise.   At least that is my understanding.


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