Memory, swap, and limits
Patrick O'Callaghan
pocallaghan at gmail.com
Wed Jun 18 17:04:51 UTC 2008
On Wed, 2008-06-18 at 11:06 -0500, Mikkel L. Ellertson wrote:
> > OK; but then there's something else I don't know, or don't
> > understand. Does a Fedora machine do any swapping while it has
> memory
> > left? I didn't think I had (or needed) any control at all over
> swapping,
> > beyond choosing how much space to afford it.
> >
> What I have seen is that when the system needs memory, it will swap
> out idle programs, and it will leave them swapped out until they are
> needed again. (This is a somewhat simplified explanation...) It will
> even use freed memory for thing like disk cache instead of swapping
> the programs back in.
This can be noticeable if you leave a session logged in all night and
your system runs updatedb at 3am, causing all your idle processes to be
swapped out. You then find the system really slow for a minute or two in
the morning as it drags images back in.
To be fair, I've noticed this a lot less with recent versions of Fedora.
Maybe I just have more RAM :-)
poc
More information about the fedora-list
mailing list