Kubuntu uses too much memory. What is the cause?

[Derek Broughton]

Alvin wrote:

> My computer has 2GB ram. After running Jaunty for a while (an hour and
> up), the swap starts to fill and things start to get slow.
> 
> $ free -m
>              total       used       free
> Mem:          1978       1944         33
> -/+ buffers/cache:        621       1356
> Swap:         1906        759       1146
> 
> Programs I'm running:
> - Kontact
> - Amarok
> - Dropbox
> - Konsole
> 
> Other that that, there's not much activity.
> Now, I don't see this behaviour on other Kubuntu boxes. Is there a way to
> see what process is filling the swap?

The swap is hardly "full" - it's well under 50% utilized.  It's in the 
nature of swap space that it tends to collect cruft.  Things stay in swap 
until they're no longer needed AND something else needs the space.  Unless 
you can show situations where you have a lot less free swap than this, I'd 
have to say it isn't your problem (my last machine slowed down as memory 
filled, too, and I thought it was actually lack of memory, when the problem 
turned out to be a failing drive, making it very hard for the system to swap 
anything - I only clued in when the drive failed completely).

fwiw, some of the filling of virtual memory over time comes from files built 
in tmpfs filesystems.  Normally, iirc, /var/run, /var/lock, and a couple of 
others.  Apparently I can't check right now, as I just rebooted into a 
Karmic kernel and "mount" refuses to show me most of my mounts.  Something 
to do with "fuse", it seems.
-- 
derek