Re: Break 2.4 VM in five easy steps

[ebiederm@xmission.com (Eric W. Biederman)]

"Jeffrey W. Baker" <jwbaker@acm.org> writes:

> On Tue, 5 Jun 2001, Derek Glidden wrote:
> 
> >
> > After reading the messages to this list for the last couple of weeks and
> > playing around on my machine, I'm convinced that the VM system in 2.4 is
> > still severely broken.
> >
> > This isn't trying to test extreme low-memory pressure, just how the
> > system handles recovering from going somewhat into swap, which is a real
> > day-to-day problem for me, because I often run a couple of apps that
> > most of the time live in RAM, but during heavy computation runs, can go
> > a couple hundred megs into swap for a few minutes at a time.  Whenever
> > that happens, my machine always starts acting up afterwards, so I
> > started investigating and found some really strange stuff going on.
> 
> I reboot each of my machines every week, to take them offline for
> intrusion detection.  I use 2.4 because I need advanced features of
> iptables that ipchains lacks.  Because the 2.4 VM is so broken, and
> because my machines are frequently deeply swapped, they can sometimes take
> over 30 minutes to shutdown.  They hang of course when the shutdown rc
> script turns off the swap.  The first few times this happened I assumed
> they were dead.

Interesting.  Is it constant disk I/O?  Or constant CPU utilization.
In any case you should be able to comment that line out of your shutdown
rc script and be in perfectly good shape.

Eric