Swapfile problem in 6? (was: 6.0: during kernel compilation, 'kernel linking' freezes PC)

[Kris Kennaway]

On Mon, Nov 14, 2005 at 05:52:42PM -0800, Rob wrote:
> --- Rob <spamrefuse at yahoo.com> wrote:
> > 
> > Hi,
> > 
> > I have upgraded a Pentium-1 PC from 5 to 6-Stable,
> > which went smoothly.
> > 
> > Now I'm running 6 with GENERIC kernel, and I want
> > to compile a new kernel. When I start a new kernel
> > compilation, this process *always* freezes the PC
> > (no crash) when reaching the point of "linking
> > kernel"; this is 100 percent reproducible!!
> > 
> > Then all communication with the PC is frozen;
> > no serial port response, no ssh response etc.
> > However, I can ping the PC.....
> > 
> > Only power off/on brings the PC back to live.
> > 
> > Any idea how I can further investigate.
> > /var/log/messages has no special information while
> > the freezing occurred.
> > 
> > The output of 'dmesg' of this PC is here:
> >  http://surfion.snu.ac.kr/~lahaye/dmesg
> 
> Problem kind of solved:
> 
> As this PC has only 32 MB Ram, I add a swapfile.
> However, when I compile the new kernel without the
> swapfile, all goes well.
> 
> Since the freeze is very reproducible with the
> swapfile (always at the 'kernel linking' stage),
> and immediately disappears when I do not use the
> swapfile, I think there's something wrong with
> using swapfile in 6.0. Is it?
> 
> I do this:
> 
>  dd if=/dev/zero of=/swapfile bs=1024k count=128
>  chmod 0600 /swapfile
>  mdconfig -a -t vnode -f /swapfile -u 0
>  swapon /dev/md0
> 
> Is this OK?

Looks fine, and I use this myself (on a much larger scale).  Are you
sure it's freezing and not just taking a really long time?  Whenever
your system is swapping performance will be terrible, and that goes at
least double for swapping onto a file and not a device.

What happens if you leave it for an hour or two (or overnight)?

Kris
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