Subject: Re: memory (re-)allocation woes
To: None <>
From: theo borm <>
List: tech-kern
Date: 11/30/2004 11:17:05
Matthew Orgass wrote:

>On 2004-11-28 wrote:
>>I have run my little test on a variety of hardware (i.e. different
>>diskeless cluster nodes with /identical/ hardware and four other
>>machines with different hardware, alas all i386, and have managed to
>>crash all diskless nodes (somehow swap over NFS seems to be quite
>>sensitive to long delays in the pagedaemon), and two of the four other
>>machines. One of these I have used some time ago to build all in pkgsrc
>>*). To me it seems as if the problem is not hardware related, and that
>>it is only a matter finding the correct parameters to reboot them too
>  There does seem to be a problem.  I just remembered kern/9308.  I was
>not able to reproduce that problem on my current (fast) i386 machine, but
>I did get a hang on my Clio 1050 (hpcmips) running -current (possibly a
>month old).  To get this I ran "grep foo /dev/zero & && grep foo /dev/zero
>&" then kept pushing up and return until it hung (maybe 10-15 times).  I
>also don't use swap now, and I think I did at the time of the PR.  When
>breaking into ddb, I now see a variety of uvm related functions, but
>apparently no progress is made (I waited about five minutes).  It may be
>that NFS swap would increase the chance of the race condition being hit
>(however, I don't have any idea what is really going on).  It is also
>possible that your problem may be NFS related.  I guess either way it
>could potentially cause reboots.  Can you break into ddb several times
>while it is hung to see what functions are using up the CPU?
Well, Ive been running some tests on my diskless cluster nodes, and have
in the process managed to crash my NFS server (ctrl-alt-esc didn't even
work!). I'll be setting up a few nodes with their own NFS server for testing
purposes to limit interruptions in normal work flow and to limit the number
of variables I have to deal with.... This may take some time, so please bear
with me....

As a minor b.t.w., the GENERIC kernel shipping with 1.6.2 /was/ compiled
from the sources and (native?) tools shipping with it? I'm having some
trouble compiling a functionally equivalent GENERIC kernel...

with kind regards,

>Matthew Orgass