[OpenAFS] PAG garbage collection on linux

[Andy Cobaugh]

I recently ran into a situation where I had a process on linux that gets 
pags probably 10 times per minute on linux (dovecot, fwiw). After 3 weeks 
of uptime after upgrading afs to 1.4.7, we had to reboot the machine, as 
we were no longer able to create new pags.

This is on debian stable, kernel 2.6.18-6-amd64, and afs 1.4.7 as 
previously mentioned.

/proc/sys/afs/GCPAGS gets set to 8, which from my understanding means it 
was unable to walk the process tree.

I see that it works with 1.4.7 on fedora 9 with a 2.6.25 kernel.

I have since reworked my dovecot setup so that imap logins don't 
needlessly get tokens and create a pag (the entire dovecot process stack 
already runs in a pag with tokens for a pts user with appropriate access).

I am curious what combinations of linux kernel / openafs that GC actually 
works. This would be helpful to know, and I'm sure others would benefit 
from this as well.

Thanks.

--andy