Re: VM deadlock?

On Tue, Nov 07, 2006 at 01:24:22PM -0500, John Baldwin wrote:
> On Sunday 05 November 2006 10:24, Pawel Jakub Dawidek wrote:
> > db> sh allchain
> > chain 1:
> >  thread 100260 (pid 90346, qmail-smtpd) blocked on lock 0xc07177e0 (sleep 
> mutex) "Giant"
> >  thread 100133 (pid 89997, qmail-smtpd) blocked on lock 0xc0722700 (sleep 
> mutex) "vm page queue mutex"
> >  thread 100105 (pid 4315, drwebd) is on a run queue
> > chain 2:
> >  thread 100098 (pid 4316, qmail-smtpd) blocked on lock 0xc0722700 (sleep 
> mutex) "vm page queue mutex"
> >  thread 100105 (pid 4315, drwebd) is on a run queue
> > chain 3:
> >  thread 100031 (pid 34, pagezero) blocked on lock 0xc0722700 (sleep 
> mutex) "vm page queue mutex"
> >  thread 100105 (pid 4315, drwebd) is on a run queue
> > chain 4:
> >  thread 100015 (pid 3, g_up) blocked on lock 0xc0722700 (sleep mutex) "vm 
> page queue mutex"
> >  thread 100105 (pid 4315, drwebd) is on a run queue
> > chain 5:
> >  thread 100002 (pid 14, swi4: clock sio) blocked on lock 0xc072146c (sleep 
> mutex) "tcp"
> >  thread 100000 (pid 16, swi1: net) blocked on lock 0xc0722700 (sleep 
> mutex) "vm page queue mutex"
> >  thread 100105 (pid 4315, drwebd) is on a run queue
> > db> sh locktree
> > db> sh turnstile
> > 
> > Process drwebd (pid 4315) doesn't seem to go any further.
> 
> How about 'show allpcpu' to see which threads are running?

I get some feedback from tegge_at_ and kib_at_ is willing to investigate it
further. This looks more like scheduler issue, not VM issue.

There are 4 CPUs. 3 are idle, one is stuck running userland process at
this point.

Disabling PREEMPTION seemed to help.

-- 
Pawel Jakub Dawidek                       http://www.wheel.pl
pjd_at_FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!