A couple of SMP deadlock patches

[Brian Fundakowski Feldman]

On Thu, Jul 29, 2004 at 07:29:41AM +0400, Maxim Maximov wrote:
> John Baldwin wrote:
> >Included below are two patches for two different potential deadlocks on 
> >SMP.  The first one I have sent to the list before, but it didn't seem to 
> >help anyone.  I do believe it is a fix for a possible deadlock though so 
> >I'd like some more testing feedback with the aim of committing it.  The 
> >second patch works around a lock order reversal introduced with the sleep 
> >queue code (since sched_lock's scope was reduced) at the expense of 
> >increasing the latency between a swapped out thread becoming runnable and 
> >the swapper waking up to swap the process back in.
> 
> I'm sorry, but for me PREEMPTION defined in kernel with these patches is 
> still causing deadlocks. SMP, HTT enabled.

These changes seem totally unrelated to my instability with PREEMPTION
(so I didn't try to enable it at all, but am running with these changes).
They should instead fix some issues Kris Kennaway has been seeing with
the ports cluster (but I have not tried to reproduce myself).

-- 
Brian Fundakowski Feldman                           \'[ FreeBSD ]''''''''''\
  <> green at FreeBSD.org                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\