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Date:      Wed, 28 Jul 2004 23:57:04 -0400
From:      Brian Fundakowski Feldman <green@freebsd.org>
To:        Maxim Maximov <mcsi@mcsi.pp.ru>
Cc:        current@freebsd.org
Subject:   Re: A couple of SMP deadlock patches
Message-ID:  <20040729035704.GA1021@green.homeunix.org>
In-Reply-To: <41086F25.3070707@mcsi.pp.ru>
References:  <200407281329.27271.jhb@FreeBSD.org> <41086F25.3070707@mcsi.pp.ru>

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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@FreeBSD.org                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\



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