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Date: Fri, 9 Jul 2004 11:19:55 +0900
From: Taku YAMAMOTO <taku@tackymt.homeip.net>
To: John Baldwin <jhb@FreeBSD.org>
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cc: freebsd-current@FreeBSD.org
Subject: Re: Native preemption is the culprit [was Re: today's CURRENT
 lockups]
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On Thu, 8 Jul 2004 13:17:53 -0400
John Baldwin <jhb@FreeBSD.org> wrote:
> On Thursday 08 July 2004 09:21 am, Taku YAMAMOTO wrote:
> > greetings,
> >
> >
> > A quick glance showed me that there are some interesting code paths in
> > sched_ule.c that can be problematic in SMP case.
> >
> >   1. sched_choose() => kseq_idled() => sched_add()
> >   2. sched_choose() => kseq_assign() => sched_add()
> >   3. sched_runnable() => kseq_assign() => sched_add()
> >
> > Here is the patch that re-enables preemption except for the above three
> > cases.
> 
> This looks correct.  I'll test it locally first.  Has it worked for you all 
> day?

My machine (HTT) has been up for 20 hours without a hang since last update.
I tried to stress it in various ways (fsck -n, buildworld & buildkernel in
parallel, burning a CD, etc.) but failed to crash it.

I'm bit afraid since the code is not tested on real SMP machines.
How is it going on yours?


-- 
-|-__    YAMAMOTO, Taku
 | __ <	    <taku@tackymt.homeip.net>

Post Scriptum to the people who know me as taku@cent.saitama-u.ac.jp:
	My email address has been changed since April,
	because I've left the university.