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Date:      Sun, 22 Aug 2004 00:10:18 -0400
From:      Brian Fundakowski Feldman <green@FreeBSD.org>
To:        Robert Watson <rwatson@FreeBSD.org>
Cc:        cvs-all@FreeBSD.org
Subject:   Re: cvs commit: src/sys/vm vm_fault.c
Message-ID:  <20040822041018.GA937@green.homeunix.org>
In-Reply-To: <20040822033955.GA3629@green.homeunix.org>
References:  <20040822015800.GE784@green.homeunix.org> <Pine.NEB.3.96L.1040821222342.95496C-100000@fledge.watson.org> <20040822033955.GA3629@green.homeunix.org>

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On Sat, Aug 21, 2004 at 11:39:55PM -0400, Brian Fundakowski Feldman wrote:
> On Sat, Aug 21, 2004 at 10:30:03PM -0400, Robert Watson wrote:
> > 
> > On Sat, 21 Aug 2004, Brian Fundakowski Feldman wrote:
> > 
> > > > > #1. Lock order reversal.  Giant is acquired after the map read lock.
> > > > 
> > > > No, that is the order it has been in for months.  The other functions
> > > > that acquire a map lock and Giant do the same.
> > > 
> > > Giant can never be acquired after another lock has been acquired :-(
> > 
> > Actually, that's not quite accurate.  Take a look at the relationship
> > between lockmgr/sx locks and Giant, for example.
> 
> Point taken.  This is the first time I've seen Giant in a lock order
> reversal with vm locks, though, and I've been running WITNESS for years.

Also, it was the system_map lock, so it was a mutex, not an sx.

/Goes back to trying to figure out wtf portupgrade -rR kde\* keeps causing
 hangs, but only in X, not at the command line, and not seemingly
 dependant on AGP/X driver.

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



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