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Date: Sat, 21 Aug 2004 23:39:55 -0400
From: Brian Fundakowski Feldman <green@FreeBSD.org>
To: Robert Watson <rwatson@FreeBSD.org>
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References: <20040822015800.GE784@green.homeunix.org>
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Subject: Re: cvs commit: src/sys/vm vm_fault.c
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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.

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