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Date: Wed, 4 Aug 2004 23:23:49 -0400 (EDT)
From: Robert Watson <rwatson@FreeBSD.org>
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To: Brian Fundakowski Feldman <green@FreeBSD.org>
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Subject: Re: cvs commit: src/sys/net bpf.c
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On Wed, 4 Aug 2004, Brian Fundakowski Feldman wrote:

> On Thu, Aug 05, 2004 at 02:37:36AM +0000, Robert Watson wrote:
> > rwatson     2004-08-05 02:37:36 UTC
> > 
> >   FreeBSD src repository
> > 
> >   Modified files:
> >     sys/net              bpf.c 
> >   Log:
> >   Do a lockless read of the BPF interface structure descriptor list head
> >   before grabbing BPF locks to see if there are any entries in order to
> >   avoid the cost of locking if there aren't any.  Avoids a mutex lock/
> >   unlock for each packet received if there are no BPF listeners.
> 
> While you're there, do you want to check out the other problems I've
> been noticing, relating to consistency/locking? 

Yes.  Can you e-mail me the pointer to your patch and/or p4 branch again?
I'll try to look at it tomorrow.

Thanks!

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert@fledge.watson.org      Principal Research Scientist, McAfee Research