From owner-freebsd-net  Tue Jun  4  6:57:25 2002
Delivered-To: freebsd-net@freebsd.org
Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1])
	by hub.freebsd.org (Postfix) with ESMTP id 964CF37B403
	for <freebsd-net@FreeBSD.ORG>; Tue,  4 Jun 2002 06:57:20 -0700 (PDT)
Received: from moe.cs.duke.edu (moe.cs.duke.edu [152.3.140.74])
	by duke.cs.duke.edu (8.9.3/8.9.3) with ESMTP id JAA09101;
	Tue, 4 Jun 2002 09:57:10 -0400 (EDT)
Received: (gallatin@localhost) 
	by moe.cs.duke.edu (8.8.5/8.6.9)
	id JAA03663; Tue, 4 Jun 2002 09:57:10 -0400 (EDT)
From: Andrew Gallatin <gallatin@cs.duke.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-ID: <15612.50998.79685.943067@moe.cs.duke.edu>
Date: Tue, 4 Jun 2002 09:57:10 -0400 (EDT)
To: Archie Cobbs <archie@dellroad.org>
Cc: Bosko Milekic <bmilekic@unixdaemons.com>,
	Julian Elischer <julian@elischer.org>,
	Alfred Perlstein <bright@mu.org>, freebsd-net@FreeBSD.ORG
Subject: Re: Race condition with M_EXT ref count?
In-Reply-To: <200206040553.g545rXH49446@arch20m.dellroad.org>
References: <20020603193651.A29296@unixdaemons.com>
	<200206040553.g545rXH49446@arch20m.dellroad.org>
X-Mailer: VM 6.72 under 21.1 (patch 9) "Canyonlands" XEmacs Lucid
Sender: owner-freebsd-net@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-net.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-net>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-net>
X-Loop: FreeBSD.org


Archie Cobbs writes:
 > Re: the -stable patch. I agree we need a more general MFC/cleanup
 > of some of the mbuf improvements from -current into -stable.
 > If I find time perhaps I'll do that as well, but in a separate patch.
 > For the present time, I'll commit this once 4.6-REL is done.

The best improvements (IMHO, anyway) are the changes in the way
external mbufs are referenced and dereferenced.  It greatly simplifies
writing code that uses external mbufs.

However, you need to carefully consider what you backport.  We want to
try to avoid breaking ABI compatibility for 3rd party vendors who ship
binary network interface drivers.  At Myricom, we offer a binary driver
built on 4.1.1-RELEASE and it works through 4.5-RELEASE(*).  It would be
bad to loose this feature.    

So I'd oppose MFC'ing anything that breaks binary compatibility for
network drivers in the 4.x line.  The last thing we want to do is make
extra work for the few companies who offer FreeBSD drivers for their
hardare. 

Cheers,

Drew

(*) We also ship source, but building from source is somewhat of a pain.

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-net" in the body of the message