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Date: Thu, 7 Dec 2006 15:22:54 +0100
From: Paolo Pisati <piso@freebsd.org>
To: Andre Oppermann <andre@freebsd.org>
Message-ID: <20061207142254.GA1195@tin.it>
References: <200612062319.kB6NJgsq031755@repoman.freebsd.org>
	<20061207110225.GU32700@FreeBSD.org> <4578070A.2030609@freebsd.org>
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Cc: Gleb Smirnoff <glebius@freebsd.org>,
	Perforce Change Reviews <perforce@freebsd.org>,
	Paolo Pisati <piso@freebsd.org>
Subject: Re: PERFORCE change 111230 for review
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On Thu, Dec 07, 2006 at 01:20:26PM +0100, Andre Oppermann wrote:
> Gleb Smirnoff wrote:
> >On Wed, Dec 06, 2006 at 11:19:42PM +0000, Paolo Pisati wrote:
> >P> http://perforce.freebsd.org/chv.cgi?CH=111230
> >P> 
> >P> Change 111230 by piso@piso_newluxor on 2006/12/06 23:19:06
> >P> 
> >P> 	To workaround a problem when an mbuf is bigger than MCLBYTES
> >P> 	(and thus not handled by m_megapullup()), introduce & use
> >P> 	m_jumbo16pullup() that uses 16k jumbo size cluster.
> >P> 	
> >P> 	This problem only showed up on traffic generated on a box with 
> >P> 	a nic tso enabled.
> >
> >Paolo,
> >
> >this isn't a fix. Another application will do write(,, 16k + 1) and
> >m_jumbo16pullup() will fail again. Please backout it, it is a hack.
> >
> >We need to fix TSO in such way that real packets, that will be
> >transmitted to wire, will be passed to pfil handlers.
> 
> That is not possible.

Then, after a discussion on irc, pull the plug on any
present (and future) hackery & half-baked solution, and declare
in kernel libalias incompatible with tso.

bye
-- 

Paolo

Piso's first law: nothing works as expected!