From owner-freebsd-net@FreeBSD.ORG Sat Mar 12 16:55:09 2005 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A74CE16A4CE for ; Sat, 12 Mar 2005 16:55:09 +0000 (GMT) Received: from c00l3r.networx.ch (c00l3r.networx.ch [62.48.2.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 92FBC43D1F for ; Sat, 12 Mar 2005 16:55:08 +0000 (GMT) (envelope-from andre@freebsd.org) Received: (qmail 83206 invoked from network); 12 Mar 2005 16:28:00 -0000 Received: from unknown (HELO freebsd.org) ([62.48.0.54]) (envelope-sender ) by c00l3r.networx.ch (qmail-ldap-1.03) with SMTP for ; 12 Mar 2005 16:28:00 -0000 Message-ID: <42331EED.D7714E05@freebsd.org> Date: Sat, 12 Mar 2005 17:55:09 +0100 From: Andre Oppermann X-Mailer: Mozilla 4.8 [en] (Windows NT 5.0; U) X-Accept-Language: en MIME-Version: 1.0 To: Sam Leffler References: <20050311110234.GA87255@cell.sick.ru> <20050311141450.GF9291@darkness.comp.waw.pl> <42320A3E.1020708@elischer.org><42322875.4030404@errno.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit cc: dima <_pppp@mail.ru> cc: Pawel Jakub Dawidek cc: John Baldwin cc: Luigi Rizzo cc: rwatson@freebsd.org cc: Julian Elischer cc: net@freebsd.org Subject: Re: Giant-free polling [PATCH] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 12 Mar 2005 16:55:09 -0000 Sam Leffler wrote: > > Pawel Jakub Dawidek wrote: > > On Fri, Mar 11, 2005 at 01:14:38PM -0800, Julian Elischer wrote: > > +> >P> There is still an unresolved problem (in your and our patch as well) of > > +> >P> using ifnet structure fields without synchronization, as we don't have > > +> >P> access tointerface's internal mutex, which protects those fields. > > +> > > > +> > > > +> > > +> you need to add an interface method that has access to it.. > > > > I was thinking more about moving interface mutex into ifnet structure, > > but Robert has some objections IIRC. > > > > I don't know what Robert's objections are but I've considered doing it > for a while to deal with some locking issues in net80211-based drivers. > The only issue I can see is if this mutex boxes drivers into a locking > model that interlocks the rx+tx paths. We don't want this. This would paint us into a corner with modern high speed hardware that can hanle the rx+tx paths simulaneously. Depending on the hardware DMA model and driver architecture you want to have a different locking model. I agree with Robert in objecting to this. -- Andre