From owner-cvs-all@FreeBSD.ORG Tue Sep 20 21:33:44 2005 Return-Path: X-Original-To: cvs-all@FreeBSD.org Delivered-To: cvs-all@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 33A4F16A41F; Tue, 20 Sep 2005 21:33:44 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [204.156.12.53]) by mx1.FreeBSD.org (Postfix) with ESMTP id C9BC243D45; Tue, 20 Sep 2005 21:33:43 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by cyrus.watson.org (Postfix) with ESMTP id 6F77746BA2; Tue, 20 Sep 2005 17:33:43 -0400 (EDT) Date: Tue, 20 Sep 2005 22:33:43 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: John Baldwin In-Reply-To: <20050920222930.N34322@fledge.watson.org> Message-ID: <20050920223315.V34322@fledge.watson.org> References: <200509190310.j8J3ALgt095979@repoman.freebsd.org> <20050919055028.GC65954@ip.net.ua> <20050919.083146.105425670.imp@bsdimp.com> <200509201551.11396.jhb@FreeBSD.org> <20050920222930.N34322@fledge.watson.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, ru@FreeBSD.org, cvs-all@FreeBSD.org, "M. Warner Losh" Subject: Re: cvs commit: src/sys/dev/an if_an.c src/sys/dev/arl if_arl_isa.c src/sys/dev/awi if_awi_pccard.c src/sys/dev/cm if_cm_isa.c src/sys/dev/cnw if_cnw.c src/sys/dev/cp if_cp.c src/sys/dev/cs if_cs.c src/sys/dev/ed if_ed.c src/sys/dev/em if_em.c ... X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Sep 2005 21:33:44 -0000 On Tue, 20 Sep 2005, Robert Watson wrote: > > On Tue, 20 Sep 2005, John Baldwin wrote: > >> Regarding other comments I saw today on some e-mail or another, I do think >> that to make the locking sane, we might should push the checks for >> IFF_DRV_RUNNING down into the foo_start() routines rather than doing it in >> the network layer where the driver lock isn't held. > > This was a change I was thinking of trying to get into 6.0 a few weeks > ago, but was worried that wholesale frobbing of the network interface > drivers would introduce too many bugs. Also, it will increase the cost > of injecting packets into the send queue under load as you'll always > have to acquire and drop the driver mutex to test the flag. I.e., it's > not clear we're actually racing, but we might pay a hefty cost for > fixing it. If you want to take a cut at it, I'm happy to help > characterize the cost and decide if it's the right thing to do. It > would be nice to get it into 6.0 if possible as it will become part of > the device driver API if so. ... getting late ... I mean the IFF_DRV_OACTIVE flag test used in the handoff. Robert N M Watson