From owner-svn-src-all@freebsd.org Mon Feb 20 19:22:21 2017 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 1E5BACE65A2; Mon, 20 Feb 2017 19:22:21 +0000 (UTC) (envelope-from ken@kdm.org) Received: from mithlond.kdm.org (mithlond.kdm.org [96.89.93.250]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "A1-33714", Issuer "A1-33714" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id D6A5818E1; Mon, 20 Feb 2017 19:22:20 +0000 (UTC) (envelope-from ken@kdm.org) Received: from mithlond.kdm.org (localhost [127.0.0.1]) by mithlond.kdm.org (8.15.2/8.14.9) with ESMTPS id v1KJMG8U013570 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 20 Feb 2017 14:22:16 -0500 (EST) (envelope-from ken@mithlond.kdm.org) Received: (from ken@localhost) by mithlond.kdm.org (8.15.2/8.14.9/Submit) id v1KJMG6h013569; Mon, 20 Feb 2017 14:22:16 -0500 (EST) (envelope-from ken) Date: Mon, 20 Feb 2017 14:22:16 -0500 From: "Kenneth D. Merry" To: Sean Bruno Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r299182 - head/sys/dev/e1000 Message-ID: <20170220192216.GA12821@mithlond.kdm.org> References: <201605061541.u46FfcQo010183@repo.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201605061541.u46FfcQo010183@repo.freebsd.org> User-Agent: Mutt/1.5.23 (2014-03-12) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3 (mithlond.kdm.org [127.0.0.1]); Mon, 20 Feb 2017 14:22:16 -0500 (EST) X-Spam-Status: No, score=-2.9 required=5.0 tests=ALL_TRUSTED,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS autolearn=ham autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on mithlond.kdm.org X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Feb 2017 19:22:21 -0000 On Fri, May 06, 2016 at 15:41:38 +0000, Sean Bruno wrote: > Author: sbruno > Date: Fri May 6 15:41:38 2016 > New Revision: 299182 > URL: https://svnweb.freebsd.org/changeset/base/299182 > > Log: > If ALTQ is defined in the kern conf, switch to Legacy Mode. > > PR: 208409 > Submitted by: freebsd@mcwest.org > MFC after: 2 weeks > > Modified: > head/sys/dev/e1000/if_igb.h Just for the mail archives (and hopefully for someone who is interested in fixing it), IGB_LEGACY_TX is broken. (It leads to panics.) See: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=213257 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=212413 And some comments about it in this particular bug as well: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=208409 This bit me last night on 10-stable. I have ALTQ in my kernel configuration, but I'm only using it on em(4) interfaces, not igb(4) interfaces. (I bought an em(4) NIC in mid-2015 because of this particular problem.) Some folks have been able to get around the problem by rate-limiting traffic on the igb(4) interfaces, but that is fairly kludgy. IMO, we shouldn't enable IGB_LEGACY_TX automatically when ALTQ is enabled when it can lead to crashes. There are several possible ways to fix things: 1. Actually fix IGB_LEGACY_TX so that it doesn't cause crashes. 2. If ALTQ is actually in use with igb(4), switch igb(4) into single queue mode. (Not sure how feasible that is.) 3. Come up with a way for ALTQ to generically and easily work on top of multiqueue interfaces. I'm sure other folks more well versed in the network stack will have additional ideas. Ken -- Kenneth Merry ken@FreeBSD.ORG