From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [PATCH]: Schedule correct qdisc in watchdog. Date: Mon, 18 Aug 2008 09:47:27 +0000 Message-ID: <20080818094727.GA6388@ff.dom.local> References: <20080818.013954.187452037.davem@davemloft.net> <20080818091011.GC5434@ff.dom.local> <20080818.023105.01989851.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org To: David Miller Return-path: Received: from fk-out-0910.google.com ([209.85.128.189]:8266 "EHLO fk-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751514AbYHRJrd (ORCPT ); Mon, 18 Aug 2008 05:47:33 -0400 Received: by fk-out-0910.google.com with SMTP id 18so2110083fkq.5 for ; Mon, 18 Aug 2008 02:47:31 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20080818.023105.01989851.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Aug 18, 2008 at 02:31:05AM -0700, David Miller wrote: > From: Jarek Poplawski > Date: Mon, 18 Aug 2008 09:10:12 +0000 > > > Yes, this was one of the reasons, but not the only one, and my oldbie > > version of this fix could be found here as "02-fix1.patch": > > > > http://permalink.gmane.org/gmane.linux.network/103039 > > This is what I get for failing to be able to follow that > flurry of patches :) I'll apply your version in the > end, thanks. > > > It's a bit different, because I think wd->qdisc can probably > > point to the noop_qdisc (if it's the root qdisc). > > noop_qdisc does not use the watchdogs as far as I can see. > > But, if we are in dev_deactivate() state, root qdisc can > be &noop_qdisc and scheduling that is fine and just a nop. Maybe I wrote this wrong. wd->qdisc stores qdisc from the qdisc_watchdog_init() time, and this could be &noop_qdisc. So qdisc_root() would schedule wrong qdisc later. BTW, my version would probably do the same for root qdisc, but in these tests there was a problem with leafs. And of course, scheduling &noop_qdisc isn't bad, until we sometimes schedule something else too. Jarek P.