From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [PATCH]: Schedule correct qdisc in watchdog. Date: Tue, 19 Aug 2008 05:42:03 +0000 Message-ID: <20080819054203.GB2722@ff.dom.local> References: <20080818113531.GB7158@ff.dom.local> <200808181545.30146.denys@visp.net.lb> <20080818125805.GA7938@ff.dom.local> <20080818.165638.169012226.davem@davemloft.net> <20080819053745.GA2722@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: denys@visp.net.lb, netdev@vger.kernel.org To: David Miller Return-path: Received: from nf-out-0910.google.com ([64.233.182.190]:48005 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752763AbYHSFmJ (ORCPT ); Tue, 19 Aug 2008 01:42:09 -0400 Received: by nf-out-0910.google.com with SMTP id d3so1354140nfc.21 for ; Mon, 18 Aug 2008 22:42:07 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20080819053745.GA2722@ff.dom.local> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Aug 19, 2008 at 05:37:45AM +0000, Jarek Poplawski wrote: > On Mon, Aug 18, 2008 at 04:56:38PM -0700, David Miller wrote: > > From: Jarek Poplawski > > Date: Mon, 18 Aug 2008 12:58:05 +0000 > > > > > On Mon, Aug 18, 2008 at 03:45:29PM +0300, Denys Fedoryshchenko wrote: > > > > Patch applied, got another warning. > > > > > > I hope I'll figure this out before evening. Probably it's safer > > > to stop testing for a while. > > > > We have to put the kfree() of the qdisc back into an RCU handler, > > that's all. > > As a matter of fact, I still have some doubts about this. Top level > qdiscs must be deactivated before destroy and during this process we > make sure nothing can use them anymore. So, since this all is under > rtnl_lock(), I wonder if we really need this qdisc root_lock around > qdisc_destroy() for root qdiscs at all. > > Maybe there are some common lists which depend on this and rtnl_lock > isn't enough for them. If so, maybe it's easier to change locking in > these places. But, of course, I can miss something. > > I'm not against RCU here if it's really needed. Otherwise, this > destroying in softirq context, without rtnl_lock() looks like a > potential obstacle for the future. Hmm.. I see it is considered in another messages - I've to do some reading then. Jarek P.