From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [PATCH] pkt_sched: Destroy gen estimators under rtnl_lock(). Date: Wed, 13 Aug 2008 10:50:52 +0000 Message-ID: <20080813105052.GA6838@ff.dom.local> References: <20080813061317.GA4251@ff.dom.local> <20080812.231633.193696650.davem@davemloft.net> <20080813065302.GB4251@ff.dom.local> <20080813.022549.203848195.davem@davemloft.net> <20080813102701.GD5367@ff.dom.local> <20080813104238.GA11374@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , netdev@vger.kernel.org To: Herbert Xu Return-path: Received: from fg-out-1718.google.com ([72.14.220.159]:39988 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752411AbYHMKvB (ORCPT ); Wed, 13 Aug 2008 06:51:01 -0400 Received: by fg-out-1718.google.com with SMTP id 19so1636734fgg.17 for ; Wed, 13 Aug 2008 03:50:59 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20080813104238.GA11374@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Aug 13, 2008 at 08:42:38PM +1000, Herbert Xu wrote: > On Wed, Aug 13, 2008 at 10:27:01AM +0000, Jarek Poplawski wrote: > > > > - in net_tx_action() we can hit a place just after clear_bit() where > > none of these bits is set. Of course, hitting this 2 times in a row > > seems to be very unprobable, yet possible, and a lock isn't helpful > > here, so probably some change around this would make this nicer. > > > > - isn't there possible some longer ping-pong between qdic_run() and > > net_tx_action() when dev_requeue_skb() would get it back to > > __netif_schedule() and so on (with NETDEV_TX_BUSY)? > > Good point. I think we should add an aliveness check in both > net_tx_action and qdisc_run. In fact the net_tx_action problem > existed previously as well. But it is pretty darn unlikely. Yes, it seems qdisc_reset() doesn't have to help with this, so probably there is needed some requeue counter or something... Jarek P.