From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Gospodarek Subject: Re: Is skb->queue_mapping valid for received packets? Date: Mon, 13 Jun 2011 22:21:59 -0400 Message-ID: <20110614022159.GL21309@gospo.rdu.redhat.com> References: <4DF6C091.5050301@candelatech.com> <4DF6C23D.9020704@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: NetDev To: Ben Greear Return-path: Received: from mx1.redhat.com ([209.132.183.28]:54327 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753950Ab1FNCWB (ORCPT ); Mon, 13 Jun 2011 22:22:01 -0400 Content-Disposition: inline In-Reply-To: <4DF6C23D.9020704@candelatech.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Jun 13, 2011 at 07:06:53PM -0700, Ben Greear wrote: > On 06/13/2011 06:59 PM, Ben Greear wrote: >> >> Anyone know if skb->queue_mapping is set for incoming packets, ie to >> notify which queue they came in on? I can't find it set anywhere, >> and it appears it is sometimes set to 1 when it should be 0 in >> my system. >> >> Maybe it's never actually set, and I'm just reading some stale >> data? > > Bleh, found it the second I posted. > > Seems it's skb_record_rx_queue(), and funny enough, it seems to add +1, > so if you are trying to bridge pkts from eth0 to eth1 on the same queues, > looks like you need to subtract one on xmit before finding the txqueue. > > Or something like that. > Just saw your response after I replied. :-) The queue_mapping storage is a bit odd, but it generally works. The value stored in queue_mapping should be decremented properly in dev_pick_tx and it should go out of your card with a tx queue that matches the rx queue. There were some issues discovered and fixed with bonding last week related to queue_mapping and I would not be surprised if another stacked interface like bridging had an issue.