From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] net: reset skb queue mapping when rx'ing over tunnel Date: Sun, 26 Sep 2010 18:48:56 -0700 (PDT) Message-ID: <20100926.184856.229756077.davem@davemloft.net> References: <1285293960.2380.23.camel@edumazet-laptop> <1285397350.2478.102.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: therbert@google.com, netdev@vger.kernel.org, chavey@google.com To: eric.dumazet@gmail.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:60203 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757665Ab0I0Bsg convert rfc822-to-8bit (ORCPT ); Sun, 26 Sep 2010 21:48:36 -0400 In-Reply-To: <1285397350.2478.102.camel@edumazet-laptop> Sender: netdev-owner@vger.kernel.org List-ID: =46rom: Eric Dumazet Date: Sat, 25 Sep 2010 08:49:10 +0200 > Le vendredi 24 septembre 2010 =E0 09:18 -0700, Tom Herbert a =E9crit = : >> > Hmm... >> > >> > This would need to be reverted later when tunnels are updated to b= e >> > multiqueue aware ? I made an attempt with GRE some days ago. >> > >> > I dont understand why this patch is needed, since get_rps_cpu() ha= s a >> > check anyway >> > >> I think the skb queue_mapping should correspond to a queue in the >> skb's device as an invariant. In the case that an skb's device is >> change from a multiqueue device to single queue device (like GRE), t= he >> inconsistency in the queue_mapping is fairly innocuous, we get one >> warning but will pretty much take the unlikely branch for GRE packet= s >> then on. But imagine a case where skb's device was change from one >> multiqueue device to another, but the queue mapping was not also >> updated. This would cause poor weighting in get_rps_cpus. For >> example, if the new device had fewer queues than the old one, >> get_rps_cpu will bias toward using queue 0's rps mask. >=20 > I believe your patch is fine. Thanks >=20 > Acked-by: Eric Dumazet Applied, thanks everyone.