From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [net-next 2/2] macvlan: Enable qdisc backoff logic. Date: Thu, 26 Aug 2010 15:55:35 +0200 Message-ID: <201008261555.35250.arnd@arndb.de> References: <1282762851-3612-1-git-send-email-greearb@candelatech.com> <201008252159.11227.arnd@arndb.de> <4C7581D2.3010007@candelatech.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Ben Greear Return-path: Received: from moutng.kundenserver.de ([212.227.17.8]:64244 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753255Ab0HZNzi (ORCPT ); Thu, 26 Aug 2010 09:55:38 -0400 In-Reply-To: <4C7581D2.3010007@candelatech.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wednesday 25 August 2010, Ben Greear wrote: > On 08/25/2010 12:59 PM, Arnd Bergmann wrote: > > On Wednesday 25 August 2010 21:27:43 Ben Greear wrote: > >>> I suppose we need to do something in macvtap to handle this as > >>> well, right? A guest trying to send a frame through qemu > >>> or vhost net into macvtap needs to be prevented from sending > >>> more when we get into this path. Right now, we just ignore > >>> the return value of macvlan_start_xmit. > >> > >> I have a similar, though slightly more complex, patch for 802.1q > >> vlans, but I haven't looked at macvtap at all. > >> > >> If these two patches are accepted, I'll post the .1q patch as well. > > > > I think one of us needs to fix macvtap in order for your patch to > > go in, because otherwise there is a memory leak or worse when > > macvtap fails to retransmit the frame. > > With no change, the try_ logic will not be called, so it should > be fully backwards compatible. How? The macvlan driver is used as the back-end for macvtap, so it calls all the same functions: macvtap_write -> macvtap_get_user -> macvlan_start_xmit -> macvlan->queue_xmit -> try_dev_queue_xmit Arnd