From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net 1/2] macvlan: forbid L2 fowarding offload for macvtap Date: Tue, 07 Jan 2014 00:57:47 -0500 (EST) Message-ID: <20140107.005747.2228695405723185015.davem@davemloft.net> References: <1388978467-2075-1-git-send-email-jasowang@redhat.com> <20140106.154740.590358835696689785.davem@davemloft.net> <52CB71B2.4070005@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com, john.r.fastabend@intel.com, nhorman@tuxdriver.com To: jasowang@redhat.com Return-path: In-Reply-To: <52CB71B2.4070005@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Jason Wang Date: Tue, 07 Jan 2014 11:17:06 +0800 > On 01/07/2014 04:47 AM, David Miller wrote: >> From: Jason Wang >> Date: Mon, 6 Jan 2014 11:21:06 +0800 >> >>> L2 fowarding offload will bypass the rx handler of real device. This will make >>> the packet could not be forwarded to macvtap device. Another problem is the >>> dev_hard_start_xmit() called for macvtap does not have any synchronization. >>> >>> Fix this by forbidding L2 forwarding for macvtap. >>> >>> Cc: John Fastabend >>> Cc: Neil Horman >>> Signed-off-by: Jason Wang >> I think I agree with Neil that the rx_handler change might be the best >> way to fix this. That change seems to have a lot of nice unintended >> side effects, no? > > Not all sides effects are nice. > > One obvious issue is it disables the multiqueue macvtap transmission, > since all queues will contend on a single qdisc lock of macvlan. And > even more, multiqueue macvtap support creating and destroying a queue on > demand which is not supported by L2 forwarding offload. > > So L2 forwarding offload needs more fixes to let the multiqueue macvtap > works. Currently, we really need this patch to make sure macvtap works > as expected. Ok I moved these two patches back to "Under Review". These are pretty last minute and we'll need to make a decision on what to do before Friday if you want these changes to really make it into 3.13