From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: regression: UFO removal breaks kvm live migration Date: Wed, 8 Nov 2017 21:53:27 +0900 Message-ID: <360943ad-2882-dda4-fb68-fd94f78dbfff@redhat.com> References: <446b71fc-6ffc-2bb0-bae1-69424805de91@redhat.com> <20171108.203231.310648804772108001.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Cc: willemdebruijn.kernel@gmail.com, mkubecek@suse.cz, netdev@vger.kernel.org, mst@redhat.com, vyasevic@redhat.com, Paolo Bonzini To: David Miller Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46266 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752336AbdKHMxj (ORCPT ); Wed, 8 Nov 2017 07:53:39 -0500 In-Reply-To: <20171108.203231.310648804772108001.davem@davemloft.net> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 2017年11月08日 20:32, David Miller wrote: > From: Jason Wang > Date: Wed, 8 Nov 2017 17:25:48 +0900 > >> On 2017年11月08日 17:08, Willem de Bruijn wrote: >>> That won't help in the short term. I'm still reading up to see if >>> there are >>> any other options besides reimplement or advertise-but-drop, such as >>> an implicit trigger that would make the guest renegotiate. It's >>> unlikely, but >>> worth a look.. >> Yes, this looks hard. And even if we can manage to do this, it looks >> an overkill since it will impact all guest after migration. > Like Willem I would much prefer "advertise-but-drop" if it works. This makes migration work but all guest UFO traffic will stall. > > In the long term feature renegotiation triggers are a must. > > There is no way for us to remove features otherwise. We can remove if we don't break userspace(guest). > In my opinion > this will even make migrations more powerful. But this does not help for guest running old version of kernel which still think UFO work. Thanks