From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout1.w1.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) by dpdk.org (Postfix) with ESMTP id F0FFCA6A for ; Tue, 15 Dec 2015 13:24:51 +0100 (CET) Received: from eucpsbgm1.samsung.com (unknown [203.254.199.244]) by mailout1.w1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NZE005ZGFTEN890@mailout1.w1.samsung.com> for dev@dpdk.org; Tue, 15 Dec 2015 12:24:50 +0000 (GMT) X-AuditID: cbfec7f4-f79026d00000418a-0c-56700692efdb Received: from eusync1.samsung.com ( [203.254.199.211]) by eucpsbgm1.samsung.com (EUCPMTA) with SMTP id 1F.3C.16778.29600765; Tue, 15 Dec 2015 12:24:50 +0000 (GMT) Received: from fedinw7x64 ([106.109.131.169]) by eusync1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTPA id <0NZE007ONFTCNG10@eusync1.samsung.com>; Tue, 15 Dec 2015 12:24:50 +0000 (GMT) From: Pavel Fedin To: 'Thibaut Collet' , 'Peter Xu' References: <000001d133ed$b2446eb0$16cd4c10$@samsung.com> <20151211094934.GX29571@yliu-dev.sh.intel.com> <001c01d133fd$d3a7d870$7af78950$@samsung.com> <20151214035842.GB18437@pxdev.xzpeter.org> <20151215082324.GG29571@yliu-dev.sh.intel.com> <007f01d13715$042a0a80$0c7e1f80$@samsung.com> <20151215100548.GD32243@pxdev.xzpeter.org> In-reply-to: Date: Tue, 15 Dec 2015 15:24:48 +0300 Message-id: <00b601d13733$97e063a0$c7a12ae0$@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=UTF-8 Content-transfer-encoding: quoted-printable X-Mailer: Microsoft Outlook 14.0 Thread-index: AQOYHvn87qB/n3eE/cMtloPRrGw32gEpxH/xAfOP4FMB9WC4FAK9V+xZANbfXxkC1IozlQF4nG1RAiBA49CaxYVXkA== Content-language: ru X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrBLMWRmVeSWpSXmKPExsVy+t/xy7qT2ArCDLrfSFu8+7SdyWLL/m/s Ft0999gtFh84zOzA4nGx/w6jx68FS1k93u+7yhbAHMVlk5Kak1mWWqRvl8CVMf/FbtaC19wV Cw9OYm9g3M7ZxcjJISFgInHmQDcLhC0mceHeerYuRi4OIYGljBIL9k+Gcr4zSlw695gNpIpN QF3i9NcPYB0iAv4S/2bsB7OZBSwldh3fBdXwmFli/5lT7CAJToFgif6N91hBbGEBX4mXS58w gdgsAqoS10/9ALI5OHiBmldOFwEJ8woISvyYfA9qprrEpHmLmCFsbYkn7y6wQlyqILHj7GtG iBtyJL7cfw5VIyIx7d895gmMQrOQjJqFZNQsJKNmIWlZwMiyilE0tTS5oDgpPddQrzgxt7g0 L10vOT93EyMk/L/sYFx8zOoQowAHoxIP7w/W/DAh1sSy4srcQ4wSHMxKIrwP/wGFeFMSK6tS i/Lji0pzUosPMUpzsCiJ887d9T5ESCA9sSQ1OzW1ILUIJsvEwSnVwCi+cjKz/obftxds+r8+ Nn/mdabcgO4VDY96z3g01Tzh3MLZvsv8nshdVd+aPbnejgdtWoV+ralMUtCJstl+Y0ttyi7O yc8bHk/febafe31ejsuRoNTEPuf1K8TcHoYaMN7v0BP02Na/8WWA0wLv5ctnT54geXqOWcDf ee3q5+Z9frSTt231KV8lluKMREMt5qLiRACsWaafewIAAA== Cc: dev@dpdk.org, 'Victor Kaplansky' Subject: Re: [dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Dec 2015 12:24:52 -0000 Hello! > After a migration, to avoid network outage, the guest must announce = its new location to the L2 layer, typically with a GARP. Otherwise = requests sent to > the guest arrive to the old host until a ARP request is sent (after 30 = seconds) or the guest sends some data. > QEMU implementation of self announce after a migration with a vhost = backend is the following: > - If the VIRTIO_GUEST_ANNOUNCE feature has been negotiated the guest = sends automatically a GARP. > - Else if the vhost backend implements VHOST_USER_SEND_RARP this = request is sent to the vhost backend. When this message is received the = vhost backend > must act as it receives a RARP from the guest (purpose of this RARP is = to update switches' MAC->port maaping as a GARP). This RARP is a false = one, > created by the vhost backend, > - Else nothing is done and we have a network outage until a ARP is = sent or the guest sends some data. But what is qemu_announce_self() then? It's just unconditionally = triggered after migration, but indeed sends some strange thing. > VIRTIO_GUEST_ANNOUNCE feature is negotiated if: > - the vhost backend announces the support of this feature. Maybe QEMU = can be updated to support unconditionnaly this feature Wrong. I tried to unconditionally enforce it in qemu (my guest does = support it), and the link stopped working at all. I don't understand = why. Kind regards, Pavel Fedin Expert Engineer Samsung Electronics Research center Russia