From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Thibaut Collet <thibaut.collet@6wind.com>
Cc: dev@dpdk.org, Victor Kaplansky <victork@redhat.com>
Subject: Re: [dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support
Date: Tue, 15 Dec 2015 21:18:12 +0800 [thread overview]
Message-ID: <20151215131812.GI29571@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <CABUUfwOkSG92yJ_OH+un4Xp2v+9aN5O_z7Md9z-j-DgNkTwabg@mail.gmail.com>
On Tue, Dec 15, 2015 at 12:47:47PM +0100, Thibaut Collet wrote:
> On Tue, Dec 15, 2015 at 12:43 PM, Thibaut Collet <thibaut.collet@6wind.com>
> wrote:
>
> >
> >
> > On Tue, Dec 15, 2015 at 11:05 AM, Peter Xu <peterx@redhat.com> wrote:
> >
> >> On Tue, Dec 15, 2015 at 11:45:56AM +0300, Pavel Fedin wrote:
> >> > To tell the truth, i don't know. I am also learning qemu internals on
> >> the fly. Indeed, i see that it should announce itself. But
> >> > this brings up a question: why do we need special announce procedure in
> >> vhost-user then?
> >>
> >> I have the same question. Here is my guess...
> >>
> >> In customized networks, maybe people are not using ARP at all? When
> >> we use DPDK, we directly pass through the network logic inside
> >> kernel itself. So logically all the network protocols could be
> >> customized by the user of it. In the customized network, maybe there
> >> is some other protocol (rather than RARP) that would do the same
> >> thing as what ARP/RARP does. So, this SEND_RARP request could give
> >> the vhost-user backend a chance to format its own announce packet
> >> and broadcast (in the SEND_RARP request, the guest's mac address
> >> will be appended).
> >>
> >> CCing Victor to better know the truth...
> >>
> >> Peter
> >>
> >
Hey Thibaut,
First of all, thanks a lot for your lengthy explanation.
> > Hi,
> >
> > 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.
I'm kind of clear how VIRTIO_GUEST_ANNOUNCE works so far, except that I
met a bug, which I will describe in another email.
> > - 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
Can you be more specific about this? Say, what kind of acts the vhost
backend should do exactly?
> > is to update switches' MAC->port maaping as a GARP).
Isn't it vhost library is not aware of swtich at all? How could we
update switches's MAC-port mapping inside vhost library?
> This RARP is a false
> > one, created by the vhost backend,
I'm a bit confused now. You were just saying "vhost backend must act
as it __recevives__ a RARP from the guest", and you are now saying
"the RARP is a false one __created__ by the vhost backend".
Thanks.
--yliu
next prev parent reply other threads:[~2015-12-15 13:18 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-11 8:26 Pavel Fedin
2015-12-11 9:49 ` Yuanhan Liu
2015-12-11 10:22 ` Pavel Fedin
2015-12-14 3:58 ` Peter Xu
2015-12-14 7:30 ` Pavel Fedin
2015-12-14 9:04 ` Peter Xu
2015-12-14 9:46 ` Pavel Fedin
2015-12-14 10:09 ` Peter Xu
2015-12-14 12:09 ` Yuanhan Liu
2015-12-14 13:00 ` Peter Xu
2015-12-14 13:21 ` Yuanhan Liu
2015-12-14 13:28 ` Peter Xu
2015-12-14 13:51 ` Yuanhan Liu
2015-12-14 14:54 ` Pavel Fedin
2015-12-15 8:23 ` Yuanhan Liu
2015-12-15 8:45 ` Pavel Fedin
2015-12-15 8:56 ` Yuanhan Liu
2015-12-15 9:04 ` Pavel Fedin
2015-12-15 10:05 ` Peter Xu
2015-12-15 11:43 ` Thibaut Collet
2015-12-15 11:47 ` Thibaut Collet
2015-12-15 12:24 ` Pavel Fedin
2015-12-15 13:36 ` Yuanhan Liu
2015-12-15 13:48 ` Pavel Fedin
2015-12-15 13:59 ` Yuanhan Liu
2015-12-15 14:58 ` Pavel Fedin
2015-12-16 7:28 ` Yuanhan Liu
2015-12-16 11:57 ` Pavel Fedin
2015-12-16 12:08 ` Yuanhan Liu
2015-12-16 12:43 ` Pavel Fedin
2015-12-16 13:00 ` Yuanhan Liu
2015-12-15 13:18 ` Yuanhan Liu [this message]
2015-12-15 15:07 ` Thibaut Collet
2015-12-15 15:36 ` Pavel Fedin
2015-12-16 2:38 ` Peter Xu
2015-12-16 2:50 ` Yuanhan Liu
2015-12-16 7:05 ` Pavel Fedin
2015-12-15 9:42 ` Peter Xu
-- strict thread matches above, loose matches on Subject: below --
2015-12-02 3:43 Yuanhan Liu
2015-12-02 14:10 ` Victor Kaplansky
2015-12-02 14:33 ` Yuanhan Liu
2015-12-09 3:41 ` Xie, Huawei
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