From: "Michael S. Tsirkin" <mst@redhat.com>
To: "Xin, Xiaohui" <xiaohui.xin@intel.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mingo@elte.hu" <mingo@elte.hu>,
"jdike@c2.user-mode-linux.org" <jdike@c2.user-mode-linux.org>,
"yzhao81@gmail.com" <yzhao81@gmail.com>
Subject: Re: [PATCH 1/3] A device for zero-copy based on KVM virtio-net.
Date: Wed, 7 Apr 2010 11:15:32 +0300 [thread overview]
Message-ID: <20100407081532.GB9550@redhat.com> (raw)
In-Reply-To: <97F6D3BD476C464182C1B7BABF0B0AF5C183234A@shzsmsx502.ccr.corp.intel.com>
On Wed, Apr 07, 2010 at 10:41:08AM +0800, Xin, Xiaohui wrote:
> Michael,
>
> >> Qemu needs a userspace write, is that a synchronous one or
> >>asynchronous one?
>
> >It's a synchronous non-blocking write.
> Sorry, why the Qemu live migration needs the device have a userspace write?
> how does the write operation work? And why a read operation is not cared here?
>
> Thanks
> Xiaohui
Roughly, with ethernet bridges, moving a device from one location in
the network to another makes forwarding tables incorrect (or incomplete),
until outgoing traffic from the device causes these tables
to be updated. Since there's no guarantee that guest
will generate outgoing traffic, after migration qemu sends out several
dummy packets itself.
--
MST
next prev parent reply other threads:[~2010-04-07 8:19 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1267868318-19268-1-git-send-email-xiaohui.xin@intel.com>
2010-03-07 10:50 ` [PATCH v1 0/3] Provide a zero-copy method on KVM virtio-net Michael S. Tsirkin
2010-03-09 7:47 ` Xin, Xiaohui
[not found] ` <1267868318-19268-2-git-send-email-xiaohui.xin@intel.com>
[not found] ` <1267868318-19268-3-git-send-email-xiaohui.xin@intel.com>
[not found] ` <1267868318-19268-4-git-send-email-xiaohui.xin@intel.com>
2010-03-06 17:18 ` [PATCH v1 3/3] Let host NIC driver to DMA to guest user space Stephen Hemminger
2010-03-08 11:18 ` Michael S. Tsirkin
2010-03-07 11:18 ` [PATCH v1 2/3] Provides multiple submits and asynchronous notifications Michael S. Tsirkin
2010-03-15 8:46 ` Xin, Xiaohui
2010-03-15 9:23 ` Michael S. Tsirkin
2010-03-16 9:32 ` Xin Xiaohui
2010-03-16 11:33 ` [PATCH " Michael S. Tsirkin
2010-03-17 9:48 ` Xin, Xiaohui
2010-03-17 10:27 ` Michael S. Tsirkin
2010-04-01 9:14 ` Xin Xiaohui
2010-04-01 11:02 ` [PATCH " Michael S. Tsirkin
2010-04-02 2:16 ` Xin, Xiaohui
2010-04-04 11:40 ` Michael S. Tsirkin
2010-04-06 5:46 ` Xin, Xiaohui
2010-04-06 7:51 ` Michael S. Tsirkin
2010-04-07 1:36 ` Xin, Xiaohui
2010-04-07 8:18 ` Michael S. Tsirkin
2010-04-08 9:07 ` xiaohui.xin
2010-03-08 11:28 ` [PATCH v1 1/3] A device for zero-copy based on KVM virtio-net Michael S. Tsirkin
2010-04-01 9:27 ` Xin Xiaohui
2010-04-01 11:08 ` [PATCH " Michael S. Tsirkin
2010-04-06 5:41 ` Xin, Xiaohui
2010-04-06 7:49 ` Michael S. Tsirkin
2010-04-07 2:41 ` Xin, Xiaohui
2010-04-07 8:15 ` Michael S. Tsirkin [this message]
2010-04-07 9:00 ` xiaohui.xin
2010-04-07 11:17 ` [PATCH " Michael S. Tsirkin
2010-02-10 11:48 [PATCH 0/3] Provide a zero-copy method " Xin Xiaohui
2010-02-10 11:48 ` [PATCH 1/3] A device for zero-copy based " Xin Xiaohui
2010-02-10 15:17 ` Eric Dumazet
2010-02-11 5:33 ` Xin, Xiaohui
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