From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: "Yongji Xie" <elohimes@gmail.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Coquelin, Maxime" <maxime.coquelin@redhat.com>,
"Yury Kotov" <yury-kotov@yandex-team.ru>,
"Евгений Яковлев" <wrfsh@yandex-team.ru>,
qemu-devel <qemu-devel@nongnu.org>,
zhangyu31@baidu.com, chaiwen@baidu.com, nixun@baidu.com,
lilin24@baidu.com, "Xie Yongji" <xieyongji@baidu.com>
Subject: Re: [Qemu-devel] [PATCH v4 for-4.0 4/7] libvhost-user: Support tracking inflight I/O in shared memory
Date: Tue, 15 Jan 2019 10:58:22 -0500 [thread overview]
Message-ID: <20190115105548-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <a6e0c0b2-bd0b-454c-8280-12e0ec964240@redhat.com>
On Tue, Jan 15, 2019 at 03:52:21PM +0800, Jason Wang wrote:
> Well, this may work but here're my points:
>
> 1) The code want to recover from backed crash by introducing extra space to
> store inflight data, but it still depends on the backend to set/get the
> inflight state
>
> 2) Since the backend could be killed at any time, the backend must have the
> ability to recover from the partial inflight state
>
> So it looks to me 1) tends to be self-contradictory and 2) tends to be
> recursive. The above lines show how tricky could the code looks like.
This is a well studied field. Basically you make sure you commit with an
atomic write. Restartable sequences allow accelerating this even
further.
> Solving this at vhost-user level through at backend is probably wrong. It's
> time to consider the support from virtio itself.
>
> Thanks
I think both approaches have their space.
--
MST
next prev parent reply other threads:[~2019-01-15 15:58 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-09 11:27 [Qemu-devel] [PATCH v4 for-4.0 0/7] vhost-user-blk: Add support for backend reconnecting elohimes
2019-01-09 11:27 ` [Qemu-devel] [PATCH v4 for-4.0 1/7] char-socket: Enable "nowait" option on client sockets elohimes
2019-01-10 12:49 ` Daniel P. Berrangé
2019-01-10 13:19 ` Yongji Xie
2019-01-10 13:24 ` Daniel P. Berrangé
2019-01-10 14:08 ` Yongji Xie
2019-01-10 14:11 ` Daniel P. Berrangé
2019-01-10 14:29 ` Yongji Xie
2019-01-10 16:41 ` Daniel P. Berrangé
2019-01-11 7:50 ` Yongji Xie
2019-01-11 8:32 ` Daniel P. Berrangé
2019-01-11 8:36 ` Yongji Xie
2019-01-15 15:39 ` Daniel P. Berrangé
2019-01-15 16:53 ` Yury Kotov
2019-01-15 17:15 ` Daniel P. Berrangé
2019-01-16 5:39 ` Yongji Xie
2019-01-09 11:27 ` [Qemu-devel] [PATCH v4 for-4.0 2/7] vhost-user: Support transferring inflight buffer between qemu and backend elohimes
2019-01-14 22:25 ` Michael S. Tsirkin
2019-01-15 6:46 ` Yongji Xie
2019-01-15 12:54 ` Michael S. Tsirkin
2019-01-15 14:18 ` Yongji Xie
2019-01-18 2:45 ` Yongji Xie
2019-01-09 11:27 ` [Qemu-devel] [PATCH v4 for-4.0 3/7] libvhost-user: Introduce vu_queue_map_desc() elohimes
2019-01-09 11:27 ` [Qemu-devel] [PATCH v4 for-4.0 4/7] libvhost-user: Support tracking inflight I/O in shared memory elohimes
2019-01-11 3:56 ` Jason Wang
2019-01-11 6:10 ` Yongji Xie
2019-01-15 7:52 ` Jason Wang
2019-01-15 14:51 ` Yongji Xie
2019-01-17 9:57 ` Jason Wang
2019-01-17 14:59 ` Michael S. Tsirkin
2019-01-18 3:57 ` Jason Wang
2019-01-18 3:32 ` Yongji Xie
2019-01-18 3:56 ` Michael S. Tsirkin
2019-01-18 3:59 ` Jason Wang
2019-01-18 4:03 ` Michael S. Tsirkin
2019-01-18 7:01 ` Yongji Xie
2019-01-18 9:26 ` Jason Wang
2019-01-19 12:19 ` Yongji Xie
2019-01-15 15:58 ` Michael S. Tsirkin [this message]
2019-01-17 10:01 ` Jason Wang
2019-01-17 15:04 ` Michael S. Tsirkin
2019-01-09 11:27 ` [Qemu-devel] [PATCH v4 for-4.0 5/7] vhost-user-blk: Add support to get/set inflight buffer elohimes
2019-01-09 11:27 ` [Qemu-devel] [PATCH v4 for-4.0 6/7] vhost-user-blk: Add support to reconnect backend elohimes
2019-01-09 11:27 ` [Qemu-devel] [PATCH v4 for-4.0 7/7] contrib/vhost-user-blk: enable inflight I/O tracking elohimes
2019-01-10 10:25 ` [Qemu-devel] [PATCH v4 for-4.0 0/7] vhost-user-blk: Add support for backend reconnecting Stefan Hajnoczi
2019-01-10 10:59 ` Yongji Xie
2019-01-11 15:53 ` Stefan Hajnoczi
2019-01-11 17:24 ` Michael S. Tsirkin
2019-01-12 4:50 ` Yongji Xie
2019-01-14 10:22 ` Stefan Hajnoczi
2019-01-14 10:55 ` Yongji Xie
2019-01-16 14:28 ` Stefan Hajnoczi
2019-01-10 10:39 ` Marc-André Lureau
2019-01-10 11:09 ` Yongji Xie
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