From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
Bobby Eshleman <bobby.eshleman@gmail.com>
Cc: Bobby Eshleman <bobbyeshleman@gmail.com>,
Bobby Eshleman <bobby.eshleman@bytedance.com>,
Cong Wang <cong.wang@bytedance.com>,
Jiang Wang <jiang.wang@bytedance.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Stefano Garzarella <sgarzare@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hyperv@vger.kernel.org
Subject: Re: [PATCH 0/6] virtio/vsock: introduce dgrams, sk_buff, and qdisc
Date: Thu, 18 Aug 2022 12:28:48 +0800 [thread overview]
Message-ID: <3abb1be9-b12c-e658-0391-8461e28f1b33@redhat.com> (raw)
In-Reply-To: <20220817025250-mutt-send-email-mst@kernel.org>
在 2022/8/17 14:54, Michael S. Tsirkin 写道:
> On Mon, Aug 15, 2022 at 10:56:03AM -0700, Bobby Eshleman wrote:
>> Hey everybody,
>>
>> This series introduces datagrams, packet scheduling, and sk_buff usage
>> to virtio vsock.
>>
>> The usage of struct sk_buff benefits users by a) preparing vsock to use
>> other related systems that require sk_buff, such as sockmap and qdisc,
>> b) supporting basic congestion control via sock_alloc_send_skb, and c)
>> reducing copying when delivering packets to TAP.
>>
>> The socket layer no longer forces errors to be -ENOMEM, as typically
>> userspace expects -EAGAIN when the sk_sndbuf threshold is reached and
>> messages are being sent with option MSG_DONTWAIT.
>>
>> The datagram work is based off previous patches by Jiang Wang[1].
>>
>> The introduction of datagrams creates a transport layer fairness issue
>> where datagrams may freely starve streams of queue access. This happens
>> because, unlike streams, datagrams lack the transactions necessary for
>> calculating credits and throttling.
>>
>> Previous proposals introduce changes to the spec to add an additional
>> virtqueue pair for datagrams[1]. Although this solution works, using
>> Linux's qdisc for packet scheduling leverages already existing systems,
>> avoids the need to change the virtio specification, and gives additional
>> capabilities. The usage of SFQ or fq_codel, for example, may solve the
>> transport layer starvation problem. It is easy to imagine other use
>> cases as well. For example, services of varying importance may be
>> assigned different priorities, and qdisc will apply appropriate
>> priority-based scheduling. By default, the system default pfifo qdisc is
>> used. The qdisc may be bypassed and legacy queuing is resumed by simply
>> setting the virtio-vsock%d network device to state DOWN. This technique
>> still allows vsock to work with zero-configuration.
> The basic question to answer then is this: with a net device qdisc
> etc in the picture, how is this different from virtio net then?
> Why do you still want to use vsock?
Or maybe it's time to revisit an old idea[1] to unify at least the
driver part (e.g using virtio-net driver for vsock then we can all
features that vsock is lacking now)?
Thanks
[1]
https://lists.linuxfoundation.org/pipermail/virtualization/2018-November/039783.html
>
>> In summary, this series introduces these major changes to vsock:
>>
>> - virtio vsock supports datagrams
>> - virtio vsock uses struct sk_buff instead of virtio_vsock_pkt
>> - Because virtio vsock uses sk_buff, it also uses sock_alloc_send_skb,
>> which applies the throttling threshold sk_sndbuf.
>> - The vsock socket layer supports returning errors other than -ENOMEM.
>> - This is used to return -EAGAIN when the sk_sndbuf threshold is
>> reached.
>> - virtio vsock uses a net_device, through which qdisc may be used.
>> - qdisc allows scheduling policies to be applied to vsock flows.
>> - Some qdiscs, like SFQ, may allow vsock to avoid transport layer congestion. That is,
>> it may avoid datagrams from flooding out stream flows. The benefit
>> to this is that additional virtqueues are not needed for datagrams.
>> - The net_device and qdisc is bypassed by simply setting the
>> net_device state to DOWN.
>>
>> [1]: https://lore.kernel.org/all/20210914055440.3121004-1-jiang.wang@bytedance.com/
>>
>> Bobby Eshleman (5):
>> vsock: replace virtio_vsock_pkt with sk_buff
>> vsock: return errors other than -ENOMEM to socket
>> vsock: add netdev to vhost/virtio vsock
>> virtio/vsock: add VIRTIO_VSOCK_F_DGRAM feature bit
>> virtio/vsock: add support for dgram
>>
>> Jiang Wang (1):
>> vsock_test: add tests for vsock dgram
>>
>> drivers/vhost/vsock.c | 238 ++++----
>> include/linux/virtio_vsock.h | 73 ++-
>> include/net/af_vsock.h | 2 +
>> include/uapi/linux/virtio_vsock.h | 2 +
>> net/vmw_vsock/af_vsock.c | 30 +-
>> net/vmw_vsock/hyperv_transport.c | 2 +-
>> net/vmw_vsock/virtio_transport.c | 237 +++++---
>> net/vmw_vsock/virtio_transport_common.c | 771 ++++++++++++++++--------
>> net/vmw_vsock/vmci_transport.c | 9 +-
>> net/vmw_vsock/vsock_loopback.c | 51 +-
>> tools/testing/vsock/util.c | 105 ++++
>> tools/testing/vsock/util.h | 4 +
>> tools/testing/vsock/vsock_test.c | 195 ++++++
>> 13 files changed, 1176 insertions(+), 543 deletions(-)
>>
>> --
>> 2.35.1
next prev parent reply other threads:[~2022-08-18 4:29 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-15 17:56 [PATCH 0/6] virtio/vsock: introduce dgrams, sk_buff, and qdisc Bobby Eshleman
2022-08-15 17:56 ` [PATCH 1/6] vsock: replace virtio_vsock_pkt with sk_buff Bobby Eshleman
2022-08-16 2:30 ` Bobby Eshleman
2022-08-15 17:56 ` [PATCH 2/6] vsock: return errors other than -ENOMEM to socket Bobby Eshleman
2022-08-15 20:01 ` kernel test robot
2022-08-15 23:13 ` kernel test robot
2022-08-16 2:16 ` kernel test robot
2022-08-16 2:30 ` Bobby Eshleman
2022-08-17 5:28 ` [virtio-dev] " Arseniy Krasnov
2022-09-26 13:21 ` Stefano Garzarella
2022-09-26 21:30 ` Bobby Eshleman
2022-08-15 17:56 ` [PATCH 3/6] vsock: add netdev to vhost/virtio vsock Bobby Eshleman
2022-08-16 2:31 ` Bobby Eshleman
2022-08-16 16:38 ` Michael S. Tsirkin
2022-08-16 6:18 ` Bobby Eshleman
2022-08-16 18:07 ` Jakub Kicinski
2022-08-16 7:02 ` Bobby Eshleman
2022-08-16 23:07 ` Jakub Kicinski
2022-08-16 8:29 ` Bobby Eshleman
2022-08-17 1:15 ` Jakub Kicinski
2022-08-16 10:50 ` Bobby Eshleman
2022-08-17 17:20 ` Michael S. Tsirkin
2022-08-18 4:34 ` Jason Wang
2022-08-17 1:23 ` [External] " Cong Wang .
2022-09-06 10:58 ` Michael S. Tsirkin
2022-08-18 14:20 ` Bobby Eshleman
2022-08-15 17:56 ` [PATCH 4/6] virtio/vsock: add VIRTIO_VSOCK_F_DGRAM feature bit Bobby Eshleman
2022-08-16 2:31 ` Bobby Eshleman
2022-09-26 13:17 ` Stefano Garzarella
2022-09-26 21:52 ` Bobby Eshleman
2022-08-15 17:56 ` [PATCH 5/6] virtio/vsock: add support for dgram Bobby Eshleman
2022-08-15 21:02 ` kernel test robot
2022-08-16 2:32 ` Bobby Eshleman
2022-08-17 5:01 ` [virtio-dev] " Arseniy Krasnov
2022-08-16 9:57 ` Bobby Eshleman
2022-08-18 8:24 ` Arseniy Krasnov
2022-08-17 5:42 ` Arseniy Krasnov
2022-08-16 9:58 ` Bobby Eshleman
2022-08-18 8:35 ` Arseniy Krasnov
2022-08-16 20:52 ` Bobby Eshleman
2022-08-19 4:30 ` Arseniy Krasnov
2022-08-15 17:56 ` [PATCH 6/6] vsock_test: add tests for vsock dgram Bobby Eshleman
2022-08-16 2:32 ` Bobby Eshleman
2022-08-15 20:39 ` [PATCH 0/6] virtio/vsock: introduce dgrams, sk_buff, and qdisc Michael S. Tsirkin
2022-08-16 1:55 ` Bobby Eshleman
2022-08-16 2:29 ` Bobby Eshleman
[not found] ` <CAGxU2F7+L-UiNPtUm4EukOgTVJ1J6Orqs1LMvhWWvfL9zWb23g@mail.gmail.com>
2022-08-16 2:35 ` Bobby Eshleman
2022-08-17 6:54 ` Michael S. Tsirkin
2022-08-16 9:42 ` Bobby Eshleman
2022-08-17 17:02 ` Michael S. Tsirkin
2022-08-16 11:08 ` Bobby Eshleman
2022-08-17 17:53 ` Michael S. Tsirkin
2022-08-16 12:10 ` Bobby Eshleman
2022-08-18 4:28 ` Jason Wang [this message]
2022-09-06 9:00 ` Stefano Garzarella
2022-09-06 13:26 ` Stefan Hajnoczi
2022-08-18 14:39 ` Bobby Eshleman
2022-09-08 8:30 ` Stefano Garzarella
2022-09-08 14:36 ` Call to discuss vsock netdev/sk_buff [was Re: [PATCH 0/6] virtio/vsock: introduce dgrams, sk_buff, and qdisc] Stefano Garzarella
2022-09-09 18:13 ` Bobby Eshleman
2022-09-12 18:12 ` Stefano Garzarella
2022-09-09 23:33 ` Bobby Eshleman
2022-09-16 3:51 ` Stefano Garzarella
2022-09-10 16:29 ` Bobby Eshleman
2022-09-26 13:42 ` [PATCH 0/6] virtio/vsock: introduce dgrams, sk_buff, and qdisc Stefano Garzarella
2022-09-26 21:44 ` Bobby Eshleman
2022-09-27 17:45 ` Stefano Garzarella
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