Re: [PATCH RFC net-next v2 0/3] vsock: add support for sockmap

[Stefano Garzarella <sgarzare@redhat.com>]

Hi Bobby,
sorry for my late reply, but I have been offline these days.
I came back a few days ago and had to work off some accumulated work :-)

On Mon, Jan 30, 2023 at 08:35:11PM -0800, Bobby Eshleman wrote:
>Add support for sockmap to vsock.
>
>We're testing usage of vsock as a way to redirect guest-local UDS requests to
>the host and this patch series greatly improves the performance of such a
>setup.
>
>Compared to copying packets via userspace, this improves throughput by 121% in
>basic testing.
>
>Tested as follows.
>
>Setup: guest unix dgram sender -> guest vsock redirector -> host vsock server
>Threads: 1
>Payload: 64k
>No sockmap:
>- 76.3 MB/s
>- The guest vsock redirector was
>  "socat VSOCK-CONNECT:2:1234 UNIX-RECV:/path/to/sock"
>Using sockmap (this patch):
>- 168.8 MB/s (+121%)
>- The guest redirector was a simple sockmap echo server,
>  redirecting unix ingress to vsock 2:1234 egress.
>- Same sender and server programs
>
>*Note: these numbers are from RFC v1
>
>Only the virtio transport has been tested. The loopback transport was used in
>writing bpf/selftests, but not thoroughly tested otherwise.
>
>This series requires the skb patch.
>
>Changes in v2:
>- vsock/bpf: rename vsock_dgram_* -> vsock_*
>- vsock/bpf: change sk_psock_{get,put} and {lock,release}_sock() order to
>	     minimize slock hold time
>- vsock/bpf: use "new style" wait
>- vsock/bpf: fix bug in wait log
>- vsock/bpf: add check that recvmsg sk_type is one dgram, seqpacket, or stream.
>	     Return error if not one of the three.
>- virtio/vsock: comment __skb_recv_datagram() usage
>- virtio/vsock: do not init copied in read_skb()
>- vsock/bpf: add ifdef guard around struct proto in dgram_recvmsg()
>- selftests/bpf: add vsock loopback config for aarch64
>- selftests/bpf: add vsock loopback config for s390x
>- selftests/bpf: remove vsock device from vmtest.sh qemu machine
>- selftests/bpf: remove CONFIG_VIRTIO_VSOCKETS=y from config.x86_64
>- vsock/bpf: move transport-related (e.g., if (!vsk->transport)) checks out of
>	     fast path

The series looks in a good shape.
I left some small comments on the first patch, but I think the next
version could be without RFC, so we can receive some feedbacks from
net/bpf maintainers.

Great job!

Thanks,
Stefano