* Re: [PATCH net-next v4 0/4] vsock/virtio/vhost: MSG_ZEROCOPY preparations
[not found] <20230727222627.1895355-1-AVKrasnov@sberdevices.ru>
@ 2023-07-28 5:45 ` Michael S. Tsirkin
0 siblings, 0 replies; only message in thread
From: Michael S. Tsirkin @ 2023-07-28 5:45 UTC (permalink / raw)
To: Arseniy Krasnov
Cc: Bobby Eshleman, kvm, netdev, linux-kernel, virtualization,
oxffffaa, Eric Dumazet, Stefan Hajnoczi, kernel, Jakub Kicinski,
Paolo Abeni, David S. Miller
On Fri, Jul 28, 2023 at 01:26:23AM +0300, Arseniy Krasnov wrote:
> Hello,
>
> this patchset is first of three parts of another big patchset for
> MSG_ZEROCOPY flag support:
> https://lore.kernel.org/netdev/20230701063947.3422088-1-AVKrasnov@sberdevices.ru/
overall looks good. Two points I'd like to see addressed:
- what's the performance with all these changes - still same?
- most systems have a copybreak scheme where buffers
smaller than a given size are copied directly.
This will address regression you see with small buffers -
but need to find that value. we know it's between 4k and 32k :)
> During review of this series, Stefano Garzarella <sgarzare@redhat.com>
> suggested to split it for three parts to simplify review and merging:
>
> 1) virtio and vhost updates (for fragged skbs) <--- this patchset
> 2) AF_VSOCK updates (allows to enable MSG_ZEROCOPY mode and read
> tx completions) and update for Documentation/.
> 3) Updates for tests and utils.
>
> This series enables handling of fragged skbs in virtio and vhost parts.
> Newly logic won't be triggered, because SO_ZEROCOPY options is still
> impossible to enable at this moment (next bunch of patches from big
> set above will enable it).
>
> I've included changelog to some patches anyway, because there were some
> comments during review of last big patchset from the link above.
>
> Head for this patchset is 9d0cd5d25f7d45bce01bbb3193b54ac24b3a60f3
>
> Link to v1:
> https://lore.kernel.org/netdev/20230717210051.856388-1-AVKrasnov@sberdevices.ru/
> Link to v2:
> https://lore.kernel.org/netdev/20230718180237.3248179-1-AVKrasnov@sberdevices.ru/
> Link to v3:
> https://lore.kernel.org/netdev/20230720214245.457298-1-AVKrasnov@sberdevices.ru/
>
> Changelog:
> * Patchset rebased and tested on new HEAD of net-next (see hash above).
> * See per-patch changelog after ---.
>
> Arseniy Krasnov (4):
> vsock/virtio/vhost: read data from non-linear skb
> vsock/virtio: support to send non-linear skb
> vsock/virtio: non-linear skb handling for tap
> vsock/virtio: MSG_ZEROCOPY flag support
>
> drivers/vhost/vsock.c | 14 +-
> include/linux/virtio_vsock.h | 6 +
> net/vmw_vsock/virtio_transport.c | 79 +++++-
> net/vmw_vsock/virtio_transport_common.c | 312 ++++++++++++++++++------
> 4 files changed, 330 insertions(+), 81 deletions(-)
>
> --
> 2.25.1
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