Re: [PATCH net-next v8 0/4] vsock/virtio/vhost: MSG_ZEROCOPY preparations

[Arseniy Krasnov]

Hello Stefano,

On 14.09.2023 17:07, Stefano Garzarella wrote:
> Hi Arseniy,
> 
> On Mon, Sep 11, 2023 at 11:22:30PM +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@xxxxxxxxxxxxxx/
>>
>> During review of this series, Stefano Garzarella <sgarzare@xxxxxxxxxx>
>> 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.
> 
> Thanks, I left some comments on patch 4, the others LGTM.
> Sorry to not having spotted them before, but moving
> virtio_transport_alloc_skb() around the file, made the patch a little
> confusing and difficult to review.

Sure, no problem, I'll fix them! Thanks for review.

> 
> In addition, I started having failures of test 14 (server: host,
> client: guest), so I looked better to see if there was anything wrong,
> but it fails me even without this series applied.
> 
> It happens to me intermittently (~30%), does it happen to you?
> Can you take a look at it?

Yes! sometime ago I also started to get fails of this test, not ~30%,
significantly rare, but it depends on environment I guess, anyway I'm going to
look at this on the next few days

Thanks, Arseniy

> 
> host$ ./vsock_test --mode=server --control-port=12345 --peer-cid=4
> ...
> 14 - SOCK_STREAM virtio skb merge...expected recv(2) returns 8 bytes, got 3
> 
> guest$ ./vsock_test --mode=client --control-host=192.168.133.2 --control-port=12345 --peer-cid=2
> 
> Thanks,
> Stefano
>