Re: [PATCH 1/1] virtio/vsock: Make vsock virtio packet buff size configurable

[Stefano Garzarella]

On Fri, Dec 09, 2022 at 07:48:02PM +0000, Carlos Llamas wrote:
> On Thu, Jul 22, 2021 at 02:55:19PM +0200, Stefano Garzarella wrote:
> > >
> > > +uint virtio_transport_max_vsock_pkt_buf_size = 1024 * 64;
> > > +module_param(virtio_transport_max_vsock_pkt_buf_size, uint, 0444);
> > > +EXPORT_SYMBOL_GPL(virtio_transport_max_vsock_pkt_buf_size);
> > > +
>
> I'm interested on this functionality, so I could take this on.

Great!
We are changing the packet handling using sk_buff [1], so I think it's 
better to rebase on that work that should be merged in net-next after 
the current merge window will close.

> > Maybe better to add an entry under sysfs similar to what Jiang proposed
> > here:
> > https://lists.linuxfoundation.org/pipermail/virtualization/2021-June/054769.html
>
> Having a look at Jiang's RFC patch it seems the proposed sysfs node
> hangs off from the main kernel object e.g. /sys/kernel. So I wonder if
> there is a more appropriate parent for this knob?

Agree, what about /sys/devices ?
I would take a closer look at what is recommend in this case.

> Also, I noticed that Ram's patch here is using read-only permissions for
> the module parameter and switching to sysfs would mean opening this knob
> up to be dynamically configured? I'd need to be careful here.

True, but even if it's changed while we're running, I don't think it's a 
big problem.

Maybe the problem here would be the allocation of RX buffers made during 
the probe. Could this be a good reason to use a module parameter?

Thanks,
Stefano

[1] 
https://lore.kernel.org/lkml/20221202173520.10428-1-bobby.eshleman@xxxxxxxxxxxxx/