Linux Virtualization - Feb 2019 - Resource management for ndo_xdp_xmit (Was: [PATCH net] virtio_net: Account for tx bytes and packets on sending xdp_frames)

On Sat, 9 Feb 2019 00:18:31 +0000, Saeed Mahameed wrote:
> On Fri, 2019-02-08 at 15:17 -0800, Saeed Mahameed wrote:
> > On Thu, 2019-02-07 at 19:08 +0000, Saeed Mahameed wrote:  
> > > 
> > > So 
> > > 1) on dev_map_update_elem() we will call
> > > dev->dev->ndo_bpf() to notify the device on the intention
to
> > > start/stop
> > > redirect, and wait for it to create/destroy the HW resources
> > > before/after actually updating the map
> > >   
> > 
> > silly me, dev_map_update_elem must be atomic, we can't hook driver
> > resource allocation to it, it must come as a separate request
> > (syscall)
> > from user space to request to create XDP redirect resources.
> >   
> 
> Well, it is possible to render dev_map_update_elem non-atomic and fail
> BPF programs who try to update it in the verifier
> check_map_func_compatibility.
> 
> if you know of any case where devmap needs to be updated from the BPF
> program please let me know.
Did we find a solution to non-map redirect?

Sorry if I missed the discussion, I couldn't make the iovisor call this
week due to travel.