Re: [PATCH net-next 7/8] net/mlx5e: XDP TX forwarding support

On Tue, 20 Sep 2016 08:58:30 -0700
Eric Dumazet [off-list ref] wrote:

On Tue, 2016-09-20 at 08:51 -0700, Tom Herbert wrote:

quoted

On Tue, Sep 20, 2016 at 8:40 AM, Alexei Starovoitov
[off-list ref] wrote:  

quoted

On Tue, Sep 20, 2016 at 03:53:10PM +0300, Tariq Toukan wrote:  

quoted

quoted

quoted

quoted

+  case XDP_ABORTED:  

It is not clearly defined, but I believe XDP_ABORTED should also result
in a warning (calling bpf_warn_invalid_xdp_action(act)).  

I'll add this.  

Certainly NOT.
XDP_ABORTED is an exception case when program does divide by zero.
It should NOT do bpf_warn. It must drop the packet.
We discussed it several months ago.
See mlx4/en_rx.c for canonical implementation.
 

It should at least bump a counter so that the user knows that aborts
are happening.  

I agree.

Same for XDP_TX if/when packet is dropped because output ring is full.

For the XDP_TX case a counter is already incremented[1] but it is a
local ring counter (ring->tx_dropped++).

Do you think we should maintain separate counters for XDP? (to have a
more consistent interface across drivers...)


[1] https://github.com/torvalds/linux/blob/master/drivers/net/ethernet/mellanox/mlx4/en_tx.c#L1181

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer