Re: [net PATCH] mlx4: fix XDP_TX is acting like XDP_PASS on TX ring full

On Fri, 16 Sep 2016 13:43:50 -0700
Brenden Blanco [off-list ref] wrote:

On Fri, Sep 16, 2016 at 10:36:12PM +0200, Jesper Dangaard Brouer wrote:

quoted

The XDP_TX action can fail transmitting the frame in case the TX ring
is full or port is down.  In case of TX failure it should drop the
frame, and not as now call 'break' which is the same as XDP_PASS.

Fixes: 9ecc2d86171a ("net/mlx4_en: add xdp forwarding and data write support")
Signed-off-by: Jesper Dangaard Brouer <redacted>  

You could in theory have also tried to recycle the page instead of
dropping it, but that's probably not worth optimizing when tx is backed
up, as you'll only save a handful of page_put's. The code to do so
wouldn't have been pretty.

Yes, we could (and perhaps should) recycle the page instead. But as you
also mention it would not look pretty. I'll send a V3, as XDPs primary
concern is performance.

Reviewed-by: Brenden Blanco <redacted>

-- 
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