On 2018/08/01 10:31, Jason Wang wrote:

On 2018年07月31日 17:57, Toshiaki Makita wrote:

quoted

On 2018/07/31 18:43, Jason Wang wrote:

quoted

Commit 5b8f3c8d30a6 ("virtio_net: Add XDP related stats") tries to
count TX XDP stats in virtnet_receive(). This will cause several
issues:

- virtnet_xdp_sq() was called without checking whether or not XDP is
   set. This may cause out of bound access when there's no enough txq
   for XDP.
- Stats were updated even if there's no XDP/XDP_TX.>
Fixing this by reusing virtnet_xdp_xmit() for XDP_TX which can counts
TX XDP counter itself and remove the unnecessary tx stats embedded in
rx stats.

Thanks for fixing this.
I wanted to avoid calling u64_stats_update_begin() (i.e. smp_wmb() in 32
bit systems) for every packet. So I'd like to keep sq stats in
virtnet_rx_stats.

We can optimize this by adding batching on top. (virtnet_xdp_xmit()
accepts an array of xdp frames). If you like, please send a patch for this.

Yes, that sounds like a better optimization. will think about it...

Thanks,
Toshiaki Makita

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