Re: [PATCH net-next v3] virtio-net: xsk: support tx wake up

[Menglong Dong]

On 2026/6/22 10:40 Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> write:
> On Tue, 16 Jun 2026 19:59:12 +0800, Menglong Dong <menglong8.dong@xxxxxxxxx> wrote:
> > For now, XDP_RING_NEED_WAKEUP is not supported properly by the virtio-net
> > in the tx path for example: we set xsk_set_tx_need_wakeup() in
> > virtnet_xsk_xmit(), but we didn't call xsk_clear_tx_need_wakeup()
> > anywhere, which means the user will call send() for every packet.
> >
> > We call xsk_set_tx_need_wakeup() after virtnet_xsk_xmit_batch() if sq->vq
> > is empty, as we can't be wakeup by the skb_xmit_done() in this case.
> > Otherwise, we will clear the wakeup flag.
> >
> > Race condition is considered for tx path.
> >
> > Fixes: 89f86675cb03 ("virtio_net: xsk: tx: support xmit xsk buffer")
> 
> This is not a bug, so we do not need this.
> And you post this to net-next.

Okay, I'll remove this tag in the V4.

> 
> 
> > Signed-off-by: Menglong Dong <dongml2@xxxxxxxxxxxxxxx>
> > ---
> > v3:
[...]
> > +
> > +	if (need_wakeup && vring_size == sq->vq->num_free)
> > +		xsk_set_tx_need_wakeup(pool);
> 
> You need to comment this.

Ack!

> 
> 
> > +
[...]
> > +
> >  	if (!is_xdp_raw_buffer_queue(vi, sq - vi->sq))
> >  		check_sq_full_and_disable(vi, vi->dev, sq);
> 
> 
> After fixed above comments, you can add:
> 
> Reviewed-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>

OK! Thanks for the review :)

> 
> Thanks.
> 
> 
> >
> > @@ -1470,9 +1488,6 @@ static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool,
> >  	u64_stats_add(&sq->stats.xdp_tx,  sent);
> >  	u64_stats_update_end(&sq->stats.syncp);
> >
> > -	if (xsk_uses_need_wakeup(pool))
> > -		xsk_set_tx_need_wakeup(pool);
> > -
> >  	return sent;
> >  }
> >
> > --
> > 2.54.0
> >
> 
>