Re: [PATCH 29/33] virtio_net: xsk: tx: support tx

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

On Fri, 3 Feb 2023 09:39:25 +0100, Maciej Fijalkowski <maciej.fijalkowski@intel.com> wrote:
> On Thu, Feb 02, 2023 at 07:00:54PM +0800, Xuan Zhuo wrote:
> > The driver's tx napi is very important for XSK. It is responsible for
> > obtaining data from the XSK queue and sending it out.
> >
> > At the beginning, we need to trigger tx napi.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> >  drivers/net/virtio/main.c |  12 +++-
> >  drivers/net/virtio/xsk.c  | 146 ++++++++++++++++++++++++++++++++++++++
> >  drivers/net/virtio/xsk.h  |   2 +
> >  3 files changed, 159 insertions(+), 1 deletion(-)
> >
>
> (...)
>
> > +static int virtnet_xsk_xmit_batch(struct send_queue *sq,
> > +				  struct xsk_buff_pool *pool,
> > +				  unsigned int budget,
> > +				  struct virtnet_sq_stats *stats)
> > +{
> > +	int ret = XSK_XMIT_NO_BUDGET;
> > +	struct xdp_desc desc;
> > +	int err, packet = 0;
> > +
> > +	while (budget-- > 0) {
> > +		if (sq->vq->num_free < 2) {
> > +			__free_old_xmit(sq, true, stats);
> > +			if (sq->vq->num_free < 2) {
> > +				ret = XSK_XMIT_DEV_BUSY;
> > +				break;
> > +			}
> > +		}
> > +
> > +		if (!xsk_tx_peek_desc(pool, &desc)) {
>
> anything that stopped from using xsk_tx_peek_release_desc_batch() ?


Great!

Will fix.

Thanks.


>
> > +			ret = XSK_XMIT_DONE;
> > +			break;
> > +		}
> > +
> > +		err = virtnet_xsk_xmit_one(sq, pool, &desc);
> > +		if (unlikely(err)) {
> > +			ret = XSK_XMIT_DEV_BUSY;
> > +			break;
> > +		}
> > +
> > +		++packet;
> > +
> > +		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))
> > +			++stats->kicks;
> > +	}
> > +
> > +	if (packet) {
> > +		stats->xdp_tx += packet;
> > +
> > +		xsk_tx_release(pool);
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool,
> > +		      int budget)
> > +{
> > +	struct virtnet_sq_stats stats = {};
> > +	bool busy;
> > +	int ret;
> > +
> > +	__free_old_xmit(sq, true, &stats);
> > +
> > +	if (xsk_uses_need_wakeup(pool))
> > +		xsk_set_tx_need_wakeup(pool);
> > +
> > +	ret = virtnet_xsk_xmit_batch(sq, pool, budget, &stats);
> > +	switch (ret) {
> > +	case XSK_XMIT_DONE:
> > +		/* xsk tx qeueu has been consumed done. should complete napi. */
> > +		busy = false;
> > +		break;
> > +
> > +	case XSK_XMIT_NO_BUDGET:
> > +		/* reach the budget limit. should let napi run again. */
> > +		busy = true;
> > +		break;
> > +
> > +	case XSK_XMIT_DEV_BUSY:
> > +		/* sq vring is full, should complete napi. wait for tx napi been
> > +		 * triggered by interrupt.
> > +		 */
> > +		busy = false;
> > +		break;
> > +	}
> > +
> > +	virtnet_xsk_check_queue(sq);
> > +
> > +	u64_stats_update_begin(&sq->stats.syncp);
> > +	sq->stats.packets += stats.packets;
> > +	sq->stats.bytes += stats.bytes;
> > +	sq->stats.kicks += stats.kicks;
> > +	sq->stats.xdp_tx += stats.xdp_tx;
> > +	u64_stats_update_end(&sq->stats.syncp);
> > +
> > +	return busy;
> > +}
> > +
> >  static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct receive_queue *rq,
> >  				    struct xsk_buff_pool *pool, struct net_device *dev)
> >  {
> > diff --git a/drivers/net/virtio/xsk.h b/drivers/net/virtio/xsk.h
> > index ad684c812091..15f1540a5803 100644
> > --- a/drivers/net/virtio/xsk.h
> > +++ b/drivers/net/virtio/xsk.h
> > @@ -20,4 +20,6 @@ static inline u32 ptr_to_xsk(void *ptr)
> >  }
> >
> >  int virtnet_xsk_pool_setup(struct net_device *dev, struct netdev_bpf *xdp);
> > +bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool,
> > +		      int budget);
> >  #endif
> > --
> > 2.32.0.3.g01195cf9f
> >
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