On Thu, Nov 20, 2025 at 09:53:20AM +0800, [email protected] wrote:
> From: Liming Wu <[email protected]>
> 
> This patch refines and strengthens the statistics collection of TX queue
> wake/stop events introduced by commit c39add9b2423 ("virtio_net: Add TX
> stopped and wake counters").
> 
> Previously, the driver only recorded partial wake/stop statistics
> for TX queues. Some wake events triggered by 'skb_xmit_done()' or resume
> operations were not counted, which made the per-queue metrics incomplete.
> 
> Signed-off-by: Liming Wu <[email protected]>

Acked-by: Michael S. Tsirkin <[email protected]>

> ---
>  drivers/net/virtio_net.c | 44 ++++++++++++++++++++++++----------------
>  1 file changed, 26 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 8e8a179aaa49..b714b190db2a 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -775,10 +775,26 @@ static bool virtqueue_napi_complete(struct napi_struct 
> *napi,
>       return false;
>  }
>  
> +static void virtnet_tx_wake_queue(struct virtnet_info *vi,
> +                             struct send_queue *sq)
> +{
> +     unsigned int index = vq2txq(sq->vq);
> +     struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, index);
> +
> +     if (netif_tx_queue_stopped(txq)) {
> +             u64_stats_update_begin(&sq->stats.syncp);
> +             u64_stats_inc(&sq->stats.wake);
> +             u64_stats_update_end(&sq->stats.syncp);
> +             netif_tx_wake_queue(txq);
> +     }
> +}
> +
>  static void skb_xmit_done(struct virtqueue *vq)
>  {
>       struct virtnet_info *vi = vq->vdev->priv;
> -     struct napi_struct *napi = &vi->sq[vq2txq(vq)].napi;
> +     unsigned int index = vq2txq(vq);
> +     struct send_queue *sq = &vi->sq[index];
> +     struct napi_struct *napi = &sq->napi;
>  
>       /* Suppress further interrupts. */
>       virtqueue_disable_cb(vq);
> @@ -786,8 +802,7 @@ static void skb_xmit_done(struct virtqueue *vq)
>       if (napi->weight)
>               virtqueue_napi_schedule(napi, vq);
>       else
> -             /* We were probably waiting for more output buffers. */
> -             netif_wake_subqueue(vi->dev, vq2txq(vq));
> +             virtnet_tx_wake_queue(vi, sq);
>  }
>  
>  #define MRG_CTX_HEADER_SHIFT 22
> @@ -3068,13 +3083,8 @@ static void virtnet_poll_cleantx(struct receive_queue 
> *rq, int budget)
>                       free_old_xmit(sq, txq, !!budget);
>               } while (unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
>  
> -             if (sq->vq->num_free >= MAX_SKB_FRAGS + 2 &&
> -                 netif_tx_queue_stopped(txq)) {
> -                     u64_stats_update_begin(&sq->stats.syncp);
> -                     u64_stats_inc(&sq->stats.wake);
> -                     u64_stats_update_end(&sq->stats.syncp);
> -                     netif_tx_wake_queue(txq);
> -             }
> +             if (sq->vq->num_free >= MAX_SKB_FRAGS + 2)
> +                     virtnet_tx_wake_queue(vi, sq);
>  
>               __netif_tx_unlock(txq);
>       }
> @@ -3264,13 +3274,8 @@ static int virtnet_poll_tx(struct napi_struct *napi, 
> int budget)
>       else
>               free_old_xmit(sq, txq, !!budget);
>  
> -     if (sq->vq->num_free >= MAX_SKB_FRAGS + 2 &&
> -         netif_tx_queue_stopped(txq)) {
> -             u64_stats_update_begin(&sq->stats.syncp);
> -             u64_stats_inc(&sq->stats.wake);
> -             u64_stats_update_end(&sq->stats.syncp);
> -             netif_tx_wake_queue(txq);
> -     }
> +     if (sq->vq->num_free >= MAX_SKB_FRAGS + 2)
> +             virtnet_tx_wake_queue(vi, sq);
>  
>       if (xsk_done >= budget) {
>               __netif_tx_unlock(txq);
> @@ -3521,6 +3526,9 @@ static void virtnet_tx_pause(struct virtnet_info *vi, 
> struct send_queue *sq)
>  
>       /* Prevent the upper layer from trying to send packets. */
>       netif_stop_subqueue(vi->dev, qindex);
> +     u64_stats_update_begin(&sq->stats.syncp);
> +     u64_stats_inc(&sq->stats.stop);
> +     u64_stats_update_end(&sq->stats.syncp);
>  
>       __netif_tx_unlock_bh(txq);
>  }
> @@ -3537,7 +3545,7 @@ static void virtnet_tx_resume(struct virtnet_info *vi, 
> struct send_queue *sq)
>  
>       __netif_tx_lock_bh(txq);
>       sq->reset = false;
> -     netif_tx_wake_queue(txq);
> +     virtnet_tx_wake_queue(vi, sq);
>       __netif_tx_unlock_bh(txq);
>  
>       if (running)
> -- 
> 2.34.1


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