Commit cfeb7cd8 authored by Liming Wu's avatar Liming Wu Committed by Jakub Kicinski
Browse files

virtio_net: enhance wake/stop tx queue statistics accounting 



This patch refines and strengthens the statistics collection of TX queue
wake/stop events introduced by commit c39add9b ("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: default avatarLiming Wu <liming.wu@jaguarmicro.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Link: https://patch.msgid.link/20251120015320.1418-1-liming.wu@jaguarmicro.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 8ccd1160

drivers/net/virtio_net.c

+26 −18
Original line number Diff line number Diff line
@@ -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
@@ -3080,13 +3095,8 @@ 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);

	}
@@ -3276,13 +3286,8 @@ 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);
@@ -3537,6 +3542,9 @@ 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);

}
@@ -3553,7 +3561,7 @@ 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)