[PATCH] virtio_net: enhance wake/stop tx queue statistics accounting
From: <hidden>
Date: 2025-11-18 09:10:04
Also in:
kvm, lkml, virtualization
Subsystem:
networking drivers, the rest, virtio net driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, "Michael S. Tsirkin", Jason Wang
From: Liming Wu <redacted> This patch refines and strengthens the statistics collection of TX queue wake/stop events introduced by a previous patch. 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 <redacted> --- drivers/net/virtio_net.c | 49 ++++++++++++++++++++++------------------ 1 file changed, 27 insertions(+), 22 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 8e8a179aaa49..f92a90dde2b3 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
@@ -1166,10 +1181,7 @@ static void check_sq_full_and_disable(struct virtnet_info *vi, /* More just got used, free them then recheck. */ free_old_xmit(sq, txq, false); if (sq->vq->num_free >= MAX_SKB_FRAGS + 2) { - netif_start_subqueue(dev, qnum); - u64_stats_update_begin(&sq->stats.syncp); - u64_stats_inc(&sq->stats.wake); - u64_stats_update_end(&sq->stats.syncp); + virtnet_tx_wake_queue(vi, sq); virtqueue_disable_cb(sq->vq); } }
@@ -3068,13 +3080,8 @@ 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 +3271,8 @@ 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 +3523,9 @@ 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 +3542,7 @@ 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