Fri, May 10, 2024 at 09:11:16AM CEST, hengqi@xxxxxxxxxxxxxxxxx wrote: >On Thu, 9 May 2024 13:46:15 +0200, Jiri Pirko <jiri@xxxxxxxxxxx> wrote: >> From: Jiri Pirko <jiri@xxxxxxxxxx> >> >> Add support for Byte Queue Limits (BQL). > >Historically both Jason and Michael have attempted to support BQL >for virtio-net, for example: > >https://lore.kernel.org/netdev/21384cb5-99a6-7431-1039-b356521e1bc3@xxxxxxxxxx/ > >These discussions focus primarily on: > >1. BQL is based on napi tx. Therefore, the transfer of statistical information >needs to rely on the judgment of use_napi. When the napi mode is switched to >orphan, some statistical information will be lost, resulting in temporary >inaccuracy in BQL. > >2. If tx dim is supported, orphan mode may be removed and tx irq will be more >reasonable. This provides good support for BQL. Thanks for the pointers, will check that out. > >Thanks. > >> >> Signed-off-by: Jiri Pirko <jiri@xxxxxxxxxx> >> --- >> drivers/net/virtio_net.c | 33 ++++++++++++++++++++------------- >> 1 file changed, 20 insertions(+), 13 deletions(-) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index 218a446c4c27..c53d6dc6d332 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -84,7 +84,9 @@ struct virtnet_stat_desc { >> >> struct virtnet_sq_free_stats { >> u64 packets; >> + u64 xdp_packets; >> u64 bytes; >> + u64 xdp_bytes; >> }; >> >> struct virtnet_sq_stats { >> @@ -512,19 +514,19 @@ static void __free_old_xmit(struct send_queue *sq, bool in_napi, >> void *ptr; >> >> while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) { >> - ++stats->packets; >> - >> if (!is_xdp_frame(ptr)) { >> struct sk_buff *skb = ptr; >> >> pr_debug("Sent skb %p\n", skb); >> >> + stats->packets++; >> stats->bytes += skb->len; >> napi_consume_skb(skb, in_napi); >> } else { >> struct xdp_frame *frame = ptr_to_xdp(ptr); >> >> - stats->bytes += xdp_get_frame_len(frame); >> + stats->xdp_packets++; >> + stats->xdp_bytes += xdp_get_frame_len(frame); >> xdp_return_frame(frame); >> } >> } >> @@ -965,7 +967,8 @@ static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf) >> virtnet_rq_free_buf(vi, rq, buf); >> } >> >> -static void free_old_xmit(struct send_queue *sq, bool in_napi) >> +static void free_old_xmit(struct send_queue *sq, struct netdev_queue *txq, >> + bool in_napi) >> { >> struct virtnet_sq_free_stats stats = {0}; >> >> @@ -974,9 +977,11 @@ static void free_old_xmit(struct send_queue *sq, bool in_napi) >> /* Avoid overhead when no packets have been processed >> * happens when called speculatively from start_xmit. >> */ >> - if (!stats.packets) >> + if (!stats.packets && !stats.xdp_packets) >> return; >> >> + netdev_tx_completed_queue(txq, stats.packets, stats.bytes); >> + >> u64_stats_update_begin(&sq->stats.syncp); >> u64_stats_add(&sq->stats.bytes, stats.bytes); >> u64_stats_add(&sq->stats.packets, stats.packets); >> @@ -1013,13 +1018,15 @@ static void check_sq_full_and_disable(struct virtnet_info *vi, >> * early means 16 slots are typically wasted. >> */ >> if (sq->vq->num_free < 2+MAX_SKB_FRAGS) { >> - netif_stop_subqueue(dev, qnum); >> + struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum); >> + >> + netif_tx_stop_queue(txq); >> if (use_napi) { >> if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) >> virtqueue_napi_schedule(&sq->napi, sq->vq); >> } else if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) { >> /* More just got used, free them then recheck. */ >> - free_old_xmit(sq, false); >> + free_old_xmit(sq, txq, false); >> if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) { >> netif_start_subqueue(dev, qnum); >> virtqueue_disable_cb(sq->vq); >> @@ -2319,7 +2326,7 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) >> >> do { >> virtqueue_disable_cb(sq->vq); >> - free_old_xmit(sq, true); >> + free_old_xmit(sq, txq, true); >> } while (unlikely(!virtqueue_enable_cb_delayed(sq->vq))); >> >> if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) >> @@ -2471,7 +2478,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget) >> txq = netdev_get_tx_queue(vi->dev, index); >> __netif_tx_lock(txq, raw_smp_processor_id()); >> virtqueue_disable_cb(sq->vq); >> - free_old_xmit(sq, true); >> + free_old_xmit(sq, txq, true); >> >> if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) >> netif_tx_wake_queue(txq); >> @@ -2553,7 +2560,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) >> struct send_queue *sq = &vi->sq[qnum]; >> int err; >> struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum); >> - bool kick = !netdev_xmit_more(); >> + bool xmit_more = netdev_xmit_more(); >> bool use_napi = sq->napi.weight; >> >> /* Free up any pending old buffers before queueing new ones. */ >> @@ -2561,9 +2568,9 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) >> if (use_napi) >> virtqueue_disable_cb(sq->vq); >> >> - free_old_xmit(sq, false); >> + free_old_xmit(sq, txq, false); >> >> - } while (use_napi && kick && >> + } while (use_napi && !xmit_more && >> unlikely(!virtqueue_enable_cb_delayed(sq->vq))); >> >> /* timestamp packet in software */ >> @@ -2592,7 +2599,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) >> >> check_sq_full_and_disable(vi, dev, sq); >> >> - if (kick || netif_xmit_stopped(txq)) { >> + if (__netdev_tx_sent_queue(txq, skb->len, xmit_more)) { >> if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) { >> u64_stats_update_begin(&sq->stats.syncp); >> u64_stats_inc(&sq->stats.kicks); >> -- >> 2.44.0 >> >>
