From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: [PATCH RFC 1/2] virtio-net: bql support Date: Wed, 5 Dec 2018 17:54:15 -0500 Message-ID: <20181205225323.12555-2-mst__17174.1081904203$1544050348$gmane$org@redhat.com> References: <20181205225323.12555-1-mst@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20181205225323.12555-1-mst@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, maxime.coquelin@redhat.com, wexu@redhat.com, "David S. Miller" List-Id: virtualization@lists.linuxfoundation.org When use_napi is set, let's enable BQLs. Note: some of the issues are similar to wifi. It's worth considering whether something similar to commit 36148c2bbfbe ("mac80211: Adjust TSQ pacing shift") might be benefitial. Signed-off-by: Michael S. Tsirkin --- drivers/net/virtio_net.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index cecfd77c9f3c..b657bde6b94b 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1325,7 +1325,8 @@ static int virtnet_receive(struct receive_queue *rq, int budget, return stats.packets; } -static void free_old_xmit_skbs(struct send_queue *sq) +static void free_old_xmit_skbs(struct send_queue *sq, struct netdev_queue *txq, + bool use_napi) { struct sk_buff *skb; unsigned int len; @@ -1347,6 +1348,9 @@ static void free_old_xmit_skbs(struct send_queue *sq) if (!packets) return; + if (use_napi) + netdev_tx_completed_queue(txq, packets, bytes); + u64_stats_update_begin(&sq->stats.syncp); sq->stats.bytes += bytes; sq->stats.packets += packets; @@ -1364,7 +1368,7 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) return; if (__netif_tx_trylock(txq)) { - free_old_xmit_skbs(sq); + free_old_xmit_skbs(sq, txq, true); __netif_tx_unlock(txq); } @@ -1440,7 +1444,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget) struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, vq2txq(sq->vq)); __netif_tx_lock(txq, raw_smp_processor_id()); - free_old_xmit_skbs(sq); + free_old_xmit_skbs(sq, txq, true); __netif_tx_unlock(txq); virtqueue_napi_complete(napi, sq->vq, 0); @@ -1505,13 +1509,15 @@ 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 = !skb->xmit_more; + bool more = skb->xmit_more; bool use_napi = sq->napi.weight; + unsigned int bytes = skb->len; + bool kick; /* Free up any pending old buffers before queueing new ones. */ - free_old_xmit_skbs(sq); + free_old_xmit_skbs(sq, txq, use_napi); - if (use_napi && kick) + if (use_napi && !more) virtqueue_enable_cb_delayed(sq->vq); /* timestamp packet in software */ @@ -1552,7 +1558,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) if (!use_napi && unlikely(!virtqueue_enable_cb_delayed(sq->vq))) { /* More just got used, free them then recheck. */ - free_old_xmit_skbs(sq); + free_old_xmit_skbs(sq, txq, false); if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) { netif_start_subqueue(dev, qnum); virtqueue_disable_cb(sq->vq); @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) } } - if (kick || netif_xmit_stopped(txq)) { + if (use_napi) + kick = __netdev_tx_sent_queue(txq, bytes, more); + else + kick = !more || netif_xmit_stopped(txq); + + if (kick) { if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) { u64_stats_update_begin(&sq->stats.syncp); sq->stats.kicks++; -- MST