diff options
| -rw-r--r-- | drivers/net/virtio_net.c | 207 |
1 files changed, 147 insertions, 60 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 666ada6130ab..003143835766 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -33,9 +33,10 @@ static int napi_weight = NAPI_POLL_WEIGHT; module_param(napi_weight, int, 0444); -static bool csum = true, gso = true; +static bool csum = true, gso = true, napi_tx; module_param(csum, bool, 0444); module_param(gso, bool, 0444); +module_param(napi_tx, bool, 0644); /* FIXME: MTU in config. */ #define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN) @@ -86,6 +87,8 @@ struct send_queue { /* Name of the send queue: output.$index */ char name[40]; + + struct napi_struct napi; }; /* Internal representation of a receive virtqueue */ @@ -239,15 +242,39 @@ static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask) return p; } +static void virtqueue_napi_schedule(struct napi_struct *napi, + struct virtqueue *vq) +{ + if (napi_schedule_prep(napi)) { + virtqueue_disable_cb(vq); + __napi_schedule(napi); + } +} + +static void virtqueue_napi_complete(struct napi_struct *napi, + struct virtqueue *vq, int processed) +{ + int opaque; + + opaque = virtqueue_enable_cb_prepare(vq); + if (napi_complete_done(napi, processed) && + unlikely(virtqueue_poll(vq, opaque))) + virtqueue_napi_schedule(napi, vq); +} + static void skb_xmit_done(struct virtqueue *vq) { struct virtnet_info *vi = vq->vdev->priv; + struct napi_struct *napi = &vi->sq[vq2txq(vq)].napi; /* Suppress further interrupts. */ virtqueue_disable_cb(vq); - /* We were probably waiting for more output buffers. */ - netif_wake_subqueue(vi->dev, vq2txq(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)); } static unsigned int mergeable_ctx_to_buf_truesize(unsigned long mrg_ctx) @@ -936,27 +963,38 @@ static void skb_recv_done(struct virtqueue *rvq) struct virtnet_info *vi = rvq->vdev->priv; struct receive_queue *rq = &vi->rq[vq2rxq(rvq)]; - /* Schedule NAPI, Suppress further interrupts if successful. */ - if (napi_schedule_prep(&rq->napi)) { - virtqueue_disable_cb(rvq); - __napi_schedule(&rq->napi); - } + virtqueue_napi_schedule(&rq->napi, rvq); } -static void virtnet_napi_enable(struct receive_queue *rq) +static void virtnet_napi_enable(struct virtqueue *vq, struct napi_struct *napi) { - napi_enable(&rq->napi); + napi_enable(napi); /* If all buffers were filled by other side before we napi_enabled, we - * won't get another interrupt, so process any outstanding packets - * now. virtnet_poll wants re-enable the queue, so we disable here. - * We synchronize against interrupts via NAPI_STATE_SCHED */ - if (napi_schedule_prep(&rq->napi)) { - virtqueue_disable_cb(rq->vq); - local_bh_disable(); - __napi_schedule(&rq->napi); - local_bh_enable(); + * won't get another interrupt, so process any outstanding packets now. + * Call local_bh_enable after to trigger softIRQ processing. + */ + local_bh_disable(); + virtqueue_napi_schedule(napi, vq); + local_bh_enable(); +} + +static void virtnet_napi_tx_enable(struct virtnet_info *vi, + struct virtqueue *vq, + struct napi_struct *napi) +{ + if (!napi->weight) + return; + + /* Tx napi touches cachelines on the cpu handling tx interrupts. Only + * enable the feature if this is likely affine with the transmit path. + */ + if (!vi->affinity_hint_set) { + napi->weight = 0; + return; } + + return virtnet_napi_enable(vq, napi); } static void refill_work(struct work_struct *work) @@ -971,7 +1009,7 @@ static void refill_work(struct work_struct *work) napi_disable(&rq->napi); still_empty = !try_fill_recv(vi, rq, GFP_KERNEL); - virtnet_napi_enable(rq); + virtnet_napi_enable(rq->vq, &rq->napi); /* In theory, this can happen: if we don't get any buffers in * we will *never* try to fill again. @@ -1007,25 +1045,68 @@ static int virtnet_receive(struct receive_queue *rq, int budget) return received; } +static void free_old_xmit_skbs(struct send_queue *sq) +{ + struct sk_buff *skb; + unsigned int len; + struct virtnet_info *vi = sq->vq->vdev->priv; + struct virtnet_stats *stats = this_cpu_ptr(vi->stats); + unsigned int packets = 0; + unsigned int bytes = 0; + + while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) { + pr_debug("Sent skb %p\n", skb); + + bytes += skb->len; + packets++; + + dev_kfree_skb_any(skb); + } + + /* Avoid overhead when no packets have been processed + * happens when called speculatively from start_xmit. + */ + if (!packets) + return; + + u64_stats_update_begin(&stats->tx_syncp); + stats->tx_bytes += bytes; + stats->tx_packets += packets; + u64_stats_update_end(&stats->tx_syncp); +} + +static void virtnet_poll_cleantx(struct receive_queue *rq) +{ + struct virtnet_info *vi = rq->vq->vdev->priv; + unsigned int index = vq2rxq(rq->vq); + struct send_queue *sq = &vi->sq[index]; + struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, index); + + if (!sq->napi.weight) + return; + + if (__netif_tx_trylock(txq)) { + free_old_xmit_skbs(sq); + __netif_tx_unlock(txq); + } + + if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) + netif_tx_wake_queue(txq); +} + static int virtnet_poll(struct napi_struct *napi, int budget) { struct receive_queue *rq = container_of(napi, struct receive_queue, napi); - unsigned int r, received; + unsigned int received; + + virtnet_poll_cleantx(rq); received = virtnet_receive(rq, budget); /* Out of packets? */ - if (received < budget) { - r = virtqueue_enable_cb_prepare(rq->vq); - if (napi_complete_done(napi, received)) { - if (unlikely(virtqueue_poll(rq->vq, r)) && - napi_schedule_prep(napi)) { - virtqueue_disable_cb(rq->vq); - __napi_schedule(napi); - } - } - } + if (received < budget) + virtqueue_napi_complete(napi, rq->vq, received); return received; } @@ -1040,40 +1121,29 @@ static int virtnet_open(struct net_device *dev) /* Make sure we have some buffers: if oom use wq. */ if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL)) schedule_delayed_work(&vi->refill, 0); - virtnet_napi_enable(&vi->rq[i]); + virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi); + virtnet_napi_tx_enable(vi, vi->sq[i].vq, &vi->sq[i].napi); } return 0; } -static void free_old_xmit_skbs(struct send_queue *sq) +static int virtnet_poll_tx(struct napi_struct *napi, int budget) { - struct sk_buff *skb; - unsigned int len; + struct send_queue *sq = container_of(napi, struct send_queue, napi); struct virtnet_info *vi = sq->vq->vdev->priv; - struct virtnet_stats *stats = this_cpu_ptr(vi->stats); - unsigned int packets = 0; - unsigned int bytes = 0; - - while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) { - pr_debug("Sent skb %p\n", skb); + struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, vq2txq(sq->vq)); - bytes += skb->len; - packets++; + __netif_tx_lock(txq, raw_smp_processor_id()); + free_old_xmit_skbs(sq); + __netif_tx_unlock(txq); - dev_kfree_skb_any(skb); - } + virtqueue_napi_complete(napi, sq->vq, 0); - /* Avoid overhead when no packets have been processed - * happens when called speculatively from start_xmit. - */ - if (!packets) - return; + if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) + netif_tx_wake_queue(txq); - u64_stats_update_begin(&stats->tx_syncp); - stats->tx_bytes += bytes; - stats->tx_packets += packets; - u64_stats_update_end(&stats->tx_syncp); + return 0; } static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) @@ -1125,10 +1195,14 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) int err; struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum); bool kick = !skb->xmit_more; + bool use_napi = sq->napi.weight; /* Free up any pending old buffers before queueing new ones. */ free_old_xmit_skbs(sq); + if (use_napi && kick) + virtqueue_enable_cb_delayed(sq->vq); + /* timestamp packet in software */ skb_tx_timestamp(skb); @@ -1147,8 +1221,10 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) } /* Don't wait up for transmitted skbs to be freed. */ - skb_orphan(skb); - nf_reset(skb); + if (!use_napi) { + skb_orphan(skb); + nf_reset(skb); + } /* If running out of space, stop queue to avoid getting packets that we * are then unable to transmit. @@ -1162,7 +1238,8 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) */ if (sq->vq->num_free < 2+MAX_SKB_FRAGS) { netif_stop_subqueue(dev, qnum); - if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) { + if (!use_napi && + unlikely(!virtqueue_enable_cb_delayed(sq->vq))) { /* More just got used, free them then recheck. */ free_old_xmit_skbs(sq); if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) { @@ -1366,8 +1443,10 @@ static int virtnet_close(struct net_device *dev) /* Make sure refill_work doesn't re-enable napi! */ cancel_delayed_work_sync(&vi->refill); - for (i = 0; i < vi->max_queue_pairs; i++) + for (i = 0; i < vi->max_queue_pairs; i++) { napi_disable(&vi->rq[i].napi); + napi_disable(&vi->sq[i].napi); + } return 0; } @@ -1722,8 +1801,10 @@ static void virtnet_freeze_down(struct virtio_device *vdev) cancel_delayed_work_sync(&vi->refill); if (netif_running(vi->dev)) { - for (i = 0; i < vi->max_queue_pairs; i++) + for (i = 0; i < vi->max_queue_pairs; i++) { napi_disable(&vi->rq[i].napi); + napi_disable(&vi->sq[i].napi); + } } } @@ -1746,8 +1827,11 @@ static int virtnet_restore_up(struct virtio_device *vdev) if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL)) schedule_delayed_work(&vi->refill, 0); - for (i = 0; i < vi->max_queue_pairs; i++) - virtnet_napi_enable(&vi->rq[i]); + for (i = 0; i < vi->max_queue_pairs; i++) { + virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi); + virtnet_napi_tx_enable(vi, vi->sq[i].vq, + &vi->sq[i].napi); + } } netif_device_attach(vi->dev); @@ -1952,6 +2036,7 @@ static void virtnet_free_queues(struct virtnet_info *vi) for (i = 0; i < vi->max_queue_pairs; i++) { napi_hash_del(&vi->rq[i].napi); netif_napi_del(&vi->rq[i].napi); + netif_napi_del(&vi->sq[i].napi); } /* We called napi_hash_del() before netif_napi_del(), @@ -2137,6 +2222,8 @@ static int virtnet_alloc_queues(struct virtnet_info *vi) vi->rq[i].pages = NULL; netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll, napi_weight); + netif_napi_add(vi->dev, &vi->sq[i].napi, virtnet_poll_tx, + napi_tx ? napi_weight : 0); sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg)); ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len); |