um: Migrate vector drivers to NAPI
Migrate UML vector drivers from a bespoke scheduling mechanism to NAPI. Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Anton Ivanov
Richard Weinberger
parent
39508aab4a
commit
b35507a4cf
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@ -67,6 +67,7 @@ static LIST_HEAD(vector_devices);
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static int driver_registered;
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static void vector_eth_configure(int n, struct arglist *def);
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static int vector_mmsg_rx(struct vector_private *vp, int budget);
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/* Argument accessors to set variables (and/or set default values)
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* mtu, buffer sizing, default headroom, etc
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@ -77,7 +78,6 @@ static void vector_eth_configure(int n, struct arglist *def);
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#define DEFAULT_VECTOR_SIZE 64
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#define TX_SMALL_PACKET 128
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#define MAX_IOV_SIZE (MAX_SKB_FRAGS + 1)
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#define MAX_ITERATIONS 64
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static const struct {
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const char string[ETH_GSTRING_LEN];
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@ -458,7 +458,6 @@ static int vector_send(struct vector_queue *qi)
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vp->estats.tx_queue_running_average =
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(vp->estats.tx_queue_running_average + result) >> 1;
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}
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netif_trans_update(qi->dev);
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netif_wake_queue(qi->dev);
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/* if TX is busy, break out of the send loop,
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* poll write IRQ will reschedule xmit for us
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@ -470,8 +469,6 @@ static int vector_send(struct vector_queue *qi)
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}
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}
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spin_unlock(&qi->head_lock);
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} else {
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tasklet_schedule(&vp->tx_poll);
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}
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return queue_depth;
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}
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@ -608,7 +605,7 @@ static struct vector_queue *create_queue(
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/*
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* We do not use the RX queue as a proper wraparound queue for now
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* This is not necessary because the consumption via netif_rx()
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* This is not necessary because the consumption via napi_gro_receive()
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* happens in-line. While we can try using the return code of
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* netif_rx() for flow control there are no drivers doing this today.
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* For this RX specific use we ignore the tail/head locks and
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@ -896,7 +893,7 @@ static int vector_legacy_rx(struct vector_private *vp)
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skb->protocol = eth_type_trans(skb, skb->dev);
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vp->dev->stats.rx_bytes += skb->len;
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vp->dev->stats.rx_packets++;
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netif_rx(skb);
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napi_gro_receive(&vp->napi, skb);
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} else {
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dev_kfree_skb_irq(skb);
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}
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@ -955,7 +952,7 @@ static int writev_tx(struct vector_private *vp, struct sk_buff *skb)
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* mmsg vector matched to an skb vector which we prepared earlier.
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*/
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static int vector_mmsg_rx(struct vector_private *vp)
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static int vector_mmsg_rx(struct vector_private *vp, int budget)
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{
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int packet_count, i;
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struct vector_queue *qi = vp->rx_queue;
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@ -972,6 +969,9 @@ static int vector_mmsg_rx(struct vector_private *vp)
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/* Fire the Lazy Gun - get as many packets as we can in one go. */
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if (budget > qi->max_depth)
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budget = qi->max_depth;
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packet_count = uml_vector_recvmmsg(
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vp->fds->rx_fd, qi->mmsg_vector, qi->max_depth, 0);
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@ -1021,7 +1021,7 @@ static int vector_mmsg_rx(struct vector_private *vp)
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*/
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vp->dev->stats.rx_bytes += skb->len;
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vp->dev->stats.rx_packets++;
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netif_rx(skb);
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napi_gro_receive(&vp->napi, skb);
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} else {
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/* Overlay header too short to do anything - discard.
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* We can actually keep this skb and reuse it,
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@ -1044,23 +1044,6 @@ static int vector_mmsg_rx(struct vector_private *vp)
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return packet_count;
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}
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static void vector_rx(struct vector_private *vp)
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{
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int err;
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int iter = 0;
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if ((vp->options & VECTOR_RX) > 0)
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while (((err = vector_mmsg_rx(vp)) > 0) && (iter < MAX_ITERATIONS))
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iter++;
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else
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while (((err = vector_legacy_rx(vp)) > 0) && (iter < MAX_ITERATIONS))
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iter++;
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if ((err != 0) && net_ratelimit())
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netdev_err(vp->dev, "vector_rx: error(%d)\n", err);
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if (iter == MAX_ITERATIONS)
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netdev_err(vp->dev, "vector_rx: device stuck, remote end may have closed the connection\n");
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}
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static int vector_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct vector_private *vp = netdev_priv(dev);
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@ -1085,25 +1068,15 @@ static int vector_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
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netdev_sent_queue(vp->dev, skb->len);
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queue_depth = vector_enqueue(vp->tx_queue, skb);
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/* if the device queue is full, stop the upper layers and
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* flush it.
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*/
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if (queue_depth >= vp->tx_queue->max_depth - 1) {
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vp->estats.tx_kicks++;
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netif_stop_queue(dev);
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vector_send(vp->tx_queue);
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return NETDEV_TX_OK;
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}
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if (netdev_xmit_more()) {
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if (queue_depth < vp->tx_queue->max_depth && netdev_xmit_more()) {
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mod_timer(&vp->tl, vp->coalesce);
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return NETDEV_TX_OK;
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} else {
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queue_depth = vector_send(vp->tx_queue);
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if (queue_depth > 0)
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napi_schedule(&vp->napi);
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}
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if (skb->len < TX_SMALL_PACKET) {
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vp->estats.tx_kicks++;
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vector_send(vp->tx_queue);
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} else
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tasklet_schedule(&vp->tx_poll);
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return NETDEV_TX_OK;
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}
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@ -1114,7 +1087,7 @@ static irqreturn_t vector_rx_interrupt(int irq, void *dev_id)
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if (!netif_running(dev))
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return IRQ_NONE;
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vector_rx(vp);
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napi_schedule(&vp->napi);
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return IRQ_HANDLED;
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}
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@ -1133,8 +1106,7 @@ static irqreturn_t vector_tx_interrupt(int irq, void *dev_id)
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* tweaking the IRQ mask less costly
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*/
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if (vp->in_write_poll)
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tasklet_schedule(&vp->tx_poll);
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napi_schedule(&vp->napi);
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return IRQ_HANDLED;
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}
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@ -1161,7 +1133,8 @@ static int vector_net_close(struct net_device *dev)
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um_free_irq(vp->tx_irq, dev);
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vp->tx_irq = 0;
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}
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tasklet_kill(&vp->tx_poll);
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napi_disable(&vp->napi);
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netif_napi_del(&vp->napi);
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if (vp->fds->rx_fd > 0) {
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if (vp->bpf)
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uml_vector_detach_bpf(vp->fds->rx_fd, vp->bpf);
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@ -1193,15 +1166,32 @@ static int vector_net_close(struct net_device *dev)
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return 0;
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}
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/* TX tasklet */
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static void vector_tx_poll(struct tasklet_struct *t)
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static int vector_poll(struct napi_struct *napi, int budget)
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{
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struct vector_private *vp = from_tasklet(vp, t, tx_poll);
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struct vector_private *vp = container_of(napi, struct vector_private, napi);
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int work_done = 0;
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int err;
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bool tx_enqueued = false;
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vp->estats.tx_kicks++;
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vector_send(vp->tx_queue);
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if ((vp->options & VECTOR_TX) != 0)
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tx_enqueued = (vector_send(vp->tx_queue) > 0);
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if ((vp->options & VECTOR_RX) > 0)
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err = vector_mmsg_rx(vp, budget);
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else {
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err = vector_legacy_rx(vp);
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if (err > 0)
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err = 1;
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}
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if (err > 0)
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work_done += err;
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if (tx_enqueued || err > 0)
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napi_schedule(napi);
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if (work_done < budget)
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napi_complete_done(napi, work_done);
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return work_done;
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}
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static void vector_reset_tx(struct work_struct *work)
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{
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struct vector_private *vp =
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@ -1265,6 +1255,9 @@ static int vector_net_open(struct net_device *dev)
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goto out_close;
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}
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netif_napi_add(vp->dev, &vp->napi, vector_poll, get_depth(vp->parsed));
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napi_enable(&vp->napi);
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/* READ IRQ */
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err = um_request_irq(
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irq_rr + VECTOR_BASE_IRQ, vp->fds->rx_fd,
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@ -1306,15 +1299,15 @@ static int vector_net_open(struct net_device *dev)
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uml_vector_attach_bpf(vp->fds->rx_fd, vp->bpf);
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netif_start_queue(dev);
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vector_reset_stats(vp);
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/* clear buffer - it can happen that the host side of the interface
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* is full when we get here. In this case, new data is never queued,
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* SIGIOs never arrive, and the net never works.
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*/
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vector_rx(vp);
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napi_schedule(&vp->napi);
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vector_reset_stats(vp);
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vdevice = find_device(vp->unit);
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vdevice->opened = 1;
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@ -1543,15 +1536,16 @@ static const struct net_device_ops vector_netdev_ops = {
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#endif
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};
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static void vector_timer_expire(struct timer_list *t)
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{
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struct vector_private *vp = from_timer(vp, t, tl);
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vp->estats.tx_kicks++;
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vector_send(vp->tx_queue);
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napi_schedule(&vp->napi);
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}
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static void vector_eth_configure(
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int n,
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struct arglist *def
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@ -1634,7 +1628,6 @@ static void vector_eth_configure(
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});
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dev->features = dev->hw_features = (NETIF_F_SG | NETIF_F_FRAGLIST);
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tasklet_setup(&vp->tx_poll, vector_tx_poll);
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INIT_WORK(&vp->reset_tx, vector_reset_tx);
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timer_setup(&vp->tl, vector_timer_expire, 0);
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@ -14,6 +14,7 @@
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#include <linux/ctype.h>
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#include <linux/workqueue.h>
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#include <linux/interrupt.h>
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#include "vector_user.h"
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/* Queue structure specially adapted for multiple enqueue/dequeue
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@ -72,6 +73,7 @@ struct vector_private {
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struct list_head list;
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spinlock_t lock;
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struct net_device *dev;
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struct napi_struct napi ____cacheline_aligned;
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int unit;
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@ -115,7 +117,6 @@ struct vector_private {
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spinlock_t stats_lock;
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struct tasklet_struct tx_poll;
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bool rexmit_scheduled;
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bool opened;
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bool in_write_poll;
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