macvtap: switch to use skb array
This patch switch to use skb array instead of sk_receive_queue to avoid spinlock contentions. Tests shows about 21% improvements for guest rx pps: Before: 1472731 pkts/s After: 1786289 pkts/s Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>hifive-unleashed-5.1
Jason Wang
David S. Miller
parent
1b16bf42d1
commit
362899b872
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@ -21,6 +21,7 @@
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#include <net/rtnetlink.h>
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#include <net/sock.h>
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#include <linux/virtio_net.h>
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#include <linux/skb_array.h>
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/*
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* A macvtap queue is the central object of this driver, it connects
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@ -43,6 +44,7 @@ struct macvtap_queue {
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u16 queue_index;
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bool enabled;
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struct list_head next;
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struct skb_array skb_array;
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};
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#define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)
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@ -273,6 +275,7 @@ static void macvtap_put_queue(struct macvtap_queue *q)
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rtnl_unlock();
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synchronize_rcu();
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skb_array_cleanup(&q->skb_array);
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sock_put(&q->sk);
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}
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@ -366,7 +369,7 @@ static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
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if (!q)
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return RX_HANDLER_PASS;
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if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len)
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if (__skb_array_full(&q->skb_array))
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goto drop;
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skb_push(skb, ETH_HLEN);
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@ -384,7 +387,8 @@ static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
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goto drop;
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if (!segs) {
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skb_queue_tail(&q->sk.sk_receive_queue, skb);
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if (skb_array_produce(&q->skb_array, skb))
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goto drop;
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goto wake_up;
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}
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@ -393,7 +397,11 @@ static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
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struct sk_buff *nskb = segs->next;
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segs->next = NULL;
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skb_queue_tail(&q->sk.sk_receive_queue, segs);
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if (skb_array_produce(&q->skb_array, segs)) {
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kfree_skb(segs);
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kfree_skb_list(nskb);
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break;
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}
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segs = nskb;
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}
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} else {
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@ -406,7 +414,8 @@ static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
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!(features & NETIF_F_CSUM_MASK) &&
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skb_checksum_help(skb))
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goto drop;
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skb_queue_tail(&q->sk.sk_receive_queue, skb);
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if (skb_array_produce(&q->skb_array, skb))
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goto drop;
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}
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wake_up:
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@ -523,7 +532,11 @@ static void macvtap_sock_write_space(struct sock *sk)
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static void macvtap_sock_destruct(struct sock *sk)
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{
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skb_queue_purge(&sk->sk_receive_queue);
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struct macvtap_queue *q = container_of(sk, struct macvtap_queue, sk);
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struct sk_buff *skb;
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while ((skb = skb_array_consume(&q->skb_array)) != NULL)
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kfree(skb);
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}
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static int macvtap_open(struct inode *inode, struct file *file)
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@ -536,13 +549,13 @@ static int macvtap_open(struct inode *inode, struct file *file)
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rtnl_lock();
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dev = dev_get_by_macvtap_minor(iminor(inode));
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if (!dev)
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goto out;
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goto err;
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err = -ENOMEM;
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q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
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&macvtap_proto, 0);
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if (!q)
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goto out;
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goto err;
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RCU_INIT_POINTER(q->sock.wq, &q->wq);
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init_waitqueue_head(&q->wq.wait);
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@ -566,11 +579,24 @@ static int macvtap_open(struct inode *inode, struct file *file)
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if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
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sock_set_flag(&q->sk, SOCK_ZEROCOPY);
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err = -ENOMEM;
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if (skb_array_init(&q->skb_array, dev->tx_queue_len, GFP_KERNEL))
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goto err_array;
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err = macvtap_set_queue(dev, file, q);
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if (err)
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sock_put(&q->sk);
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goto err_queue;
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out:
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dev_put(dev);
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rtnl_unlock();
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return err;
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err_queue:
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skb_array_cleanup(&q->skb_array);
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err_array:
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sock_put(&q->sk);
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err:
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if (dev)
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dev_put(dev);
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@ -596,7 +622,7 @@ static unsigned int macvtap_poll(struct file *file, poll_table * wait)
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mask = 0;
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poll_wait(file, &q->wq.wait, wait);
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if (!skb_queue_empty(&q->sk.sk_receive_queue))
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if (!skb_array_empty(&q->skb_array))
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mask |= POLLIN | POLLRDNORM;
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if (sock_writeable(&q->sk) ||
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@ -856,7 +882,7 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q,
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TASK_INTERRUPTIBLE);
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/* Read frames from the queue */
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skb = skb_dequeue(&q->sk.sk_receive_queue);
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skb = skb_array_consume(&q->skb_array);
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if (skb)
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break;
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if (noblock) {
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@ -1180,10 +1206,18 @@ static int macvtap_recvmsg(struct socket *sock, struct msghdr *m,
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return ret;
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}
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static int macvtap_peek_len(struct socket *sock)
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{
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struct macvtap_queue *q = container_of(sock, struct macvtap_queue,
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sock);
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return skb_array_peek_len(&q->skb_array);
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}
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/* Ops structure to mimic raw sockets with tun */
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static const struct proto_ops macvtap_socket_ops = {
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.sendmsg = macvtap_sendmsg,
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.recvmsg = macvtap_recvmsg,
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.peek_len = macvtap_peek_len,
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};
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/* Get an underlying socket object from tun file. Returns error unless file is
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@ -1202,6 +1236,28 @@ struct socket *macvtap_get_socket(struct file *file)
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}
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EXPORT_SYMBOL_GPL(macvtap_get_socket);
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static int macvtap_queue_resize(struct macvlan_dev *vlan)
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{
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struct net_device *dev = vlan->dev;
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struct macvtap_queue *q;
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struct skb_array **arrays;
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int n = vlan->numqueues;
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int ret, i = 0;
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arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
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if (!arrays)
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return -ENOMEM;
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list_for_each_entry(q, &vlan->queue_list, next)
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arrays[i++] = &q->skb_array;
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ret = skb_array_resize_multiple(arrays, n,
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dev->tx_queue_len, GFP_KERNEL);
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kfree(arrays);
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return ret;
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}
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static int macvtap_device_event(struct notifier_block *unused,
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unsigned long event, void *ptr)
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{
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@ -1249,6 +1305,10 @@ static int macvtap_device_event(struct notifier_block *unused,
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device_destroy(&macvtap_class, devt);
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macvtap_free_minor(vlan);
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break;
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case NETDEV_CHANGE_TX_QUEUE_LEN:
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if (macvtap_queue_resize(vlan))
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return NOTIFY_BAD;
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break;
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}
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return NOTIFY_DONE;
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