Commit d45276e7 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

macvlan: Skip broadcast queue if multicast with single receiver 



As it stands all broadcast and multicast packets are queued and
processed in a work queue.  This is so that we don't overwhelm
the receive softirq path by generating thousands of packets or
more (see commit 412ca155 "macvlan: Move broadcasts into a
work queue").

As such all multicast packets will be delayed, even if they will
be received by a single macvlan device.  As using a workqueue
is not free in terms of latency, we should avoid this where possible.

This patch adds a new filter to determine which addresses should
be delayed and which ones won't.  This is done using a crude
counter of how many times an address has been added to the macvlan
port (ha->synced).  For now if an address has been added more than
once, then it will be considered to be broadcast.  This could be
tuned further by making this threshold configurable.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6fc5f5bc

drivers/net/macvlan.c

+46 −28
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ struct macvlan_port { 
	u32			flags;

	int			count;

	struct hlist_head	vlan_source_hash[MACVLAN_HASH_SIZE];

	DECLARE_BITMAP(bc_filter, MACVLAN_MC_FILTER_SZ);

	DECLARE_BITMAP(mc_filter, MACVLAN_MC_FILTER_SZ);

	unsigned char           perm_addr[ETH_ALEN];

};
@@ -291,24 +292,10 @@ static void macvlan_broadcast(struct sk_buff *skb, 
	}

}



static void macvlan_process_broadcast(struct work_struct *w)

static void macvlan_multicast_rx(const struct macvlan_port *port,

				 const struct macvlan_dev *src,

				 struct sk_buff *skb)

{

	struct macvlan_port *port = container_of(w, struct macvlan_port,

						 bc_work);

	struct sk_buff *skb;

	struct sk_buff_head list;



	__skb_queue_head_init(&list);



	spin_lock_bh(&port->bc_queue.lock);

	skb_queue_splice_tail_init(&port->bc_queue, &list);

	spin_unlock_bh(&port->bc_queue.lock);



	while ((skb = __skb_dequeue(&list))) {

		const struct macvlan_dev *src = MACVLAN_SKB_CB(skb)->src;



		rcu_read_lock();



	if (!src)

		/* frame comes from an external address */

		macvlan_broadcast(skb, port, NULL,
@@ -328,7 +315,26 @@ static void macvlan_process_broadcast(struct work_struct *w) 
		 */

		macvlan_broadcast(skb, port, src->dev,

				  MACVLAN_MODE_VEPA);

}



static void macvlan_process_broadcast(struct work_struct *w)

{

	struct macvlan_port *port = container_of(w, struct macvlan_port,

						 bc_work);

	struct sk_buff *skb;

	struct sk_buff_head list;



	__skb_queue_head_init(&list);



	spin_lock_bh(&port->bc_queue.lock);

	skb_queue_splice_tail_init(&port->bc_queue, &list);

	spin_unlock_bh(&port->bc_queue.lock);



	while ((skb = __skb_dequeue(&list))) {

		const struct macvlan_dev *src = MACVLAN_SKB_CB(skb)->src;



		rcu_read_lock();

		macvlan_multicast_rx(port, src, skb);

		rcu_read_unlock();



		if (src)
@@ -476,8 +482,10 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb) 
		}



		hash = mc_hash(NULL, eth->h_dest);

		if (test_bit(hash, port->mc_filter))

		if (test_bit(hash, port->bc_filter))

			macvlan_broadcast_enqueue(port, src, skb);

		else if (test_bit(hash, port->mc_filter))

			macvlan_multicast_rx(port, src, skb);



		return RX_HANDLER_PASS;

	}
@@ -780,19 +788,26 @@ static void macvlan_change_rx_flags(struct net_device *dev, int change) 


static void macvlan_compute_filter(unsigned long *mc_filter,

				   struct net_device *dev,

				   struct macvlan_dev *vlan)

				   struct macvlan_dev *vlan, int cutoff)

{

	if (dev->flags & (IFF_PROMISC | IFF_ALLMULTI)) {

		if (cutoff >= 0)

			bitmap_fill(mc_filter, MACVLAN_MC_FILTER_SZ);

		else

			bitmap_zero(mc_filter, MACVLAN_MC_FILTER_SZ);

	} else {

		struct netdev_hw_addr *ha;

		DECLARE_BITMAP(filter, MACVLAN_MC_FILTER_SZ);

		struct netdev_hw_addr *ha;



		bitmap_zero(filter, MACVLAN_MC_FILTER_SZ);

		netdev_for_each_mc_addr(ha, dev) {

			if (cutoff >= 0 && ha->synced <= cutoff)

				continue;



			__set_bit(mc_hash(vlan, ha->addr), filter);

		}



		if (cutoff >= 0)

			__set_bit(mc_hash(vlan, dev->broadcast), filter);



		bitmap_copy(mc_filter, filter, MACVLAN_MC_FILTER_SZ);
@@ -803,7 +818,7 @@ static void macvlan_set_mac_lists(struct net_device *dev) 
{

	struct macvlan_dev *vlan = netdev_priv(dev);



	macvlan_compute_filter(vlan->mc_filter, dev, vlan);

	macvlan_compute_filter(vlan->mc_filter, dev, vlan, 0);



	dev_uc_sync(vlan->lowerdev, dev);

	dev_mc_sync(vlan->lowerdev, dev);
@@ -821,7 +836,10 @@ static void macvlan_set_mac_lists(struct net_device *dev) 
	 * The solution is to maintain a list of broadcast addresses like

	 * we do for uc/mc, if you care.

	 */

	macvlan_compute_filter(vlan->port->mc_filter, vlan->lowerdev, NULL);

	macvlan_compute_filter(vlan->port->mc_filter, vlan->lowerdev, NULL,

			       0);

	macvlan_compute_filter(vlan->port->bc_filter, vlan->lowerdev, NULL,

			       1);

}



static int macvlan_change_mtu(struct net_device *dev, int new_mtu)