From d45276e75e90f1b67eb689fb3b4c556963796351 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 28 Mar 2023 10:57:56 +0800 Subject: 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 412ca1550cbe "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: Herbert Xu Signed-off-by: David S. Miller --- drivers/net/macvlan.c | 74 ++++++++++++++++++++++++++++++++------------------- 1 file changed, 46 insertions(+), 28 deletions(-) diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index 99a971929c8e..62b4748d3836 100644 --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -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]; }; @@ -291,6 +292,31 @@ static void macvlan_broadcast(struct sk_buff *skb, } } +static void macvlan_multicast_rx(const struct macvlan_port *port, + const struct macvlan_dev *src, + struct sk_buff *skb) +{ + if (!src) + /* frame comes from an external address */ + macvlan_broadcast(skb, port, NULL, + MACVLAN_MODE_PRIVATE | + MACVLAN_MODE_VEPA | + MACVLAN_MODE_PASSTHRU| + MACVLAN_MODE_BRIDGE); + else if (src->mode == MACVLAN_MODE_VEPA) + /* flood to everyone except source */ + macvlan_broadcast(skb, port, src->dev, + MACVLAN_MODE_VEPA | + MACVLAN_MODE_BRIDGE); + else + /* + * flood only to VEPA ports, bridge ports + * already saw the frame on the way out. + */ + 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, @@ -308,27 +334,7 @@ static void macvlan_process_broadcast(struct work_struct *w) 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, - MACVLAN_MODE_PRIVATE | - MACVLAN_MODE_VEPA | - MACVLAN_MODE_PASSTHRU| - MACVLAN_MODE_BRIDGE); - else if (src->mode == MACVLAN_MODE_VEPA) - /* flood to everyone except source */ - macvlan_broadcast(skb, port, src->dev, - MACVLAN_MODE_VEPA | - MACVLAN_MODE_BRIDGE); - else - /* - * flood only to VEPA ports, bridge ports - * already saw the frame on the way out. - */ - macvlan_broadcast(skb, port, src->dev, - MACVLAN_MODE_VEPA); - + 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; } @@ -780,20 +788,27 @@ 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)) { - bitmap_fill(mc_filter, MACVLAN_MC_FILTER_SZ); + 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); } - __set_bit(mc_hash(vlan, dev->broadcast), 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) -- cgit v1.2.3