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Date: Tue, 28 Mar 2023 10:57:56 +0800
From: "Herbert Xu" <herbert@...dor.apana.org.au>
To: netdev@...r.kernel.org
Subject: [PATCH 1/2] 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 <herbert@...dor.apana.org.au>
---
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)
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