macvlan: add a salt to mc_hash()
Some multicast addresses are common to all macvlans, so if a multicast message has a hash value collision, we have to deliver a copy to all macvlans, adding significant latency and possible packet drops if netdev_max_backlog limit is hit. Having a per macvlan hash function permits to reduce the impact of hash collisions. Suggested-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
d527043040
commit
3807ff5899
|
@ -127,10 +127,18 @@ static int macvlan_broadcast_one(struct sk_buff *skb,
|
||||||
return vlan->receive(skb);
|
return vlan->receive(skb);
|
||||||
}
|
}
|
||||||
|
|
||||||
static unsigned int mc_hash(const unsigned char *addr)
|
static u32 macvlan_hash_mix(const struct macvlan_dev *vlan)
|
||||||
|
{
|
||||||
|
return (u32)(((unsigned long)vlan) >> L1_CACHE_SHIFT);
|
||||||
|
}
|
||||||
|
|
||||||
|
|
||||||
|
static unsigned int mc_hash(const struct macvlan_dev *vlan,
|
||||||
|
const unsigned char *addr)
|
||||||
{
|
{
|
||||||
u32 val = __get_unaligned_cpu32(addr + 2);
|
u32 val = __get_unaligned_cpu32(addr + 2);
|
||||||
|
|
||||||
|
val ^= macvlan_hash_mix(vlan);
|
||||||
return hash_32(val, MACVLAN_MC_FILTER_BITS);
|
return hash_32(val, MACVLAN_MC_FILTER_BITS);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -145,7 +153,7 @@ static void macvlan_broadcast(struct sk_buff *skb,
|
||||||
struct sk_buff *nskb;
|
struct sk_buff *nskb;
|
||||||
unsigned int i;
|
unsigned int i;
|
||||||
int err;
|
int err;
|
||||||
unsigned int hash = mc_hash(eth->h_dest);
|
unsigned int hash;
|
||||||
|
|
||||||
if (skb->protocol == htons(ETH_P_PAUSE))
|
if (skb->protocol == htons(ETH_P_PAUSE))
|
||||||
return;
|
return;
|
||||||
|
@ -155,6 +163,7 @@ static void macvlan_broadcast(struct sk_buff *skb,
|
||||||
if (vlan->dev == src || !(vlan->mode & mode))
|
if (vlan->dev == src || !(vlan->mode & mode))
|
||||||
continue;
|
continue;
|
||||||
|
|
||||||
|
hash = mc_hash(vlan, eth->h_dest);
|
||||||
if (!test_bit(hash, vlan->mc_filter))
|
if (!test_bit(hash, vlan->mc_filter))
|
||||||
continue;
|
continue;
|
||||||
nskb = skb_clone(skb, GFP_ATOMIC);
|
nskb = skb_clone(skb, GFP_ATOMIC);
|
||||||
|
@ -424,10 +433,10 @@ static void macvlan_set_mac_lists(struct net_device *dev)
|
||||||
|
|
||||||
bitmap_zero(filter, MACVLAN_MC_FILTER_SZ);
|
bitmap_zero(filter, MACVLAN_MC_FILTER_SZ);
|
||||||
netdev_for_each_mc_addr(ha, dev) {
|
netdev_for_each_mc_addr(ha, dev) {
|
||||||
__set_bit(mc_hash(ha->addr), filter);
|
__set_bit(mc_hash(vlan, ha->addr), filter);
|
||||||
}
|
}
|
||||||
|
|
||||||
__set_bit(mc_hash(dev->broadcast), filter);
|
__set_bit(mc_hash(vlan, dev->broadcast), filter);
|
||||||
|
|
||||||
bitmap_copy(vlan->mc_filter, filter, MACVLAN_MC_FILTER_SZ);
|
bitmap_copy(vlan->mc_filter, filter, MACVLAN_MC_FILTER_SZ);
|
||||||
}
|
}
|
||||||
|
|
Loading…
Reference in New Issue