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ipv6: speedup inet6_dump_addr()

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When handling large number of netdevices, inet6_dump_addr()
is very slow because it has O(N^2) complexity.

Instead of scanning one single list, we can use the NETDEV_HASHENTRIES
sub lists of the dev_index hash table, and RCU lookups.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2009-11-12 04:11:50 +00:00 committed by David S. Miller
parent 5256f2ef3a
commit 234b27c3fd
1 changed files with 101 additions and 78 deletions
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73
net/ipv6/addrconf.c
View file

@ -3481,31 +3481,17 @@ enum addr_type_t
ANYCAST_ADDR,
};
static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
enum addr_type_t type)
/* called with rcu_read_lock() */
static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb,
struct netlink_callback *cb, enum addr_type_t type,
int s_ip_idx, int *p_ip_idx)
{
int idx, ip_idx;
int s_idx, s_ip_idx;
int err = 1;
struct net_device *dev;
struct inet6_dev *idev = NULL;
struct inet6_ifaddr *ifa;
struct ifmcaddr6 *ifmca;
struct ifacaddr6 *ifaca;
struct net *net = sock_net(skb->sk);
int err = 1;
int ip_idx = *p_ip_idx;
s_idx = cb->args[0];
s_ip_idx = ip_idx = cb->args[1];
idx = 0;
for_each_netdev(net, dev) {
if (idx < s_idx)
goto cont;
if (idx > s_idx)
s_ip_idx = 0;
ip_idx = 0;
if ((idev = in6_dev_get(dev)) == NULL)
goto cont;
read_lock_bh(&idev->lock);
switch (type) {
case UNICAST_ADDR:
@ -3557,15 +3543,52 @@ static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
break;
}
read_unlock_bh(&idev->lock);
in6_dev_put(idev);
*p_ip_idx = ip_idx;
return err;
}
if (err <= 0)
break;
static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
enum addr_type_t type)
{
struct net *net = sock_net(skb->sk);
int h, s_h;
int idx, ip_idx;
int s_idx, s_ip_idx;
struct net_device *dev;
struct inet6_dev *idev;
struct hlist_head *head;
struct hlist_node *node;
s_h = cb->args[0];
s_idx = idx = cb->args[1];
s_ip_idx = ip_idx = cb->args[2];
rcu_read_lock();
for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
idx = 0;
head = &net->dev_index_head[h];
hlist_for_each_entry_rcu(dev, node, head, index_hlist) {
if (idx < s_idx)
goto cont;
if (idx > s_idx)
s_ip_idx = 0;
ip_idx = 0;
if ((idev = __in6_dev_get(dev)) == NULL)
goto cont;
if (in6_dump_addrs(idev, skb, cb, type,
s_ip_idx, &ip_idx) <= 0)
goto done;
cont:
idx++;
}
cb->args[0] = idx;
cb->args[1] = ip_idx;
}
done:
rcu_read_unlock();
cb->args[0] = h;
cb->args[1] = idx;
cb->args[2] = ip_idx;
return skb->len;
}