From 84d2697d9649339215675551eae28ba04068dea1 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 9 Nov 2009 12:11:28 +0000 Subject: ipv6: speedup inet6_dump_ifinfo() When handling large number of netdevice, inet6_dump_ifinfo() is very slow because it has O(N^2) complexity. Instead of scanning one single list, we can use the 256 sub lists of the dev_index hash table, and RCU lookups. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv6/addrconf.c | 45 ++++++++++++++++++++++++++++----------------- 1 file changed, 28 insertions(+), 17 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 024bba30de21..f9f7fd6ee1f3 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -3823,28 +3823,39 @@ nla_put_failure: static int inet6_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) { struct net *net = sock_net(skb->sk); - int idx, err; - int s_idx = cb->args[0]; + int h, s_h; + int idx = 0, err, s_idx; struct net_device *dev; struct inet6_dev *idev; + struct hlist_head *head; + struct hlist_node *node; - read_lock(&dev_base_lock); - idx = 0; - for_each_netdev(net, dev) { - if (idx < s_idx) - goto cont; - if ((idev = in6_dev_get(dev)) == NULL) - goto cont; - err = inet6_fill_ifinfo(skb, idev, NETLINK_CB(cb->skb).pid, - cb->nlh->nlmsg_seq, RTM_NEWLINK, NLM_F_MULTI); - in6_dev_put(idev); - if (err <= 0) - break; + s_h = cb->args[0]; + s_idx = cb->args[1]; + + 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; + idev = __in6_dev_get(dev); + if (!idev) + goto cont; + if (inet6_fill_ifinfo(skb, idev, + NETLINK_CB(cb->skb).pid, + cb->nlh->nlmsg_seq, + RTM_NEWLINK, NLM_F_MULTI) <= 0) + goto out; cont: - idx++; + idx++; + } } - read_unlock(&dev_base_lock); - cb->args[0] = idx; +out: + rcu_read_unlock(); + cb->args[1] = idx; + cb->args[0] = h; return skb->len; } -- cgit v1.2.3