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Date: Thu, 12 Nov 2009 15:11:50 +0100
From: Eric Dumazet <eric.dumazet@...il.com>
To: "David S. Miller" <davem@...emloft.net>
CC: Linux Netdev List <netdev@...r.kernel.org>,
Stephen Hemminger <shemminger@...tta.com>
Subject: [PATCH net-next-2.6] ipv6: speedup inet6_dump_addr()
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@...il.com>
---
net/ipv6/addrconf.c | 171 +++++++++++++++++++++++-------------------
1 files changed, 97 insertions(+), 74 deletions(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9ff8ab9..522bdc7 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3481,91 +3481,114 @@ enum addr_type_t
ANYCAST_ADDR,
};
+/* 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)
+{
+ struct inet6_ifaddr *ifa;
+ struct ifmcaddr6 *ifmca;
+ struct ifacaddr6 *ifaca;
+ int err = 1;
+ int ip_idx = *p_ip_idx;
+
+ read_lock_bh(&idev->lock);
+ switch (type) {
+ case UNICAST_ADDR:
+ /* unicast address incl. temp addr */
+ for (ifa = idev->addr_list; ifa;
+ ifa = ifa->if_next, ip_idx++) {
+ if (ip_idx < s_ip_idx)
+ continue;
+ err = inet6_fill_ifaddr(skb, ifa,
+ NETLINK_CB(cb->skb).pid,
+ cb->nlh->nlmsg_seq,
+ RTM_NEWADDR,
+ NLM_F_MULTI);
+ if (err <= 0)
+ break;
+ }
+ break;
+ case MULTICAST_ADDR:
+ /* multicast address */
+ for (ifmca = idev->mc_list; ifmca;
+ ifmca = ifmca->next, ip_idx++) {
+ if (ip_idx < s_ip_idx)
+ continue;
+ err = inet6_fill_ifmcaddr(skb, ifmca,
+ NETLINK_CB(cb->skb).pid,
+ cb->nlh->nlmsg_seq,
+ RTM_GETMULTICAST,
+ NLM_F_MULTI);
+ if (err <= 0)
+ break;
+ }
+ break;
+ case ANYCAST_ADDR:
+ /* anycast address */
+ for (ifaca = idev->ac_list; ifaca;
+ ifaca = ifaca->aca_next, ip_idx++) {
+ if (ip_idx < s_ip_idx)
+ continue;
+ err = inet6_fill_ifacaddr(skb, ifaca,
+ NETLINK_CB(cb->skb).pid,
+ cb->nlh->nlmsg_seq,
+ RTM_GETANYCAST,
+ NLM_F_MULTI);
+ if (err <= 0)
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+ read_unlock_bh(&idev->lock);
+ *p_ip_idx = ip_idx;
+ return err;
+}
+
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;
- 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);
+ struct inet6_dev *idev;
+ struct hlist_head *head;
+ struct hlist_node *node;
- s_idx = cb->args[0];
- s_ip_idx = ip_idx = cb->args[1];
+ s_h = cb->args[0];
+ s_idx = idx = cb->args[1];
+ s_ip_idx = ip_idx = cb->args[2];
- 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:
- /* unicast address incl. temp addr */
- for (ifa = idev->addr_list; ifa;
- ifa = ifa->if_next, ip_idx++) {
- if (ip_idx < s_ip_idx)
- continue;
- err = inet6_fill_ifaddr(skb, ifa,
- NETLINK_CB(cb->skb).pid,
- cb->nlh->nlmsg_seq,
- RTM_NEWADDR,
- NLM_F_MULTI);
- if (err <= 0)
- break;
- }
- break;
- case MULTICAST_ADDR:
- /* multicast address */
- for (ifmca = idev->mc_list; ifmca;
- ifmca = ifmca->next, ip_idx++) {
- if (ip_idx < s_ip_idx)
- continue;
- err = inet6_fill_ifmcaddr(skb, ifmca,
- NETLINK_CB(cb->skb).pid,
- cb->nlh->nlmsg_seq,
- RTM_GETMULTICAST,
- NLM_F_MULTI);
- if (err <= 0)
- break;
- }
- break;
- case ANYCAST_ADDR:
- /* anycast address */
- for (ifaca = idev->ac_list; ifaca;
- ifaca = ifaca->aca_next, ip_idx++) {
- if (ip_idx < s_ip_idx)
- continue;
- err = inet6_fill_ifacaddr(skb, ifaca,
- NETLINK_CB(cb->skb).pid,
- cb->nlh->nlmsg_seq,
- RTM_GETANYCAST,
- NLM_F_MULTI);
- if (err <= 0)
- break;
- }
- break;
- default:
- break;
- }
- read_unlock_bh(&idev->lock);
- in6_dev_put(idev);
+ 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 (err <= 0)
- break;
+ if (in6_dump_addrs(idev, skb, cb, type,
+ s_ip_idx, &ip_idx) <= 0)
+ goto done;
cont:
- idx++;
+ 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;
}
--
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