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Commit 1d578303 authored by Mihai Maruseac's avatar Mihai Maruseac Committed by David S. Miller
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ipv6/addrconf: speedup /proc/net/if_inet6 filling 



This ensures a linear behaviour when filling /proc/net/if_inet6 thus making
ifconfig run really fast on IPv6 only addresses. In fact, with this patch and
the IPv4 one sent a while ago, ifconfig will run in linear time regardless of
address type.

IPv4 related patch: f04565dd
	 dev: use name hash for dev_seq_ops
	 ...

Some statistics (running ifconfig > /dev/null on a different setup):

iface count / IPv6 no-patch time / IPv6 patched time / IPv4 time
----------------------------------------------------------------
      6250  |       0.23 s       |      0.13 s       |  0.11 s
     12500  |       0.62 s       |      0.28 s       |  0.22 s
     25000  |       2.91 s       |      0.57 s       |  0.46 s
     50000  |      11.37 s       |      1.21 s       |  0.94 s
    128000  |      86.78 s       |      3.05 s       |  2.54 s

Signed-off-by: default avatarMihai Maruseac <mmaruseac@ixiacom.com>
Cc: Daniel Baluta <dbaluta@ixiacom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 48529680

net/ipv6/addrconf.c

+28 −15
Original line number Diff line number Diff line
@@ -3068,21 +3068,40 @@ static void addrconf_dad_run(struct inet6_dev *idev) 
struct if6_iter_state {

	struct seq_net_private p;

	int bucket;

	int offset;

};



static struct inet6_ifaddr *if6_get_first(struct seq_file *seq)

static struct inet6_ifaddr *if6_get_first(struct seq_file *seq, loff_t pos)

{

	struct inet6_ifaddr *ifa = NULL;

	struct if6_iter_state *state = seq->private;

	struct net *net = seq_file_net(seq);

	int p = 0;



	for (state->bucket = 0; state->bucket < IN6_ADDR_HSIZE; ++state->bucket) {

	/* initial bucket if pos is 0 */

	if (pos == 0) {

		state->bucket = 0;

		state->offset = 0;

	}



	for (; state->bucket < IN6_ADDR_HSIZE; ++state->bucket) {

		struct hlist_node *n;

		hlist_for_each_entry_rcu_bh(ifa, n, &inet6_addr_lst[state->bucket],

					 addr_lst)

					 addr_lst) {

			/* sync with offset */

			if (p < state->offset) {

				p++;

				continue;

			}

			state->offset++;

			if (net_eq(dev_net(ifa->idev->dev), net))

				return ifa;

		}



		/* prepare for next bucket */

		state->offset = 0;

		p = 0;

	}

	return NULL;

}
@@ -3093,13 +3112,17 @@ static struct inet6_ifaddr *if6_get_next(struct seq_file *seq, 
	struct net *net = seq_file_net(seq);

	struct hlist_node *n = &ifa->addr_lst;



	hlist_for_each_entry_continue_rcu_bh(ifa, n, addr_lst)

	hlist_for_each_entry_continue_rcu_bh(ifa, n, addr_lst) {

		state->offset++;

		if (net_eq(dev_net(ifa->idev->dev), net))

			return ifa;

	}



	while (++state->bucket < IN6_ADDR_HSIZE) {

		state->offset = 0;

		hlist_for_each_entry_rcu_bh(ifa, n,

				     &inet6_addr_lst[state->bucket], addr_lst) {

			state->offset++;

			if (net_eq(dev_net(ifa->idev->dev), net))

				return ifa;

		}
@@ -3108,21 +3131,11 @@ static struct inet6_ifaddr *if6_get_next(struct seq_file *seq, 
	return NULL;

}



static struct inet6_ifaddr *if6_get_idx(struct seq_file *seq, loff_t pos)

{

	struct inet6_ifaddr *ifa = if6_get_first(seq);



	if (ifa)

		while (pos && (ifa = if6_get_next(seq, ifa)) != NULL)

			--pos;

	return pos ? NULL : ifa;

}



static void *if6_seq_start(struct seq_file *seq, loff_t *pos)

	__acquires(rcu_bh)

{

	rcu_read_lock_bh();

	return if6_get_idx(seq, *pos);

	return if6_get_first(seq, *pos);

}



static void *if6_seq_next(struct seq_file *seq, void *v, loff_t *pos)