Commit a6272665 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ip: speedup /proc/net/rt_cache handling 



When scanning route cache hash table, we can avoid taking locks for
empty buckets.  Both /proc/net/rt_cache and NETLINK RTM_GETROUTE
interface are taken into account.

Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6be547a6

net/ipv4/route.c

+10 −4
Original line number Diff line number Diff line
@@ -282,6 +282,8 @@ static struct rtable *rt_cache_get_first(struct seq_file *seq) 
	struct rtable *r = NULL;



	for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {

		if (!rt_hash_table[st->bucket].chain)

			continue;

		rcu_read_lock_bh();

		r = rcu_dereference(rt_hash_table[st->bucket].chain);

		while (r) {
@@ -299,11 +301,14 @@ static struct rtable *__rt_cache_get_next(struct seq_file *seq, 
					  struct rtable *r)

{

	struct rt_cache_iter_state *st = seq->private;



	r = r->u.dst.rt_next;

	while (!r) {

		rcu_read_unlock_bh();

		do {

			if (--st->bucket < 0)

			break;

				return NULL;

		} while (!rt_hash_table[st->bucket].chain);

		rcu_read_lock_bh();

		r = rt_hash_table[st->bucket].chain;

	}
@@ -2840,7 +2845,9 @@ int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb) 
	if (s_h < 0)

		s_h = 0;

	s_idx = idx = cb->args[1];

	for (h = s_h; h <= rt_hash_mask; h++) {

	for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) {

		if (!rt_hash_table[h].chain)

			continue;

		rcu_read_lock_bh();

		for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt;

		     rt = rcu_dereference(rt->u.dst.rt_next), idx++) {
@@ -2859,7 +2866,6 @@ int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb) 
			dst_release(xchg(&skb->dst, NULL));

		}

		rcu_read_unlock_bh();

		s_idx = 0;

	}



done: