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: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index cca921e..71598f6 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -282,6 +282,8 @@
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 @@
struct rtable *r)
{
struct rt_cache_iter_state *st = seq->private;
+
r = r->u.dst.rt_next;
while (!r) {
rcu_read_unlock_bh();
- if (--st->bucket < 0)
- break;
+ do {
+ if (--st->bucket < 0)
+ return NULL;
+ } while (!rt_hash_table[st->bucket].chain);
rcu_read_lock_bh();
r = rt_hash_table[st->bucket].chain;
}
@@ -2840,7 +2845,9 @@
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 @@
dst_release(xchg(&skb->dst, NULL));
}
rcu_read_unlock_bh();
- s_idx = 0;
}
done: