[NETFILTER]: nf_conntrack: use hlists for conntrack hash

Convert conntrack hash to hlists to reduce its size and cache
footprint. Since the default hashsize to max. entries ratio
sucks (1:16), this patch doesn't reduce the amount of memory
used for the hash by default, but instead uses a better ratio
of 1:8, which results in the same max. entries value.

One thing worth noting is early_drop. It really should use LRU,
so it now has to iterate over the entire chain to find the last
unconfirmed entry. Since chains shouldn't be very long and the
entire operation is very rare this shouldn't be a problem.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 3 insertions, 4 deletions

diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h
index 3bf7d05..6351948 100644
--- a/include/net/netfilter/nf_conntrack_core.h
+++ b/include/net/netfilter/nf_conntrack_core.h
@@ -84,9 +84,9 @@ print_tuple(struct seq_file *s, const struct nf_conntrack_tuple *tuple,
 	    struct nf_conntrack_l3proto *l3proto,
 	    struct nf_conntrack_l4proto *proto);
 
-extern struct list_head *nf_conntrack_hash;
+extern struct hlist_head *nf_conntrack_hash;
 extern struct list_head nf_conntrack_expect_list;
 extern rwlock_t nf_conntrack_lock ;
-extern struct list_head unconfirmed;
+extern struct hlist_head unconfirmed;
 
 #endif /* _NF_CONNTRACK_CORE_H */
diff --git a/include/net/netfilter/nf_conntrack_tuple.h b/include/net/netfilter/nf_conntrack_tuple.h
index 5d72b16..d02ce87 100644
--- a/include/net/netfilter/nf_conntrack_tuple.h
+++ b/include/net/netfilter/nf_conntrack_tuple.h
@@ -125,8 +125,7 @@ DEBUGP("tuple %p: %u %u " NIP6_FMT " %hu -> " NIP6_FMT " %hu\n",	    \
 /* Connections have two entries in the hash table: one for each way */
 struct nf_conntrack_tuple_hash
 {
-	struct list_head list;
-
+	struct hlist_node hnode;
 	struct nf_conntrack_tuple tuple;
 };