trunk-47381HEADmaster

1 files changed, 64 insertions, 0 deletions

diff --git a/target/linux/generic/patches-3.18/080-07-fib_trie-Optimize-fib_find_node.patch b/target/linux/generic/patches-3.18/080-07-fib_trie-Optimize-fib_find_node.patch
new file mode 100644
index 0000000..0193f75
--- /dev/null
+++ b/target/linux/generic/patches-3.18/080-07-fib_trie-Optimize-fib_find_node.patch
@@ -0,0 +1,64 @@
+From: Alexander Duyck <alexander.h.duyck@redhat.com>
+Date: Wed, 31 Dec 2014 10:56:00 -0800
+Subject: [PATCH] fib_trie: Optimize fib_find_node
+
+This patch makes use of the same features I made use of for
+fib_table_lookup to streamline fib_find_node.  The resultant code should be
+smaller and run faster than the original.
+
+Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+
+--- a/net/ipv4/fib_trie.c
++++ b/net/ipv4/fib_trie.c
+@@ -892,28 +892,34 @@ static void insert_leaf_info(struct hlis
+ }
+ 
+ /* rcu_read_lock needs to be hold by caller from readside */
+-
+ static struct tnode *fib_find_node(struct trie *t, u32 key)
+ {
+ 	struct tnode *n = rcu_dereference_rtnl(t->trie);
+-	int pos = 0;
+ 
+-	while (n && IS_TNODE(n)) {
+-		if (tkey_sub_equals(n->key, pos, n->pos-pos, key)) {
+-			pos = n->pos + n->bits;
+-			n = tnode_get_child_rcu(n,
+-						tkey_extract_bits(key,
+-								  n->pos,
+-								  n->bits));
+-		} else
++	while (n) {
++		unsigned long index = get_index(key, n);
++
++		/* This bit of code is a bit tricky but it combines multiple
++		 * checks into a single check.  The prefix consists of the
++		 * prefix plus zeros for the bits in the cindex. The index
++		 * is the difference between the key and this value.  From
++		 * this we can actually derive several pieces of data.
++		 *   if !(index >> bits)
++		 *     we know the value is cindex
++		 *   else
++		 *     we have a mismatch in skip bits and failed
++		 */
++		if (index >> n->bits)
++			return NULL;
++
++		/* we have found a leaf. Prefixes have already been compared */
++		if (IS_LEAF(n))
+ 			break;
+-	}
+-	/* Case we have found a leaf. Compare prefixes */
+ 
+-	if (n != NULL && IS_LEAF(n) && tkey_equals(key, n->key))
+-		return n;
++		n = rcu_dereference_rtnl(n->child[index]);
++	}
+ 
+-	return NULL;
++	return n;
+ }
+ 
+ static void trie_rebalance(struct trie *t, struct tnode *tn)