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authorJames <>2015-11-04 11:49:21 +0000
committerJames <>2015-11-04 11:49:21 +0000
commit716ca530e1c4515d8683c9d5be3d56b301758b66 (patch)
tree700eb5bcc1a462a5f21dcec15ce7c97ecfefa772 /target/linux/generic/patches-3.18/080-07-fib_trie-Optimize-fib_find_node.patch
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Diffstat (limited to 'target/linux/generic/patches-3.18/080-07-fib_trie-Optimize-fib_find_node.patch')
-rw-r--r--target/linux/generic/patches-3.18/080-07-fib_trie-Optimize-fib_find_node.patch64
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)