+++ /dev/null
-From: Alexander Duyck <alexander.h.duyck@redhat.com>
-Date: Wed, 31 Dec 2014 10:56:06 -0800
-Subject: [PATCH] fib_trie: Optimize fib_table_insert
-
-This patch updates the fib_table_insert function to take advantage of the
-changes made to improve the performance of fib_table_lookup. As a result
-the code should be smaller and run faster then 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
-@@ -222,31 +222,6 @@ static inline t_key tkey_extract_bits(t_
- return 0;
- }
-
--static inline int tkey_equals(t_key a, t_key b)
--{
-- return a == b;
--}
--
--static inline int tkey_sub_equals(t_key a, int offset, int bits, t_key b)
--{
-- if (bits == 0 || offset >= KEYLENGTH)
-- return 1;
-- bits = bits > KEYLENGTH ? KEYLENGTH : bits;
-- return ((a ^ b) << offset) >> (KEYLENGTH - bits) == 0;
--}
--
--static inline int tkey_mismatch(t_key a, int offset, t_key b)
--{
-- t_key diff = a ^ b;
-- int i = offset;
--
-- if (!diff)
-- return 0;
-- while ((diff << i) >> (KEYLENGTH-1) == 0)
-- i++;
-- return i;
--}
--
- /*
- To understand this stuff, an understanding of keys and all their bits is
- necessary. Every node in the trie has a key associated with it, but not
-@@ -485,6 +460,15 @@ static void tnode_put_child_reorg(struct
- rcu_assign_pointer(tn->child[i], n);
- }
-
-+static void put_child_root(struct tnode *tp, struct trie *t,
-+ t_key key, struct tnode *n)
-+{
-+ if (tp)
-+ put_child(tp, get_index(key, tp), n);
-+ else
-+ rcu_assign_pointer(t->trie, n);
-+}
-+
- #define MAX_WORK 10
- static struct tnode *resize(struct trie *t, struct tnode *tn)
- {
-@@ -959,138 +943,100 @@ static void trie_rebalance(struct trie *
-
- static struct list_head *fib_insert_node(struct trie *t, u32 key, int plen)
- {
-- int pos, newpos;
-- struct tnode *tp = NULL, *tn = NULL;
-- struct tnode *n;
-- struct tnode *l;
-- int missbit;
- struct list_head *fa_head = NULL;
-+ struct tnode *l, *n, *tp = NULL;
- struct leaf_info *li;
-- t_key cindex;
-
-- pos = 0;
-+ li = leaf_info_new(plen);
-+ if (!li)
-+ return NULL;
-+ fa_head = &li->falh;
-+
- n = rtnl_dereference(t->trie);
-
- /* If we point to NULL, stop. Either the tree is empty and we should
- * just put a new leaf in if, or we have reached an empty child slot,
- * and we should just put our new leaf in that.
-- * If we point to a T_TNODE, check if it matches our key. Note that
-- * a T_TNODE might be skipping any number of bits - its 'pos' need
-- * not be the parent's 'pos'+'bits'!
-- *
-- * If it does match the current key, get pos/bits from it, extract
-- * the index from our key, push the T_TNODE and walk the tree.
-- *
-- * If it doesn't, we have to replace it with a new T_TNODE.
- *
-- * If we point to a T_LEAF, it might or might not have the same key
-- * as we do. If it does, just change the value, update the T_LEAF's
-- * value, and return it.
-- * If it doesn't, we need to replace it with a T_TNODE.
-+ * If we hit a node with a key that does't match then we should stop
-+ * and create a new tnode to replace that node and insert ourselves
-+ * and the other node into the new tnode.
- */
-+ while (n) {
-+ unsigned long index = get_index(key, n);
-
-- while (n && IS_TNODE(n)) {
-- if (tkey_sub_equals(n->key, pos, n->pos-pos, key)) {
-- tp = n;
-- pos = n->pos + n->bits;
-- n = tnode_get_child(n,
-- tkey_extract_bits(key,
-- n->pos,
-- n->bits));
--
-- BUG_ON(n && node_parent(n) != tp);
-- } else
-+ /* 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 prefix. 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 child index
-+ * else
-+ * we have a mismatch in skip bits and failed
-+ */
-+ if (index >> n->bits)
- break;
-- }
--
-- /*
-- * n ----> NULL, LEAF or TNODE
-- *
-- * tp is n's (parent) ----> NULL or TNODE
-- */
-
-- BUG_ON(tp && IS_LEAF(tp));
--
-- /* Case 1: n is a leaf. Compare prefixes */
--
-- if (n != NULL && IS_LEAF(n) && tkey_equals(key, n->key)) {
-- li = leaf_info_new(plen);
--
-- if (!li)
-- return NULL;
-+ /* we have found a leaf. Prefixes have already been compared */
-+ if (IS_LEAF(n)) {
-+ /* Case 1: n is a leaf, and prefixes match*/
-+ insert_leaf_info(&n->list, li);
-+ return fa_head;
-+ }
-
-- fa_head = &li->falh;
-- insert_leaf_info(&n->list, li);
-- goto done;
-+ tp = n;
-+ n = rcu_dereference_rtnl(n->child[index]);
- }
-- l = leaf_new(key);
--
-- if (!l)
-- return NULL;
-
-- li = leaf_info_new(plen);
--
-- if (!li) {
-- node_free(l);
-+ l = leaf_new(key);
-+ if (!l) {
-+ free_leaf_info(li);
- return NULL;
- }
-
-- fa_head = &li->falh;
- insert_leaf_info(&l->list, li);
-
-- if (t->trie && n == NULL) {
-- /* Case 2: n is NULL, and will just insert a new leaf */
--
-- node_set_parent(l, tp);
--
-- cindex = tkey_extract_bits(key, tp->pos, tp->bits);
-- put_child(tp, cindex, l);
-- } else {
-- /* Case 3: n is a LEAF or a TNODE and the key doesn't match. */
-- /*
-- * Add a new tnode here
-- * first tnode need some special handling
-- */
-+ /* Case 2: n is a LEAF or a TNODE and the key doesn't match.
-+ *
-+ * Add a new tnode here
-+ * first tnode need some special handling
-+ * leaves us in position for handling as case 3
-+ */
-+ if (n) {
-+ struct tnode *tn;
-+ int newpos;
-
-- if (n) {
-- pos = tp ? tp->pos+tp->bits : 0;
-- newpos = tkey_mismatch(key, pos, n->key);
-- tn = tnode_new(n->key, newpos, 1);
-- } else {
-- newpos = 0;
-- tn = tnode_new(key, newpos, 1); /* First tnode */
-- }
-+ newpos = KEYLENGTH - __fls(n->key ^ key) - 1;
-
-+ tn = tnode_new(key, newpos, 1);
- if (!tn) {
- free_leaf_info(li);
- node_free(l);
- return NULL;
- }
-
-- node_set_parent(tn, tp);
--
-- missbit = tkey_extract_bits(key, newpos, 1);
-- put_child(tn, missbit, l);
-- put_child(tn, 1-missbit, n);
--
-- if (tp) {
-- cindex = tkey_extract_bits(key, tp->pos, tp->bits);
-- put_child(tp, cindex, tn);
-- } else {
-- rcu_assign_pointer(t->trie, tn);
-- }
-+ /* initialize routes out of node */
-+ NODE_INIT_PARENT(tn, tp);
-+ put_child(tn, get_index(key, tn) ^ 1, n);
-+
-+ /* start adding routes into the node */
-+ put_child_root(tp, t, key, tn);
-+ node_set_parent(n, tn);
-
-+ /* parent now has a NULL spot where the leaf can go */
- tp = tn;
- }
-
-- if (tp && tp->pos + tp->bits > 32)
-- pr_warn("fib_trie tp=%p pos=%d, bits=%d, key=%0x plen=%d\n",
-- tp, tp->pos, tp->bits, key, plen);
--
-- /* Rebalance the trie */
-+ /* Case 3: n is NULL, and will just insert a new leaf */
-+ if (tp) {
-+ NODE_INIT_PARENT(l, tp);
-+ put_child(tp, get_index(key, tp), l);
-+ trie_rebalance(t, tp);
-+ } else {
-+ rcu_assign_pointer(t->trie, l);
-+ }
-
-- trie_rebalance(t, tp);
--done:
- return fa_head;
- }
-
-@@ -1470,11 +1416,11 @@ static void trie_leaf_remove(struct trie
- pr_debug("entering trie_leaf_remove(%p)\n", l);
-
- if (tp) {
-- t_key cindex = tkey_extract_bits(l->key, tp->pos, tp->bits);
-- put_child(tp, cindex, NULL);
-+ put_child(tp, get_index(l->key, tp), NULL);
- trie_rebalance(t, tp);
-- } else
-+ } else {
- RCU_INIT_POINTER(t->trie, NULL);
-+ }
-
- node_free(l);
- }
projects / openwrt / staging / wigyori.git / blobdiff