From 8315f5d80a90247bf92232f92ca49933ac49327b Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 11 Feb 2008 21:14:39 -0800 Subject: [PATCH] fib_trie: /proc/net/route performance improvement Use key/offset caching to change /proc/net/route (use by iputils route) from O(n^2) to O(n). This improves performance from 30sec with 160,000 routes to 1sec. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/ipv4/fib_trie.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 82 insertions(+), 11 deletions(-) diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index 2d89527..1ff446d 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -2459,6 +2459,84 @@ static const struct file_operations fib_trie_fops = { .release = seq_release_net, }; +struct fib_route_iter { + struct seq_net_private p; + struct trie *main_trie; + loff_t pos; + t_key key; +}; + +static struct leaf *fib_route_get_idx(struct fib_route_iter *iter, loff_t pos) +{ + struct leaf *l = NULL; + struct trie *t = iter->main_trie; + + /* use cache location of last found key */ + if (iter->pos > 0 && pos >= iter->pos && (l = fib_find_node(t, iter->key))) + pos -= iter->pos; + else { + iter->pos = 0; + l = trie_firstleaf(t); + } + + while (l && pos-- > 0) { + iter->pos++; + l = trie_nextleaf(l); + } + + if (l) + iter->key = pos; /* remember it */ + else + iter->pos = 0; /* forget it */ + + return l; +} + +static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos) + __acquires(RCU) +{ + struct fib_route_iter *iter = seq->private; + struct fib_table *tb; + + rcu_read_lock(); + tb = fib_get_table(iter->p.net, RT_TABLE_MAIN); + if (!tb) + return NULL; + + iter->main_trie = (struct trie *) tb->tb_data; + if (*pos == 0) + return SEQ_START_TOKEN; + else + return fib_route_get_idx(iter, *pos - 1); +} + +static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct fib_route_iter *iter = seq->private; + struct leaf *l = v; + + ++*pos; + if (v == SEQ_START_TOKEN) { + iter->pos = 0; + l = trie_firstleaf(iter->main_trie); + } else { + iter->pos++; + l = trie_nextleaf(l); + } + + if (l) + iter->key = l->key; + else + iter->pos = 0; + return l; +} + +static void fib_route_seq_stop(struct seq_file *seq, void *v) + __releases(RCU) +{ + rcu_read_unlock(); +} + static unsigned fib_flag_trans(int type, __be32 mask, const struct fib_info *fi) { static unsigned type2flags[RTN_MAX + 1] = { @@ -2482,7 +2560,6 @@ static unsigned fib_flag_trans(int type, __be32 mask, const struct fib_info *fi) */ static int fib_route_seq_show(struct seq_file *seq, void *v) { - const struct fib_trie_iter *iter = seq->private; struct leaf *l = v; struct leaf_info *li; struct hlist_node *node; @@ -2494,12 +2571,6 @@ static int fib_route_seq_show(struct seq_file *seq, void *v) return 0; } - if (iter->trie == iter->trie_local) - return 0; - - if (IS_TNODE(l)) - return 0; - hlist_for_each_entry_rcu(li, node, &l->list, hlist) { struct fib_alias *fa; __be32 mask, prefix; @@ -2542,16 +2613,16 @@ static int fib_route_seq_show(struct seq_file *seq, void *v) } static const struct seq_operations fib_route_seq_ops = { - .start = fib_trie_seq_start, - .next = fib_trie_seq_next, - .stop = fib_trie_seq_stop, + .start = fib_route_seq_start, + .next = fib_route_seq_next, + .stop = fib_route_seq_stop, .show = fib_route_seq_show, }; static int fib_route_seq_open(struct inode *inode, struct file *file) { return seq_open_net(inode, file, &fib_route_seq_ops, - sizeof(struct fib_trie_iter)); + sizeof(struct fib_route_iter)); } static const struct file_operations fib_route_fops = { -- 2.7.4