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Date: Mon, 11 Feb 2008 21:14:49 -0800 (PST)
From: David Miller <davem@...emloft.net>
To: shemminger@...tta.com
Cc: netdev@...r.kernel.org
Subject: Re: [PATCH 2/2] fib_trie: /proc/net/route performance improvement
From: Stephen Hemminger <shemminger@...tta.com>
Date: Mon, 11 Feb 2008 17:16:59 -0800
> 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 <shemminger@...tta.com>
Applied, thanks.
> 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 = {
> --
> 1.5.3.8
>
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