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 <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 @@
.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 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 @@
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 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 = {