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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>
This commit is contained in:
Stephen Hemminger 2008-02-11 21:14:39 -08:00 committed by David S. Miller
parent ec28cf738d
commit 8315f5d80a
1 changed files with 82 additions and 11 deletions
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93
net/ipv4/fib_trie.c
View File

@ -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 = {