neigh: optimize neigh_parms_release()
In neigh_parms_release() we loop over all entries to find the entry given in
argument and being able to remove it from the list. By using a double linked
list, we can avoid this loop.
Here are some numbers with 30 000 dummy interfaces configured:
Before the patch:
$ time rmmod dummy
real 2m0.118s
user 0m0.000s
sys 1m50.048s
After the patch:
$ time rmmod dummy
real 1m9.970s
user 0m0.000s
sys 0m47.976s
Suggested-by: Thierry Herbelot <thierry.herbelot@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index ef31fef..edd0411 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -773,7 +773,7 @@
if (time_after(jiffies, tbl->last_rand + 300 * HZ)) {
struct neigh_parms *p;
tbl->last_rand = jiffies;
- for (p = &tbl->parms; p; p = p->next)
+ list_for_each_entry(p, &tbl->parms_list, list)
p->reachable_time =
neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
}
@@ -1446,7 +1446,7 @@
{
struct neigh_parms *p;
- for (p = &tbl->parms; p; p = p->next) {
+ list_for_each_entry(p, &tbl->parms_list, list) {
if ((p->dev && p->dev->ifindex == ifindex && net_eq(neigh_parms_net(p), net)) ||
(!p->dev && !ifindex && net_eq(net, &init_net)))
return p;
@@ -1481,8 +1481,7 @@
}
write_lock_bh(&tbl->lock);
- p->next = tbl->parms.next;
- tbl->parms.next = p;
+ list_add(&p->list, &tbl->parms.list);
write_unlock_bh(&tbl->lock);
neigh_parms_data_state_cleanall(p);
@@ -1501,24 +1500,15 @@
void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms)
{
- struct neigh_parms **p;
-
if (!parms || parms == &tbl->parms)
return;
write_lock_bh(&tbl->lock);
- for (p = &tbl->parms.next; *p; p = &(*p)->next) {
- if (*p == parms) {
- *p = parms->next;
- parms->dead = 1;
- write_unlock_bh(&tbl->lock);
- if (parms->dev)
- dev_put(parms->dev);
- call_rcu(&parms->rcu_head, neigh_rcu_free_parms);
- return;
- }
- }
+ list_del(&parms->list);
+ parms->dead = 1;
write_unlock_bh(&tbl->lock);
- neigh_dbg(1, "%s: not found\n", __func__);
+ if (parms->dev)
+ dev_put(parms->dev);
+ call_rcu(&parms->rcu_head, neigh_rcu_free_parms);
}
EXPORT_SYMBOL(neigh_parms_release);
@@ -1535,6 +1525,8 @@
unsigned long now = jiffies;
unsigned long phsize;
+ INIT_LIST_HEAD(&tbl->parms_list);
+ list_add(&tbl->parms.list, &tbl->parms_list);
write_pnet(&tbl->parms.net, &init_net);
atomic_set(&tbl->parms.refcnt, 1);
tbl->parms.reachable_time =
@@ -2154,7 +2146,9 @@
NLM_F_MULTI) <= 0)
break;
- for (nidx = 0, p = tbl->parms.next; p; p = p->next) {
+ nidx = 0;
+ p = list_next_entry(&tbl->parms, list);
+ list_for_each_entry_from(p, &tbl->parms_list, list) {
if (!net_eq(neigh_parms_net(p), net))
continue;