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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>
This commit is contained in:
Nicolas Dichtel 2014-10-29 19:29:31 +01:00 committed by David S. Miller
parent bc9ad166e3
commit 75fbfd3323
2 changed files with 15 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/neighbour.h
View File

@ -69,7 +69,7 @@ struct neigh_parms {
struct net *net;
#endif
struct net_device *dev;
struct neigh_parms *next;
struct list_head list;
int (*neigh_setup)(struct neighbour *);
void (*neigh_cleanup)(struct neighbour *);
struct neigh_table *tbl;
@ -203,6 +203,7 @@ struct neigh_table {
void (*proxy_redo)(struct sk_buff *skb);
char *id;
struct neigh_parms parms;
struct list_head parms_list;
int gc_interval;
int gc_thresh1;
int gc_thresh2;

32
net/core/neighbour.c
View File

@ -773,7 +773,7 @@ static void neigh_periodic_work(struct work_struct *work)
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 @@ static inline struct neigh_parms *lookup_neigh_parms(struct neigh_table *tbl,
{
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 @@ struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
}
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 @@ static void neigh_rcu_free_parms(struct rcu_head *head)
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 @@ static void neigh_table_init_no_netlink(struct neigh_table *tbl)
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 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
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;