Commit 7bd8490e authored by Eric Dumazet's avatar Eric Dumazet Committed by Pablo Neira Ayuso

netfilter: xt_hashlimit: perform garbage collection from process context

xt_hashlimit cannot be used with large hash tables, because garbage
collector is run from a timer. If table is really big, its possible
to hold cpu for more than 500 msec, which is unacceptable.

Switch to a work queue, and use proper scheduling points to remove
latencies spikes.

Later, we also could switch to a smoother garbage collection done
at lookup time, one bucket at a time...
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: Patrick McHardy <kaber@trash.net>
Reviewed-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 5b96af77
......@@ -104,7 +104,7 @@ struct xt_hashlimit_htable {
spinlock_t lock; /* lock for list_head */
u_int32_t rnd; /* random seed for hash */
unsigned int count; /* number entries in table */
struct timer_list timer; /* timer for gc */
struct delayed_work gc_work;
/* seq_file stuff */
struct proc_dir_entry *pde;
......@@ -213,7 +213,7 @@ dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
call_rcu_bh(&ent->rcu, dsthash_free_rcu);
ht->count--;
}
static void htable_gc(unsigned long htlong);
static void htable_gc(struct work_struct *work);
static int htable_create(struct net *net, struct xt_hashlimit_mtinfo1 *minfo,
u_int8_t family)
......@@ -273,9 +273,9 @@ static int htable_create(struct net *net, struct xt_hashlimit_mtinfo1 *minfo,
}
hinfo->net = net;
setup_timer(&hinfo->timer, htable_gc, (unsigned long)hinfo);
hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
add_timer(&hinfo->timer);
INIT_DEFERRABLE_WORK(&hinfo->gc_work, htable_gc);
queue_delayed_work(system_power_efficient_wq, &hinfo->gc_work,
msecs_to_jiffies(hinfo->cfg.gc_interval));
hlist_add_head(&hinfo->node, &hashlimit_net->htables);
......@@ -300,29 +300,30 @@ static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
{
unsigned int i;
/* lock hash table and iterate over it */
spin_lock_bh(&ht->lock);
for (i = 0; i < ht->cfg.size; i++) {
struct dsthash_ent *dh;
struct hlist_node *n;
spin_lock_bh(&ht->lock);
hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) {
if ((*select)(ht, dh))
dsthash_free(ht, dh);
}
}
spin_unlock_bh(&ht->lock);
cond_resched();
}
}
/* hash table garbage collector, run by timer */
static void htable_gc(unsigned long htlong)
static void htable_gc(struct work_struct *work)
{
struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong;
struct xt_hashlimit_htable *ht;
ht = container_of(work, struct xt_hashlimit_htable, gc_work.work);
htable_selective_cleanup(ht, select_gc);
/* re-add the timer accordingly */
ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
add_timer(&ht->timer);
queue_delayed_work(system_power_efficient_wq,
&ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval));
}
static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo)
......@@ -341,7 +342,7 @@ static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo)
static void htable_destroy(struct xt_hashlimit_htable *hinfo)
{
del_timer_sync(&hinfo->timer);
cancel_delayed_work_sync(&hinfo->gc_work);
htable_remove_proc_entry(hinfo);
htable_selective_cleanup(hinfo, select_all);
kfree(hinfo->name);
......
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