From: Eric Dumazet <edumazet@xxxxxxxxxx>
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: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Florian Westphal <fw@xxxxxxxxx>
Cc: Patrick McHardy <kaber@xxxxxxxxx>
---
net/netfilter/xt_hashlimit.c | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index a3910fc2122b..47dc6836830a 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -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();
}
- spin_unlock_bh(&ht->lock);
}
-/* 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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