From: Eric Dumazet Date: Thu, 24 Jul 2014 04:36:50 +0000 (+0200) Subject: netfilter: xt_hashlimit: perform garbage collection from process context X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=7bd8490eef9776ced7632345df5133384b6be0fe;p=linux-beck.git 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: Eric Dumazet Cc: Florian Westphal Cc: Patrick McHardy Reviewed-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- 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);