From 9500507c61381ceda4edbefa7361a4d26f54eb17 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 10 Jun 2014 23:12:56 +0200 Subject: netfilter: conntrack: remove timer from ecache extension This brings the (per-conntrack) ecache extension back to 24 bytes in size (was 152 byte on x86_64 with lockdep on). When event delivery fails, re-delivery is attempted via work queue. Redelivery is attempted at least every 0.1 seconds, but can happen more frequently if userspace is not congested. The nf_ct_release_dying_list() function is removed. With this patch, ownership of the to-be-redelivered conntracks (on-dying-list-with-DYING-bit not yet set) is with the work queue, which will release the references once event is out. Joint work with Pablo Neira Ayuso. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_ecache.c | 96 +++++++++++++++++++++++++++++++++---- 1 file changed, 86 insertions(+), 10 deletions(-) (limited to 'net/netfilter/nf_conntrack_ecache.c') diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c index 1df176146567..4e78c57b818f 100644 --- a/net/netfilter/nf_conntrack_ecache.c +++ b/net/netfilter/nf_conntrack_ecache.c @@ -29,6 +29,90 @@ static DEFINE_MUTEX(nf_ct_ecache_mutex); +#define ECACHE_RETRY_WAIT (HZ/10) + +enum retry_state { + STATE_CONGESTED, + STATE_RESTART, + STATE_DONE, +}; + +static enum retry_state ecache_work_evict_list(struct ct_pcpu *pcpu) +{ + struct nf_conn *refs[16]; + struct nf_conntrack_tuple_hash *h; + struct hlist_nulls_node *n; + unsigned int evicted = 0; + enum retry_state ret = STATE_DONE; + + spin_lock(&pcpu->lock); + + hlist_nulls_for_each_entry(h, n, &pcpu->dying, hnnode) { + struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); + + if (nf_ct_is_dying(ct)) + continue; + + if (nf_conntrack_event(IPCT_DESTROY, ct)) { + ret = STATE_CONGESTED; + break; + } + + /* we've got the event delivered, now it's dying */ + set_bit(IPS_DYING_BIT, &ct->status); + refs[evicted] = ct; + + if (++evicted >= ARRAY_SIZE(refs)) { + ret = STATE_RESTART; + break; + } + } + + spin_unlock(&pcpu->lock); + + /* can't _put while holding lock */ + while (evicted) + nf_ct_put(refs[--evicted]); + + return ret; +} + +static void ecache_work(struct work_struct *work) +{ + struct netns_ct *ctnet = + container_of(work, struct netns_ct, ecache_dwork.work); + int cpu, delay = -1; + struct ct_pcpu *pcpu; + + local_bh_disable(); + + for_each_possible_cpu(cpu) { + enum retry_state ret; + + pcpu = per_cpu_ptr(ctnet->pcpu_lists, cpu); + + ret = ecache_work_evict_list(pcpu); + + switch (ret) { + case STATE_CONGESTED: + delay = ECACHE_RETRY_WAIT; + goto out; + case STATE_RESTART: + delay = 0; + break; + case STATE_DONE: + break; + } + } + + out: + local_bh_enable(); + + ctnet->ecache_dwork_pending = delay > 0; + if (delay >= 0) + schedule_delayed_work(&ctnet->ecache_dwork, delay); +} + /* deliver cached events and clear cache entry - must be called with locally * disabled softirqs */ void nf_ct_deliver_cached_events(struct nf_conn *ct) @@ -157,7 +241,6 @@ EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier); #define NF_CT_EVENTS_DEFAULT 1 static int nf_ct_events __read_mostly = NF_CT_EVENTS_DEFAULT; -static int nf_ct_events_retry_timeout __read_mostly = 15*HZ; #ifdef CONFIG_SYSCTL static struct ctl_table event_sysctl_table[] = { @@ -168,13 +251,6 @@ static struct ctl_table event_sysctl_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, - { - .procname = "nf_conntrack_events_retry_timeout", - .data = &init_net.ct.sysctl_events_retry_timeout, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec_jiffies, - }, {} }; #endif /* CONFIG_SYSCTL */ @@ -196,7 +272,6 @@ static int nf_conntrack_event_init_sysctl(struct net *net) goto out; table[0].data = &net->ct.sysctl_events; - table[1].data = &net->ct.sysctl_events_retry_timeout; /* Don't export sysctls to unprivileged users */ if (net->user_ns != &init_user_ns) @@ -238,12 +313,13 @@ static void nf_conntrack_event_fini_sysctl(struct net *net) int nf_conntrack_ecache_pernet_init(struct net *net) { net->ct.sysctl_events = nf_ct_events; - net->ct.sysctl_events_retry_timeout = nf_ct_events_retry_timeout; + INIT_DELAYED_WORK(&net->ct.ecache_dwork, ecache_work); return nf_conntrack_event_init_sysctl(net); } void nf_conntrack_ecache_pernet_fini(struct net *net) { + cancel_delayed_work_sync(&net->ct.ecache_dwork); nf_conntrack_event_fini_sysctl(net); } -- cgit v1.2.3