[Devel] [PATCH rh7 01/19] ms/netfilter: conntrack: don't attempt to iterate over empty table

[Konstantin Khorenko]

From: Florian Westphal <fw at strlen.de>

Once we place all conntracks into same table iteration becomes more
costly because the table contains conntracks that we are not interested
in (belonging to other netns).

So don't bother scanning if the current namespace has no entries.

Signed-off-by: Florian Westphal <fw at strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>

https://jira.sw.ru/browse/PSBM-103515

(cherry picked from commit 88b68bc5237c84c6ff6f78568653780869a94a95)
Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
---
 net/netfilter/nf_conntrack_core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index c6c2af8db9f6e..e2af1d742a20f 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -1575,6 +1575,9 @@ void nf_ct_iterate_cleanup(struct net *net,
 
 	might_sleep();
 
+	if (atomic_read(&net->ct.count) == 0)
+		return;
+
 	while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
 		/* Time to push up daises... */
 		if (del_timer(&ct->timeout))
-- 
2.15.1