Subject: Reduce timer updates in __nf_ct_refresh_acct()

Only update the conntrack timer if there's been at least HZ jiffies since the
last update. Reduces the number of del_timer/add_timer cycles from one per
packet to one per connection per second (plus once for each state change of a
connection)
Should handle timer wraparounds and connection timeout changes.

Signed-off-by: Martin Josefsson <gandalf@wlug.westbo.se>

---
 net/netfilter/nf_conntrack_core.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

Index: linux-2.6.19-rc3-git4.quilt/net/netfilter/nf_conntrack_core.c
===================================================================
--- linux-2.6.19-rc3-git4.quilt.orig/net/netfilter/nf_conntrack_core.c	2006-11-02 19:15:58.000000000 +0100
+++ linux-2.6.19-rc3-git4.quilt/net/netfilter/nf_conntrack_core.c	2006-11-02 19:16:02.000000000 +0100
@@ -926,9 +926,14 @@ void __nf_ct_refresh_acct(struct nf_conn
 		ct->timeout.expires = extra_jiffies;
 		event = IPCT_REFRESH;
 	} else {
-		/* Need del_timer for race avoidance (may already be dying). */
-		if (del_timer(&ct->timeout)) {
-			ct->timeout.expires = jiffies + extra_jiffies;
+		unsigned long newtime = jiffies + extra_jiffies;
+
+		/* Only update the timeout if the new timeout is at least
+		   HZ jiffies from the old timeout. Need del_timer for race
+		   avoidance (may already be dying). */
+		if (newtime - ct->timeout.expires >= HZ
+		    && del_timer(&ct->timeout)) {
+			ct->timeout.expires = newtime;
 			add_timer(&ct->timeout);
 			event = IPCT_REFRESH;
 		}