[PATCH] remove exessive timer updates (3/4)

[Martin Josefsson <gandalf@wlug.westbo.se>]

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Here's the patch that lead up to the first patch (the renaming of
death_by_timeout and exporting it).

This patch adds a check to ip_ct_refresh() so it doesn't update the
timer of a connection unless it's been >HZ ticks since the last update.
both del_timer() and add_timer() disables interrupts while
removing/inserting the timer, no reason to do this for each packet.

-- 
/Martin

Never argue with an idiot. They drag you down to their level, then beat
you with experience.

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--- linux-2.4.19-pre9/net/ipv4/netfilter/ip_conntrack_core.c.orig	Mon Jun  3 20:32:28 2002
+++ linux-2.4.19-pre9/net/ipv4/netfilter/ip_conntrack_core.c	Mon Jun  3 20:48:13 2002
@@ -1091,8 +1091,10 @@
 	if (!is_confirmed(ct))
 		ct->timeout.expires = extra_jiffies;
 	else {
-		/* Need del_timer for race avoidance (may already be dying). */
-		if (del_timer(&ct->timeout)) {
+		/* Don't update timer for each packet, only if it's been >HZ
+		 * ticks since last update.
+		 * Need del_timer for race avoidance (may already be dying). */
+		if (time_after(jiffies, ct->timeout.expires - extra_jiffies + HZ) && del_timer(&ct->timeout)) {
 			ct->timeout.expires = jiffies + extra_jiffies;
 			add_timer(&ct->timeout);
 		}