[PATCH] Reduce frequency of cleanup timer in bridge

[PATCH] Reduce frequency of cleanup timer in bridge

[Baruch Even]

The bridge cleanup timer is fired 10 times a second for timers that are
at least 15 seconds ahead in time and that are not critical to be
cleaned asap.

This patch calculates the next time to run the timer as the minimum of
all timers or a minimum based on the current state.

Signed-Off-By: Baruch Even <baruch@ev-en.org>

--- 2.6.22-rc2/net/bridge/br_fdb.c	2007-05-20 00:51:11.000000000 +0300
+++ 2.6-rc2/net/bridge/br_fdb.c	2007-05-20 00:50:31.000000000 +0300
@@ -121,6 +121,7 @@
 {
 	struct net_bridge *br = (struct net_bridge *)_data;
 	unsigned long delay = hold_time(br);
+	unsigned long next_timer = jiffies + br->forward_delay;
 	int i;
 
 	spin_lock_bh(&br->hash_lock);
@@ -129,14 +130,21 @@
 		struct hlist_node *h, *n;
 
 		hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
+			unsigned long this_timer;
+			if (f->is_static)
+				continue;
+			this_timer = f->ageing_timer + delay;
+			if (time_before_eq(this_timer, jiffies))
-			if (!f->is_static &&
-			    time_before_eq(f->ageing_timer + delay, jiffies))
 				fdb_delete(f);
+			else if (this_timer < next_timer)
+				next_timer = this_timer;
 		}
 	}
 	spin_unlock_bh(&br->hash_lock);
 
+	/* Add HZ/4 to ensure we round the jiffies upwards to be after the next
+	 * timer, otherwise we might round down and will have no-op run. */
+	mod_timer(&br->gc_timer, round_jiffies(next_timer + HZ/4));
-	mod_timer(&br->gc_timer, jiffies + HZ/10);
 }
 
 /* Completely flush all dynamic entries in forwarding database.*/

[PATCH 1/2] bridge: reduce frequency of forwarding cleanup timer in bridge

[Stephen Hemminger]

The bridge cleanup timer is fired 10 times a second for timers that are
at least 15 seconds ahead in time and that are not critical to be
cleaned asap.

This patch calculates the next time to run the timer as the minimum of
all timers or a minimum based on the current state.

Signed-off-by: Baruch Even <baruch@ev-en.org>
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>

--- 2.6.22-rc2/net/bridge/br_fdb.c	2007-05-20 00:51:11.000000000 +0300
+++ 2.6-rc2/net/bridge/br_fdb.c	2007-05-20 00:50:31.000000000 +0300
@@ -121,6 +121,7 @@
 {
 	struct net_bridge *br = (struct net_bridge *)_data;
 	unsigned long delay = hold_time(br);
+	unsigned long next_timer = jiffies + br->forward_delay;
 	int i;
 
 	spin_lock_bh(&br->hash_lock);
@@ -129,14 +130,21 @@
 		struct hlist_node *h, *n;
 
 		hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
+			unsigned long this_timer;
+			if (f->is_static)
+				continue;
+			this_timer = f->ageing_timer + delay;
+			if (time_before_eq(this_timer, jiffies))
-			if (!f->is_static &&
-			    time_before_eq(f->ageing_timer + delay, jiffies))
 				fdb_delete(f);
+			else if (this_timer < next_timer)
+				next_timer = this_timer;
 		}
 	}
 	spin_unlock_bh(&br->hash_lock);
 
+	/* Add HZ/4 to ensure we round the jiffies upwards to be after the next
+	 * timer, otherwise we might round down and will have no-op run. */
+	mod_timer(&br->gc_timer, round_jiffies(next_timer + HZ/4));
-	mod_timer(&br->gc_timer, jiffies + HZ/10);
 }
 
 /* Completely flush all dynamic entries in forwarding database.*/

[PATCH 2/2] bridge: round off STP perodic timers

[Stephen Hemminger]

Peroidic STP timers don't have to be exact.
The hold timer runs at 1HZ, and the hello timer normally runs
at 2HZ; save power by aligning it them to next second.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>

---
 net/bridge/br_stp.c       |    3 ++-
 net/bridge/br_stp_timer.c |    2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

--- a/net/bridge/br_stp.c	2007-05-30 11:42:16.000000000 -0700
+++ b/net/bridge/br_stp.c	2007-05-30 11:51:51.000000000 -0700
@@ -178,7 +178,8 @@ void br_transmit_config(struct net_bridg
 		br_send_config_bpdu(p, &bpdu);
 		p->topology_change_ack = 0;
 		p->config_pending = 0;
-		mod_timer(&p->hold_timer, jiffies + BR_HOLD_TIME);
+		mod_timer(&p->hold_timer,
+			  round_jiffies(jiffies + BR_HOLD_TIME));
 	}
 }
 
--- a/net/bridge/br_stp_timer.c	2007-05-30 11:42:16.000000000 -0700
+++ b/net/bridge/br_stp_timer.c	2007-05-30 11:53:08.000000000 -0700
@@ -42,7 +42,7 @@ static void br_hello_timer_expired(unsig
 	if (br->dev->flags & IFF_UP) {
 		br_config_bpdu_generation(br);
 
-		mod_timer(&br->hello_timer, jiffies + br->hello_time);
+		mod_timer(&br->hello_timer, round_jiffies(jiffies + br->hello_time));
 	}
 	spin_unlock(&br->lock);
 }

Re: [PATCH 2/2] bridge: round off STP perodic timers

[David Miller]

From: Stephen Hemminger <shemminger@linux-foundation.org>
Date: Wed, 30 May 2007 12:14:22 -0700

> Peroidic STP timers don't have to be exact.
> The hold timer runs at 1HZ, and the hello timer normally runs
> at 2HZ; save power by aligning it them to next second.
> 
> Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>

Applied, thanks Stephen.