Re: [PATCH] net/bonding: send arp in interval if no active slave

From: Jarod Wilson
Date: Mon Sep 28 2015 - 09:31:43 EST


Uwe Koziolek wrote:
Am 03.09.2015 um 17:05 schrieb Jay Vosburgh:
Uwe Koziolek <uwe.koziolek@xxxxxxxxxxx> wrote:

On Tue, Sep 01, 2015 at 05:41 PM +0200, Andy Gospodarek wrote:
On Mon, Aug 17, 2015 at 10:51:27PM +0200, Uwe Koziolek wrote:
On Mon, Aug 17, 2015 at 09:14PM +0200, Jay Vosburgh wrote:
Uwe Koziolek <uwe.koziolek@xxxxxxxxxxx> wrote:
...
I probably should have asked this in the beginning, but at what
range of arp_interval values does the problem manifest? If it's a race
condition with the switch update, I'd expect that only very small
arp_interval values would be affected.

Also, your proposed comment wraps past 80 columns.

-J

Only 500 msecs arp interval is used, no other values are checked.
Wraps in patch are now removed.

diff -up ./drivers/net/bonding/bond_main.c.orig
./drivers/net/bonding/bond_main.c
--- ./drivers/net/bonding/bond_main.c.orig 2015-08-30 20:34:09.000000000
+0200
+++ ./drivers/net/bonding/bond_main.c 2015-09-04 11:59:05.755897182 +0200
@@ -2795,6 +2795,17 @@ static bool bond_ab_arp_probe(struct bon
return should_notify_rtnl;
}

+ /* sometimes the forwarding tables of the switches are not updated
+ * fast enough. the first arp response after a slave change is received
+ * on the wrong slave.
+ * the arp requests will be retried 2 times on the same slave
+ */
+
+ if (bond_time_in_interval(bond, curr_arp_slave->last_link_up, 2)) {
+ bond_arp_send_all(bond, curr_arp_slave);
+ return should_notify_rtnl;
+ }
+
bond_set_slave_inactive_flags(curr_arp_slave, BOND_SLAVE_NOTIFY_LATER);

bond_for_each_slave_rcu(bond, slave, iter) {

Jay, any further issues with this patch? I know Veaceslav was concerned about it breaking the logic for link state management if there's no current active slave for 2 * arp_interval, while Andy seemed okay with it, provided there was a comment explaining. Just looking at what might have to be done next here to keep heading towards a resolution.

Thanks much,

--
Jarod Wilson
jarod@xxxxxxxxxx


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