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From: Petr Tesarik <ptesarik@suse•cz>
To: Jay Vosburgh <fubar@us•ibm.com>
Cc: Chris Friesen <chris.friesen@genband•com>,
	Jiri Bohac <jbohac@suse•cz>, Andy Gospodarek <andy@greyhouse•net>,
	netdev@vger•kernel.org
Subject: Re: bonding: time limits too tight in bond_ab_arp_inspect
Date: Thu, 23 Aug 2012 09:34:18 +0200	[thread overview]
Message-ID: <201208230934.18652.ptesarik@suse.cz> (raw)
In-Reply-To: <24655.1345660922@death.nxdomain>

Dne St 22. srpna 2012 20:42:02 Jay Vosburgh napsal(a):
> Chris Friesen <chris.friesen@genband•com> wrote:
> >On 08/22/2012 11:45 AM, Jiri Bohac wrote:
> >> This code is run from bond_activebackup_arp_mon() about
> >> delta_in_ticks jiffies after the previous ARP probe has been
> >> sent. If the delayed work gets executed exactly in delta_in_ticks
> >> jiffies, there is a chance the slave will be brought up.  If the
> >> delayed work runs one jiffy later, the slave will stay down.
> 
> 	Presumably the ARP reply is coming back in less than one jiffy,
> then, so the slave_last_rx() value is the same jiffy as when the
> _inspect was previously called?

Yes, that's what happens. Keep in mind that the backup slave validates the 
original ARP query, so on a fast network, you get it more or less immediately 
(for my case, I can see a delay of ~70us).

Anyway, why do we have to wait until the next ARP send? Couldn't we simply 
kick the work queue when we receive a valid packet on a down interface?

Petr Tesarik
SUSE Linux

  parent reply	other threads:[~2012-08-23  7:34 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-22 17:45 bonding: time limits too tight in bond_ab_arp_inspect Jiri Bohac
2012-08-22 17:54 ` Chris Friesen
2012-08-22 18:42   ` Jay Vosburgh
2012-08-22 18:58     ` Chris Friesen
2012-08-23  7:34     ` Petr Tesarik [this message]
2012-08-30 22:02     ` [PATCH] bonding: add some slack to arp monitoring time limits Jiri Bohac
2012-08-31 20:37       ` David Miller

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