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From: Don Zickus <dzickus@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-watchdog@vger.kernel.org, kexec@lists.infradead.org,
	LKML <linux-kernel@vger.kernel.org>,
	wim@iguana.be, linux@roeck-us.net, dyoung@redhat.com,
	vgoyal@redhat.com
Subject: Re: [PATCH v3] watchdog: Add hook for kicking in kdump path
Date: Thu, 18 Apr 2013 09:00:09 -0400	[thread overview]
Message-ID: <20130418130009.GH79013@redhat.com> (raw)
In-Reply-To: <87li8gaku0.fsf@xmission.com>

On Wed, Apr 17, 2013 at 02:49:59PM -0700, Eric W. Biederman wrote:
> Don Zickus <dzickus@redhat.com> writes:
> 
> > A common problem with kdump is that during the boot up of the
> > second kernel, the hardware watchdog times out and reboots the
> > machine before a vmcore can be captured.
> >
> > Instead of tellling customers to disable their hardware watchdog
> > timers, I hacked up a hook to put in the kdump path that provides
> > one last kick before jumping into the second kernel.
> >
> > The assumption is the watchdog timeout is at least 10-30 seconds
> > long, enough to get the second kernel to userspace to kick the watchdog
> > again, if needed.
> 
> Why not double the watchdog timeout? and/or pet the watchdog a little
> more frequently.

I am not sure if the watchdog timeouts can be doubled.  I think Guenter
was saying some have a max of a couple seconds?? Petting a little more
frequently might be an option.  Guenter can that be done with a softdog
option?

Cheers,
Don

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WARNING: multiple messages have this Message-ID (diff)
From: Don Zickus <dzickus@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-watchdog@vger.kernel.org, kexec@lists.infradead.org,
	wim@iguana.be, LKML <linux-kernel@vger.kernel.org>,
	vgoyal@redhat.com, dyoung@redhat.com, linux@roeck-us.net
Subject: Re: [PATCH v3] watchdog: Add hook for kicking in kdump path
Date: Thu, 18 Apr 2013 09:00:09 -0400	[thread overview]
Message-ID: <20130418130009.GH79013@redhat.com> (raw)
In-Reply-To: <87li8gaku0.fsf@xmission.com>

On Wed, Apr 17, 2013 at 02:49:59PM -0700, Eric W. Biederman wrote:
> Don Zickus <dzickus@redhat.com> writes:
> 
> > A common problem with kdump is that during the boot up of the
> > second kernel, the hardware watchdog times out and reboots the
> > machine before a vmcore can be captured.
> >
> > Instead of tellling customers to disable their hardware watchdog
> > timers, I hacked up a hook to put in the kdump path that provides
> > one last kick before jumping into the second kernel.
> >
> > The assumption is the watchdog timeout is at least 10-30 seconds
> > long, enough to get the second kernel to userspace to kick the watchdog
> > again, if needed.
> 
> Why not double the watchdog timeout? and/or pet the watchdog a little
> more frequently.

I am not sure if the watchdog timeouts can be doubled.  I think Guenter
was saying some have a max of a couple seconds?? Petting a little more
frequently might be an option.  Guenter can that be done with a softdog
option?

Cheers,
Don

  parent reply	other threads:[~2013-04-18 13:00 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-17 21:19 [PATCH v3] watchdog: Add hook for kicking in kdump path Don Zickus
2013-04-17 21:19 ` Don Zickus
2013-04-17 21:33 ` Guenter Roeck
2013-04-17 21:33   ` Guenter Roeck
2013-04-17 21:49 ` Eric W. Biederman
2013-04-17 21:49   ` Eric W. Biederman
2013-04-18  3:03   ` Guenter Roeck
2013-04-18  3:03     ` Guenter Roeck
2013-04-18 13:00   ` Don Zickus [this message]
2013-04-18 13:00     ` Don Zickus
2013-04-18 13:49     ` Guenter Roeck
2013-04-18 13:49       ` Guenter Roeck
2013-04-18 13:52       ` Don Zickus
2013-04-18 13:52         ` Don Zickus
2013-04-18 14:54         ` Guenter Roeck
2013-04-18 14:54           ` Guenter Roeck
2013-04-24 14:42           ` Don Zickus
2013-04-24 14:42             ` Don Zickus
2013-04-24 15:21             ` Guenter Roeck
2013-04-24 15:21               ` Guenter Roeck
2013-05-27 19:16               ` Wim Van Sebroeck
2013-05-28  1:10                 ` Guenter Roeck
2013-05-28  1:10                   ` Guenter Roeck
2013-05-30 20:37                   ` Wim Van Sebroeck
2013-05-28 15:34                 ` Guenter Roeck
2013-05-28 15:34                   ` Guenter Roeck
2013-05-30 21:54                   ` Wim Van Sebroeck
2013-04-18 16:35 ` Eric W. Biederman
2013-04-18 16:35   ` Eric W. Biederman
2013-04-18 17:44   ` Don Zickus
2013-04-18 17:44     ` Don Zickus
2013-04-18 18:09     ` Eric W. Biederman
2013-04-18 18:09       ` Eric W. Biederman

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