Re: nfs server lockup (again)

[David Young <dyoung%pobox.com@localhost>]

On Fri, Jun 24, 2011 at 04:41:44PM +0000, David Holland wrote:
> On Fri, Jun 24, 2011 at 12:11:22PM +0200, Manuel Bouyer wrote:
>  > > I've been thinking that the nfs client problems I've been seeing,
>  > > which seem to be callout-related, are maybe connected, as could be the
>  > > odd problem mrg has been having with raidframe.
>  > > 
>  > > Do we have a debug hook or other method that will raise a panic if
>  > > callouts stop getting processed?
>  > 
>  > unfortunably, no (AFAIK).
> 
> without looking at the code (today) I'm wondering if it would be
> feasible to have callout_schedule panic if the head of the callout
> queue is more than, say, one second in the past. Maybe only for
> DIAGNOSTIC kernels?

I fear this will lead to some spurious panics.  Maybe make this a
printf() instead of a panic()?  Or else explicitly suspend callout
processing before entering ddb, putting the machine to sleep, or
suspending/migrating the VM?

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 344-0444 x24