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Date: Tue, 29 Apr 2008 07:44:26 -0500
From: Dimitri Sivanich <sivanich@sgi.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] disable softlockup detection at boottime
Message-ID: <20080429124426.GA20775@sgi.com>
References: <20080423201613.GA8546@sgi.com> <20080428165544.GE18210@elte.hu> <20080428185252.GC1167@sgi.com> <20080429123522.GK31271@elte.hu>
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On Tue, Apr 29, 2008 at 02:35:22PM +0200, Ingo Molnar wrote:
> * Dimitri Sivanich <sivanich@sgi.com> wrote:
> 
> > I'm getting unaligned access errors trying to set it to anything, so 
> > it's not working for me currently (2.6.25):
> > 
> > It's tripping up on the address of 'one', which is an int that is not 
> > properly aligned for the unsigned long comparison in 
> > proc_doulongvec_minmax on my 64 bit machine.  Also, the value '0' is 
> > invalid for softlockup_thresh, correct?
> > 
> > I temporarily got around these issues with the following hack.
> 
> ah, sorry. But ... perhaps using threshold -1 would be the most 
> intuitive setting? (for 'infinite timeout' ==> softlockup detector 
> turned off) That way it all becomes configurable as part of the 
> threshold? No strong opinion though.
>

Having the ability to switch it off dynamically would be nice to have, but
will need a little work yet.  Any solution should also minimize the amount
of time spent in softlockup_tick.

Either '0' or '-1' seems OK to me, but if '-1' turns it off, do we allow
a value of '0'?.