[poll / rfc] kdb_stop_cpus

Andriy Gapon avg at FreeBSD.org
Tue Jun 7 14:20:34 UTC 2011


on 04/06/2011 12:11 Robert N. M. Watson said the following:
> 
> On 4 Jun 2011, at 09:22, Andriy Gapon wrote:
>> commit 458ebd9aca7e91fc6e0825c727c7220ab9f61016
>> 
>> generic_stop_cpus: move timeout detection code from under DIAGNOSTIC
>> 
>> ... and also increase it a bit. IMO it's better to detect and report the
>> (rather serious) condition and allow a system to proceed somehow rather than
>> be stuck in an endless loop.
> 
> Agreed on detecting and reporting. It would be good to confirm that it works in
> practice, however,

What is your concern here? :)
The code seems rather simple - the loop is no longer infinite.

> and also that there are no false positives. I'm not sure
> what the best test scenarios are for that.

As to the false positives - I think that that can only be verified by practice
(very wide testing), because that would greatly depend on hardware.
Maybe we should use some time-based approach instead of the iteration count
approach or maybe we should calibrate the iteration count based on hardware
characteristics...

-- 
Andriy Gapon


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