Re: [Xen-devel] [PATCH] Fix softlockup issue after vcpu hotplug

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 30/1/07 12:57 pm, "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx> wrote:

>> So saying this new watchdog model, simply walking timer wheel is
>> not enough. Maybe we can force max timeout value to 1s in safe_halt
>> to special this case? I'll make a try on this. But this will make current
>> tick-less model to a bit tick-ful back. :-)
> 
> I'm sure this will fix the issue. But who knows what real underlying issue
> it might be hiding?

There could be a bug in next_timer_event(), for example. Maybe events a long
way out (multiple seconds) don't always get considered but we are normally
saved by the fact that CPUs have a few sooner events also queued up. But
that may not be the case for a newly-onlined CPU.

This is just an example hypothesis to explain why we need to properly track
this down.

 -- Keir



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