Re: CPU Hotplug: Hotplug Script And SIGPWR

[Tim Hockin]

On Tue, Jan 20, 2004 at 06:11:49PM +1100, Nick Piggin wrote:
> I thought hotplug is allowed to fail? Thus you can have a hung system.
> Or what if the hotplug script itself becomes TASK_UNRUNNABLE? What if the
> process needs a guaranteed scheduling latency?

I guess a hotplug script MAY fail.  I don't think it's a good idea to make
your CPU hotplug script fail.  May and Misght are different.  It's up to the
implementor whether the script can get into a failure condition.

The hotplug script can only become unrunnable if you yank out all the CPUs
on the system.  I'd assume it would have an affinity of 0xffffffff.

What if <which> process needs guaranteed scheduling latency?  Do we really
_guarantee_ scheduling latency *anywhere*?

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