Re: [PATCH] x86, smpboot: allow manual hotplug of CPUs

["H. Peter Anvin" <hpa@zytor.com>]

On 11/21/2012 11:19 AM, Sasha Levin wrote:
>>
>> So, are there any mptables platforms which support hotplug?  If the
>> answer is "KVM" then the answer is that KVM needs to move to ACPI to get
>> the proper functionality; putting a hack in is really not okay.
> 
> There are no platforms which support actual hotplug, but you can still set
> existing processors as disabled in the table and without this patch there's
> no way enable them.
> 
> I'm not sure if it's a "hack" though - the presentation of hotpluggable cpus
> is the almost the same between mptable and acpi, and acpi provides a way to
> manually probe/release cpus as well. The only difference is that acpi also
> provides notifications about such events.
> 
> Actually, maybe acpi should start using probe/release as well... hmm...
> 

The bottom line is that I don't want the underlying implementation to
end up with a user-visible difference... therein lies madness and lots
of bugs.

	-hpa