From: "H. Peter Anvin" <hpa@zytor.com>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: tglx@linutronix.de, mingo@redhat.com, x86@kernel.org,
linux-kernel@vger.kernel.org, penberg@kernel.org
Subject: Re: [PATCH] x86, smpboot: allow manual hotplug of CPUs
Date: Wed, 21 Nov 2012 10:38:00 -0800 [thread overview]
Message-ID: <50AD1F88.1010006@zytor.com> (raw)
In-Reply-To: <50AD1EE7.6020304@oracle.com>
On 11/21/2012 10:35 AM, Sasha Levin wrote:
>>
>> Reading between the lines, this sounds like would cause a user-visible
>> difference between mptable platforms and ACPI platforms? If so, that is
>> totally unacceptable. If not, the description is confusing.
>
> With ACPI platforms you don't need probe/release because the hardware notifies
> on CPU insert/eject - this doesn't exist on mptable which is why you have to
> do it manually with probe/release.
>
> The difference is already user visible: you can hotplug on ACPI, but can't on
> mptables.
>
> Yes, reading back the subject does sound confusing - a better one would probably
> be "provide interface for CPU hotplug on mptable platforms" or something similar.
>
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.
-hpa
next prev parent reply other threads:[~2012-11-21 18:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-21 18:22 [PATCH] x86, smpboot: allow manual hotplug of CPUs Sasha Levin
2012-11-21 18:25 ` H. Peter Anvin
2012-11-21 18:35 ` Sasha Levin
2012-11-21 18:38 ` H. Peter Anvin [this message]
2012-11-21 19:19 ` Sasha Levin
2012-11-21 19:24 ` H. Peter Anvin
2012-11-21 19:35 ` Sasha Levin
2012-11-21 19:39 ` H. Peter Anvin
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