Re: [PATCHSET] percpu: generalize first chunk allocators and improvelpage NUMA support

From: Christoph Lameter
Date: Tue Jun 30 2009 - 15:40:38 EST


On Tue, 30 Jun 2009, Ingo Molnar wrote:

> Yeah, it's a bug for something like a virtual environment which
> boots generic kernels that might have 64 possible CPUs (on a true
> 64-way system), but which will have fewer in practice.

A machine (and a virtual environment) can indicate via the BIOS tables or
ACPI that there are less "possible" cpus. That is actually very common.

The difference between actual and possible cpus only has to be the number
of processors that could be brought up later. In a regular system that is
pretty much zero. In a fancy system with actual hotpluggable cpus there
would be a difference but usually the number of hotpluggable cpus is
minimal.

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