Re: [PATCH 1/5] x86/smpboot: Add the missing description of possible_cpus

[Peter Zijlstra]

On Wed, Mar 21, 2018 at 01:33:24PM +0800, Dou Liyang wrote:
> How about:
> 
> possible_cpus=	[s390,x86_64] Set the number of possible CPUs which
> 		are determined by the ACPI tables MADT or mptables by
> 		default. possible_cpus=n : n >= 1 enforces the possible
> 		number to be 'n'.
> 		While nr_cpus is also be set: nr_cpus=m, choice the
> 		minimum one for the number of possible CPUs.

So what is the exact difference between possible_cpus and nr_cpus ? I
konw maxcpus= limits the number of CPUs we bring up, and possible_cpus
limits the possible_map, but I'm not entirely sure what nr_cpus does
here.