Re: [PATCH v2 0/5] cpumask: cleanup nr_cpu_ids vs nr_cpumask_bits mess

[Peter Zijlstra]

On Tue, Sep 06, 2022 at 01:06:47PM +0100, Valentin Schneider wrote:

>   #define nr_cpumask_bits nr_cpu_ids

That assumes the CPU space is dense; is this so? That is, you can have 4
CPUs while the highest cpu number is vastly larger than 4.

It's uncommon, but not unheard of I think. ISTR some BIOSes leaving
holes in the CPU space when there were empty CPU sockets on the
motherboard.