Re: [PATCH] sched/isolcpus: Show isolated cpu map

From: Peter Zijlstra
Date: Mon Feb 13 2017 - 07:07:00 EST


On Mon, Feb 13, 2017 at 05:43:59PM +0800, Kefeng Wang wrote:
> The commit a6e4491c682a ("sched/isolcpus: Output warning when the
> 'isolcpus=' kernel parameter is invalid") adds an error message
> when specified cpu bigger than nr_cpu_ids, but nr_cpumask_bits in
> cpulist_parse() could be nr_cpu_ids or NR_CPUS.
>
> eg, NR_CPUS=64, nr_cpu_ids=8 in ARM64, cpulist_parse() won't return
> -ERANGE if isolcpus=1-10;
>

But why does cpulist_parse() use nr_cpumask_bits, that seems to be the
problem, so why not look there?