Re: [PATCH] affine kernel threads to specified cpumask

[Chris Friesen]

On 3/23/2020 10:22 AM, Thomas Gleixner wrote:
> Marcelo,
> Marcelo Tosatti <mtosatti@xxxxxxxxxx> writes:
>
> the subject lacks a prefix and the CC list a few people.
>
> > This is a kernel enhancement to configure the cpu affinity of kernel
> > threads via kernel boot option kthread_cpus=<cpulist>.
> >
> > With kthread_cpus specified, the cpumask is immediately applied upon
> > thread launch. This does not affect kernel threads that specify cpu
> > and node.
> >
> > This allows CPU isolation (that is not allowing certain threads
> > to execute on certain CPUs) without using the isolcpus= parameter,
> > making it possible to enable load balancing on such CPUs
> > during runtime.
>
> I'm surely missing some background information, but that sentence does
> not make any sense to me.
>
> Thanks,
>
>          tglx

The idea is to affine general kernel threads to specific "housekeeping" 
CPUs, while still allowing load balancing of tasks.

The isolcpus= boot parameter would prevent kernel threads from running 
on the isolated CPUs, but it disables load balancing on the isolated CPUs.

Chris