Re: [PATCH] cpu-topology: warn if NUMA configurations conflicts with lower layer

[Dietmar Eggemann]

On 09/01/2020 12:05, Morten Rasmussen wrote:
> On Mon, Jan 06, 2020 at 03:31:24PM +0100, Dietmar Eggemann wrote:
>> Your issue is related to the 'numa mask check for scheduler MC
>> selection' functionality.  It was introduced by commit 37c3ec2d810f and
>> re-introduced by commit e67ecf647020 later. I don't know why we need
>> this functionality?
> 
> That functionality is to ensure that we don't break the sched_domain
> hierarchy for numa-in-cluster systems. We have to be sure that the MC
> domain is always smaller or equal to the NUMA node span.

Thanks! And we already have Arm64 systems today using 'numa-in-cluster',
as I learned yesterday.