Subject: Re: [PATCH] sched/topology: Use Identity node only if required

From: Peter Zijlstra <[email-masked]>
Date: Wed, 29 Aug 2018 10:57:38 +0200

On Wed, Aug 29, 2018 at 10:43:48AM +0200, Peter Zijlstra wrote:
> DIE(j) should be:
> 
> 	cpu_cpu_mask(j) := cpumask_of_node(cpu_to_node(j))

FWIW, I was expecting that to be topology_core_cpumask(), so I'm a
little confused myself just now.

> and NODE(j) should be:
> 
> 	\Union_k cpumask_of_node(k) ; where node_distance(j,k) <= node_distance(0,0)
> 
> which, _should_ reduce to:
> 
> 	cpumask_of_node(j)
> 
> and thus DIE and NODE _should_ be the same here.
> 
> So what's going sideways?