Re: [RFC 3/3] sched/topology: Different sched groups must not have the same balance cpu

[Peter Zijlstra]

On Thu, Apr 13, 2017 at 10:56:09AM -0300, Lauro Ramos Venancio wrote:
> Currently, the group balance cpu is the groups's first CPU. But with
> overlapping groups, two different groups can have the same first CPU.
> 
> This patch uses the group mask to mark all the CPUs that have a
> particular group as its main sched group. The group balance cpu is the
> first group CPU that is also in the mask.

Please give a NUMA configuration and CPU number where this goes wrong.

Because only the first group of a domain matters, and with the other
thing fixed, I'm not immediately seeing where we go wobbly.