On Wed, 17 Feb 2016 17:04:41 +0100 (CET)
Thomas Gleixner [off-list ref] wrote:

quoted

quoted

 
 	for_each_online_cpu(i) {
 		if (topology_physical_package_id(i) ==
package_id)  

This is still crap. We really want a proper handling for that which
does not require these silly for_each_cpu() loops.

That code already has a hotplug notifier, so you can track one online
cpu in the package like we do in cqm and other facilities.

The first online cpu of a package sets itself as 'owner'. On unplug
it looks up:

	rpl->cpu = cpumask_any_but(topology_core_cpumask(cpu), cpu);

So if this is the last cpu then rpl->cpu becomes nr_cpu_ids.

So that whole nonsense can be avoided completely.

ok, that would work nicely, similar to cqm_pick_event_reader().
thanks for the tip. just fyi, unlike perf cqm, rapl runtime change is
expected to be low frequency.