Changes from v1: * Use memory_notify->status_change_nid to detect node online/offline events instead of building a new mechanism. -- This contains two fixes for the "automatic demotion" code which was merged into 5.15: * Fix memory hotplug performance regression by watching suppressing any real action on irrelevant hotplug events. * Ensure CPU hotplug handler is registered when memory hotplug is disabled. Cc: "Huang, Ying" <ying.huang@xxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Wei Xu <weixugc@xxxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Greg Thelen <gthelen@xxxxxxxxxx> Cc: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
