Linux 4.18 Scheduler Updates Benefit Schedutil, NUMA, vCPUs

The scheduler updates submitted today for the Linux 4.18 kernel merge window include a few notable changes.

This pull does contain the previously-covered scheduler optimization for virtual CPUs. That change is about not scheduling threads on pre-empted vCPUs and in some synthetic scheduler benchmarks yielded a change by as much as 8~25%.

There are also power-aware scheduling improvements with this pull by taking account more information about the current state when making use of Schedutil for scheduler utilization data.

Also rounding things out are more NUMA balancing improvements. The list of Linux 4.18 scheduler changes via this pull request.