[$] Controlling the CPU scheduler with BPF

While the BPF virtual machine has been supported by Linux for most ofthe kernel's existence, its role for much of that time was limited to, asits fullname (Berkeley packet filter) would suggest, filtering packets. That began to change in 2012 with the introductionof seccomp() filtering, and the pace picked up in 2014 with the arrivalof the extended BPF virtual machine. At this point, BPF hooks have found theirway into many kernel subsystems. One area that has remained BPF-free,though, is the CPU scheduler; that could change if some version ofthis patchset from Roman Gushchin finds its way into the mainline.