[$] Another push for sched_ext

The extensible scheduler class (or "sched_ext") is a comprehensiveframework that enables the implementation of CPU schedulers as a set of BPFprograms that can be loaded at run time. Despite having attracted a fairamount of interest from the development community, sched_ext has run intoconsiderable opposition and seems far from acceptance into the mainline.The posting by Tejun Heo of a newversion of the sched_ext series at the beginning of May has restartedthis long-running discussion, but it is not clear what the end result willbe.