[$] Scheduling for asymmetric Arm systems

The Arm processor architecture has pushed the boundaries in a number ofways, some of which have required significant kernel changes in response.For example, the big.LITTLE architectureplaced fast (but power-hungry) and slower (but more power-efficient) CPUsin the same system-on-chip (SoC); significant scheduler changes were neededfor Linux to be able to properly distribute tasks on such systems. For alltheir quirkiness, big.LITTLE systems still feature CPUs that are in somesense identical: they can all run any task in the system. What is thescheduler to do, though, if confronted with a system where that is nolonger true?