Question

What process will be pointed by “current” pointer in linux kernel, when CPU load is 0% and there isn’t any ready-to-run process?

Consider situation without any power-saving.
What is the name of this process? I think task with PID 0 will be running and code will be

rep nop

or

HLT

Answer 1

Current will be pid 0, process swapper or the last process, which called blocking syscall?

http://oreilly.com/catalog/linuxkernel/chapter/ch10.html

Notice that if the runqueue list is
empty (no runnable process exists
except for swapper), the cycle is not
entered and next points to init_task.
Moreover, if all processes in the
runqueue list have a priority lesser
than or equal to the priority of prev,
no process switch will take place and
the old process will continue to be
executed.