kernel code test: view the workqueue

I am thinking how to view the workqueues in userspace.

Seems one way is use 'ps -ef'. The workqueue process will be shown with the
name in [].

Not sure there would be another way to see in /sys?
kernel code reading: workqueue init
kernel code test: percpu funtion insight

During this patch, two functions are created to mimic the behavior of
pcpu_build_alloc_info().