Where is calculation for number of parallel udev children performed?

Issue

• Where is calculation for number of parallel udev children performed?
• I'm just looking for the calculation associated with the original bug given here.

* Previously, for machines with relatively big RAM sizes and lots of disks, a
number of udevd workers were running in parallel, maximizing CPU and I/O. This
could cause udev events to time out due to hardware bottlenecks. With this
update, the number of udevd workers is limited by the CPU count and
significantly lower on machines with a big RAM size. Now, fewer udev workers
running concurrently do not bottleneck easily and cause less or no timeouts.
(BZ#833172, BZ#885978, BZ#918511)