kernel - Automatically downscasle NPROC resource limit
* Downscale the NPROC resource limit based on fork and chroot depth, up
to 50%, and also make the limit apply to root processes. This is intended
to be a poor-man's safety, preventing run-away (root or other) process
creation from completely imploding a system.
* Each level of fork() downscales the NPROC resource limit by 1/3%,
capped at 32 levels (~10%)
* Each chroot (including that made by a jail) downscales the NPROC
resource limit by 10%, up to 40%.