The linux-kernel mailing list has recently seen more than the usual amount
of traffic proposing new system calls. LWN is endeavoring to catch up with
that stream, starting with a couple of proposals for the management of file
descriptors. pidfd_open() is a new way to create a “pidfd” file
descriptor that refers to a process in the system, while
close_range() is an efficient way to close many open descriptors
with a single call.

Source: LWN.net – [$] New system calls: pidfd_open() and close_range()