[$] BPF: what's good, what's coming, and what's needed

The 2019 Linux Storage, Filesystem, and Memory-Management Summit differed
somewhat from its predecessors in that it contained a fourth track
dedicated to the BPF virtual machine. LWN was unable to attend most of
those sessions, but a couple of BPF-related talks were a part of the
broader program. Among those was a plenary talk by Dave Miller, described
as "a wholistic view" of why BPF is successful, its current state, and
where things are going.