[$] BPF at Facebook (and beyond)

It is no secret that much of the work on the in-kernel BPF virtual machine and associated user-space support code is being done at Facebook. But lessis known about how Facebook is actually using BPF. At Kernel Recipes 2019,BPF developer Alexei Starovoitov describeda bit of that work, though even he admitted that he didn't know what mostof the BPF programs running there were doing. He also summarized recentdevelopments with BPF and some near-future work.