I wouldn't be doing my job if I failed to mention that both Alexei (eBPF) and Jens (io_uring, block) work at Facebook. Beyond them, we've got a bunch of folks working on the primitives as well as low-level userspace libraries [0] that enable us to use all of this stuff in production, so, by the time you're seeing it, we've demonstrated that it works well for all of Facebook's load balancers, container systems, etc.

[0] https://github.com/facebook/folly/blob/16d6394130b0961f6d688...