Emacs uses pselect for IO multiplexing, limiting the number of available
file descriptors to FD_SETSIZE. Rather, epoll/kqueue should be used, if
available.
Some good counter-arguments were brought up:
- pselect is in the POSIX standard, whereas the possible replacements (ppoll/epoll/kqueue) are not.
- The file descriptor limit should only be hit in pathological cases, e.g. when leaking background processes, and is only a symptom of a bug somewhere else. A higher FD limit would only hide the symptom, but not fix the underlying root cause.
Given that, I'm no longer convinced that switching away from pselect would be a good idea (but I'll leave this bug open for now to provide a space for discussion).