MINOR: init: pre-allocate kernel data structures on init

MINOR: init: pre-allocate kernel data structures on init

The Linux kernel maintains data structures to track a processes' open file
descriptors, and it expands these structures as necessary when FD usage grows
(at every FD=2^X starting at 64). However when threading is in use, during
expansion the kernel will pause (observed up to 47ms) while it waits for thread
synchronization (see https://bugzilla.kernel.org/show_bug.cgi?id=217366).

This change addresses the issue and avoids the random pauses by opening the
maximum file descriptor during initialization, so that expansion will not occur
while processing traffic.