A ceiling rather than a reservation: nothing is held for a directory
never walked, so this only materialises for a mount that really does walk
that many cached children, and one that does wants the speedup. A
chunkless child measured about 480 bytes, so the doc and the flag help
both say what reaching the ceiling costs -- near 450MB -- since that is
the number an operator needs to lower it against.
Chris Lu
819a39c1f6