Hi Jason, This should have helped.
6542676 ARC needs to track meta-data memory overhead
Some of the lines to arc.c:
1551 1.36 if (arc_meta_used = arc_meta_limit) {
1552/*
1553 * We are exceeding our meta-data cache
Hello All,
Awhile back (Feb '07) when we noticed ZFS was hogging all the memory
on the system, y'all were kind enough to help us use the arc_max
tunable to attempt to limit that usage to a hard value. Unfortunately,
at the time a sticky problem was that the hard limit did not include
DNLC entries
