3946 ::gcore
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>

6554564 slab allocator cannot release slabs with lonely buffers
6676406 kmem client constructors and destructors need some cleanup

PSARC 2002/240 ZFS
6338653 Integrate ZFS
PSARC 2004/652 - DKIOCFLUSH
5096886 Write caching disks need mechanism to flush cache to physical media