Change to use zones for allocations, to avoid running out.
Add the kernel dependency hack kext to SPL instead of ZFS.
Cleanup condvars to ignore waiters.
Fix zone names, and gather more statistics
Add more sysctl, and counters, fix missing 1024 entry.
total was counted twice, kmem_used() was returning available, added
kmem_avail().
Some hack'n'slashery
Base available memory on actual kernel limitations, and allow zsize adjustment.
Make sure to obey KM_NOSLEEP in kmem_alloc.
If 'zsize' is used, clamp it to no more than 50% of memory.
"kmem_alloc" alternate branch to test more direct allocations.