Assert mc_vd != NULL earlier so we can get more information.
Intel S3700 SSD quirks

Conflicts:
	sys/cam/scsi/scsi_da.c
ata_da: handle ATA_SF_ENAB_WCACHE
ZFS/GFS handling fixes
Tunable and sysctl for arc_shrink_shift
arc_reclaim_needed(): not taking kmem_used into account
arc_lowmem(): only signalling arc_reclaim_thread
MFV r272495:

In arc_kmem_reap_now(), reap range_seg_cache too to reclaim memory in
response of memory pressure.

Illumos issue:
	5163 arc should reap range_seg_cache

MFC after:	1 week
kmem_malloc(): sleep more