MFC r249514 (by gnn):
Point args[0] not at the thread that is ending but at the one that
is starting.  This is in line with practice in OpenSolaris.

Note that this change is only in ULE and not in the 4BSD scheduler.
Once this change settles in (MFC timeout has expired) we'll try it out
on 4BSD as well.

MFC r260043:
The arguments to sched:::off-cpu are the thread and associated process of
the thread selected to run, not the currently running thread.
MFC r252895: Add a man page for the SDT_* macros
MFC r253720: Use kern_ioctl() rather than ioctl() for testing the FBT provider
MFC r214019: Update links for taskqueue(9) functions
MFC r258713,262062: add taskqueue_drain_all
MFC r261122: dtrace: remove unexplained 16MB limitation from dt_alloc/dt_zalloc
MFC r258715: opensolaris compat: add taskq_wait emulation
MFC r255226: Add sysctl/tunables for various metaslab variables

MFC slacker:	pjd
MFC r261401:

  Fix newsyslog(8) to use the size of the file instead of the blocks it
  takes on disk, as advertised in newsyslog.conf(5).

Approved by:	bapt (mentor, implicit)
MFC r253441: Manually merge part of vendor import r238583 from Illumos
MFC r254591,255753: Enhance the ZFS vdev layer to maintain both a
logical and a physical minimum allocation size for devices

Note: on this branch the commit is adjusted for absence of U64
type support in sysctl infrastructure.
MFC r252840: 3836 zio_free() can be processed immediately in the common case

MFC slacker:	mm
MFC r254077: MFV r254071: Fix a regression introduced by fix for Illumos bug #3834
MFC r254112: MFV r254079: multiple ZFS issues
MFC r255750: MFV r254750: Add support of Illumos dumps on zvol over RAID-Z.

Note that this only adds the features.  FreeBSD would
still need more work to support dumping on zvols.

MFC slacker:	delphij
MFC r258717: MFV r258371,r258372: 4101 metaslab_debug should allow for
fine-grained control
MFC r260706: zfs_deleteextattr: name buffer from namei is needed by zfs_remove
MFC r254591,255753: Enhance the ZFS vdev layer to maintain both a
logical and a physical minimum allocation size for devices

Missed userland bits.
MFC r260703: zinject must use ioctl(2) compatibility wrapper
MFC r260811: zdb -R: do not treat numeric parameters to a flag as more flags