Add a comment to explain the EAGAIN is only there for POSIX compliance

Resquested by:	kib
Reviewed by:	des
Fix build with SMP disabled.

CR:		https://phabric.freebsd.org/D407
Reviewed by:	royger
Actually set the "no execute" bit on 1 MB page mappings in pmap_protect().
Previously, the "no execute" bit was being set directly in the PTE, instead
of the local variable in which the new PTE value is being constructed.  So,
when the local variable was finally assigned to the PTE, the "no execute"
bit setting was lost.
Add support for operand size and address size override prefixes in bhyve's
instruction emulation [1].

Fix bug in emulation of opcode 0x8A where the destination is a legacy high
byte register and the guest vcpu is in 32-bit mode. Prior to this change
instead of modifying %ah, %bh, %ch or %dh the emulation would end up
modifying %spl, %bpl, %sil or %dil instead.

Add support for moffsets by treating it as a 2, 4 or 8 byte immediate value
during instruction decoding.

Fix bug in verify_gla() where the linear address computed after decoding
the instruction was not being truncated to the effective address size [2].

Tested by:	Leon Dang [1]
Reported by:	Peter Grehan [2]
Sponsored by:	Nahanni Systems
cxgbe(4): Display CF facility correctly in the device log.

MFC after:	3 days
Change the calculation of the kinfo_vmentry field kve_private_resident
to reflect its name.

Noted and reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Followup to r268466.

- Move the code to calculate resident count into separate function.
  It reduces the indent level and makes the operation of
  vmmap_skip_res_cnt tunable more clear.
- Optimize the calculation of the resident page count for map entry.
  Skip directly to the next lowest available index and page among the
  whole shadow chain.
- Restore the use of pmap_incore(9), only to verify that current
  mapping is indeed superpage.
- Note the issue with the invalid pages.

Suggested and reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
MFV r268702:

Add missing *_destroy() calls in various places with ZFS.

Illumos issue:
  4975 missing mutex_destroy() calls in zfs

MFC after:	2 weeks
Document the 'show bio' command added in 2009.

While here also reword 'show buffer' to have an 'addr' argument and to
match other struct documentation.

MFC after:	1 week
Sponsored by:	EMC / Isilon Storage Division
MFV r268714:

Improve extreme rewind import.

When doing an "extreme rewind" import ("zpool import -XF"), we attempt
to verify all data in the pool, essentially scrubbing the entire pool.
The problem is that spa_load_verify_cb() issues an unbounded number of
concurrent scrub i/os.  This can lead to all of memory being used for
these zio's, wedging the system. Like normal scrub, we need to put a
cap on the number of outstanding i/os, and have the traverse thread
block when we reach this cap.

For this purpose the cap can be very large (10,000) to optimize the
elevator algorithm.  Three kernel tunables have been added:

	vfs.zfs.spa_load_verify_maxinflight
	vfs.zfs.spa_load_verify_metadata
	vfs.zfs.spa_load_verify_data

The latter two tunables controls whether metadata and/or user data
when doing extreme rewind.

Make 'zpool import -T' imply scrub.

Make zpool import -T <txg> accept hexadecimal values for the txg when
prefixed with 0x.

Skip txg's for which there is no uberblock when doing extreme rewind.

Skip reading all user data twice by skipping prefetches when doing
extreme rewinds as we do not access via the ARC.

Illumos issues:
  4970 need controls on i/o issued by zpool import -XF
  4971 zpool import -T should accept hex values
  4972 zpool import -T implies extreme rewind, and thus a scrub
  4973 spa_load_retry retries the same txg
  4974 spa_load_verify() reads all data twice

MFC after:	2 weeks
Also link 'show bio' to g_bio(9.)

X-MFC-With:	r268715
MFC after:	1 week
Sponsored by:	EMC / Isilon Storage Division
Since r202933, kthread_suspend_check() takes no arguments.  Update the
example to match.

MFC after:	3 days
Move the "retry:" label so that the calls to m_pullup() are
not done after the call to m_defrag(). This fixes a problem
where m_pullup() would prepend an mbuf to the list created
by m_defrag() making the chain greater than 32 again.

Tested by:	rcarter@pinyon.org
Reviewed by:	yongari, jfv
MFC after:	2 weeks
Add a bandaid to fix GCC build (on sparc64 et al).
When we fail to extract the pkg binaries (for example, / is read-only),
give a more helpful error message.

MFC after:	1 week