Small performance optimization.  Clobber only cr0, rather than the entire CR.

Discussed with:	rdivacky,nwhitehorn
MFC after:	3 weeks
Correct IMOD default value according to comment.

Reported by:	Daniel O'Connor <doconnor@gsoft.com.au>
MFC after:	1 week
Create zvol devices on zfs clone.

While big and shiny patch is not ready, it is better to have something.

PR:		kern/178999
MFC after:	1 week
Don't leak the TCP pcbinfo lock if a time wait connection is closed
in between grabbing a reference on the connection structure and obtaining
the pcbinfo lock.

Reviewed by:	Julien Charbon
Add SRC_UPDATE_SKIP, DOC_UPDATE_SKIP, and PORTS_UPDATE_SKIP
variables.  These are intended to allow bypassing the
'svn co /usr/{src,doc,ports}' step in the chroot when the
tree exists from external means.

The use case here is that /usr/src, /usr/doc, and /usr/ports
in the chroot exist as result of zfs dataset clones, so it
is possible (and happens quite often) that the included
distributions may not be consistent.  (This is not the case
for -RELEASE builds, but does happen for snapshot builds.)

Tested on:	stable/9@r264319
MFC After:	3 days
Sponsored by:	The FreeBSD Foundation
Tune buffer sizes for SuperSpeed USB when using LibUSB v0.1 and v1.0
APIs to increase the maximum bandwidth limit.

MFC after:	1 week
Amend r263891, by making clang default to DWARF2 debug info format for
all FreeBSD versions, not just 10.x and earlier.  Apparently too many
people seem to have trouble with post-1993 formats.

Also remove the related notes about messing with kernel configuration
files from UPDATING, which are now superfluous.

Requested by:	many
MFC after:	3 days
Before calling mmap() on a shared library's text and data sections, rtld
first calls mmap() with the arguments PROT_NONE and MAP_ANON to reserve a
single, contiguous range of virtual addresses for the entire shared library.
Later, rtld calls mmap() with the the shared library's file descriptor
and the argument MAP_FIXED to place the text and data sections within the
reserved range.  The rationale for mapping shared libraries in this way is
explained in the commit message for Revision 190885.  However, this approach
does have an unintended, negative consequence.  Since the first call to
mmap() specifies MAP_ANON and not the shared library's file descriptor, the
kernel has no idea what alignment the vm object backing the file prefers.
As a result, the reserved range's alignment is unlikely to be the same as
the vm object's, and so mapping with superpages becomes impossible.  To
address this problem, this revision adds the argument MAP_ALIGNED_SUPER to
the first call to mmap() if the text section is larger than the smallest
superpage size.

To determine if the text section is larger than the smallest superpage
size, rtld must always fetch the page size information.  As a result, the
private code for fetching the base page size in rtld's builtin malloc is
redundant.  Eliminate it.  Requested by: kib

Tested by:	zbb (on arm)
Reviewed by:	kib (an earlier version)
Discussed with:	jhb
Account for the "plus 1" encoding of the CPUID Function 4 reported
core per package and cache sharing values.

Approved by:	grehan (co-mentor)
Improve use of socket buffer upcalls.

Use soreadable()/sowriteable() in socket upcalls to avoid extra wakeups
until we have enough data to read or space to write.

Increase partial receive len from 1K to 128K to not wake up on every
received packet.

This significantly reduces locks congestion and CPU usage and improves
throughput for large I/Os on NICs without TSO and LRO.

Reviewed by:	trasz
Sponsored by:	iXsystems, Inc.
mdoc and spelling cleanup.

MFC after:	3 days
Update the llvm/clang patch for r264345.
The tw_pcbrele() function does not need the global timewait lock.

Submitted by:	Julien Charbon
Suggested by:	glebius
There is no need to save and restore the host's return address in the
'struct vmxctx'. It is preserved on the host stack across a guest entry
and exit and just restoring the host's '%rsp' is sufficient.

Pointed out by:	grehan@
Fix insta-panic on assert of unlocked periph mtx in ciss(4) when
logical volume state changes.

Currently, I view this as a critical fix for users and will MFC this rapidly as
my testing has shown data loss when the disk is failed by removing it when
under some amount of write activity and this code panics the box.

Reviewed by:	mav@ scottl@
MFC after:	3 days
Sponsored by:	Yahoo! Inc.
Remove unused val argument value from SYSCTL_INT() calls.
Some whitespace and style fixes.

Submitted by:	bde
MFV r258194-264360: nc(1) from OpenBSD 5.5.

MFC after:	2 weeks
Remove stray .Nm macro.

MFC after:	3 days
Update the SDT(9) examples to reflect the removal of the sname parameter
in r258622.

MFC after:	3 days