Implement mechanism to safely but slowly purge UMA per-CPU caches.

This is a last resort for very low memory condition in case other measures
to free memory were ineffective.  Sequentially cycle through all CPUs and
extract per-CPU cache buckets into zone cache from where they can be freed.
Reenable vfs.zfs.zio.use_uma for amd64, disabled at r209261.

On machines with seveal CPUs and enough RAM this can easily twice improve
ZFS performance or twice reduce CPU usage.  It was disabled three years
ago due to memory and KVA exhaustion reports, but our VM subsystem got
improved a lot since that time, hopefully enough to make another try.
One more BIND remnant: /etc/mtree/BIND.chroot.dist

Discussed with:	des
Support SNI in libfetch

SNI is Server Name Indentification which is a protocol for TLS that
indicates the host that is being connected to at the start of the
handshake. It allows to use Virtual Hosts on HTTPS.

Submitted by:	sbz
Submitted by:	Michael Gmelin <freebsd@grem.de> [1]
PR:		kern/183583 [1]
Reviewed by:	des
Approved by:	bapt
MFC after:	1 week
Follow-up to r258227 and document 'enabled' as a boolean instead of
a string.

Approved by:	bapt
MFC after:	2 days
X-MFC-With:	r258227
Fix build with GCC

SSL_set_tlsext_host_name(3) internally does not modify the host buffer
pased to it. So it is safe to DECONST the struct url* here.

Reported by:	gjb
Approved by:	bapt (implicit)
MFC after:	1 week
X-MFC-With:	r258347
Pull in r191896 from upstream llvm trunk:

  CaptureTracking: Plug a loophole in the "too many uses" heuristic.

  The heuristic was added to avoid spending too much compile time in a
  specially crafted test case (PR17461, PR16474) with many uses on a
  select or bitcast instruction can still trigger the slow case. Add a
  check for that case.

  This only affects compile time, don't have a good way to test it.

This fixes the excessive compile time spent on a specific file of the
graphics/rawtherapee port.

Reported by:	mandree
MFC after:	3 days
fsx: new option to disable msync(MS_SYNC) after each write via mmaped region

This option should be useful for testing if a filesystem uses the
unified buffer / page cache.
Or, if filesystem's emulation of the unified cache works as expected.
This should be the case for e.g. ZFS.

MFC after:	1 week
fsx: add an option to randomly call msync(MS_INVALIDATE)

This call should be a sufficiently close approximation of what happens
when a filesystem is unmounted and remounted.  To be more specific, it
should test that the data that was in the page cache is the same data
that ends up on a stable storage or in a filesystem's internal cache,
if any.
This will catch the cases where a page with modified data is marked as
a clean page for whatever reason.

While there, make logging of the special events (open+close before
plus invalidation now) more generic and slightly better than the previous
hack.

MFC after:	10 days
zfs page_busy: fix the boundaries of the cleared range

This is a fix for a regression introduced in r246293.

vm_page_clear_dirty expects the range to have DEV_BSIZE aligned boundaries,
otherwise it extends them.  Thus it can happen that the whole page is
marked clean while actually having some small dirty region(s).
This commit makes the range properly aligned and ensures that only
the clean data is marked as such.

It would interesting to evaluate how much benefit clearing with DEV_BSIZE
granularity produces.  Perhaps instead we should clear the whole page
when it is completely overwritten and don't bother clearing any bits
if only a portion a page is written.

Reported by:	George Hartzell <hartzell@alerce.com>,
		Richard Todd <rmtodd@servalan.servalan.com>
Tested by:	George Hartzell <hartzell@alerce.com>,
Reviewed by:	kib
MFC after:	5 days
taskqueue_cancel: garbage collect a write-only variable

MFC after:	3 days
"Tim trailing" -> "Trim trailing"
Bugfixes... the host capabilties from FDT data are stored in host.caps, not
host.host_ocr, examine the correct field when setting up the hardware.  Also,
the offset for the capabilties register should be 0x140, not 0x240.

Submitted by:	Ilya Bakulin <ilya@bakulin.de>
Pointy hat to:	me
Add "resize" verb to gmirror(8) and such functionality to geom_mirror(4).
Now it is easy to expand the size of the mirror when all its components
are replaced. Also add g_resize method to geom_mirror class. It will write
updated metadata to new last sector, when parent provider is resized.

Silence from:	geom@
MFC after:	1 month
Avoid clearing EXEC permission bit when setting the page RW on ARMv6/v7

When emulating modified bit the executable attribute was cleared by
mistake when calling pmap_set_prot(). This was not a problem before
changes to ref/mod emulation since all the pages were created RW basing
on the "prot" argument in pmap_enter(). Now however not all pages are RW
and the RW permission can be cleared in the process.

Added proper KTRs accordingly.

Spotted by:	cognet
Reviewed by:	gber
Apply access flags for managed and unmanaged pages properly on ARMv6/v7

When entering a mapping via pmap_enter() unmanaged pages ought to be
naturally excluded from the "modified" and "referenced" emulation.
RW permission should be granted implicitly when requested,
otherwise unmanaged page will not recover from the permission fault
since there will be no PV entry to indicate that the page can be written.

In addition, only managed pages that participate in "modified"
emulation need to be marked as "dirty" and "writeable" when entered
with RW permissions. Likewise with "referenced" flag for managed pages.
Unmanaged ones however should not be marked as such.

Reviewed by:	cognet, gber
Whitespace, style, sub-shells, and standardize variable name
(s/interfaces/menu_list/).
Fix the function search space.

Submitted by:	Howard Su
Use 'int' to store the return value of getopt(), rather than char.

On some architectures (powerpc), char is unsigned by default, which means
comparisons against -1 always fail, so the programs get stuck in an
infinite loop.

MFC after:	1 week
Add alternate ID for Novatel MiFi 2200 CDMA, which is used by my
Virgin Mobile branded device.  It needs the U3GINIT_SCSIEJECT quirk.

Reviewed by:	hselasky
MFC after:	1 month