Prior to r254304, a separate function, vm_pageout_page_stats(), was used to
periodically update the reference status of the active pages.  This function
was called, instead of vm_pageout_scan(), when memory was not scarce.  The
objective was to provide up to date reference status for active pages in
case memory did become scarce and active pages needed to be deactivated.

The active page queue scan performed by vm_pageout_page_stats() was
virtually identical to that performed by vm_pageout_scan(), and so r254304
eliminated vm_pageout_page_stats().  Instead, vm_pageout_scan() is
called with the parameter "pass" set to zero.  The intention was that when
pass is zero, vm_pageout_scan() would only scan the active queue.  However,
the variable page_shortage can still be greater than zero when memory is not
scarce and vm_pageout_scan() is called with pass equal to zero.
Consequently, the inactive queue may be scanned and dirty pages laundered
even though that was not intended by r254304.  This revision fixes that.

Reported by:	avg
MFC after:	1 week
Sponsored by:	EMC / Isilon Storage Division
Move the /usr/src specific options to src.opts.mk. Move inclusion of
/etc/src.conf to this file as well. Now, it will only affect builds of
/usr/src and not others that use the bsd.*.mk files. Specifically
don't install src.opts.mk so we can catch when it 'leaks' into
bsd.*.mk again and have there be errors when this happens. Future
commits will move to including src.opts.mk instead of bsd.own.mk when
all that's needed is one of the MK_FOO options from src.opts.mk.
Future options should be placed here, unless they directly affect a
bsd.*.mk file, in which case they should be placed in bsd.opts.mk.
Use src.opts.mk in preference to bsd.own.mk except where we need stuff
from the latter.
Document src.opts.mk changes and the decoupling of /etc/src.conf from
anything but the source tree.
Remove support for WITHOUT_BMAKE. bmake is now the only make that can
build world, so it is the only make we build or install. fmake is
still in the tree, but disconnected, and upgrades from older systems
that still have bmake has not been removed, but its state has not been
tested (it should work given how minimal the work to upgrade to bmake
is).
Fix a problem with async notifications in the mpr(4) driver.

This problem only occurs on versions of FreeBSD prior to the recent CAM
locking changes.  (i.e. stable/9 and older versions of stable/10)  This
change should be a no-op for head and stable/10.

If a path isn't specified, xpt_register_async() will create a fully
wildcarded path and acquire a lock (the XPT lock in older versions,
and via xpt_path_lock() in newer versions) to call xpt_action() for the
XPT_SASYNC_CB CCB.  It will then drop the lock and if the requested event
includes AC_FOUND_DEVICE or AC_PATH_REGISTERED, it will get the caller up
to date with any device arrivals or path registrations.

The issue is that before the locking changes, each SIM lock would get
acquired in turn during the EDT tree traversal process.  If a path is
specified for xpt_register_async(), it won't acquire and drop its own lock,
but instead expects the caller to hold its own SIM lock.  That works for
the first part of xpt_register_async(), but causes a recursive lock
acquisition once the EDT traversal happens and it comes to the SIM in
question.  And it isn't possible to call xpt_action() without holding a SIM
lock.

The locking changes fix this by using the XPT topology lock for EDT
traversal, so it is no longer an issue to hold the SIM lock while calling
xpt_register_async().

The solution for FreeBSD versions before the locking changes is to request
notification of all device arrivals (so we pass a NULL path into
xpt_register_async()) and then filter out the arrivals that are not ours.

MFC After:	3 days
Sponsored by:	Spectra Logic Corporation
Reduce the number of interrupts in USB host mode for the DWC OTG
controller driver by piggybacking the SOF interrupt when issuing new
and checking old transfers. Number of interrupts was reduced by 30%
when doing Isochronous transfers.

Use correct GINTMSK_XXX macros when accessing the DWC OTG interrupt
mask register.

Add code to adjust the frame interval register which influences the
SOF rate.

MFC after:	2 weeks
Spell raccdt in a more conventional way in a comment.

MFC after:	3 days
Fix buildkernel breakage, which was fall-out from the move of options to
src.opts.mk.
Fix include statement to accept src.opts.mk from a source directory
instead of from /usr/share/mk.

I'm not sure that this will let buildworld complete on a system with
no installed src.opts.mk (make buildworld is still running), but the
tinderbox builds are all failing earlyon without this patch.
Move the pl310.enabled tunable to hw.pl310.enabled.  Clean up a few minor
style(9) nits.  Use DEVMETHOD_END.
Break out the code that figures out the L2 cache geometry to its own
routine, so that it can be called from multiple places in upcoming changes.
Implement KDMKTONE ioctl.

Submitted by:	Matthew D.Fuller <fullermd@over-yonder.net> (original version)
MFC:		7 days
PR:		kern/189170

Sponsored by:	The FreeBSD Foundation
Revert r265436, since it is not the correct fix.
Call platform_pl310_init() before enabling the controller, and handle the
case where the controller is already enabled.

Some of the pl310 configuration registers cannot be changed while the
controller is active, so if there is any platform-specific init to be done
it must happen before enabling the controller.

The controller should not be enabled upon entry to the kernel, but u-boot
has recently developed the bad habit of leaving caches enabled when
launching the kernel, and since we have no control over that source code
we have to do our best to cope with it.  The PL310 manual doesn't document
a safe sequence for disabling the controller, but the sequence used here
(force write-through mode and disable linefill allocations, then clean and
invalidate the current contents before disabling the hardware) appears to
be sound both by analysis and empirical testing.

These changes were developed and tested in collaboration with
Svatopluk Kraus <onwahe@gmail.com>.

Reviewed by:	cognet@
Add defines for the bits in the PL310 debug control register.

This should have been part of r265444.
Add a public routine to set the L2 cache ram latencies.  This can be
called by platform init routines to fine-tune cache performance.
Enable PL310 power-saving modes and tune the cache ram latencies for imx6.
Fix the upgrade path for fmake by allowing the include of src.opts.mk
to fail and falling back on the conservative testing of variables
already in place. This should stop the tide of tinderbox mail.
Add helpful note about possible workarounds for (as yet) unknown
breakage. Also fix typo.