NFS problems associated with forcible dismounts.

the one place that depended on it.  wakeup() is now prototyped in
<sys/systm.h> so that it is normally visible.

Added nested include of <sys/queue.h> in <vm/vm_object.h>.  The queue
macros are a more fundamental prerequisite for <vm/vm_object.h> than
the wakeup prototype and previously happened to be included by
namespace pollution from <sys/proc.h> or elsewhere.

Submitted by:
Obtained from:

The default level works with minimal overhead, but one can also enable
full, efficient use of a 512K cache.  (Parameters can be generated
to support arbitrary cache sizes also.)

The interface into the "VMIO" system has changed to be more consistant
and robust.  Essentially, it is now no longer necessary to call vn_open
to get merged VM/Buffer cache operation, and exceptional conditions
such as merged operation of VBLK devices is simpler and more correct.

This code corrects a potentially large set of problems including the
problems with ktrace output and loaded systems, file create/deletes,
etc.

Most of the changes to NFS are cosmetic and name changes, eliminating
a layer of subroutine calls.  The direct calls to vput/vrele have
been re-instituted for better cross platform compatibility.

Reviewed by: davidg

supported, except madvise does not page in with MADV_WILLNEED, and
MADV_DONTNEED doesn't force dirty pages out.

2) Eliminate unnecessary copying of pages during/after forks.
3) Add user map simplification.

(object,index) pair instead of (object,offset) pair.