'RELENG_4_1_0_RELEASE'.

This commit was manufactured to restore the state of the 4.1-RELEASE image.
Releases prior to 5.3-RELEASE are omitting the secure/ and crypto/ subdirs.

Reviewd by: alc
Tested by: "Sean O'Connell" <sean@stat.Duke.EDU>

This
This feature allows you to specify if mmap'd data is included in
an application's corefile.

Change the type of eflags in struct vm_map_entry from u_char to
vm_eflags_t (an unsigned int).

Reviewed by:	dillon,jdp,alfred
Approved by:	jkh

    run out of KVM through a mmap()/fork() bomb that allocates hundreds
    of thousands of vm_map_entry structures.

    Add panic to make null-pointer dereference crash a little more verbose.

    Add a new sysctl, vm.max_proc_mmap, which specifies the maximum number
    of mmap()'d spaces (discrete vm_map_entry's in the process).  The value
    defaults to around 9000 for a 128MB machine.  The test is scaled for the
    number of processes sharing a vmspace (aka linux threads).  Setting
    the value to 0 disables the feature.

PR: kern/16573
Approved by: jkh

    invalidation code cannot wait for paging to complete while holding a
    vnode lock, so we don't wait.  Instead we simply allow the lower level
    code to simply block on any busy pages it encounters.  I think Yahoo
    may be the only entity in the entire world that actually uses this
    msync feature :-).

Bug reported by:  Paul Saab <paul@mu.org>

    madvise().

    This feature prevents the update daemon from gratuitously flushing
    dirty pages associated with a mapped file-backed region of memory.  The
    system pager will still page the memory as necessary and the VM system
    will still be fully coherent with the filesystem.  Modifications made
    by other means to the same area of memory, for example by write(), are
    unaffected.  The feature works on a page-granularity basis.

    MAP_NOSYNC allows one to use mmap() to share memory between processes
    without incuring any significant filesystem overhead, putting it in
    the same performance category as SysV Shared memory and anonymous memory.

Reviewed by: julian, alc, dg

from vm_map_pageable().  At the point they called, vm_map_pageable()
holds a read (or shared) lock on the map.  The purpose
of vm_map_{clear,set}_recursive() is to disable/enable repeated
write (or exclusive) lock requests by the same process.

 vm_map always failed because vm_map_lookup() looked at
 "vm_map_entry->wired_count" instead of "(vm_map_entry->eflags &
 MAP_ENTRY_USER_WIRED)".  The effect was that many page
 wiring operations by sysctl were (silently) failing.

Submitted by:	phk

Submitted by:	phk (in part)