reorder uvm init to avoid use before initialisation.

the particular use before init was in uvm_init step 6, which calls
kmeminit to set up malloc(9), which calls uvm_km_zalloc, which calls
pmap_enter, which calls pool_get, which tries to allocate a page
using km_alloc, which isnt initalised until step 9 in uvm_init.

uvm_km_page_init calls kthread_create though, which uses malloc
internally, so it cant be reordered before malloc init.

to cope with this, uvm_km_page_init is split up. it sets up the
subsystem, and is called before kmeminit. the thread init is moved
to uvm_km_page_lateinit, which is called after kmeminit in uvm_init.

Introduce VM_KERNEL_SPACE_SIZE as a replacement for
(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS). This will allow these to no
longer be constants in the future.

ok guenther@

Chuck Cranor rescinded clauses in his license
on the 2nd of February 2011 in NetBSD.

http://marc.info/?l=netbsd-source-changes&m=129658899212732&w=2
http://marc.info/?l=netbsd-source-changes&m=129659095515558&w=2
http://marc.info/?l=netbsd-source-changes&m=129659157916514&w=2
http://marc.info/?l=netbsd-source-changes&m=129665962324372&w=2
http://marc.info/?l=netbsd-source-changes&m=129666033625342&w=2
http://marc.info/?l=netbsd-source-changes&m=129666052825545&w=2
http://marc.info/?l=netbsd-source-changes&m=129666922906480&w=2
http://marc.info/?l=netbsd-source-changes&m=129667725518082&w=2

decouple struct uvmexp into a new file, so that uvm_extern.h and sysctl.h
don't need to be married.
ok guenther miod beck jsing kettenis

the uvm_km_putpage is calling into tangly uvm guts again on not pmap direct.
go back to something more like the previous design, and have the thread do
the heavy lifting. solves vmmaplk panics.
ok deraadt oga thib
[and even simple diffs are hard to get perfect. help from mdempsky and deraadt]

Move uvm_km_pages struct declaration and watermark bounds to uvm_km.h, so
that md code can peek at it, and update m68k !__HAVE_PMAP_DIRECT setup code
to the recent uvm_km changes.
ok thib@

Instead of managing pages for intrsafe maps in special objects (aka.
kmem_object) just so that we can remove them, just use pmap_extract
to get the pages to free and simplify a lot of code to not deal with
the list of intrsafe maps, intrsafe objects, etc.

miod@ ok

introduce a new km_page allocator that gets pages from kernel_map using
an interrupt safe thread.
use this as the new backend for mbpool and mclpool, eliminating the mb_map.
introduce a sysctl kern.maxclusters which controls the limit of clusters
allocated.
testing by many people, works everywhere but m68k. ok deraadt@

this essentially deprecates the NMBCLUSTERS option, don't use it.
this should reduce pressure on the kmem_map and the uvm reserve of static
map entries.

First round of __P removal in sys

branches: 1.6.6;
Protect protypes, certain macros, and inlines from userland. Checked userland
with a 'make build'. From NetBSD. art@ ok

$OpenBSD$

Bring in some new UVM code from NetBSD (not current).

- Introduce a new type of map that are interrupt safe and never allow faults
in them. mb_map and kmem_map are made intrsafe.
- Add "access protection" to uvm_vslock (to be passed down to uvm_fault and
later to pmap_enter).
- madvise(2) now works.
- various cleanups.

branches: 1.3.4;
sync with NetBSD from 1999.05.24 (there is a reason for this date)
Mostly cleanups, but also a few improvements to pagedaemon for better
handling of low memory and/or low swap conditions.

add OpenBSD tags

Import of uvm from NetBSD. Some local changes, some code disabled