UVM was written by chuck cranor <chuck@maria.wustl.edu>, with some
minor portions derived from the old Mach code. i provided some help
getting swap and paging working, and other bug fixes/ideas. chuck
silvers <chuq@chuq.com> also provided some other fixes.
these are the changes to the old Mach VM system to allow both to be
available in the kernel.
string. The actual functional changes are:
1. in vm_page_alloc(), restore some long lost code by Paul Kranenburg
that reserves the last few pages for kernel objects, adding an
additional escape for the pageout daemon.
2. In vm_wait() (replaces VM_WAIT), recognize the amusing fatal
deadlock where the pagedemon sleeps on a channel that only it ever
wakes up, and add a timeout and printf. Mod 1 should generally
prevent this from happening in any case.
3. Fix a livelock in vm_pageout_page() caused by a pre-wakeup of
page consumers prior to the pageout, which can easily fail over
memory issues in NFS and IP code. Also, ++ cnt.v_pageouts only
if the pageout succeeded.
architectures), truncate them intelligently instead.
The truncation is done centralized in vnode_pager.c.
This prevents from wrap-over effects when parts of large (>2^32 byte) files
are mmapped.
Don't allow to mmap above the numerical range of vm_offset_t.
This is considered a temporary solution until the vm system handles the
object sizes/offsets more cleanly.
setrunqueue(), but remrq() was never renamed. Rename remrq() to
remrunqueue(). Also, move remrunqueue() prototype from vm/vm_extern.h
to sys/proc.h, so that it's in the same place as the setrunqueue() prototype
and other related prototypes.
(Note that it needs config support, too, which isn't there yet, but
might be soon...) Also, general cleanup. use NODEV to terminate swdevt,
so that sparc port (and future) is happy.
