Close race between vmspace_exitfree() and exit1() and races between
vmspace_exitfree() and vmspace_free() which could result in the same
vmspace being freed twice.

Factor out part of exit1() into ne

Close race between vmspace_exitfree() and exit1() and races between
vmspace_exitfree() and vmspace_free() which could result in the same
vmspace being freed twice.

Factor out part of exit1() into new function vmspace_exit(). Attach
to vmspace0 to allow old vmspace to be freed earlier.

Add new function, vmspace_acquire_ref(), for obtaining a vmspace
reference for a vmspace belonging to another process. Avoid changing
vmspace refcount from 0 to 1 since that could also lead to the same
vmspace being freed twice.

Change vmtotal() and swapout_procs() to use vmspace_acquire_ref().

Reviewed by: alc

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Use sf_buf_alloc() instead of vm_map_find() on exec_map to create the
ephemeral mappings that are used as the source for three copy
operations from kernel space to user space. There are two reasons

Use sf_buf_alloc() instead of vm_map_find() on exec_map to create the
ephemeral mappings that are used as the source for three copy
operations from kernel space to user space. There are two reasons for
making this change: (1) Under heavy load exec_map can fill up causing
vm_map_find() to fail. When it fails, the nascent process is aborted
(SIGABRT). Whereas, this reimplementation using sf_buf_alloc()
sleeps. (2) Although it is possible to sleep on vm_map_find()'s
failure until address space becomes available (see kmem_alloc_wait()),
using sf_buf_alloc() is faster. Furthermore, the reimplementation
uses a CPU private mapping, avoiding a TLB shootdown on
multiprocessors.

Problem uncovered by: kris@
Reviewed by: tegge@
MFC after: 3 weeks

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Use low level constructs borrowed from interrupt threads to wait for
work in proc0.
Remove the TDP_WAKEPROC0 workaround.

Swap in can occur safely without Giant. Release Giant on entry to
scheduler().

Remove GIANT_REQUIRED from swapout_procs().

Guard against address wrap in kernacc(). Otherwise, a program accessing a
bad address range through /dev/kmem can panic the machine.

Submitted by: Mark W. Krentel
Reported by: Kris Kennaway
MFC aft

Guard against address wrap in kernacc(). Otherwise, a program accessing a
bad address range through /dev/kmem can panic the machine.

Submitted by: Mark W. Krentel
Reported by: Kris Kennaway
MFC after: 1 week

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/* -> /*- for license, minor formatting changes

Don't include sys/user.h merely for its side-effect of recursively
including other headers.

Disable U area swapping and remove the routines that create, destroy,
copy, and swap U areas.

Reviewed by: arch@

The synchronization provided by vm object locking has eliminated the
need for most calls to vm_page_busy(). Specifically, most calls to
vm_page_busy() occur immediately prior to a call to vm_page_re

The synchronization provided by vm object locking has eliminated the
need for most calls to vm_page_busy(). Specifically, most calls to
vm_page_busy() occur immediately prior to a call to vm_page_remove().
In such cases, the containing vm object is locked across both calls.
Consequently, the setting of the vm page's PG_BUSY flag is not even
visible to other threads that are following the synchronization
protocol.

This change (1) eliminates the calls to vm_page_busy() that
immediately precede a call to vm_page_remove() or functions, such as
vm_page_free() and vm_page_rename(), that call it and (2) relaxes the
requirement in vm_page_remove() that the vm page's PG_BUSY flag is
set. Now, the vm page's PG_BUSY flag is set only when the vm object
lock is released while the vm page is still in transition. Typically,
this is when it is undergoing I/O.

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Use VM_ALLOC_NOBUSY instead of calling vm_page_wakeup().

The zone from which proc structures are allocated is marked
UMA_ZONE_NOFREE to guarantee type stability, so proc_fini() should
never be called. Move an assertion from proc_fini() to proc_dtor()
and

The zone from which proc structures are allocated is marked
UMA_ZONE_NOFREE to guarantee type stability, so proc_fini() should
never be called. Move an assertion from proc_fini() to proc_dtor()
and garbage-collect the rest of the unreachable code. I have retained
vm_proc_dispose(), since I consider its disuse a bug.

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Push Giant deep into vm_forkproc(), acquiring it only if the process has
mapped System V shared memory segments (see shmfork_myhook()) or requires
the allocation of an ldt (see vm_fault_wire()).

Giant is no longer required by vm_waitproc() and vmspace_exitfree().
Eliminate it acquisition and release around vm_waitproc() in kern_wait().

- Use atomic ops for updating the vmspace's refcnt and exitingcnt.
- Push down Giant into shmexit(). (Giant is acquired only if the vmspace
contains shm segments.)
- Eliminate the acquisition o

- Use atomic ops for updating the vmspace's refcnt and exitingcnt.
- Push down Giant into shmexit(). (Giant is acquired only if the vmspace
contains shm segments.)
- Eliminate the acquisition of Giant from proc_rwmem().
- Reduce the scope of Giant in exit1(), uncovering the destruction of the
address space.

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- Don't use a variable to point to the user area that we only use once.
Just use p2->p_uarea directly instead.
- Remove an old and mostly bogus assertion regarding p2->p_sigacts.
- Use RANGEOF macr

- Don't use a variable to point to the user area that we only use once.
Just use p2->p_uarea directly instead.
- Remove an old and mostly bogus assertion regarding p2->p_sigacts.
- Use RANGEOF macro ala fork1() to clean up bzero/bcopy of p_stats.

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Update a stale comment. The heuristic to swap processes out based on
the number of pages already paged out was broken in rev 1.10 and
removed in rev 1.11.

Nice, is a property of a process as a whole..
I mistakenly moved it to the ksegroup when breaking up the process
structure. Put it back in the proc structure.

In r1.190, vslock() and vsunlock() were bogusly made to do a "user wire"
and a "system unwire." Make this a "system wire" and "system unwire."

Reviewed by: alc

Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core

Make overflow/wraparound checking more robust and unbreak len=0 in
vslock(), mlock(), and munlock().

Reviewed by: bde

Style(9) changes.

Pointed out by: bde

Revert to the original vslock() and vsunlock() API with the following
exceptions:
Retain the recently added vslock() error return.

The type of the len argument should be size_t, not u_int.

Sugges

Revert to the original vslock() and vsunlock() API with the following
exceptions:
Retain the recently added vslock() error return.

The type of the len argument should be size_t, not u_int.

Suggested by: bde

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Retire pmap_pinit2(). Alpha was the last platform that used it. However,
ever since alpha/alpha/pmap.c revision 1.81 introduced the list allpmaps,
there has been no reason for having this function

Retire pmap_pinit2(). Alpha was the last platform that used it. However,
ever since alpha/alpha/pmap.c revision 1.81 introduced the list allpmaps,
there has been no reason for having this function on Alpha. Briefly,
when pmap_growkernel() relied upon the list of all processes to find and
update the various pmaps to reflect a growth in the kernel's valid
address space, pmap_init2() served to avoid a race between pmap
initialization and pmap_growkernel(). Specifically, pmap_pinit2() was
responsible for initializing the kernel portions of the pmap and
pmap_pinit2() was called after the process structure contained a pointer
to the new pmap for use by pmap_growkernel(). Thus, an update to the
kernel's address space might be applied to the new pmap unnecessarily,
but an update would never be lost.

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Undo the merger of mlock()/vslock and munlock()/vsunlock() and the
introduction of kern_mlock() and kern_munlock() in
src/sys/kern/kern_sysctl.c 1.150
src/sys/vm/vm_extern.h

Undo the merger of mlock()/vslock and munlock()/vsunlock() and the
introduction of kern_mlock() and kern_munlock() in
src/sys/kern/kern_sysctl.c 1.150
src/sys/vm/vm_extern.h 1.69
src/sys/vm/vm_glue.c 1.190
src/sys/vm/vm_mmap.c 1.179
because different resource limits are appropriate for transient and
"permanent" page wiring requests.

Retain the kern_mlock() and kern_munlock() API in the revived
vslock() and vsunlock() functions.

Combine the best parts of each of the original sets of implementations
with further code cleanup. Make the mclock() and vslock()
implementations as similar as possible.

Retain the RLIMIT_MEMLOCK check in mlock(). Move the most strigent
test, which can return EAGAIN, last so that requests that have no
hope of ever being satisfied will not be retried unnecessarily.

Disable the test that can return EAGAIN in the vslock() implementation
because it will cause the sysctl code to wedge.

Tested by: Cy Schubert <Cy.Schubert AT komquats.com>

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