Remove dodgy and unused mutex_owner_running() & rw_owner_running().

sys/rwlock.h: Make this more self-contained for bool.

XXX pullup-10

rwlock(9): Nix extern _rw_init in .c; use sys/rwlock.h.

Add rw_lock_op(): return either RW_READER or RW_WRITER for a lock that is
known to be held by the caller. Panic if the lock is not held.

Add a rw_owner_running() for the pagedaemon.

Update a comment.

Tidy rwlocks a bit, no functional change intended. Mainly:

- rw_downgrade(): do it in a for () loop like all the others.
- Explicitly carry around RW_NODEBUG - don't be lazy.
- Remove pointless mac

Tidy rwlocks a bit, no functional change intended. Mainly:

- rw_downgrade(): do it in a for () loop like all the others.
- Explicitly carry around RW_NODEBUG - don't be lazy.
- Remove pointless macros.
- Don't make assertions conditional on LOCKDEBUG, there's no reason.
- Make space for a new flag bit (not added yet).

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Add some new functions for lock objects:

mutex_obj_refcnt(), mutex_obj_tryalloc()
rw_obj_refcnt(), rw_obj_tryalloc()

Largely eliminate the MD rwlock.h header file.

This was full of definitions that have been obsolete for over a
decade. The file still remains for __HAVE_RW_STUBS but that's all.
Used only internall

Largely eliminate the MD rwlock.h header file.

This was full of definitions that have been obsolete for over a
decade. The file still remains for __HAVE_RW_STUBS but that's all.
Used only internally in kern_rwlock.c now, not by <sys/rwlock.h>.

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Re-apply:

Invert the sense of the bit to mark if LOCKDEBUG is enabled to
disabled.

This will help my fellow developers spot "use before initialised"
problems that hppa picks up very well.

but

Re-apply:

Invert the sense of the bit to mark if LOCKDEBUG is enabled to
disabled.

This will help my fellow developers spot "use before initialised"
problems that hppa picks up very well.

but fix the !LOCKDEBUG case by defining the "no debug" bits to zero so
they have no effect on lock stubs.

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Revert commit from Fri Feb 5 06:43:17 UTC 2010 by skrll:

Invert the sense of the bit to mark if LOCKDEBUG is enabled to disabled.

This will help my fellow developers spot "use before i

Revert commit from Fri Feb 5 06:43:17 UTC 2010 by skrll:

Invert the sense of the bit to mark if LOCKDEBUG is enabled to disabled.

This will help my fellow developers spot "use before initialised" problems
that hppa picks up very well.

It has to be done differently, because the semantics of mtx_owner in the non-
LOCKDEBUG case can vary significantly between archs, and thus it is not
possible to simply flip a bit to 1.

Ok core@, as at least i386 is unbootable right now.

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Invert the sense of the bit to mark if LOCKDEBUG is enabled to disabled.

This will help my fellow developers spot "use before initialised" problems
that hppa picks up very well.

Add rw_obj_*() functions to mirror the existing mutex functions.
Proposed on tech-kern quite some time ago.

Remove clause 3 and 4 from TNF licenses

rwlock changes, discussed on tech-kern:

- Use atomic ops directly, since rwlocks work the same way on all platforms.
- Try to make it a bit more cache efficient, and use branch hints.
- Fix a bug in

rwlock changes, discussed on tech-kern:

- Use atomic ops directly, since rwlocks work the same way on all platforms.
- Try to make it a bit more cache efficient, and use branch hints.
- Fix a bug in rw_downgrade() where the turnstile lock was not released.
- Remove a couple of redundant assertions.
- Use atomic_swap instead of atomic_cas where it's safe to do so.
- After acquiring the turnstile lock in rw_vector_enter, check if the
owner is running again and spin if so.
- Introduce and use rw_onproc() instead of abusing mutex_onproc().
- Change the handoff/release algorithm to reduce the window when a rwlock
can held, but the owner not on a CPU.

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- Prevent LOCKDEBUG from complaining if we do rw_tryenter() on a lock
that we already own.
- Add an assembly stub for rw_tryenter().

make kmutex_t and krwlock_t smaller by killing lock id.
ok'ed by Andrew Doran.

Merge newlock2 to head.