9ed346bab0
mtx_enter(lock, type) becomes:
mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)
similarily, for releasing a lock, we now have:
mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.
The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.
Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:
MTX_QUIET and MTX_NOSWITCH
The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:
mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.
Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.
Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.
Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.
Finally, caught up to the interface changes in all sys code.
Contributors: jake, jhb, jasone (in no particular order)
107 lines
3.5 KiB
C
107 lines
3.5 KiB
C
/*-
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* Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Berkeley Software Design Inc's name may not be used to endorse or
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* promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
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* $FreeBSD$
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*/
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#ifndef _MACHINE_MUTEX_H_
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#define _MACHINE_MUTEX_H_
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#ifndef LOCORE
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#ifdef _KERNEL
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/*
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* Debugging
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*/
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#define ASS_IEN MPASS2((alpha_pal_rdps() & ALPHA_PSL_IPL_MASK) \
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== ALPHA_PSL_IPL_0, "ps & IPL == IPL_0")
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#define ASS_IDIS MPASS2((alpha_pal_rdps() & ALPHA_PSL_IPL_MASK) \
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== ALPHA_PSL_IPL_HIGH, "ps & IPL == IPL_HIGH")
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#define ASS_SIEN(mpp) MPASS2((mpp)->mtx_saveintr \
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== ALPHA_PSL_IPL_0, "mpp->mtx_saveintr == IPL_0")
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#define mtx_legal2block() \
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((alpha_pal_rdps() & ALPHA_PSL_IPL_MASK) == ALPHA_PSL_IPL_0)
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/*
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* Assembly macros (for internal use only)
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*--------------------------------------------------------------------------
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*/
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/*
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* Get a spin lock, handle recusion inline.
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*/
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#define _get_spin_lock(mp, tid, opts) do { \
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u_int _ipl = alpha_pal_swpipl(ALPHA_PSL_IPL_HIGH); \
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if (!_obtain_lock((mp), (tid))) { \
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if ((mp)->mtx_lock == (uintptr_t)(tid)) \
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(mp)->mtx_recurse++; \
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else \
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_mtx_lock_spin((mp), (opts), _ipl, __FILE__, \
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__LINE__); \
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} else { \
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alpha_mb(); \
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(mp)->mtx_saveintr = _ipl; \
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} \
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} while (0)
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#endif /* _KERNEL */
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#else /* !LOCORE */
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/*
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* Simple assembly macros to get and release non-recursive spin locks
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*
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* XXX: These are presently unused and cannot be used right now. Need to be
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* re-written (they are wrong). If you plan to use this and still see
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* this message, know not to unless you fix them first! :-)
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*/
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#define MTX_ENTER(lck) \
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ldiq a0, ALPHA_PSL_IPL_HIGH; \
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call_pal PAL_OSF1_swpipl; \
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1: ldq_l a0, lck+MTX_LOCK; \
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cmpeq a0, MTX_UNOWNED, a1; \
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beq a1, 1b; \
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ldq a0, PC_CURPROC(globalp); \
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stq_c a0, lck+MTX_LOCK; \
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beq a0, 1b; \
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mb; \
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stl v0, lck+MTX_SAVEINTR
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#define MTX_EXIT(lck) \
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mb; \
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ldiq a0, MTX_UNOWNED; \
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stq a0, lck+MTX_LOCK; \
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ldl a0, lck+MTX_SAVEINTR; \
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call_pal PAL_OSF1_swpipl
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#endif /* !LOCORE */
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#endif /* __MACHINE_MUTEX_H */
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