Add missing BDB include file

storage/bdb/dbinc/mutex_int.h

+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2005
+ *	Sleepycat Software.  All rights reserved.
+ *
+ * $Id: mutex_int.h,v 12.17 2005/11/08 22:26:49 mjc Exp $
+ */
+
+#ifndef _DB_MUTEX_INT_H_
+#define	_DB_MUTEX_INT_H_
+
+/*********************************************************************
+ * POSIX.1 pthreads interface.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_PTHREADS
+#include <pthread.h>
+
+#define	MUTEX_FIELDS							\
+	pthread_mutex_t mutex;		/* Mutex. */			\
+	pthread_cond_t  cond;		/* Condition variable. */
+#endif
+
+#ifdef HAVE_MUTEX_UI_THREADS
+#include <thread.h>
+#endif
+
+/*********************************************************************
+ * Solaris lwp threads interface.
+ *
+ * !!!
+ * We use LWP mutexes on Solaris instead of UI or POSIX mutexes (both of
+ * which are available), for two reasons.  First, the Solaris C library
+ * includes versions of the both UI and POSIX thread mutex interfaces, but
+ * they are broken in that they don't support inter-process locking, and
+ * there's no way to detect it, e.g., calls to configure the mutexes for
+ * inter-process locking succeed without error.  So, we use LWP mutexes so
+ * that we don't fail in fairly undetectable ways because the application
+ * wasn't linked with the appropriate threads library.  Second, there were
+ * bugs in SunOS 5.7 (Solaris 7) where if an application loaded the C library
+ * before loading the libthread/libpthread threads libraries (e.g., by using
+ * dlopen to load the DB library), the pwrite64 interface would be translated
+ * into a call to pwrite and DB would drop core.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_SOLARIS_LWP
+/*
+ * XXX
+ * Don't change <synch.h> to <sys/lwp.h> -- although lwp.h is listed in the
+ * Solaris manual page as the correct include to use, it causes the Solaris
+ * compiler on SunOS 2.6 to fail.
+ */
+#include <synch.h>
+
+#define	MUTEX_FIELDS							\
+	lwp_mutex_t mutex;		/* Mutex. */			\
+	lwp_cond_t cond;		/* Condition variable. */
+#endif
+
+/*********************************************************************
+ * Solaris/Unixware threads interface.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_UI_THREADS
+#include <thread.h>
+#include <synch.h>
+
+#define	MUTEX_FIELDS							\
+	mutex_t mutex;			/* Mutex. */			\
+	cond_t  cond;			/* Condition variable. */
+#endif
+
+/*********************************************************************
+ * AIX C library functions.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_AIX_CHECK_LOCK
+#include <sys/atomic_op.h>
+typedef int tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#define	MUTEX_INIT(x)	0
+#define	MUTEX_SET(x)	(!_check_lock(x, 0, 1))
+#define	MUTEX_UNSET(x)	_clear_lock(x, 0)
+#endif
+#endif
+
+/*********************************************************************
+ * Apple/Darwin library functions.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_DARWIN_SPIN_LOCK_TRY
+typedef u_int32_t tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+extern int _spin_lock_try(tsl_t *);
+extern void _spin_unlock(tsl_t *);
+#define	MUTEX_SET(tsl)          _spin_lock_try(tsl)
+#define	MUTEX_UNSET(tsl)        _spin_unlock(tsl)
+#define	MUTEX_INIT(tsl)         (MUTEX_UNSET(tsl), 0)
+#endif
+#endif
+
+/*********************************************************************
+ * General C library functions (msemaphore).
+ *
+ * !!!
+ * Check for HPPA as a special case, because it requires unusual alignment,
+ * and doesn't support semaphores in malloc(3) or shmget(2) memory.
+ *
+ * !!!
+ * Do not remove the MSEM_IF_NOWAIT flag.  The problem is that if a single
+ * process makes two msem_lock() calls in a row, the second one returns an
+ * error.  We depend on the fact that we can lock against ourselves in the
+ * locking subsystem, where we set up a mutex so that we can block ourselves.
+ * Tested on OSF1 v4.0.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_HPPA_MSEM_INIT
+#define	MUTEX_ALIGN	16
+#endif
+
+#if defined(HAVE_MUTEX_MSEM_INIT) || defined(HAVE_MUTEX_HPPA_MSEM_INIT)
+#include <sys/mman.h>
+typedef msemaphore tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#define	MUTEX_INIT(x)	(msem_init(x, MSEM_UNLOCKED) <= (msemaphore *)0)
+#define	MUTEX_SET(x)	(!msem_lock(x, MSEM_IF_NOWAIT))
+#define	MUTEX_UNSET(x)	msem_unlock(x, 0)
+#endif
+#endif
+
+/*********************************************************************
+ * Plan 9 library functions.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_PLAN9
+typedef Lock tsl_t;
+
+#define	MUTEX_INIT(x)	(memset(x, 0, sizeof(Lock)), 0)
+#define	MUTEX_SET(x)	canlock(x)
+#define	MUTEX_UNSET(x)	unlock(x)
+#endif
+
+/*********************************************************************
+ * Reliant UNIX C library functions.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_RELIANTUNIX_INITSPIN
+#include <ulocks.h>
+typedef spinlock_t tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#define	MUTEX_INIT(x)	(initspin(x, 1), 0)
+#define	MUTEX_SET(x)	(cspinlock(x) == 0)
+#define	MUTEX_UNSET(x)	spinunlock(x)
+#endif
+#endif
+
+/*********************************************************************
+ * General C library functions (POSIX 1003.1 sema_XXX).
+ *
+ * !!!
+ * Never selected by autoconfig in this release (semaphore calls are known
+ * to not work in Solaris 5.5).
+ *********************************************************************/
+#ifdef HAVE_MUTEX_SEMA_INIT
+#include <synch.h>
+typedef sema_t tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#define	MUTEX_DESTROY(x) sema_destroy(x)
+#define	MUTEX_INIT(x)	 (sema_init(x, 1, USYNC_PROCESS, NULL) != 0)
+#define	MUTEX_SET(x)	 (sema_wait(x) == 0)
+#define	MUTEX_UNSET(x)	 sema_post(x)
+#endif
+#endif
+
+/*********************************************************************
+ * SGI C library functions.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_SGI_INIT_LOCK
+#include <abi_mutex.h>
+typedef abilock_t tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#define	MUTEX_INIT(x)	(init_lock(x) != 0)
+#define	MUTEX_SET(x)	(!acquire_lock(x))
+#define	MUTEX_UNSET(x)	release_lock(x)
+#endif
+#endif
+
+/*********************************************************************
+ * Solaris C library functions.
+ *
+ * !!!
+ * These are undocumented functions, but they're the only ones that work
+ * correctly as far as we know.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_SOLARIS_LOCK_TRY
+#include <sys/machlock.h>
+typedef lock_t tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#define	MUTEX_INIT(x)	0
+#define	MUTEX_SET(x)	_lock_try(x)
+#define	MUTEX_UNSET(x)	_lock_clear(x)
+#endif
+#endif
+
+/*********************************************************************
+ * VMS.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_VMS
+#include <sys/mman.h>;
+#include <builtins.h>
+typedef volatile unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#ifdef __ALPHA
+#define	MUTEX_SET(tsl)		(!__TESTBITSSI(tsl, 0))
+#else /* __VAX */
+#define	MUTEX_SET(tsl)		(!(int)_BBSSI(0, tsl))
+#endif
+#define	MUTEX_UNSET(tsl)	(*(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * VxWorks
+ * Use basic binary semaphores in VxWorks, as we currently do not need
+ * any special features.  We do need the ability to single-thread the
+ * entire system, however, because VxWorks doesn't support the open(2)
+ * flag O_EXCL, the mechanism we normally use to single thread access
+ * when we're first looking for a DB environment.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_VXWORKS
+#include "taskLib.h"
+typedef SEM_ID tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#define	MUTEX_SET(tsl)		(semTake((*tsl), WAIT_FOREVER) == OK)
+#define	MUTEX_UNSET(tsl)	(semGive((*tsl)))
+#define	MUTEX_INIT(tsl)							\
+	((*(tsl) = semBCreate(SEM_Q_FIFO, SEM_FULL)) == NULL)
+#define	MUTEX_DESTROY(tsl)	semDelete(*tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * Win16
+ *
+ * Win16 spinlocks are simple because we cannot possibly be preempted.
+ *
+ * !!!
+ * We should simplify this by always returning a no-need-to-lock lock
+ * when we initialize the mutex.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_WIN16
+typedef unsigned int tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#define	MUTEX_INIT(x)		0
+#define	MUTEX_SET(tsl)		(*(tsl) = 1)
+#define	MUTEX_UNSET(tsl)	(*(tsl) = 0)
+#endif
+#endif
+
+/*********************************************************************
+ * Win32
+ *********************************************************************/
+#if defined(HAVE_MUTEX_WIN32) || defined(HAVE_MUTEX_WIN32_GCC)
+#define	MUTEX_FIELDS							\
+	LONG volatile tas;						\
+	LONG nwaiters;							\
+	u_int32_t id;	/* ID used for creating events */		\
+
+#if defined(LOAD_ACTUAL_MUTEX_CODE)
+#define	MUTEX_SET(tsl)		(!InterlockedExchange((PLONG)tsl, 1))
+#define	MUTEX_UNSET(tsl)	InterlockedExchange((PLONG)tsl, 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+
+/*
+ * From Intel's performance tuning documentation (and see SR #6975):
+ * ftp://download.intel.com/design/perftool/cbts/appnotes/sse2/w_spinlock.pdf
+ *
+ * "For this reason, it is highly recommended that you insert the PAUSE
+ * instruction into all spin-wait code immediately. Using the PAUSE
+ * instruction does not affect the correctness of programs on existing
+ * platforms, and it improves performance on Pentium 4 processor platforms."
+ */
+#ifdef HAVE_MUTEX_WIN32
+#ifndef _WIN64
+#define	MUTEX_PAUSE		{__asm{_emit 0xf3}; __asm{_emit 0x90}}
+#endif
+#endif
+#ifdef HAVE_MUTEX_WIN32_GCC
+#define	MUTEX_PAUSE		asm volatile ("rep; nop" : : );
+#endif
+#endif
+#endif
+
+/*********************************************************************
+ * 68K/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_68K_GCC_ASSEMBLY
+typedef unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/* gcc/68K: 0 is clear, 1 is set. */
+#define	MUTEX_SET(tsl) ({						\
+	register tsl_t *__l = (tsl);					\
+	int __r;							\
+	    asm volatile("tas  %1; \n					\
+			  seq  %0"					\
+		: "=dm" (__r), "=m" (*__l)				\
+		: "1" (*__l)						\
+		);							\
+	__r & 1;							\
+})
+
+#define	MUTEX_UNSET(tsl)	(*(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * ALPHA/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_ALPHA_GCC_ASSEMBLY
+typedef u_int32_t tsl_t;
+
+#define	MUTEX_ALIGN	4
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/*
+ * For gcc/alpha.  Should return 0 if could not acquire the lock, 1 if
+ * lock was acquired properly.
+ */
+static inline int
+MUTEX_SET(tsl_t *tsl) {
+	register tsl_t *__l = tsl;
+	register tsl_t __r;
+	asm volatile(
+		"1:	ldl_l	%0,%2\n"
+		"	blbs	%0,2f\n"
+		"	or	$31,1,%0\n"
+		"	stl_c	%0,%1\n"
+		"	beq	%0,3f\n"
+		"	mb\n"
+		"	br	3f\n"
+		"2:	xor	%0,%0\n"
+		"3:"
+		: "=&r"(__r), "=m"(*__l) : "1"(*__l) : "memory");
+	return __r;
+}
+
+/*
+ * Unset mutex. Judging by Alpha Architecture Handbook, the mb instruction
+ * might be necessary before unlocking
+ */
+static inline int
+MUTEX_UNSET(tsl_t *tsl) {
+	asm volatile("	mb\n");
+	return *tsl = 0;
+}
+
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * Tru64/cc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_TRU64_CC_ASSEMBLY
+typedef volatile u_int32_t tsl_t;
+
+#define	MUTEX_ALIGN	4
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#include <alpha/builtins.h>
+#define	MUTEX_SET(tsl)		(__LOCK_LONG_RETRY((tsl), 1) != 0)
+#define	MUTEX_UNSET(tsl)	(__UNLOCK_LONG(tsl))
+
+#define	MUTEX_INIT(tsl)		(MUTEX_UNSET(tsl), 0)
+#endif
+#endif
+
+/*********************************************************************
+ * ARM/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_ARM_GCC_ASSEMBLY
+typedef unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/* gcc/arm: 0 is clear, 1 is set. */
+#define	MUTEX_SET(tsl) ({						\
+	int __r;							\
+	asm volatile(							\
+		"swpb	%0, %1, [%2]\n\t"				\
+		"eor	%0, %0, #1\n\t"					\
+	    : "=&r" (__r)						\
+	    : "r" (1), "r" (tsl)					\
+	    );								\
+	__r & 1;							\
+})
+
+#define	MUTEX_UNSET(tsl)	(*(volatile tsl_t *)(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * HPPA/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_HPPA_GCC_ASSEMBLY
+typedef u_int32_t tsl_t;
+
+#define	MUTEX_ALIGN	16
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/*
+ * The PA-RISC has a "load and clear" instead of a "test and set" instruction.
+ * The 32-bit word used by that instruction must be 16-byte aligned.  We could
+ * use the "aligned" attribute in GCC but that doesn't work for stack variables.
+ */
+#define	MUTEX_SET(tsl) ({						\
+	register tsl_t *__l = (tsl);					\
+	int __r;							\
+	asm volatile("ldcws 0(%1),%0" : "=r" (__r) : "r" (__l));	\
+	__r & 1;							\
+})
+
+#define	MUTEX_UNSET(tsl)        (*(volatile tsl_t *)(tsl) = -1)
+#define	MUTEX_INIT(tsl)		(MUTEX_UNSET(tsl), 0)
+#endif
+#endif
+
+/*********************************************************************
+ * IA64/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_IA64_GCC_ASSEMBLY
+typedef volatile unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/* gcc/ia64: 0 is clear, 1 is set. */
+#define	MUTEX_SET(tsl) ({						\
+	register tsl_t *__l = (tsl);					\
+	long __r;							\
+	asm volatile("xchg1 %0=%1,%2" :					\
+		     "=r"(__r), "+m"(*__l) : "r"(1));			\
+	__r ^ 1;							\
+})
+
+/*
+ * Store through a "volatile" pointer so we get a store with "release"
+ * semantics.
+ */
+#define	MUTEX_UNSET(tsl)	(*(tsl_t *)(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * PowerPC/gcc assembly.
+ *********************************************************************/
+#if defined(HAVE_MUTEX_PPC_GCC_ASSEMBLY)
+typedef u_int32_t tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/*
+ * The PowerPC does a sort of pseudo-atomic locking.  You set up a
+ * 'reservation' on a chunk of memory containing a mutex by loading the
+ * mutex value with LWARX.  If the mutex has an 'unlocked' (arbitrary)
+ * value, you then try storing into it with STWCX.  If no other process or
+ * thread broke your 'reservation' by modifying the memory containing the
+ * mutex, then the STCWX succeeds; otherwise it fails and you try to get
+ * a reservation again.
+ *
+ * While mutexes are explicitly 4 bytes, a 'reservation' applies to an
+ * entire cache line, normally 32 bytes, aligned naturally.  If the mutex
+ * lives near data that gets changed a lot, there's a chance that you'll
+ * see more broken reservations than you might otherwise.  The only
+ * situation in which this might be a problem is if one processor is
+ * beating on a variable in the same cache block as the mutex while another
+ * processor tries to acquire the mutex.  That's bad news regardless
+ * because of the way it bashes caches, but if you can't guarantee that a
+ * mutex will reside in a relatively quiescent cache line, you might
+ * consider padding the mutex to force it to live in a cache line by
+ * itself.  No, you aren't guaranteed that cache lines are 32 bytes.  Some
+ * embedded processors use 16-byte cache lines, while some 64-bit
+ * processors use 128-bit cache lines.  But assuming a 32-byte cache line
+ * won't get you into trouble for now.
+ *
+ * If mutex locking is a bottleneck, then you can speed it up by adding a
+ * regular LWZ load before the LWARX load, so that you can test for the
+ * common case of a locked mutex without wasting cycles making a reservation.
+ *
+ * gcc/ppc: 0 is clear, 1 is set.
+ */
+static inline int
+MUTEX_SET(int *tsl)  {
+        int __r;
+        asm volatile (
+"0:                             \n\t"
+"       lwarx   %0,0,%1         \n\t"
+"       cmpwi   %0,0            \n\t"
+"       bne-    1f              \n\t"
+"       stwcx.  %1,0,%1         \n\t"
+"       isync                   \n\t"
+"       beq+    2f              \n\t"
+"       b       0b              \n\t"
+"1:                             \n\t"
+"       li      %1,0            \n\t"
+"2:                             \n\t"
+         : "=&r" (__r), "+r" (tsl)
+         :
+         : "cr0", "memory");
+         return (int)tsl;
+}
+
+static inline int
+MUTEX_UNSET(tsl_t *tsl) {
+         asm volatile("sync" : : : "memory");
+         return *tsl = 0;
+}
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * OS/390 C
+ *********************************************************************/
+#ifdef HAVE_MUTEX_S390_CC_ASSEMBLY
+typedef int tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/*
+ * cs() is declared in <stdlib.h> but is built in to the compiler.
+ * Must use LANGLVL(EXTENDED) to get its declaration.
+ */
+#define	MUTEX_SET(tsl)		(!cs(&zero, (tsl), 1))
+#define	MUTEX_UNSET(tsl)	(*(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * S/390 32-bit assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_S390_GCC_ASSEMBLY
+typedef int tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/* gcc/S390: 0 is clear, 1 is set. */
+static inline int
+MUTEX_SET(tsl_t *tsl) {							\
+	register tsl_t *__l = (tsl);					\
+	int __r;							\
+  asm volatile(								\
+       "    la    1,%1\n"						\
+       "    lhi   0,1\n"						\
+       "    l     %0,%1\n"						\
+       "0:  cs    %0,0,0(1)\n"						\
+       "    jl    0b"							\
+       : "=&d" (__r), "+m" (*__l)					\
+       : : "0", "1", "cc");						\
+	return !__r;							\
+}
+
+#define	MUTEX_UNSET(tsl)	(*(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * SCO/cc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_SCO_X86_CC_ASSEMBLY
+typedef unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/*
+ * UnixWare has threads in libthread, but OpenServer doesn't (yet).
+ *
+ * cc/x86: 0 is clear, 1 is set.
+ */
+#if defined(__USLC__)
+asm int
+_tsl_set(void *tsl)
+{
+%mem tsl
+	movl	tsl, %ecx
+	movl	$1, %eax
+	lock
+	xchgb	(%ecx),%al
+	xorl	$1,%eax
+}
+#endif
+
+#define	MUTEX_SET(tsl)		_tsl_set(tsl)
+#define	MUTEX_UNSET(tsl)	(*(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * Sparc/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_SPARC_GCC_ASSEMBLY
+typedef unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/*
+ *
+ * The ldstub instruction takes the location specified by its first argument
+ * (a register containing a memory address) and loads its contents into its
+ * second argument (a register) and atomically sets the contents the location
+ * specified by its first argument to a byte of 1s.  (The value in the second
+ * argument is never read, but only overwritten.)
+ *
+ * The stbar is needed for v8, and is implemented as membar #sync on v9,
+ * so is functional there as well.  For v7, stbar may generate an illegal
+ * instruction and we have no way to tell what we're running on.  Some
+ * operating systems notice and skip this instruction in the fault handler.
+ *
+ * gcc/sparc: 0 is clear, 1 is set.
+ */
+#define	MUTEX_SET(tsl) ({						\
+	register tsl_t *__l = (tsl);					\
+	register tsl_t __r;						\
+	__asm__ volatile						\
+	    ("ldstub [%1],%0; stbar"					\
+	    : "=r"( __r) : "r" (__l));					\
+	!__r;								\
+})
+
+#define	MUTEX_UNSET(tsl)	(*(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * UTS/cc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_UTS_CC_ASSEMBLY
+typedef int tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+#define	MUTEX_INIT(x)	0
+#define	MUTEX_SET(x)	(!uts_lock(x, 1))
+#define	MUTEX_UNSET(x)	(*(x) = 0)
+#endif
+#endif
+
+/*********************************************************************
+ * MIPS/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_MIPS_GCC_ASSEMBLY
+typedef u_int32_t tsl_t;
+
+#define MUTEX_ALIGN	4
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/*
+ * For gcc/MIPS.  Should return 0 if could not acquire the lock, 1 if
+ * lock was acquired properly.
+ */
+static inline int
+MUTEX_SET(tsl_t *tsl) {
+       register tsl_t *__l = tsl;
+       register tsl_t __r;
+       __asm__ __volatile__(
+               "       .set push           \n"
+               "       .set mips2          \n"
+               "       .set noreorder      \n"
+               "       .set nomacro        \n"
+               "1:     ll      %0,%1       \n"
+               "       bne     %0,$0,1f    \n"
+               "       xori    %0,%0,1     \n"
+               "       sc      %0,%1       \n"
+               "       beql    %0,$0,1b    \n"
+               "       xori    %0,1        \n"
+               "1:     .set pop              "
+               : "=&r" (__r), "+R" (*__l));
+       return __r;
+}
+
+#define	MUTEX_UNSET(tsl)        (*(volatile tsl_t *)(tsl) = 0)
+#define	MUTEX_INIT(tsl)         MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*********************************************************************
+ * x86/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_X86_GCC_ASSEMBLY
+typedef unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/* gcc/x86: 0 is clear, 1 is set. */
+#define	MUTEX_SET(tsl) ({						\
+	register tsl_t *__l = (tsl);					\
+	int __r;							\
+	asm volatile("movl $1,%%eax\n"					\
+		     "lock\n"						\
+		     "xchgb %1,%%al\n"					\
+		     "xorl $1,%%eax"					\
+	    : "=&a" (__r), "=m" (*__l)					\
+	    : "m1" (*__l)						\
+	    );								\
+	__r & 1;							\
+})
+
+#define	MUTEX_UNSET(tsl)        (*(volatile tsl_t *)(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+
+/*
+ * From Intel's performance tuning documentation (and see SR #6975):
+ * ftp://download.intel.com/design/perftool/cbts/appnotes/sse2/w_spinlock.pdf
+ *
+ * "For this reason, it is highly recommended that you insert the PAUSE
+ * instruction into all spin-wait code immediately. Using the PAUSE
+ * instruction does not affect the correctness of programs on existing
+ * platforms, and it improves performance on Pentium 4 processor platforms."
+ */
+#define	MUTEX_PAUSE		asm volatile ("rep; nop" : : );
+#endif
+#endif
+
+/*********************************************************************
+ * x86_64/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_X86_64_GCC_ASSEMBLY
+typedef unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/* gcc/x86_64: 0 is clear, 1 is set. */
+#define  MUTEX_SET(tsl) ({           					\
+	register tsl_t *__l = (tsl);          				\
+	int __r;              						\
+	asm volatile("mov $1,%%rax\n"					\
+		     "lock\n"						\
+		     "xchgb %1,%%al\n"					\
+		     "xor $1,%%rax"					\
+		: "=&a" (__r), "=m" (*__l)				\
+		: "1m" (*__l)						\
+		);							\
+	__r & 1;							\
+})
+
+#define	MUTEX_UNSET(tsl)	(*(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
+/*
+ * Mutex alignment defaults to sizeof(unsigned int).
+ *
+ * !!!
+ * Various systems require different alignments for mutexes (the worst we've
+ * seen so far is 16-bytes on some HP architectures).  Malloc(3) is assumed
+ * to return reasonable alignment, all other mutex users must ensure proper
+ * alignment locally.
+ */
+#ifndef	MUTEX_ALIGN
+#define	MUTEX_ALIGN	sizeof(unsigned int)
+#endif
+
+/*
+ * Mutex destruction defaults to a no-op.
+ */
+#ifndef	MUTEX_DESTROY
+#define	MUTEX_DESTROY(x)
+#endif
+
+/*
+ * DB_MUTEXMGR --
+ *	The mutex manager encapsulates the mutex system.
+ */
+typedef struct __db_mutexmgr {
+	/* These fields are never updated after creation, so not protected. */
+	DB_ENV	*dbenv;			/* Environment */
+	REGINFO	 reginfo;		/* Region information */
+
+	void	*mutex_array;		/* Base of the mutex array */
+} DB_MUTEXMGR;
+
+/* Macros to lock/unlock the mutex region as a whole. */
+#define	MUTEX_SYSTEM_LOCK(dbenv)					\
+	MUTEX_LOCK(dbenv, ((DB_MUTEXREGION *)((DB_MUTEXMGR *)		\
+	    (dbenv)->mutex_handle)->reginfo.primary)->mtx_region)
+#define	MUTEX_SYSTEM_UNLOCK(dbenv)					\
+	MUTEX_UNLOCK(dbenv, ((DB_MUTEXREGION *)((DB_MUTEXMGR *)		\
+	    (dbenv)->mutex_handle)->reginfo.primary)->mtx_region)
+
+/*
+ * DB_MUTEXREGION --
+ *	The primary mutex data structure in the shared memory region.
+ */
+typedef struct __db_mutexregion {
+	/* These fields are initialized at create time and never modified. */
+	roff_t		mutex_offset;	/* Offset of mutex array */
+	size_t		mutex_size;	/* Size of the aligned mutex */
+	roff_t		thread_off;	/* Offset of the thread area. */
+
+	db_mutex_t	mtx_region;	/* Region mutex. */
+
+	/* Protected using the region mutex. */
+	u_int32_t	mutex_next;	/* Next free mutex */
+
+	DB_MUTEX_STAT	stat;		/* Mutex statistics */
+} DB_MUTEXREGION;
+
+typedef struct __mutex_t {		/* Mutex. */
+#ifdef MUTEX_FIELDS
+	MUTEX_FIELDS
+#endif
+#if !defined(MUTEX_FIELDS) && !defined(HAVE_MUTEX_FCNTL)
+	tsl_t		tas;		/* Test and set. */
+#endif
+	pid_t 		pid;		/* Process owning mutex */
+	db_threadid_t 	tid;		/* Thread owning mutex */
+
+	u_int32_t mutex_next_link;	/* Linked list of free mutexes. */
+
+#ifdef HAVE_STATISTICS
+	int	  alloc_id;		/* Allocation ID. */
+
+	u_int32_t mutex_set_wait;	/* Granted after wait. */
+	u_int32_t mutex_set_nowait;	/* Granted without waiting. */
+#endif
+
+	/*
+	 * A subset of the flag arguments for __mutex_alloc().
+	 *
+	 * Flags should be an unsigned integer even if it's not required by
+	 * the possible flags values, getting a single byte on some machines
+	 * is expensive, and the mutex structure is a MP hot spot.
+	 */
+	u_int32_t flags;		/* MUTEX_XXX */
+} DB_MUTEX;
+
+/* Macro to get a reference to a specific mutex. */
+#define	MUTEXP_SET(indx)						\
+	(DB_MUTEX *)							\
+	    ((u_int8_t *)mtxmgr->mutex_array + (indx) * mtxregion->mutex_size);
+
+#endif /* !_DB_MUTEX_INT_H_ */