Index: thread/thr_mutex.c
===================================================================
RCS file: /home/ncvs/src/lib/libthr/thread/thr_mutex.c,v
retrieving revision 1.73
diff -u -u -r1.73 thr_mutex.c
--- thread/thr_mutex.c	26 Apr 2008 13:19:07 -0000	1.73
+++ thread/thr_mutex.c	8 May 2008 03:00:15 -0000
@@ -418,7 +418,8 @@
 
 		count = m->m_spinloops;
 		while (count--) {
-			if (m->m_lock.m_owner == UMUTEX_UNOWNED) {
+			if (m->m_lock.m_owner == UMUTEX_UNOWNED ||
+			    m->m_lock.m_owner == (int32_t)UMUTEX_CONTESTED) {
 				ret = _thr_umutex_trylock2(&m->m_lock, id);
 				if (ret == 0)
 					goto done;
@@ -437,7 +438,7 @@
 
 sleep_in_kernel:
 		if (abstime == NULL) {
-			ret = __thr_umutex_lock(&m->m_lock);
+			ret = __thr_umutex_lock(&m->m_lock, id);
 		} else if (__predict_false(
 			   abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
 			   abstime->tv_nsec >= 1000000000)) {
Index: thread/thr_umtx.c
===================================================================
RCS file: /home/ncvs/src/lib/libthr/thread/thr_umtx.c,v
retrieving revision 1.16
diff -u -u -r1.16 thr_umtx.c
--- thread/thr_umtx.c	29 Apr 2008 03:58:18 -0000	1.16
+++ thread/thr_umtx.c	8 May 2008 03:00:15 -0000
@@ -48,9 +48,23 @@
 }
 
 int
-__thr_umutex_lock(struct umutex *mtx)
+__thr_umutex_lock(struct umutex *mtx, uint32_t id)
 {
-	return _umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0);
+	if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
+		for (;;) {
+			/* wait in kernel */
+			_umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0, 0, 0);
+
+			/* now try to lock it */
+			if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_UNOWNED, id) ||
+    			    atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_CONTESTED,
+				id | UMUTEX_CONTESTED)) {
+				return (0);
+			}
+		}
+	}
+
+	return	_umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0);
 }
 
 int
@@ -65,8 +79,12 @@
 }
 
 int
-__thr_umutex_unlock(struct umutex *mtx)
+__thr_umutex_unlock(struct umutex *mtx, uint32_t id)
 {
+	if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
+		atomic_cmpset_rel_32(&mtx->m_owner, id | UMUTEX_CONTESTED, UMUTEX_CONTESTED);
+		return _umtx_op_err(mtx, UMTX_OP_MUTEX_WAKE, 0, 0, 0);
+	}
 	return _umtx_op_err(mtx, UMTX_OP_MUTEX_UNLOCK, 0, 0, 0);
 }
 
@@ -123,7 +141,8 @@
 {
 	if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
 	    timeout->tv_nsec <= 0))) {
-		__thr_umutex_unlock(m);
+		struct pthread *curthread = _get_curthread();
+		_thr_umutex_unlock(m, TID(curthread));
                 return (ETIMEDOUT);
 	}
 	return _umtx_op_err(cv, UMTX_OP_CV_WAIT,
Index: thread/thr_umtx.h
===================================================================
RCS file: /home/ncvs/src/lib/libthr/thread/thr_umtx.h,v
retrieving revision 1.13
diff -u -u -r1.13 thr_umtx.h
--- thread/thr_umtx.h	29 Apr 2008 03:58:18 -0000	1.13
+++ thread/thr_umtx.h	8 May 2008 03:00:15 -0000
@@ -34,10 +34,10 @@
 
 #define DEFAULT_UMUTEX	{0,0, {0,0},{0,0,0,0}}
 
-int __thr_umutex_lock(struct umutex *mtx) __hidden;
+int __thr_umutex_lock(struct umutex *mtx, uint32_t id) __hidden;
 int __thr_umutex_timedlock(struct umutex *mtx,
 	const struct timespec *timeout) __hidden;
-int __thr_umutex_unlock(struct umutex *mtx) __hidden;
+int __thr_umutex_unlock(struct umutex *mtx, uint32_t id) __hidden;
 int __thr_umutex_trylock(struct umutex *mtx) __hidden;
 int __thr_umutex_set_ceiling(struct umutex *mtx, uint32_t ceiling,
 	uint32_t *oldceiling) __hidden;
@@ -63,6 +63,9 @@
 {
     if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_UNOWNED, id))
 	return (0);
+    if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0 &&
+    	atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_CONTESTED, id | UMUTEX_CONTESTED))
+	return (0);
     if ((mtx->m_flags & UMUTEX_PRIO_PROTECT) == 0)
     	return (EBUSY);
     return (__thr_umutex_trylock(mtx));
@@ -73,22 +76,25 @@
 {
     if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_UNOWNED, id))
 	return (0);
+    if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0 &&
+    	atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_CONTESTED, id | UMUTEX_CONTESTED))
+	return (0);
     return (EBUSY);
 }
 
 static inline int
 _thr_umutex_lock(struct umutex *mtx, uint32_t id)
 {
-    if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_UNOWNED, id))
+    if (_thr_umutex_trylock2(mtx, id) == 0)
 	return (0);
-    return (__thr_umutex_lock(mtx));
+    return (__thr_umutex_lock(mtx, id));
 }
 
 static inline int
 _thr_umutex_timedlock(struct umutex *mtx, uint32_t id,
 	const struct timespec *timeout)
 {
-    if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_UNOWNED, id))
+    if (_thr_umutex_trylock2(mtx, id) == 0)
 	return (0);
     return (__thr_umutex_timedlock(mtx, timeout));
 }
@@ -98,7 +104,7 @@
 {
     if (atomic_cmpset_rel_32(&mtx->m_owner, id, UMUTEX_UNOWNED))
 	return (0);
-    return (__thr_umutex_unlock(mtx));
+    return (__thr_umutex_unlock(mtx, id));
 }
 
 static inline int