diff -ur mod_watch-4.3/mod_watch.c mod_watch-4.3-mutex/mod_watch.c
--- mod_watch-4.3/mod_watch.c	2011-03-28 14:15:48.017826697 +0200
+++ mod_watch-4.3-mutex/mod_watch.c	2011-03-28 14:07:07.613894883 +0200
@@ -1466,6 +1466,63 @@
 }
 
 /*
+ * WatchMutexMech directory
+ *
+ * Mutex mechanism to use for shared memory lock.
+ */
+static const char *
+WatchMutexMech(cmd_parms *cmd, void *dconf, const char *mech)
+{
+	if (!strcasecmp(mech, "default")) {
+		shMutexMech = APR_LOCK_DEFAULT;
+	}
+#if APR_HAS_FCNTL_SERIALIZE
+	else if (!strcasecmp(mech, "fcntl") || !strcasecmp(mech, "file")) {
+		shMutexMech = APR_LOCK_FCNTL;
+	}
+#endif
+#if APR_HAS_FLOCK_SERIALIZE
+	else if (!strcasecmp(mech, "flock") || !strcasecmp(mech, "file")) {
+		shMutexMech = APR_LOCK_FLOCK;
+	}
+#endif
+#if APR_HAS_POSIXSEM_SERIALIZE
+	else if (!strcasecmp(mech, "posixsem") || !strcasecmp(mech, "sem")) {
+		shMutexMech = APR_LOCK_POSIXSEM;
+	}
+#endif
+#if APR_HAS_PROC_PTHREAD_SERIALIZE
+	else if (!strcasecmp(mech, "pthread")) {
+		shMutexMech = APR_LOCK_PROC_PTHREAD;
+	}
+#endif
+	else {
+		return apr_pstrcat(cmd->pool, "Invalid WatchMutexMech argument ", mech,
+				" (Valid WatchMutexMech mechanisms are: default"
+#if APR_HAS_FLOCK_SERIALIZE || APR_HAS_FCNTL_SERIALIZE
+				", file"
+#endif
+#if APR_HAS_FLOCK_SERIALIZE
+				", flock"
+#endif
+#if APR_HAS_FCNTL_SERIALIZE
+				", fcntl"
+#endif
+#if APR_HAS_POSIXSEM_SERIALIZE
+				", sem"
+#endif
+#if APR_HAS_POSIXSEM_SERIALIZE
+				", posixsem"
+#endif
+#if APR_HAS_PROC_PTHREAD_SERIALIZE
+				", pthread"
+#endif
+				")", NULL);
+	}
+	return (const char *) 0;
+}
+
+/*
  * WatchStateDirectory directory
  *
  * Absolute or server root relative directory where support and runtime
@@ -1645,6 +1702,11 @@
 	),
 
 	AP_INIT_TAKE1(
+		"WatchMutexMech", WatchMutexMech, NULL, RSRC_CONF,
+		"Mutex mechanism to use for shared memory lock."
+	),
+
+	AP_INIT_TAKE1(
 		"WatchStateDirectory", WatchStateDirectory, NULL, RSRC_CONF,
 		"Spool directory for any support and runtime files."
 	),
diff -ur mod_watch-4.3/SharedHash.c mod_watch-4.3-mutex/SharedHash.c
--- mod_watch-4.3/SharedHash.c	2011-03-28 14:15:48.017826697 +0200
+++ mod_watch-4.3-mutex/SharedHash.c	2011-03-28 14:06:00.950400565 +0200
@@ -95,6 +95,8 @@
 const char shScanFormat[] = SH_SCAN_FORMAT;
 const char shPrintFormat[] = SH_PRINT_FORMAT;
 
+int shMutexMech = APR_LOCK_DEFAULT;
+
 #ifdef BOUNDARY_CHECKING
 char *
 shVerifyString(struct shTable *tp, char *str)
@@ -509,7 +515,7 @@
 
 	rc = apr_global_mutex_create(
 		(apr_global_mutex_t **) &tp->mutex,
-		tp->lockfile, APR_LOCK_DEFAULT, p
+		tp->lockfile, shMutexMech, p
 	);
 	if (rc != APR_SUCCESS) {
 		ap_log_error(
diff -ur mod_watch-4.3/SharedHash.h mod_watch-4.3-mutex/SharedHash.h
--- mod_watch-4.3/SharedHash.h	2003-03-14 10:12:48.000000000 +0100
+++ mod_watch-4.3-mutex/SharedHash.h	2011-03-28 14:04:55.726981348 +0200
@@ -110,6 +110,8 @@
 extern "C" {
 #endif
 
+extern int shMutexMech;
+
 extern const char shLockFile[];
 extern const char shScanFormat[];
 extern const char shPrintFormat[];