src/share/vm/runtime/task.cpp

rev 4773 : 8005849: JEP 167: Event-Based JVM Tracing
Reviewed-by: acorn, coleenp, sla
Contributed-by: Karen Kinnear <karen.kinnear@oracle.com>, Bengt Rutisson <bengt.rutisson@oracle.com>, Calvin Cheung <calvin.cheung@oracle.com>, Erik Gahlin <erik.gahlin@oracle.com>, Erik Helin <erik.helin@oracle.com>, Jesper Wilhelmsson <jesper.wilhelmsson@oracle.com>, Keith McGuigan <keith.mcguigan@oracle.com>, Mattias Tobiasson <mattias.tobiasson@oracle.com>, Markus Gronlund <markus.gronlund@oracle.com>, Mikael Auno <mikael.auno@oracle.com>, Nils Eliasson <nils.eliasson@oracle.com>, Nils Loodin <nils.loodin@oracle.com>, Rickard Backman <rickard.backman@oracle.com>, Staffan Larsen <staffan.larsen@oracle.com>, Stefan Karlsson <stefan.karlsson@oracle.com>, Yekaterina Kantserova <yekaterina.kantserova@oracle.com>

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -112,13 +112,15 @@
 
 PeriodicTask::~PeriodicTask() {
   disenroll();
 }
 
+/* enroll could be called from a JavaThread, so we have to check for
+ * safepoint when taking the lock to avoid deadlocking */
 void PeriodicTask::enroll() {
   MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
-                     NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
+                     NULL : PeriodicTask_lock);
 
   if (_num_tasks == PeriodicTask::max_tasks) {
     fatal("Overflow in PeriodicTask table");
   }
   _tasks[_num_tasks++] = this;

@@ -129,13 +131,15 @@
   } else {
     WatcherThread::start();
   }
 }
 
+/* disenroll could be called from a JavaThread, so we have to check for
+ * safepoint when taking the lock to avoid deadlocking */
 void PeriodicTask::disenroll() {
   MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
-                     NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
+                     NULL : PeriodicTask_lock);
 
   int index;
   for(index = 0; index < _num_tasks && _tasks[index] != this; index++)
     ;