1 /*
   2  * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_SHARED_CONCURRENTGCTHREAD_HPP
  26 #define SHARE_VM_GC_SHARED_CONCURRENTGCTHREAD_HPP
  27 
  28 #include "runtime/thread.hpp"
  29 #include "utilities/macros.hpp"
  30 
  31 class ConcurrentGCThread: public NamedThread {
  32   friend class VMStructs;
  33 
  34 protected:
  35   bool volatile _should_terminate;
  36   bool _has_terminated;
  37 
  38   // Create and start the thread (setting it's priority high.)
  39   void create_and_start();
  40 
  41   // Do initialization steps in the thread: record stack base and size,
  42   // init thread local storage, set JNI handle block.
  43   void initialize_in_thread();
  44 
  45   // Wait until Universe::is_fully_initialized();
  46   void wait_for_universe_init();
  47 
  48   // Record that the current thread is terminating, and will do more
  49   // concurrent work.
  50   void terminate();
  51 
  52 public:
  53   ConcurrentGCThread();
  54 
  55   // Tester
  56   bool is_ConcurrentGC_thread() const { return true; }
  57 };
  58 
  59 // The SurrogateLockerThread is used by concurrent GC threads for
  60 // manipulating Java monitors, in particular, currently for
  61 // manipulating the pending_list_lock. XXX
  62 class SurrogateLockerThread: public JavaThread {
  63   friend class VMStructs;
  64  public:
  65   enum SLT_msg_type {
  66     empty = 0,           // no message
  67     acquirePLL,          // acquire pending list lock
  68     releaseAndNotifyPLL  // notify and release pending list lock
  69   };
  70  private:
  71   // the following are shared with the CMSThread
  72   SLT_msg_type  _buffer;  // communication buffer
  73   Monitor       _monitor; // monitor controlling buffer
  74   BasicLock     _basicLock; // used for PLL locking
  75 
  76  public:
  77   static SurrogateLockerThread* make(TRAPS);
  78 
  79   // Terminate VM with error message that SLT needed but not yet created.
  80   static void report_missing_slt();
  81 
  82   SurrogateLockerThread();
  83 
  84   bool is_hidden_from_external_view() const     { return true; }
  85 
  86   void loop(); // main method
  87 
  88   void manipulatePLL(SLT_msg_type msg);
  89 
  90 };
  91 
  92 #endif // SHARE_VM_GC_SHARED_CONCURRENTGCTHREAD_HPP