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   // Most implementations of ConcurrentGCThread use ConcurrentGCThread's termination protocol,
  53   // run(), and stop() methods, and provide specific implementations of run_service() and stop_service.
  54   // Otherwise run_service() and stop_service should not be called.)
  55   
  56   // Do the specific GC work. Called by run() after initialization complete.
  57   virtual void run_service() { ShouldNotReachHere(); }
  58   
  59   // Shut down the specific GC work. Called by stop() as part of termination protocol.
  60   virtual void stop_service() { ShouldNotReachHere(); }
  61 
  62 public:
  63   ConcurrentGCThread();
  64 
  65   // Tester
  66   bool is_ConcurrentGC_thread() const { return true; }
  67   
  68   virtual void run();
  69   
  70   // shutdown following termination protocol
  71   virtual void stop();
  72 };
  73 
  74 // The SurrogateLockerThread is used by concurrent GC threads for
  75 // manipulating Java monitors, in particular, currently for
  76 // manipulating the pending_list_lock. XXX
  77 class SurrogateLockerThread: public JavaThread {
  78   friend class VMStructs;
  79  public:
  80   enum SLT_msg_type {
  81     empty = 0,           // no message
  82     acquirePLL,          // acquire pending list lock
  83     releaseAndNotifyPLL  // notify and release pending list lock
  84   };
  85  private:
  86   // the following are shared with the CMSThread
  87   SLT_msg_type  _buffer;  // communication buffer
  88   Monitor       _monitor; // monitor controlling buffer
  89   BasicLock     _basicLock; // used for PLL locking
  90 
  91  public:
  92   static SurrogateLockerThread* make(TRAPS);
  93 
  94   // Terminate VM with error message that SLT needed but not yet created.
  95   static void report_missing_slt();
  96 
  97   SurrogateLockerThread();
  98 
  99   bool is_hidden_from_external_view() const     { return true; }
 100 
 101   void loop(); // main method
 102 
 103   void manipulatePLL(SLT_msg_type msg);
 104 
 105 };
 106 
 107 #endif // SHARE_VM_GC_SHARED_CONCURRENTGCTHREAD_HPP