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   bool volatile _should_terminate;
  35   bool _has_terminated;
  36 
  37   // Do initialization steps in the thread: record stack base and size,
  38   // init thread local storage, set JNI handle block.
  39   void initialize_in_thread();
  40 
  41   // Wait until Universe::is_fully_initialized();
  42   void wait_for_universe_init();
  43 
  44   // Record that the current thread is terminating, and will do more
  45   // concurrent work.
  46   void terminate();
  47 
  48 protected:
  49   // Create and start the thread (setting it's priority.)
  50   void create_and_start(ThreadPriority prio = NearMaxPriority);
  51 
  52   // Do the specific GC work. Called by run() after initialization complete.
  53   virtual void run_service() = 0;
  54 
  55   // Shut down the specific GC work. Called by stop() as part of termination protocol.
  56   virtual void stop_service()  = 0;
  57 
  58 public:
  59   ConcurrentGCThread();
  60 
  61   // Tester
  62   bool is_ConcurrentGC_thread() const { return true; }
  63 
  64   virtual void run();
  65 
  66   // shutdown following termination protocol
  67   virtual void stop();
  68 
  69   bool should_terminate() { return _should_terminate; }
  70   bool has_terminated()   { return _has_terminated; }
  71 };
  72 
  73 // The SurrogateLockerThread is used by concurrent GC threads for
  74 // manipulating Java monitors, in particular, currently for
  75 // manipulating the pending_list_lock. XXX
  76 class SurrogateLockerThread: public JavaThread {
  77   friend class VMStructs;
  78  public:
  79   enum SLT_msg_type {
  80     empty = 0,           // no message
  81     acquirePLL,          // acquire pending list lock
  82     releaseAndNotifyPLL  // notify and release pending list lock
  83   };
  84  private:
  85   // the following are shared with the CMSThread
  86   SLT_msg_type  _buffer;  // communication buffer
  87   Monitor       _monitor; // monitor controlling buffer
  88   BasicLock     _basicLock; // used for PLL locking
  89 
  90  public:
  91   static SurrogateLockerThread* make(TRAPS);
  92 
  93   // Terminate VM with error message that SLT needed but not yet created.
  94   static void report_missing_slt();
  95 
  96   SurrogateLockerThread();
  97 
  98   bool is_hidden_from_external_view() const     { return true; }
  99 
 100   void loop(); // main method
 101 
 102   void manipulatePLL(SLT_msg_type msg);
 103 
 104 };
 105 
 106 #endif // SHARE_VM_GC_SHARED_CONCURRENTGCTHREAD_HPP