1 /*
   2  * Copyright (c) 2014, 2015, Dynatrace and/or its affiliates. All rights reserved.
   3  *
   4  * This file is part of the Lock Contention Tracing Subsystem for the HotSpot
   5  * Virtual Machine, which is developed at Christian Doppler Laboratory on
   6  * Monitoring and Evolution of Very-Large-Scale Software Systems. Please
   7  * contact us at <http://mevss.jku.at/> if you need additional information
   8  * or have any questions.
   9  *
  10  * This code is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License version 2 only, as
  12  * published by the Free Software Foundation.
  13  *
  14  * This code is distributed in the hope that it will be useful, but WITHOUT
  15  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17  * version 2 for more details (a copy is included in the LICENSE file that
  18  * accompanied this code).
  19  *
  20  * You should have received a copy of the GNU General Public License version
  21  * 2 along with this work. If not, see <http://www.gnu.org/licenses/>.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_EVTRACE_TRACEBUFFERQUEUE_HPP
  26 #define SHARE_VM_EVTRACE_TRACEBUFFERQUEUE_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 class TraceBuffer;
  31 
  32 class TraceBufferQueue: public CHeapObj<mtEventTracing> {
  33 private:
  34   volatile jlong _enqueue_ops;
  35   volatile jlong _dequeue_ops;
  36   volatile int _mtx;
  37   TraceBuffer * volatile _head;
  38   TraceBuffer * volatile _tail;
  39 
  40   class SpinLocker;
  41 
  42 public:
  43   TraceBufferQueue();
  44   virtual ~TraceBufferQueue();
  45 
  46   bool is_empty() { return (_head == NULL); }
  47   size_t count();
  48 
  49   void enqueue(TraceBuffer *buffer);
  50   TraceBuffer * try_dequeue();
  51 
  52   jlong fill_mark()   { return _dequeue_ops; }
  53   bool has_dequeued_at_mark(jlong mark) { return (_dequeue_ops >= mark); }
  54 
  55   jlong enqueue_ops() { return _enqueue_ops; }
  56   jlong dequeue_ops() { return _dequeue_ops; }
  57 };
  58 
  59 #endif /* SHARE_VM_EVTRACE_TRACEBUFFERQUEUE_HPP */