Java example source code file (memoryPool.hpp)

This example Java source code file (memoryPool.hpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

codeheappool, collectedmemorypool, compactiblefreelistspacepool, defnewgeneration, heap, include_all_gcs, memorymanager, memorypool, memoryusage, nonheap, pooltype, sensorinfo, share_vm_services_memorypool_hpp, thresholdsupport

The memoryPool.hpp Java example source code

/*
 * Copyright (c) 2003, 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.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#ifndef SHARE_VM_SERVICES_MEMORYPOOL_HPP
#define SHARE_VM_SERVICES_MEMORYPOOL_HPP

#include "gc_implementation/shared/mutableSpace.hpp"
#include "memory/defNewGeneration.hpp"
#include "memory/heap.hpp"
#include "memory/space.hpp"
#include "services/memoryUsage.hpp"
#include "utilities/macros.hpp"
#if INCLUDE_ALL_GCS
#include "gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp"
#endif // INCLUDE_ALL_GCS

// A memory pool represents the memory area that the VM manages.
// The Java virtual machine has at least one memory pool
// and it may create or remove memory pools during execution.
// A memory pool can belong to the heap or the non-heap memory.
// A Java virtual machine may also have memory pools belonging to
// both heap and non-heap memory.

// Forward declaration
class MemoryManager;
class SensorInfo;
class Generation;
class DefNewGeneration;
class ThresholdSupport;

class MemoryPool : public CHeapObj<mtInternal> {
  friend class MemoryManager;
 public:
  enum PoolType {
    Heap    = 1,
    NonHeap = 2
  };

 private:
  enum {
    max_num_managers = 5
  };

  // We could make some of the following as performance counters
  // for external monitoring.
  const char*      _name;
  PoolType         _type;
  size_t           _initial_size;
  size_t           _max_size;
  bool             _available_for_allocation; // Default is true
  MemoryManager*   _managers[max_num_managers];
  int              _num_managers;
  MemoryUsage      _peak_usage;               // Peak memory usage
  MemoryUsage      _after_gc_usage;           // After GC memory usage

  ThresholdSupport* _usage_threshold;
  ThresholdSupport* _gc_usage_threshold;

  SensorInfo*      _usage_sensor;
  SensorInfo*      _gc_usage_sensor;

  volatile instanceOop _memory_pool_obj;

  void add_manager(MemoryManager* mgr);

 public:
  MemoryPool(const char* name,
             PoolType type,
             size_t init_size,
             size_t max_size,
             bool support_usage_threshold,
             bool support_gc_threshold);

  const char* name()                       { return _name; }
  bool        is_heap()                    { return _type == Heap; }
  bool        is_non_heap()                { return _type == NonHeap; }
  size_t      initial_size()   const       { return _initial_size; }
  int         num_memory_managers() const  { return _num_managers; }
  // max size could be changed
  virtual size_t max_size()    const       { return _max_size; }

  bool is_pool(instanceHandle pool) { return (pool() == _memory_pool_obj); }

  bool available_for_allocation()   { return _available_for_allocation; }
  bool set_available_for_allocation(bool value) {
    bool prev = _available_for_allocation;
    _available_for_allocation = value;
    return prev;
  }

  MemoryManager* get_memory_manager(int index) {
    assert(index >= 0 && index < _num_managers, "Invalid index");
    return _managers[index];
  }

  // Records current memory usage if it's a peak usage
  void record_peak_memory_usage();

  MemoryUsage get_peak_memory_usage() {
    // check current memory usage first and then return peak usage
    record_peak_memory_usage();
    return _peak_usage;
  }
  void        reset_peak_memory_usage() {
    _peak_usage = get_memory_usage();
  }

  ThresholdSupport* usage_threshold()      { return _usage_threshold; }
  ThresholdSupport* gc_usage_threshold()   { return _gc_usage_threshold; }

  SensorInfo*       usage_sensor()         {  return _usage_sensor; }
  SensorInfo*       gc_usage_sensor()      { return _gc_usage_sensor; }

  void        set_usage_sensor_obj(instanceHandle s);
  void        set_gc_usage_sensor_obj(instanceHandle s);
  void        set_last_collection_usage(MemoryUsage u)  { _after_gc_usage = u; }

  virtual instanceOop get_memory_pool_instance(TRAPS);
  virtual MemoryUsage get_memory_usage() = 0;
  virtual size_t      used_in_bytes() = 0;
  virtual bool        is_collected_pool()         { return false; }
  virtual MemoryUsage get_last_collection_usage() { return _after_gc_usage; }

  // GC support
  void oops_do(OopClosure* f);
};

class CollectedMemoryPool : public MemoryPool {
public:
  CollectedMemoryPool(const char* name, PoolType type, size_t init_size, size_t max_size, bool support_usage_threshold) :
    MemoryPool(name, type, init_size, max_size, support_usage_threshold, true) {};
  bool is_collected_pool()            { return true; }
};

class ContiguousSpacePool : public CollectedMemoryPool {
private:
  ContiguousSpace* _space;

public:
  ContiguousSpacePool(ContiguousSpace* space, const char* name, PoolType type, size_t max_size, bool support_usage_threshold);

  ContiguousSpace* space()              { return _space; }
  MemoryUsage get_memory_usage();
  size_t used_in_bytes()                { return space()->used(); }
};

class SurvivorContiguousSpacePool : public CollectedMemoryPool {
private:
  DefNewGeneration* _gen;

public:
  SurvivorContiguousSpacePool(DefNewGeneration* gen,
                              const char* name,
                              PoolType type,
                              size_t max_size,
                              bool support_usage_threshold);

  MemoryUsage get_memory_usage();

  size_t used_in_bytes() {
    return _gen->from()->used();
  }
  size_t committed_in_bytes() {
    return _gen->from()->capacity();
  }
};

#if INCLUDE_ALL_GCS
class CompactibleFreeListSpacePool : public CollectedMemoryPool {
private:
  CompactibleFreeListSpace* _space;
public:
  CompactibleFreeListSpacePool(CompactibleFreeListSpace* space,
                               const char* name,
                               PoolType type,
                               size_t max_size,
                               bool support_usage_threshold);

  MemoryUsage get_memory_usage();
  size_t used_in_bytes()            { return _space->used(); }
};
#endif // INCLUDE_ALL_GCS


class GenerationPool : public CollectedMemoryPool {
private:
  Generation* _gen;
public:
  GenerationPool(Generation* gen, const char* name, PoolType type, bool support_usage_threshold);

  MemoryUsage get_memory_usage();
  size_t used_in_bytes()                { return _gen->used(); }
};

class CodeHeapPool: public MemoryPool {
private:
  CodeHeap* _codeHeap;
public:
  CodeHeapPool(CodeHeap* codeHeap, const char* name, bool support_usage_threshold);
  MemoryUsage get_memory_usage();
  size_t used_in_bytes()            { return _codeHeap->allocated_capacity(); }
};

class MetaspacePool : public MemoryPool {
  size_t calculate_max_size() const;
 public:
  MetaspacePool();
  MemoryUsage get_memory_usage();
  size_t used_in_bytes();
};

class CompressedKlassSpacePool : public MemoryPool {
 public:
  CompressedKlassSpacePool();
  MemoryUsage get_memory_usage();
  size_t used_in_bytes();
};

#endif // SHARE_VM_SERVICES_MEMORYPOOL_HPP