vm/memory/heapInspection.hpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
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 * 2 along with this work; if not, write to the Free Software Foundation,
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#ifndef SHARE_VM_MEMORY_HEAPINSPECTION_HPP
#define SHARE_VM_MEMORY_HEAPINSPECTION_HPP

#include "memory/allocation.inline.hpp"
#include "oops/oop.inline.hpp"


// HeapInspection

// KlassInfoTable is a bucket hash table that
// maps klassOops to extra information:
//    instance count and instance word size.
//
// A KlassInfoBucket is the head of a link list
// of KlassInfoEntry's
//
// KlassInfoHisto is a growable array of pointers
// to KlassInfoEntry's and is used to sort
// the entries.

class KlassInfoEntry: public CHeapObj<mtInternal> {
 private:
  KlassInfoEntry* _next;
  klassOop        _klass;
  long            _instance_count;
  size_t          _instance_words;

 public:
  KlassInfoEntry(klassOop k, KlassInfoEntry* next) :
    _klass(k), _instance_count(0), _instance_words(0), _next(next)
  {}
  KlassInfoEntry* next()     { return _next; }
  bool is_equal(klassOop k)  { return k == _klass; }
  klassOop klass() const     { return _klass; }
  long count() const         { return _instance_count; }
  void set_count(long ct)    { _instance_count = ct; }
  size_t words() const       { return _instance_words; }
  void set_words(size_t wds) { _instance_words = wds; }
  int compare(KlassInfoEntry* e1, KlassInfoEntry* e2);
  void print_on(outputStream* st) const;
};

class KlassInfoClosure : public StackObj {
 public:
  // Called for each KlassInfoEntry.
  virtual void do_cinfo(KlassInfoEntry* cie) = 0;
};

class KlassInfoBucket: public CHeapObj<mtInternal> {
 private:
  KlassInfoEntry* _list;
  KlassInfoEntry* list()           { return _list; }
  void set_list(KlassInfoEntry* l) { _list = l; }
 public:
  KlassInfoEntry* lookup(const klassOop k);
  void initialize() { _list = NULL; }
  void empty();
  void iterate(KlassInfoClosure* cic);
};

class KlassInfoTable: public StackObj {
 private:
  int _size;
  static const int _num_buckets = 20011;
  size_t _size_of_instances_in_words;

  // An aligned reference address (typically the least
  // address in the perm gen) used for hashing klass
  // objects.
  HeapWord* _ref;

  KlassInfoBucket* _buckets;
  uint hash(klassOop p);
  KlassInfoEntry* lookup(const klassOop k);

 public:
  KlassInfoTable(HeapWord* ref);
  ~KlassInfoTable();
  bool record_instance(const oop obj);
  void iterate(KlassInfoClosure* cic);
  bool allocation_failed() { return _buckets == NULL; }
  size_t size_of_instances_in_words() const;
};

class KlassInfoHisto : public StackObj {
 private:
  GrowableArray<KlassInfoEntry*>* _elements;
  GrowableArray<KlassInfoEntry*>* elements() const { return _elements; }
  const char* _title;
  const char* title() const { return _title; }
  static int sort_helper(KlassInfoEntry** e1, KlassInfoEntry** e2);
  void print_elements(outputStream* st) const;
  static const int _histo_initial_size = 1000;
 public:
  KlassInfoHisto(const char* title);
  ~KlassInfoHisto();
  void add(KlassInfoEntry* cie);
  void print_on(outputStream* st) const;
  void sort();
};


class HeapInspection : public AllStatic {
 public:
  static void heap_inspection(outputStream* st, bool need_prologue);
  static size_t populate_table(KlassInfoTable* cit,
                               bool need_prologue,
                               BoolObjectClosure* filter = NULL);
  static HeapWord* start_of_perm_gen();
  static void find_instances_at_safepoint(klassOop k, GrowableArray<oop>* result);
 private:
  static bool is_shared_heap();
  static void prologue();
  static void epilogue();
};

#endif // SHARE_VM_MEMORY_HEAPINSPECTION_HPP