heapInspection.cpp

/*
 * Copyright (c) 2002, 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
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#include "precompiled.hpp"
#include "classfile/classLoaderData.hpp"
#include "gc_interface/collectedHeap.hpp"
#include "memory/genCollectedHeap.hpp"
#include "memory/heapInspection.hpp"
#include "memory/resourceArea.hpp"
#include "runtime/os.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/macros.hpp"
#if INCLUDE_ALL_GCS
#include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
#endif // INCLUDE_ALL_GCS

// HeapInspection

int KlassInfoEntry::compare(KlassInfoEntry* e1, KlassInfoEntry* e2) {
  if(e1->_instance_words > e2->_instance_words) {
    return -1;
  } else if(e1->_instance_words < e2->_instance_words) {
    return 1;
  }
  // Sort alphabetically, note 'Z' < '[' < 'a', but it's better to group
  // the array classes before all the instance classes.
  ResourceMark rm;
  const char* name1 = e1->klass()->external_name();
  const char* name2 = e2->klass()->external_name();
  bool d1 = (name1[0] == '[');
  bool d2 = (name2[0] == '[');
  if (d1 && !d2) {
    return -1;
  } else if (d2 && !d1) {
    return 1;
  } else {
    return strcmp(name1, name2);
  }
}

const char* KlassInfoEntry::name() const {
  const char* name;
  if (_klass->name() != NULL) {
    name = _klass->external_name();
  } else {
    if (_klass == Universe::boolArrayKlassObj())         name = "<boolArrayKlass>";         else
    if (_klass == Universe::charArrayKlassObj())         name = "<charArrayKlass>";         else
    if (_klass == Universe::singleArrayKlassObj())       name = "<singleArrayKlass>";       else
    if (_klass == Universe::doubleArrayKlassObj())       name = "<doubleArrayKlass>";       else
    if (_klass == Universe::byteArrayKlassObj())         name = "<byteArrayKlass>";         else
    if (_klass == Universe::shortArrayKlassObj())        name = "<shortArrayKlass>";        else
    if (_klass == Universe::intArrayKlassObj())          name = "<intArrayKlass>";          else
    if (_klass == Universe::longArrayKlassObj())         name = "<longArrayKlass>";         else
      name = "<no name>";
  }
  return name;
}

void KlassInfoEntry::print_on(outputStream* st) const {
  ResourceMark rm;

  // simplify the formatting (ILP32 vs LP64) - always cast the numbers to 64-bit
  st->print_cr(INT64_FORMAT_W(13) "  " UINT64_FORMAT_W(13) "  %s",
               (jlong)  _instance_count,
               (julong) _instance_words * HeapWordSize,
               name());
}

KlassInfoEntry* KlassInfoBucket::lookup(Klass* const k) {
  KlassInfoEntry* elt = _list;
  while (elt != NULL) {
    if (elt->is_equal(k)) {
      return elt;
    }
    elt = elt->next();
  }
  elt = new KlassInfoEntry(k, list());
  // We may be out of space to allocate the new entry.
  if (elt != NULL) {
    set_list(elt);
  }
  return elt;
}

void KlassInfoBucket::iterate(KlassInfoClosure* cic) {
  KlassInfoEntry* elt = _list;
  while (elt != NULL) {
    cic->do_cinfo(elt);
    elt = elt->next();
  }
}

void KlassInfoBucket::empty() {
  KlassInfoEntry* elt = _list;
  _list = NULL;
  while (elt != NULL) {
    KlassInfoEntry* next = elt->next();
    delete elt;
    elt = next;
  }
}

void KlassInfoTable::AllClassesFinder::do_klass(Klass* k) {
  // This has the SIDE EFFECT of creating a KlassInfoEntry
  // for <k>, if one doesn't exist yet.
  _table->lookup(k);
}

KlassInfoTable::KlassInfoTable(int size, HeapWord* ref,
                               bool need_class_stats) {
  _size = 0;
  _ref = ref;
  _buckets = NEW_C_HEAP_ARRAY(KlassInfoBucket, size, mtInternal);
  if (_buckets != NULL) {
    _size = size;
    for (int index = 0; index < _size; index++) {
      _buckets[index].initialize();
    }
    if (need_class_stats) {
      AllClassesFinder finder(this);
      ClassLoaderDataGraph::classes_do(&finder);
    }
  }
}

KlassInfoTable::~KlassInfoTable() {
  if (_buckets != NULL) {
    for (int index = 0; index < _size; index++) {
      _buckets[index].empty();
    }
    FREE_C_HEAP_ARRAY(KlassInfoBucket, _buckets, mtInternal);
    _size = 0;
  }
}

uint KlassInfoTable::hash(Klass* p) {
  assert(p->is_metadata(), "all klasses are metadata");
  return (uint)(((uintptr_t)p - (uintptr_t)_ref) >> 2);
}

KlassInfoEntry* KlassInfoTable::lookup(Klass* const k) {
  uint         idx = hash(k) % _size;
  assert(_buckets != NULL, "Allocation failure should have been caught");
  KlassInfoEntry*  e   = _buckets[idx].lookup(k);
  // Lookup may fail if this is a new klass for which we
  // could not allocate space for an new entry.
  assert(e == NULL || k == e->klass(), "must be equal");
  return e;
}

// Return false if the entry could not be recorded on account
// of running out of space required to create a new entry.
bool KlassInfoTable::record_instance(const oop obj) {
  Klass*        k = obj->klass();
  KlassInfoEntry* elt = lookup(k);
  // elt may be NULL if it's a new klass for which we
  // could not allocate space for a new entry in the hashtable.
  if (elt != NULL) {
    elt->set_count(elt->count() + 1);
    elt->set_words(elt->words() + obj->size());
    return true;
  } else {
    return false;
  }
}

void KlassInfoTable::iterate(KlassInfoClosure* cic) {
  assert(_size == 0 || _buckets != NULL, "Allocation failure should have been caught");
  for (int index = 0; index < _size; index++) {
    _buckets[index].iterate(cic);
  }
}

int KlassInfoHisto::sort_helper(KlassInfoEntry** e1, KlassInfoEntry** e2) {
  return (*e1)->compare(*e1,*e2);
}

KlassInfoHisto::KlassInfoHisto(KlassInfoTable* cit, const char* title, int estimatedCount) :
  _cit(cit),
  _title(title) {
  _elements = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<KlassInfoEntry*>(estimatedCount,true);
}

KlassInfoHisto::~KlassInfoHisto() {
  delete _elements;
}

void KlassInfoHisto::add(KlassInfoEntry* cie) {
  elements()->append(cie);
}

void KlassInfoHisto::sort() {
  elements()->sort(KlassInfoHisto::sort_helper);
}

void KlassInfoHisto::print_elements(outputStream* st) const {
  // simplify the formatting (ILP32 vs LP64) - store the sum in 64-bit
  jlong total = 0;
  julong totalw = 0;
  for(int i=0; i < elements()->length(); i++) {
    st->print("%4d: ", i+1);
    elements()->at(i)->print_on(st);
    total += elements()->at(i)->count();
    totalw += elements()->at(i)->words();
  }
  st->print_cr("Total " INT64_FORMAT_W(13) "  " UINT64_FORMAT_W(13),
               total, totalw * HeapWordSize);
}

#define MAKE_COL_NAME(field, name, help)     #name,
#define MAKE_COL_HELP(field, name, help)     help,

static const char *name_table[] = {
  HEAP_INSPECTION_COLUMNS_DO(MAKE_COL_NAME)
};

static const char *help_table[] = {
  HEAP_INSPECTION_COLUMNS_DO(MAKE_COL_HELP)
};

bool KlassInfoHisto::is_selected(const char *col_name) {
  if (_selected_columns == NULL) {
    return true;
  }
  if (strcmp(_selected_columns, col_name) == 0) {
    return true;
  }

  const char *start = strstr(_selected_columns, col_name);
  if (start == NULL) {
    return false;
  }

  // The following must be true, because _selected_columns != col_name
  if (start > _selected_columns && start[-1] != ',') {
    return false;
  }
  char x = start[strlen(col_name)];
  if (x != ',' && x != '\0') {
    return false;
  }

  return true;
}

void KlassInfoHisto::print_title(outputStream* st, bool csv_format,
                                 bool selected[], int width_table[],
                                 const char *name_table[]) {
  if (csv_format) {
    st->print("Index,Super");
    for (int c=0; c<KlassSizeStats::_num_columns; c++) {
       if (selected[c]) {st->print(",%s", name_table[c]);}
    }
    st->print(",ClassName");
  } else {
    st->print("Index Super");
    for (int c=0; c<KlassSizeStats::_num_columns; c++) {
      if (selected[c]) {st->print(str_fmt(width_table[c]), name_table[c]);}
    }
    st->print(" ClassName");
  }

  if (is_selected("ClassLoader")) {
    st->print(",ClassLoader");
  }
  st->cr();
}

void KlassInfoHisto::print_class_stats(outputStream* st,
                                      bool csv_format, const char *columns) {
  ResourceMark rm;
  KlassSizeStats sz, sz_sum;
  int i;
  julong *col_table = (julong*)(&sz);
  julong *colsum_table = (julong*)(&sz_sum);
  int width_table[KlassSizeStats::_num_columns];
  bool selected[KlassSizeStats::_num_columns];

  _selected_columns = columns;

  memset(&sz_sum, 0, sizeof(sz_sum));
  for (int c=0; c<KlassSizeStats::_num_columns; c++) {
    selected[c] = is_selected(name_table[c]);
  }

  for(i=0; i < elements()->length(); i++) {
    elements()->at(i)->set_index(i+1);
  }

  for (int pass=1; pass<=2; pass++) {
    if (pass == 2) {
      print_title(st, csv_format, selected, width_table, name_table);
    }
    for(i=0; i < elements()->length(); i++) {
      KlassInfoEntry* e = (KlassInfoEntry*)elements()->at(i);
      const Klass* k = e->klass();

      memset(&sz, 0, sizeof(sz));
      sz._inst_count = e->count();
      sz._inst_bytes = HeapWordSize * e->words();
      k->collect_statistics(&sz);
      sz._total_bytes = sz._ro_bytes + sz._rw_bytes;

      if (pass == 1) {
        for (int c=0; c<KlassSizeStats::_num_columns; c++) {
          colsum_table[c] += col_table[c];
        }
      } else {
        int super_index = -1;
        if (k->oop_is_instance()) {
          Klass* super = ((InstanceKlass*)k)->java_super();
          if (super) {
            KlassInfoEntry* super_e = _cit->lookup(super);
            if (super_e) {
              super_index = super_e->index();
            }
          }
        }

        if (csv_format) {
          st->print("%d,%d", e->index(), super_index);
          for (int c=0; c<KlassSizeStats::_num_columns; c++) {
            if (selected[c]) {st->print("," JULONG_FORMAT, col_table[c]);}
          }
          st->print(",%s",e->name());
        } else {
          st->print("%5d %5d", e->index(), super_index);
          for (int c=0; c<KlassSizeStats::_num_columns; c++) {
            if (selected[c]) {print_julong(st, width_table[c], col_table[c]);}
          }
          st->print(" %s", e->name());
        }
        if (is_selected("ClassLoader")) {
          ClassLoaderData* loader_data = k->class_loader_data();
          st->print(",");
          loader_data->print_value_on(st);
        }
        st->cr();
      }
    }

    if (pass == 1) {
      for (int c=0; c<KlassSizeStats::_num_columns; c++) {
        width_table[c] = col_width(colsum_table[c], name_table[c]);
      }
    }
  }

  sz_sum._inst_size = 0;

  if (csv_format) {
    st->print(",");
    for (int c=0; c<KlassSizeStats::_num_columns; c++) {
      if (selected[c]) {st->print("," JULONG_FORMAT, colsum_table[c]);}
    }
  } else {
    st->print("           ");
    for (int c=0; c<KlassSizeStats::_num_columns; c++) {
      if (selected[c]) {print_julong(st, width_table[c], colsum_table[c]);}
    }
    st->print(" Total");
    if (sz_sum._total_bytes > 0) {
      st->cr();
      st->print("           ");
      for (int c=0; c<KlassSizeStats::_num_columns; c++) {
        if (selected[c]) {
          switch (c) {
          case KlassSizeStats::_index_inst_size:
          case KlassSizeStats::_index_inst_count:
          case KlassSizeStats::_index_method_count:
            st->print(str_fmt(width_table[c]), "-");
            break;
          default:
            {
              double perc = (double)(100) * (double)(colsum_table[c]) / (double)sz_sum._total_bytes;
              st->print(perc_fmt(width_table[c]), perc);
            }
          }
        }
      }
    }
  }
  st->cr();

  if (!csv_format) {
    print_title(st, csv_format, selected, width_table, name_table);
  }
}

julong KlassInfoHisto::annotations_bytes(Array<AnnotationArray*>* p) const {
  julong bytes = 0;
  if (p != NULL) {
    for (int i = 0; i < p->length(); i++) {
      bytes += count_bytes_array(p->at(i));
    }
    bytes += count_bytes_array(p);
  }
  return bytes;
}

void KlassInfoHisto::print_histo_on(outputStream* st, bool print_stats,
                                    bool csv_format, const char *columns) {
  if (print_stats) {
    print_class_stats(st, csv_format, columns);
  } else {
    st->print_cr("%s",title());
    print_elements(st);
  }
}

class HistoClosure : public KlassInfoClosure {
 private:
  KlassInfoHisto* _cih;
 public:
  HistoClosure(KlassInfoHisto* cih) : _cih(cih) {}

  void do_cinfo(KlassInfoEntry* cie) {
    _cih->add(cie);
  }
};

class RecordInstanceClosure : public ObjectClosure {
 private:
  KlassInfoTable* _cit;
  size_t _missed_count;
 public:
  RecordInstanceClosure(KlassInfoTable* cit) :
    _cit(cit), _missed_count(0) {}

  void do_object(oop obj) {
    if (!_cit->record_instance(obj)) {
      _missed_count++;
    }
  }

  size_t missed_count() { return _missed_count; }
};

void HeapInspection::heap_inspection(outputStream* st, bool need_prologue) {
  ResourceMark rm;
  // Get some random number for ref (the hash key)
  HeapWord* ref = (HeapWord*) Universe::boolArrayKlassObj();
  CollectedHeap* heap = Universe::heap();
  bool is_shared_heap = false;

  if (_print_help) {
    for (int c=0; c<KlassSizeStats::_num_columns; c++) {
      st->print("%s:\n\t", name_table[c]);
      const int max_col = 60;
      int col = 0;
      for (const char *p = help_table[c]; *p; p++,col++) {
        if (col >= max_col && *p == ' ') {
          st->print("\n\t");
          col = 0;
        } else {
          st->print("%c", *p);
        }
      }
      st->print_cr(".\n");
    }
    return;
  }

  // Collect klass instance info
  KlassInfoTable cit(KlassInfoTable::cit_size, ref, _print_class_stats);
  if (!cit.allocation_failed()) {
    // Iterate over objects in the heap
    RecordInstanceClosure ric(&cit);
    Universe::heap()->object_iterate(&ric);

    // Report if certain classes are not counted because of
    // running out of C-heap for the histogram.
    size_t missed_count = ric.missed_count();
    if (missed_count != 0) {
      st->print_cr("WARNING: Ran out of C-heap; undercounted " SIZE_FORMAT
                   " total instances in data below",
                   missed_count);
    }
    // Sort and print klass instance info
    const char *title = "\n"
              " num     #instances         #bytes  class name\n"
              "----------------------------------------------";
    KlassInfoHisto histo(&cit, title, KlassInfoHisto::histo_initial_size);
    HistoClosure hc(&histo);
    cit.iterate(&hc);
    histo.sort();
    histo.print_histo_on(st, _print_class_stats, _csv_format, _columns);
  } else {
    st->print_cr("WARNING: Ran out of C-heap; histogram not generated");
  }
  st->flush();

  if (need_prologue && is_shared_heap) {
    SharedHeap* sh = (SharedHeap*)heap;
    sh->gc_epilogue(false /* !full */); // release all acquired locks, etc.
  }
}

class FindInstanceClosure : public ObjectClosure {
 private:
  Klass* _klass;
  GrowableArray<oop>* _result;

 public:
  FindInstanceClosure(Klass* k, GrowableArray<oop>* result) : _klass(k), _result(result) {};

  void do_object(oop obj) {
    if (obj->is_a(_klass)) {
      _result->append(obj);
    }
  }
};

void HeapInspection::find_instances_at_safepoint(Klass* k, GrowableArray<oop>* result) {
  assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
  assert(Heap_lock->is_locked(), "should have the Heap_lock");

  // Ensure that the heap is parsable
  Universe::heap()->ensure_parsability(false);  // no need to retire TALBs

  // Iterate over objects in the heap
  FindInstanceClosure fic(k, result);
  // If this operation encounters a bad object when using CMS,
  // consider using safe_object_iterate() which avoids metadata
  // objects that may contain bad references.
  Universe::heap()->object_iterate(&fic);
}