view src/share/vm/services/classLoadingService.hpp @ 452:00b023ae2d78

6722113: CMS: Incorrect overflow handling during precleaning of Reference lists Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery. Reviewed-by: apetrusenko, jcoomes
author ysr
date Thu, 20 Nov 2008 12:27:41 -0800
parents a61af66fc99e
children c18cbe5936b8
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/*
 * Copyright 2003-2005 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 */

class instanceKlass;

// VM monitoring and management support for the Class Loading subsystem
class ClassLoadingService : public AllStatic {
private:
  // Counters for classes loaded from class files
  static PerfCounter*  _classes_loaded_count;
  static PerfCounter*  _classes_unloaded_count;
  static PerfCounter*  _classbytes_loaded;
  static PerfCounter*  _classbytes_unloaded;

  // Counters for classes loaded from shared archive
  static PerfCounter*  _shared_classes_loaded_count;
  static PerfCounter*  _shared_classes_unloaded_count;
  static PerfCounter*  _shared_classbytes_loaded;
  static PerfCounter*  _shared_classbytes_unloaded;

  static PerfVariable* _class_methods_size;

  static size_t compute_class_size(instanceKlass* k);

public:
  static void init();

  static bool get_verbose() { return TraceClassLoading; }
  static bool set_verbose(bool verbose);
  static void reset_trace_class_unloading();

  static jlong loaded_class_count() {
    return _classes_loaded_count->get_value() + _shared_classes_loaded_count->get_value();
  }
  static jlong unloaded_class_count() {
    return _classes_unloaded_count->get_value() + _shared_classes_unloaded_count->get_value();
  }
  static jlong loaded_class_bytes() {
    if (UsePerfData) {
      return _classbytes_loaded->get_value() + _shared_classbytes_loaded->get_value();
    } else {
      return -1;
    }
  }
  static jlong unloaded_class_bytes() {
    if (UsePerfData) {
      return _classbytes_unloaded->get_value() + _shared_classbytes_unloaded->get_value();
    } else {
      return -1;
    }
  }

  static jlong loaded_shared_class_count() {
    return _shared_classes_loaded_count->get_value();
  }
  static jlong unloaded_shared_class_count() {
    return _shared_classes_unloaded_count->get_value();
  }
  static jlong loaded_shared_class_bytes() {
    if (UsePerfData) {
      return _shared_classbytes_loaded->get_value();
    } else {
      return -1;
    }
  }
  static jlong unloaded_shared_class_bytes() {
    if (UsePerfData) {
      return _shared_classbytes_unloaded->get_value();
    } else {
      return -1;
    }
  }
  static jlong class_method_data_size() {
    return (UsePerfData ? _class_methods_size->get_value() : -1);
  }

  static void notify_class_loaded(instanceKlass* k, bool shared_class);
  // All unloaded classes are non-shared
  static void notify_class_unloaded(instanceKlass* k);
  static void add_class_method_size(int size) {
    if (UsePerfData) {
      _class_methods_size->inc(size);
    }
  }
};

// FIXME: make this piece of code to be shared by M&M and JVMTI
class LoadedClassesEnumerator : public StackObj {
private:
  static GrowableArray<KlassHandle>* _loaded_classes;
  // _current_thread is for creating a KlassHandle with a faster version constructor
  static Thread*                     _current_thread;

  GrowableArray<KlassHandle>* _klass_handle_array;

public:
  LoadedClassesEnumerator(Thread* cur_thread);

  int num_loaded_classes()         { return _klass_handle_array->length(); }
  KlassHandle get_klass(int index) { return _klass_handle_array->at(index); }

  static void add_loaded_class(klassOop k) {
    // FIXME: For now - don't include array klasses
    // The spec is unclear at this point to count array klasses or not
    // and also indirect creation of array of super class and secondaries
    //
    // for (klassOop l = k; l != NULL; l = Klass::cast(l)->array_klass_or_null()) {
    //  KlassHandle h(_current_thread, l);
    //  _loaded_classes->append(h);
    // }
    KlassHandle h(_current_thread, k);
    _loaded_classes->append(h);
  }
};