view src/share/vm/memory/metadataFactory.hpp @ 20543:e7d0505c8a30

8059758: Footprint regressions with JDK-8038423 Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything. Reviewed-by: jwilhelm, brutisso
author tschatzl
date Fri, 10 Oct 2014 15:51:58 +0200
parents 6e0cb14ce59b
children 4cb90023bf2b
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/*
 * Copyright (c) 2010, 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_MEMORY_METADATAFACTORY_HPP
#define SHARE_VM_MEMORY_METADATAFACTORY_HPP

#include "classfile/classLoaderData.hpp"
#include "utilities/array.hpp"
#include "utilities/exceptions.hpp"
#include "utilities/globalDefinitions.hpp"

class MetadataFactory : AllStatic {
 public:
  template <typename T>
  static Array<T>* new_array(ClassLoaderData* loader_data, int length, TRAPS) {
    // The "true" argument is because all metadata arrays are read only when
    // dumped to the shared archive
    return new (loader_data, length, /*read_only*/true, THREAD) Array<T>(length);
  }

  template <typename T>
  static Array<T>* new_array(ClassLoaderData* loader_data, int length, T value, TRAPS) {
    Array<T>* array = new_array<T>(loader_data, length, CHECK_NULL);
    for (int i = 0; i < length; i++) {
      array->at_put(i, value);
    }
    return array;
  }

  template <typename T>
  static Array<T>* new_writeable_array(ClassLoaderData* loader_data, int length, TRAPS) {
    return new (loader_data, length, /*read_only*/false, THREAD) Array<T>(length);
  }

  template <typename T>
  static Array<T>* new_writeable_array(ClassLoaderData* loader_data, int length, T value, TRAPS) {
    Array<T>* array = new_writeable_array<T>(loader_data, length, CHECK_NULL);
    for (int i = 0; i < length; i++) {
      array->at_put(i, value);
    }
    return array;
  }

  template <typename T>
  static void free_array(ClassLoaderData* loader_data, Array<T>* data) {
    if (data != NULL) {
      assert(loader_data != NULL, "shouldn't pass null");
      assert(!data->is_shared(), "cannot deallocate array in shared spaces");
      int size = data->size();
      if (DumpSharedSpaces) {
        loader_data->ro_metaspace()->deallocate((MetaWord*)data, size, false);
      } else {
        loader_data->metaspace_non_null()->deallocate((MetaWord*)data, size, false);
      }
    }
  }

  // Deallocation method for metadata
  template <class T>
  static void free_metadata(ClassLoaderData* loader_data, T md) {
    if (DumpSharedSpaces) {
      // FIXME: the freeing code is buggy, especially when PrintSharedSpaces is enabled.
      // Disable for now -- this means if you specify bad classes in your classlist you
      // may have wasted space inside the archive.
      return;
    }
    if (md != NULL) {
      assert(loader_data != NULL, "shouldn't pass null");
      int size = md->size();
      // Call metadata's deallocate function which will call deallocate fields
      assert(!DumpSharedSpaces, "cannot deallocate metadata when dumping CDS archive");
      assert(!md->on_stack(), "can't deallocate things on stack");
      assert(!md->is_shared(), "cannot deallocate if in shared spaces");
      md->deallocate_contents(loader_data);
      loader_data->metaspace_non_null()->deallocate((MetaWord*)md, size, md->is_klass());
    }
  }
};

#endif // SHARE_VM_MEMORY_METADATAFACTORY_HPP