view src/share/vm/memory/metaspaceShared.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 b23a19cd0536
children 03e6d34be1f5
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/*
 * Copyright (c) 2012, 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_METASPACE_SHARED_HPP
#define SHARE_VM_MEMORY_METASPACE_SHARED_HPP

#include "memory/allocation.hpp"
#include "memory/memRegion.hpp"
#include "runtime/virtualspace.hpp"
#include "utilities/exceptions.hpp"
#include "utilities/macros.hpp"

#define LargeSharedArchiveSize    (300*M)
#define HugeSharedArchiveSize     (800*M)
#define ReadOnlyRegionPercentage  0.4
#define ReadWriteRegionPercentage 0.55
#define MiscDataRegionPercentage  0.03
#define MiscCodeRegionPercentage  0.02
#define LargeThresholdClassCount  5000
#define HugeThresholdClassCount   40000

#define SET_ESTIMATED_SIZE(type, region)                              \
  Shared ##region## Size  = FLAG_IS_DEFAULT(Shared ##region## Size) ? \
    (uintx)(type ## SharedArchiveSize *  region ## RegionPercentage) : Shared ## region ## Size

class FileMapInfo;

// Class Data Sharing Support
class MetaspaceShared : AllStatic {

  // CDS support
  static ReservedSpace* _shared_rs;
  static int _max_alignment;
  static bool _link_classes_made_progress;
  static bool _check_classes_made_progress;
  static bool _has_error_classes;
  static bool _archive_loading_failed;
 public:
  enum {
    vtbl_list_size = 17, // number of entries in the shared space vtable list.
    num_virtuals = 200   // maximum number of virtual functions
                         // If virtual functions are added to Metadata,
                         // this number needs to be increased.  Also,
                         // SharedMiscCodeSize will need to be increased.
  };

  enum {
    ro = 0,  // read-only shared space in the heap
    rw = 1,  // read-write shared space in the heap
    md = 2,  // miscellaneous data for initializing tables, etc.
    mc = 3,  // miscellaneous code - vtable replacement.
    n_regions = 4
  };

  // Accessor functions to save shared space created for metadata, which has
  // extra space allocated at the end for miscellaneous data and code.
  static void set_max_alignment(int alignment) {
    CDS_ONLY(_max_alignment = alignment);
  }

  static int max_alignment() {
    CDS_ONLY(return _max_alignment);
    NOT_CDS(return 0);
  }

  static void prepare_for_dumping() NOT_CDS_RETURN;
  static void preload_and_dump(TRAPS) NOT_CDS_RETURN;
  static int preload_and_dump(const char * class_list_path,
                              GrowableArray<Klass*>* class_promote_order,
                              TRAPS) NOT_CDS_RETURN;

  static ReservedSpace* shared_rs() {
    CDS_ONLY(return _shared_rs);
    NOT_CDS(return NULL);
  }

  static void set_shared_rs(ReservedSpace* rs) {
    CDS_ONLY(_shared_rs = rs;)
  }

  static void set_archive_loading_failed() {
    _archive_loading_failed = true;
  }
  static bool map_shared_spaces(FileMapInfo* mapinfo) NOT_CDS_RETURN_(false);
  static void initialize_shared_spaces() NOT_CDS_RETURN;

  // Return true if given address is in the mapped shared space.
  static bool is_in_shared_space(const void* p) NOT_CDS_RETURN_(false);

  static void generate_vtable_methods(void** vtbl_list,
                                      void** vtable,
                                      char** md_top, char* md_end,
                                      char** mc_top, char* mc_end);
  static void serialize(SerializeClosure* sc);

  // JVM/TI RedefineClasses() support:
  // Remap the shared readonly space to shared readwrite, private if
  // sharing is enabled. Simply returns true if sharing is not enabled
  // or if the remapping has already been done by a prior call.
  static bool remap_shared_readonly_as_readwrite() NOT_CDS_RETURN_(true);

  static void print_shared_spaces();

  static bool try_link_class(InstanceKlass* ik, TRAPS);
  static void link_one_shared_class(Klass* obj, TRAPS);
  static void check_one_shared_class(Klass* obj);
  static void link_and_cleanup_shared_classes(TRAPS);

  static int count_class(const char* classlist_file);
  static void estimate_regions_size() NOT_CDS_RETURN;
};
#endif // SHARE_VM_MEMORY_METASPACE_SHARED_HPP