view src/share/vm/prims/jvmtiRawMonitor.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 8b46b0196eb0
children
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/*
 * Copyright (c) 1999, 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_PRIMS_JVMTIRAWMONITOR_HPP
#define SHARE_VM_PRIMS_JVMTIRAWMONITOR_HPP

#include "runtime/objectMonitor.hpp"
#include "utilities/growableArray.hpp"

//
// class JvmtiRawMonitor
//
// Used by JVMTI methods: All RawMonitor methods (CreateRawMonitor, EnterRawMonitor, etc.)
//
// Wrapper for ObjectMonitor class that saves the Monitor's name
//

class JvmtiRawMonitor : public ObjectMonitor  {
private:
  int           _magic;
  char *        _name;
  // JVMTI_RM_MAGIC is set in contructor and unset in destructor.
  enum { JVMTI_RM_MAGIC = (int)(('T' << 24) | ('I' << 16) | ('R' << 8) | 'M') };

  int       SimpleEnter (Thread * Self) ;
  int       SimpleExit  (Thread * Self) ;
  int       SimpleWait  (Thread * Self, jlong millis) ;
  int       SimpleNotify (Thread * Self, bool All) ;

public:
  JvmtiRawMonitor(const char *name);
  ~JvmtiRawMonitor();
  int       raw_enter(TRAPS);
  int       raw_exit(TRAPS);
  int       raw_wait(jlong millis, bool interruptable, TRAPS);
  int       raw_notify(TRAPS);
  int       raw_notifyAll(TRAPS);
  int            magic()   { return _magic;  }
  const char *get_name()   { return _name; }
  bool        is_valid();
};

// Onload pending raw monitors
// Class is used to cache onload or onstart monitor enter
// which will transition into real monitor when
// VM is fully initialized.
class JvmtiPendingMonitors : public AllStatic {

private:
  static GrowableArray<JvmtiRawMonitor*> *_monitors; // Cache raw monitor enter

  inline static GrowableArray<JvmtiRawMonitor*>* monitors() { return _monitors; }

  static void dispose() {
    delete monitors();
  }

public:
  static void enter(JvmtiRawMonitor *monitor) {
    monitors()->append(monitor);
  }

  static int count() {
    return monitors()->length();
  }

  static void destroy(JvmtiRawMonitor *monitor) {
    while (monitors()->contains(monitor)) {
      monitors()->remove(monitor);
    }
  }

  // Return false if monitor is not found in the list.
  static bool exit(JvmtiRawMonitor *monitor) {
    if (monitors()->contains(monitor)) {
      monitors()->remove(monitor);
      return true;
    } else {
      return false;
    }
  }

  static void transition_raw_monitors();
};

#endif // SHARE_VM_PRIMS_JVMTIRAWMONITOR_HPP