view src/share/vm/runtime/monitorChunk.hpp @ 1145:e018e6884bd8

6631166: CMS: better heuristics when combatting fragmentation Summary: Autonomic per-worker free block cache sizing, tunable coalition policies, fixes to per-size block statistics, retuned gain and bandwidth of some feedback loop filters to allow quicker reactivity to abrupt changes in ambient demand, and other heuristics to reduce fragmentation of the CMS old gen. Also tightened some assertions, including those related to locking. Reviewed-by: jmasa
author ysr
date Wed, 23 Dec 2009 09:23:54 -0800
parents a61af66fc99e
children c18cbe5936b8
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/*
 * Copyright 1997-2000 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.
 *
 */

// Data structure for holding monitors for one activation during
// deoptimization.

class MonitorChunk: public CHeapObj {
 private:
  int              _number_of_monitors;
  BasicObjectLock* _monitors;
  BasicObjectLock* monitors() const { return _monitors; }
  MonitorChunk*    _next;
 public:
  // Constructor
  MonitorChunk(int number_on_monitors);
  ~MonitorChunk();

  // link operations
  MonitorChunk* next() const                { return _next; }
  void set_next(MonitorChunk* next)         { _next = next; }

  // Tells whether the monitor chunk is linked into the JavaThread
  bool is_linked() const                    { return next() != NULL; }

  // Returns the number of monitors
  int number_of_monitors() const { return _number_of_monitors; }

  // Returns the index'th monitor
  BasicObjectLock* at(int index)            { assert(index >= 0 && index < number_of_monitors(), "out of bounds check"); return &monitors()[index]; }


  // Memory management
  void oops_do(OopClosure* f);

  // Tells whether the addr point into the monitors.
  bool contains(void* addr) const           { return (addr >= (void*) monitors()) && (addr <  (void*) (monitors() + number_of_monitors())); }
};