hotspot/src/share/vm/memory/referencePolicy.cpp
author acorn
Thu, 05 Mar 2009 22:07:29 -0500
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child 5547 f4b087cbb361
permissions -rw-r--r--
Merge
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/*
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 * Copyright 2000-2008 Sun Microsystems, Inc.  All Rights Reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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 * CA 95054 USA or visit www.sun.com if you need additional information or
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 * have any questions.
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 *
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 */
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# include "incls/_precompiled.incl"
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# include "incls/_referencePolicy.cpp.incl"
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LRUCurrentHeapPolicy::LRUCurrentHeapPolicy() {
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  setup();
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}
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// Capture state (of-the-VM) information needed to evaluate the policy
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void LRUCurrentHeapPolicy::setup() {
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  _max_interval = (Universe::get_heap_free_at_last_gc() / M) * SoftRefLRUPolicyMSPerMB;
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  assert(_max_interval >= 0,"Sanity check");
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}
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// The oop passed in is the SoftReference object, and not
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// the object the SoftReference points to.
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bool LRUCurrentHeapPolicy::should_clear_reference(oop p) {
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  jlong interval = java_lang_ref_SoftReference::clock() - java_lang_ref_SoftReference::timestamp(p);
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  assert(interval >= 0, "Sanity check");
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  // The interval will be zero if the ref was accessed since the last scavenge/gc.
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  if(interval <= _max_interval) {
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    return false;
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  }
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  return true;
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}
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/////////////////////// MaxHeap //////////////////////
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LRUMaxHeapPolicy::LRUMaxHeapPolicy() {
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  setup();
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}
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// Capture state (of-the-VM) information needed to evaluate the policy
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void LRUMaxHeapPolicy::setup() {
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  size_t max_heap = MaxHeapSize;
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  max_heap -= Universe::get_heap_used_at_last_gc();
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  max_heap /= M;
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  _max_interval = max_heap * SoftRefLRUPolicyMSPerMB;
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  assert(_max_interval >= 0,"Sanity check");
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}
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// The oop passed in is the SoftReference object, and not
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// the object the SoftReference points to.
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bool LRUMaxHeapPolicy::should_clear_reference(oop p) {
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  jlong interval = java_lang_ref_SoftReference::clock() - java_lang_ref_SoftReference::timestamp(p);
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  assert(interval >= 0, "Sanity check");
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  // The interval will be zero if the ref was accessed since the last scavenge/gc.
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  if(interval <= _max_interval) {
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    return false;
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  }
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  return true;
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}