1 #ifdef USE_PRAGMA_IDENT_SRC
   2 #pragma ident "@(#)referencePolicy.cpp  1.12 07/05/05 17:05:54 JVM"
   3 #endif
   4 /*
   5  * Copyright 2000-2003 Sun Microsystems, Inc.  All Rights Reserved.
   6  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   7  *
   8  * This code is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License version 2 only, as
  10  * published by the Free Software Foundation.
  11  *
  12  * This code is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15  * version 2 for more details (a copy is included in the LICENSE file that
  16  * accompanied this code).
  17  *
  18  * You should have received a copy of the GNU General Public License version
  19  * 2 along with this work; if not, write to the Free Software Foundation,
  20  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  21  *
  22  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  23  * CA 95054 USA or visit www.sun.com if you need additional information or
  24  * have any questions.
  25  *  
  26  */
  27 
  28 # include "incls/_precompiled.incl"
  29 # include "incls/_referencePolicy.cpp.incl"
  30 
  31 LRUCurrentHeapPolicy::LRUCurrentHeapPolicy() {
  32   _max_interval = (Universe::get_heap_free_at_last_gc() / M) * SoftRefLRUPolicyMSPerMB;
  33   assert(_max_interval >= 0,"Sanity check");
  34 }
  35 
  36 // The oop passed in is the SoftReference object, and not
  37 // the object the SoftReference points to.
  38 bool LRUCurrentHeapPolicy::should_clear_reference(oop p) {
  39   jlong interval = java_lang_ref_SoftReference::clock() - java_lang_ref_SoftReference::timestamp(p);
  40   assert(interval >= 0, "Sanity check");
  41 
  42   // The interval will be zero if the ref was accessed since the last scavenge/gc.
  43   if(interval <= _max_interval) {
  44     return false;
  45   }
  46 
  47   return true;
  48 }
  49 
  50 /////////////////////// MaxHeap //////////////////////
  51 
  52 LRUMaxHeapPolicy::LRUMaxHeapPolicy() {
  53   size_t max_heap = MaxHeapSize;
  54   max_heap -= Universe::get_heap_used_at_last_gc();
  55   max_heap /= M;
  56 
  57   _max_interval = max_heap * SoftRefLRUPolicyMSPerMB;
  58   assert(_max_interval >= 0,"Sanity check");
  59 }
  60 
  61 // The oop passed in is the SoftReference object, and not
  62 // the object the SoftReference points to.
  63 bool LRUMaxHeapPolicy::should_clear_reference(oop p) {
  64   jlong interval = java_lang_ref_SoftReference::clock() - java_lang_ref_SoftReference::timestamp(p);
  65   assert(interval >= 0, "Sanity check");
  66 
  67   // The interval will be zero if the ref was accessed since the last scavenge/gc.
  68   if(interval <= _max_interval) {
  69     return false;
  70   }
  71 
  72   return true;
  73 }
  74