1 /*
   2  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
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  23  */
  24 
  25 #ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_AGETABLE_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_AGETABLE_HPP
  27 
  28 #include "oops/markOop.hpp"
  29 #include "oops/oop.hpp"
  30 #include "runtime/perfData.hpp"
  31 
  32 /* Copyright (c) 1992-2009 Oracle and/or its affiliates, and Stanford University.
  33    See the LICENSE file for license information. */
  34 
  35 // Age table for adaptive feedback-mediated tenuring (scavenging)
  36 //
  37 // Note: all sizes are in oops
  38 
  39 class ageTable VALUE_OBJ_CLASS_SPEC {
  40   friend class VMStructs;
  41 
  42  public:
  43   // constants
  44   enum { table_size = markOopDesc::max_age + 1 };
  45 
  46   // instance variables
  47   size_t sizes[table_size];
  48 
  49   // constructor.  "global" indicates that this is the global age table
  50   // (as opposed to gc-thread-local)
  51   ageTable(bool global = true);
  52 
  53   // clear table
  54   void clear();
  55 
  56   // add entry
  57   void add(oop p, size_t oop_size) {
  58     add(p->age(), oop_size);
  59   }
  60 
  61   void add(uint age, size_t oop_size) {
  62     assert(age > 0 && age < table_size, "invalid age of object");
  63     sizes[age] += oop_size;
  64   }
  65 
  66   // Merge another age table with the current one.  Used
  67   // for parallel young generation gc.
  68   void merge(ageTable* subTable);
  69   void merge_par(ageTable* subTable);
  70 
  71   // calculate new tenuring threshold based on age information
  72   uint compute_tenuring_threshold(size_t survivor_capacity);
  73 
  74  private:
  75   PerfVariable* _perf_sizes[table_size];
  76 };
  77 
  78 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_AGETABLE_HPP