1 /*

     2  * Copyright (c) 1997, 2016, 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

    21  * questions.

    22  *

    23  */

    24 

    25 #ifndef SHARE_VM_GC_SHARED_AGETABLE_HPP

    26 #define SHARE_VM_GC_SHARED_AGETABLE_HPP

    27 

    28 #include "oops/markOop.hpp"

    29 #include "oops/oop.hpp"

    30 #include "runtime/perfData.hpp"

    31 

    32 /* Copyright (c) 1992, 2016, 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   inline void add(oop p, size_t oop_size);

    58 

    59   void add(uint age, size_t oop_size) {

    60     assert(age > 0 && age < table_size, "invalid age of object");

    61     sizes[age] += oop_size;

    62   }

    63 

    64   // Merge another age table with the current one.  Used

    65   // for parallel young generation gc.

    66   void merge(AgeTable* subTable);

    67 

    68   // Calculate new tenuring threshold based on age information.

    69   uint compute_tenuring_threshold(size_t desired_survivor_size);

    70   void print_age_table(uint tenuring_threshold);

    71 

    72  private:

    73 

    74   PerfVariable* _perf_sizes[table_size];

    75 };

    76 

    77 #endif // SHARE_VM_GC_SHARED_AGETABLE_HPP