jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/shared/ageTable.hpp@595c0f60d50d

8029075: String deduplication in G1
Summary: Implementation of JEP 192, http://openjdk.java.net/jeps/192
Reviewed-by: brutisso, tschatzl, coleenp

     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  */

    25 #ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_AGETABLE_HPP

    26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_AGETABLE_HPP

    28 #include "oops/markOop.hpp"

    29 #include "oops/oop.hpp"

    30 #include "runtime/perfData.hpp"

    32 /* Copyright (c) 1992-2009 Oracle and/or its affiliates, and Stanford University.

    33    See the LICENSE file for license information. */

    35 // Age table for adaptive feedback-mediated tenuring (scavenging)

    36 //

    37 // Note: all sizes are in oops

    39 class ageTable VALUE_OBJ_CLASS_SPEC {

    40   friend class VMStructs;

    42  public:

    43   // constants

    44   enum { table_size = markOopDesc::max_age + 1 };

    46   // instance variables

    47   size_t sizes[table_size];

    49   // constructor.  "global" indicates that this is the global age table

    50   // (as opposed to gc-thread-local)

    51   ageTable(bool global = true);

    53   // clear table

    54   void clear();

    56   // add entry

    57   void add(oop p, size_t oop_size) {

    58     uint age = p->age();

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

    60     sizes[age] += oop_size;

    61   }

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

    64   // for parallel young generation gc.

    65   void merge(ageTable* subTable);

    66   void merge_par(ageTable* subTable);

    68   // calculate new tenuring threshold based on age information

    69   uint compute_tenuring_threshold(size_t survivor_capacity);

    71  private:

    72   PerfVariable* _perf_sizes[table_size];

    73 };

    75 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_AGETABLE_HPP

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