1/*
2 * Copyright (c) 1997, 2019, 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_GC_SHARED_AGETABLE_HPP
26#define SHARE_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, 2019, 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
39class AgeTable {
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_GC_SHARED_AGETABLE_HPP
78