1 /*
2 * Copyright (c) 2016, 2020, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHCOLLECTIONSET_HPP
27 #define SHARE_GC_SHENANDOAH_SHENANDOAHCOLLECTIONSET_HPP
28
29 #include "memory/allocation.hpp"
30 #include "memory/virtualspace.hpp"
31 #include "gc/shenandoah/shenandoahHeap.hpp"
32 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
33 #include "gc/shenandoah/shenandoahPadding.hpp"
34
35 class ShenandoahCollectionSet : public CHeapObj<mtGC> {
36 friend class ShenandoahHeap;
37 friend class ShenandoahCollectionSetPreselector;
38
39 void establish_preselected(bool *preselected) {
40 assert(_preselected_regions == nullptr, "Over-writing");
41 _preselected_regions = preselected;
42 }
43 void abandon_preselected() { _preselected_regions = nullptr; }
44
45 private:
46 size_t const _map_size;
47 size_t const _region_size_bytes_shift;
48 ReservedSpace _map_space;
49 char* const _cset_map;
50 // Bias cset map's base address for fast test if an oop is in cset
51 char* const _biased_cset_map;
52
53 ShenandoahHeap* const _heap;
54
55 bool _has_old_regions;
56 size_t _garbage;
57 size_t _used;
58 size_t _live;
59 size_t _region_count;
60
61 size_t _young_bytes_to_evacuate;
62 size_t _young_bytes_to_promote;
63 size_t _old_bytes_to_evacuate;
64
65 // How many bytes of old garbage are present in a mixed collection set?
66 size_t _old_garbage;
67
68 // Points to array identifying which tenure-age regions have been preselected
69 // for inclusion in collection set. This field is only valid during brief
70 // spans of time while collection set is being constructed.
71 bool* _preselected_regions;
72
73 // When a region having memory available to be allocated is added to the collection set, the region's available memory
74 // should be subtracted from what's available.
75 size_t _young_available_bytes_collected;
76
77 shenandoah_padding(0);
78 volatile size_t _current_index;
79 shenandoah_padding(1);
80
81 public:
82 ShenandoahCollectionSet(ShenandoahHeap* heap, ReservedSpace space, char* heap_base);
83
84 // Add region to collection set
85 void add_region(ShenandoahHeapRegion* r);
86
87 // MT version
88 ShenandoahHeapRegion* claim_next();
89
90 // Single-thread version
91 ShenandoahHeapRegion* next();
92
93 size_t count() const { return _region_count; }
94 bool is_empty() const { return _region_count == 0; }
95
96 void clear_current_index() {
97 _current_index = 0;
98 }
99
100 inline bool is_in(ShenandoahHeapRegion* r) const;
101 inline bool is_in(size_t region_idx) const;
102 inline bool is_in(oop obj) const;
103 inline bool is_in_loc(void* loc) const;
104
105 void print_on(outputStream* out) const;
106
107 // It is not known how many of these bytes will be promoted.
108 inline size_t get_young_bytes_reserved_for_evacuation();
109 inline size_t get_old_bytes_reserved_for_evacuation();
110
111 inline size_t get_young_bytes_to_be_promoted();
112
113 size_t get_young_available_bytes_collected() { return _young_available_bytes_collected; }
114
115 inline size_t get_old_garbage();
116
117 bool is_preselected(size_t region_idx) {
118 assert(_preselected_regions != nullptr, "Missing etsablish after abandon");
119 return _preselected_regions[region_idx];
120 }
121
122 bool* preselected_regions() {
123 assert(_preselected_regions != nullptr, "Null ptr");
124 return _preselected_regions;
125 }
126
127 bool has_old_regions() const { return _has_old_regions; }
128 size_t used() const { return _used; }
129 size_t live() const { return _live; }
130 size_t garbage() const { return _garbage; }
131
132 void clear();
133
134 private:
135 char* map_address() const {
136 return _cset_map;
137 }
138 char* biased_map_address() const {
139 return _biased_cset_map;
140 }
141 };
142
143 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHCOLLECTIONSET_HPP