1 /*
2 * Copyright (c) 2016, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp"
26 #include "gc_implementation/shenandoah/shenandoahCollectionSet.inline.hpp"
27 #include "gc_implementation/shenandoah/shenandoahHeap.hpp"
28 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp"
29 #include "gc_implementation/shenandoah/shenandoahHeapRegion.hpp"
30 #include "gc_implementation/shenandoah/shenandoahHeapRegionSet.hpp"
31 #include "runtime/atomic.hpp"
32 #include "utilities/copy.hpp"
33
34 ShenandoahCollectionSet::ShenandoahCollectionSet(ShenandoahHeap* heap, HeapWord* heap_base) :
35 _map_size(heap->num_regions()),
36 _region_size_bytes_shift(ShenandoahHeapRegion::region_size_bytes_shift()),
37 _cset_map(NEW_C_HEAP_ARRAY(jbyte, _map_size, mtGC)),
38 _biased_cset_map(_cset_map - ((uintx)heap_base >> _region_size_bytes_shift)),
39 _heap(heap),
40 _garbage(0),
41 _live_data(0),
42 _used(0),
43 _region_count(0),
44 _current_index(0) {
45 // Use 1-byte data type
46 STATIC_ASSERT(sizeof(jbyte) == 1);
47
48 // Initialize cset map
49 Copy::zero_to_bytes(_cset_map, _map_size);
50 }
51
52 void ShenandoahCollectionSet::add_region(ShenandoahHeapRegion* r) {
53 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint");
54 assert(Thread::current()->is_VM_thread(), "Must be VMThread");
55 assert(!is_in(r), "Already in collection set");
56 _cset_map[r->region_number()] = 1;
57 _region_count ++;
58 _garbage += r->garbage();
59 _live_data += r->get_live_data_bytes();
60 _used += r->used();
61 }
62
63 void ShenandoahCollectionSet::remove_region(ShenandoahHeapRegion* r) {
64 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint");
65 assert(Thread::current()->is_VM_thread(), "Must be VMThread");
66 assert(is_in(r), "Not in collection set");
67 _cset_map[r->region_number()] = 0;
68 _region_count --;
69 }
70
71 void ShenandoahCollectionSet::update_region_status() {
72 for (size_t index = 0; index < _heap->num_regions(); index ++) {
73 ShenandoahHeapRegion* r = _heap->get_region(index);
74 if (is_in(r)) {
75 r->make_cset();
76 } else {
77 assert (!r->is_cset(), "should not be cset");
78 }
79 }
80 }
81
82 void ShenandoahCollectionSet::clear() {
83 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint");
84 Copy::zero_to_bytes(_cset_map, _map_size);
85
86 #ifdef ASSERT
87 for (size_t index = 0; index < _heap->num_regions(); index ++) {
88 assert (!_heap->get_region(index)->is_cset(), "should have been cleared before");
89 }
90 #endif
91
92 _garbage = 0;
93 _live_data = 0;
94 _used = 0;
95
96 _region_count = 0;
97 _current_index = 0;
98 }
99
100 ShenandoahHeapRegion* ShenandoahCollectionSet::claim_next() {
101 size_t num_regions = _heap->num_regions();
102 if (_current_index >= (jint)num_regions) {
103 return NULL;
104 }
105
106 jint saved_current = _current_index;
107 size_t index = (size_t)saved_current;
108
109 while(index < num_regions) {
110 if (is_in(index)) {
111 jint cur = Atomic::cmpxchg((jint)(index + 1), &_current_index, saved_current);
112 assert(cur >= (jint)saved_current, "Must move forward");
113 if (cur == saved_current) {
114 assert(is_in(index), "Invariant");
115 return _heap->get_region(index);
116 } else {
117 index = (size_t)cur;
118 saved_current = cur;
119 }
120 } else {
121 index ++;
122 }
123 }
124 return NULL;
125 }
126
127
128 ShenandoahHeapRegion* ShenandoahCollectionSet::next() {
129 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint");
130 assert(Thread::current()->is_VM_thread(), "Must be VMThread");
131 size_t num_regions = _heap->num_regions();
132 for (size_t index = (size_t)_current_index; index < num_regions; index ++) {
133 if (is_in(index)) {
134 _current_index = (jint)(index + 1);
135 return _heap->get_region(index);
136 }
137 }
138
139 return NULL;
140 }
141
142
143 void ShenandoahCollectionSet::print_on(outputStream* out) const {
144 out->print_cr("Collection Set : " SIZE_FORMAT "", count());
145
146 debug_only(size_t regions = 0;)
147 for (size_t index = 0; index < _heap->num_regions(); index ++) {
148 if (is_in(index)) {
149 _heap->get_region(index)->print_on(out);
150 debug_only(regions ++;)
151 }
152 }
153 assert(regions == count(), "Must match");
154 }