1/*
2 * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved.
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/shenandoah/shenandoahHeapRegionSet.inline.hpp"
26#include "gc/shenandoah/shenandoahHeap.inline.hpp"
27#include "gc/shenandoah/shenandoahHeapRegion.hpp"
28#include "gc/shenandoah/shenandoahUtils.hpp"
29#include "runtime/atomic.hpp"
30#include "utilities/copy.hpp"
31
32ShenandoahHeapRegionSetIterator::ShenandoahHeapRegionSetIterator(const ShenandoahHeapRegionSet* const set) :
33 _set(set), _heap(ShenandoahHeap::heap()), _current_index(0) {}
34
35void ShenandoahHeapRegionSetIterator::reset(const ShenandoahHeapRegionSet* const set) {
36 _set = set;
37 _current_index = 0;
38}
39
40ShenandoahHeapRegionSet::ShenandoahHeapRegionSet() :
41 _heap(ShenandoahHeap::heap()),
42 _map_size(_heap->num_regions()),
43 _region_size_bytes_shift(ShenandoahHeapRegion::region_size_bytes_shift()),
44 _set_map(NEW_C_HEAP_ARRAY(jbyte, _map_size, mtGC)),
45 _biased_set_map(_set_map - ((uintx)_heap->base() >> _region_size_bytes_shift)),
46 _region_count(0)
47{
48 // Use 1-byte data type
49 STATIC_ASSERT(sizeof(jbyte) == 1);
50
51 // Initialize cset map
52 Copy::zero_to_bytes(_set_map, _map_size);
53}
54
55ShenandoahHeapRegionSet::~ShenandoahHeapRegionSet() {
56 FREE_C_HEAP_ARRAY(jbyte, _set_map);
57}
58
59void ShenandoahHeapRegionSet::add_region(ShenandoahHeapRegion* r) {
60 assert(!is_in(r), "Already in collection set");
61 _set_map[r->region_number()] = 1;
62 _region_count++;
63}
64
65bool ShenandoahHeapRegionSet::add_region_check_for_duplicates(ShenandoahHeapRegion* r) {
66 if (!is_in(r)) {
67 add_region(r);
68 return true;
69 } else {
70 return false;
71 }
72}
73
74void ShenandoahHeapRegionSet::remove_region(ShenandoahHeapRegion* r) {
75 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint");
76 assert(Thread::current()->is_VM_thread(), "Must be VMThread");
77 assert(is_in(r), "Not in region set");
78 _set_map[r->region_number()] = 0;
79 _region_count --;
80}
81
82void ShenandoahHeapRegionSet::clear() {
83 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint");
84 Copy::zero_to_bytes(_set_map, _map_size);
85
86 _region_count = 0;
87}
88
89ShenandoahHeapRegion* ShenandoahHeapRegionSetIterator::claim_next() {
90 size_t num_regions = _heap->num_regions();
91 if (_current_index >= (jint)num_regions) {
92 return NULL;
93 }
94
95 jint saved_current = _current_index;
96 size_t index = (size_t)saved_current;
97
98 while(index < num_regions) {
99 if (_set->is_in(index)) {
100 jint cur = Atomic::cmpxchg((jint)(index + 1), &_current_index, saved_current);
101 assert(cur >= (jint)saved_current, "Must move forward");
102 if (cur == saved_current) {
103 assert(_set->is_in(index), "Invariant");
104 return _heap->get_region(index);
105 } else {
106 index = (size_t)cur;
107 saved_current = cur;
108 }
109 } else {
110 index ++;
111 }
112 }
113 return NULL;
114}
115
116ShenandoahHeapRegion* ShenandoahHeapRegionSetIterator::next() {
117 size_t num_regions = _heap->num_regions();
118 for (size_t index = (size_t)_current_index; index < num_regions; index ++) {
119 if (_set->is_in(index)) {
120 _current_index = (jint)(index + 1);
121 return _heap->get_region(index);
122 }
123 }
124
125 return NULL;
126}
127
128void ShenandoahHeapRegionSet::print_on(outputStream* out) const {
129 out->print_cr("Region Set : " SIZE_FORMAT "", count());
130
131 debug_only(size_t regions = 0;)
132 for (size_t index = 0; index < _heap->num_regions(); index ++) {
133 if (is_in(index)) {
134 _heap->get_region(index)->print_on(out);
135 debug_only(regions ++;)
136 }
137 }
138 assert(regions == count(), "Must match");
139}
140