1 /*
2 * Copyright (c) 2017, 2022, 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
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/g1/g1CollectedHeap.inline.hpp"
27 #include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
28 #include "gc/g1/g1FullCollector.inline.hpp"
29 #include "gc/g1/g1FullGCCompactionPoint.hpp"
30 #include "gc/g1/g1FullGCMarker.hpp"
31 #include "gc/g1/g1FullGCOopClosures.inline.hpp"
32 #include "gc/g1/g1FullGCPrepareTask.inline.hpp"
33 #include "gc/g1/g1HotCardCache.hpp"
34 #include "gc/g1/heapRegion.inline.hpp"
35 #include "gc/shared/gcTraceTime.inline.hpp"
36 #include "gc/shared/referenceProcessor.hpp"
37 #include "gc/shared/slidingForwarding.inline.hpp"
38 #include "logging/log.hpp"
39 #include "memory/iterator.inline.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "utilities/ticks.hpp"
42
43 G1DetermineCompactionQueueClosure::G1DetermineCompactionQueueClosure(G1FullCollector* collector) :
44 _g1h(G1CollectedHeap::heap()),
45 _collector(collector),
46 _cur_worker(0) { }
47
48 bool G1FullGCPrepareTask::G1CalculatePointersClosure::do_heap_region(HeapRegion* hr) {
49 uint region_idx = hr->hrm_index();
50 assert(_collector->is_compaction_target(region_idx), "must be");
51
52 assert(!hr->is_pinned(), "must be");
53 assert(!hr->is_closed_archive(), "must be");
54 assert(!hr->is_open_archive(), "must be");
55
56 prepare_for_compaction(hr);
57
58 return false;
59 }
60
61 G1FullGCPrepareTask::G1FullGCPrepareTask(G1FullCollector* collector) :
62 G1FullGCTask("G1 Prepare Compact Task", collector),
63 _has_free_compaction_targets(false),
64 _hrclaimer(collector->workers()) {
65 }
66
67 void G1FullGCPrepareTask::set_has_free_compaction_targets() {
68 if (!_has_free_compaction_targets) {
69 _has_free_compaction_targets = true;
70 }
71 }
72
73 bool G1FullGCPrepareTask::has_free_compaction_targets() {
74 return _has_free_compaction_targets;
75 }
76
77 void G1FullGCPrepareTask::work(uint worker_id) {
78 Ticks start = Ticks::now();
79 // Calculate the target locations for the objects in the non-free regions of
80 // the compaction queues provided by the associate compaction point.
81 {
82 G1FullGCCompactionPoint* compaction_point = collector()->compaction_point(worker_id);
83 G1CalculatePointersClosure closure(collector(), compaction_point);
84
85 for (GrowableArrayIterator<HeapRegion*> it = compaction_point->regions()->begin();
86 it != compaction_point->regions()->end();
87 ++it) {
88 closure.do_heap_region(*it);
89 }
90 compaction_point->update();
91 // Determine if there are any unused compaction targets. This is only the case if
92 // there are
93 // - any regions in queue, so no free ones either.
94 // - and the current region is not the last one in the list.
95 if (compaction_point->has_regions() &&
96 compaction_point->current_region() != compaction_point->regions()->last()) {
97 set_has_free_compaction_targets();
98 }
99 }
100
101 // Clear region metadata that is invalid after GC for all regions.
102 {
103 G1ResetMetadataClosure closure(collector());
104 G1CollectedHeap::heap()->heap_region_par_iterate_from_start(&closure, &_hrclaimer);
105 }
106 log_task("Prepare compaction task", worker_id, start);
107 }
108
109 G1FullGCPrepareTask::G1CalculatePointersClosure::G1CalculatePointersClosure(G1FullCollector* collector,
110 G1FullGCCompactionPoint* cp) :
111 _g1h(G1CollectedHeap::heap()),
112 _collector(collector),
113 _bitmap(collector->mark_bitmap()),
114 _cp(cp) { }
115
116 G1FullGCPrepareTask::G1ResetMetadataClosure::G1ResetMetadataClosure(G1FullCollector* collector) :
117 _g1h(G1CollectedHeap::heap()),
118 _collector(collector) { }
119
120 void G1FullGCPrepareTask::G1ResetMetadataClosure::reset_region_metadata(HeapRegion* hr) {
121 hr->rem_set()->clear();
122 hr->clear_cardtable();
123
124 G1HotCardCache* hcc = _g1h->hot_card_cache();
125 if (hcc->use_cache()) {
126 hcc->reset_card_counts(hr);
127 }
128 }
129
130 bool G1FullGCPrepareTask::G1ResetMetadataClosure::do_heap_region(HeapRegion* hr) {
131 uint const region_idx = hr->hrm_index();
132 if (!_collector->is_compaction_target(region_idx)) {
133 assert(!hr->is_free(), "all free regions should be compaction targets");
134 assert(_collector->is_skip_compacting(region_idx) || hr->is_closed_archive(), "must be");
135 if (hr->needs_scrubbing_during_full_gc()) {
136 scrub_skip_compacting_region(hr, hr->is_young());
137 }
138 }
139
140 // Reset data structures not valid after Full GC.
141 reset_region_metadata(hr);
142
143 return false;
144 }
145
146 G1FullGCPrepareTask::G1PrepareCompactLiveClosure::G1PrepareCompactLiveClosure(G1FullGCCompactionPoint* cp) :
147 _cp(cp), _forwarding(G1CollectedHeap::heap()->forwarding()) { }
148
149 size_t G1FullGCPrepareTask::G1PrepareCompactLiveClosure::apply(oop object) {
150 size_t size = object->size();
151 _cp->forward(_forwarding, object, size);
152 return size;
153 }
154
155 void G1FullGCPrepareTask::G1CalculatePointersClosure::prepare_for_compaction(HeapRegion* hr) {
156 if (!_collector->is_free(hr->hrm_index())) {
157 G1PrepareCompactLiveClosure prepare_compact(_cp);
158 hr->apply_to_marked_objects(_bitmap, &prepare_compact);
159 }
160 }
161
162 void G1FullGCPrepareTask::G1ResetMetadataClosure::scrub_skip_compacting_region(HeapRegion* hr, bool update_bot_for_live) {
163 assert(hr->needs_scrubbing_during_full_gc(), "must be");
164
165 HeapWord* limit = hr->top();
166 HeapWord* current_obj = hr->bottom();
167 G1CMBitMap* bitmap = _collector->mark_bitmap();
168
169 while (current_obj < limit) {
170 if (bitmap->is_marked(current_obj)) {
171 oop current = cast_to_oop(current_obj);
172 size_t size = current->size();
173 if (update_bot_for_live) {
174 hr->update_bot_for_block(current_obj, current_obj + size);
175 }
176 current_obj += size;
177 continue;
178 }
179 // Found dead object, which is potentially unloaded, scrub to next
180 // marked object.
181 HeapWord* scrub_start = current_obj;
182 HeapWord* scrub_end = bitmap->get_next_marked_addr(scrub_start, limit);
183 assert(scrub_start != scrub_end, "must advance");
184 hr->fill_range_with_dead_objects(scrub_start, scrub_end);
185
186 current_obj = scrub_end;
187 }
188 }