1 /*
2 * Copyright (c) 2022, 2023, 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.
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23 */
24
25 #ifndef SHARE_GC_G1_G1FULLGCPREPARETASK_INLINE_HPP
26 #define SHARE_GC_G1_G1FULLGCPREPARETASK_INLINE_HPP
27
28 #include "gc/g1/g1FullGCPrepareTask.hpp"
29
30 #include "gc/g1/g1CollectedHeap.inline.hpp"
31 #include "gc/g1/g1FullCollector.hpp"
32 #include "gc/g1/g1FullGCCompactionPoint.hpp"
33 #include "gc/g1/g1FullGCScope.hpp"
34 #include "gc/g1/g1HeapRegion.inline.hpp"
35
36 void G1DetermineCompactionQueueClosure::free_empty_humongous_region(HeapRegion* hr) {
37 _g1h->free_humongous_region(hr, nullptr);
38 _collector->set_free(hr->hrm_index());
39 add_to_compaction_queue(hr);
40 }
41
42 inline bool G1DetermineCompactionQueueClosure::should_compact(HeapRegion* hr) const {
43 // There is no need to iterate and forward objects in non-movable regions ie.
44 // prepare them for compaction.
45 if (hr->is_humongous() || hr->has_pinned_objects()) {
46 return false;
47 }
48 size_t live_words = _collector->live_words(hr->hrm_index());
49 size_t live_words_threshold = _collector->scope()->region_compaction_threshold();
50 // High live ratio region will not be compacted.
51 return live_words <= live_words_threshold;
52 }
53
54 inline uint G1DetermineCompactionQueueClosure::next_worker() {
55 uint result = _cur_worker;
56 _cur_worker = (_cur_worker + 1) % _collector->workers();
57 return result;
58 }
59
60 inline G1FullGCCompactionPoint* G1DetermineCompactionQueueClosure::next_compaction_point() {
61 return _collector->compaction_point(next_worker());
62 }
63
64 inline void G1DetermineCompactionQueueClosure::add_to_compaction_queue(HeapRegion* hr) {
65 _collector->set_compaction_top(hr, hr->bottom());
66 _collector->set_has_compaction_targets();
67
68 G1FullGCCompactionPoint* cp = next_compaction_point();
69 if (!cp->is_initialized()) {
70 cp->initialize(hr);
71 }
72 // Add region to the compaction queue.
73 cp->add(hr);
74 }
75
76 static bool has_pinned_objects(HeapRegion* hr) {
77 return hr->has_pinned_objects() ||
78 (hr->is_humongous() && hr->humongous_start_region()->has_pinned_objects());
79 }
80
81 inline bool G1DetermineCompactionQueueClosure::do_heap_region(HeapRegion* hr) {
82 if (should_compact(hr)) {
83 assert(!hr->is_humongous(), "moving humongous objects not supported.");
84 add_to_compaction_queue(hr);
85 return false;
86 }
87
88 assert(hr->containing_set() == nullptr, "already cleared by PrepareRegionsClosure");
89 if (has_pinned_objects(hr)) {
90 // First check regions with pinned objects: they need to be skipped regardless
91 // of region type and never be considered for reclamation.
92 assert(_collector->is_skip_compacting(hr->hrm_index()), "pinned region %u must be skip_compacting", hr->hrm_index());
93 log_trace(gc, phases)("Phase 2: skip compaction region index: %u (%s), has pinned objects",
94 hr->hrm_index(), hr->get_short_type_str());
95 } else if (hr->is_humongous()) {
96 oop obj = cast_to_oop(hr->humongous_start_region()->bottom());
97 bool is_empty = !_collector->mark_bitmap()->is_marked(obj);
98 if (is_empty) {
99 free_empty_humongous_region(hr);
100 } else {
101 _collector->set_has_humongous();
102 }
103 } else {
104 assert(MarkSweepDeadRatio > 0,
105 "only skip compaction for other regions when MarkSweepDeadRatio > 0");
106
107 // Too many live objects in the region; skip compacting it.
108 _collector->update_from_compacting_to_skip_compacting(hr->hrm_index());
109 log_trace(gc, phases)("Phase 2: skip compaction region index: %u, live words: " SIZE_FORMAT,
110 hr->hrm_index(), _collector->live_words(hr->hrm_index()));
111 }
112
113 return false;
114 }
115
116 inline size_t G1SerialRePrepareClosure::apply(oop obj) {
117 if (obj->is_forwarded()) {
118 // We skip objects compiled into the first region or
119 // into regions not part of the serial compaction point.
120 if (cast_from_oop<HeapWord*>(obj->forwardee()) < _dense_prefix_top) {
121 return obj->size();
122 }
123 }
124
125 // Get size and forward.
126 size_t size = obj->size();
127 _cp->forward(obj, size);
128
129 return size;
130 }
131
132 #endif // SHARE_GC_G1_G1FULLGCPREPARETASK_INLINE_HPP