1 /*
2 * Copyright (c) 2017, 2021, 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 "classfile/classLoaderDataGraph.hpp"
27 #include "gc/g1/g1CollectedHeap.hpp"
28 #include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
29 #include "gc/g1/g1FullCollector.inline.hpp"
30 #include "gc/g1/g1FullGCAdjustTask.hpp"
31 #include "gc/g1/g1FullGCCompactionPoint.hpp"
32 #include "gc/g1/g1FullGCMarker.hpp"
33 #include "gc/g1/g1FullGCOopClosures.inline.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/weakProcessor.inline.hpp"
38 #include "logging/log.hpp"
39 #include "memory/iterator.inline.hpp"
40 #include "runtime/atomic.hpp"
41
42 template <bool ALT_FWD>
43 class G1AdjustLiveClosure : public StackObj {
44 G1AdjustClosure<ALT_FWD>* _adjust_closure;
45 public:
46 G1AdjustLiveClosure(G1AdjustClosure<ALT_FWD>* cl) :
47 _adjust_closure(cl) { }
48
49 size_t apply(oop object) {
50 return object->oop_iterate_size(_adjust_closure);
51 }
52 };
53
54 class G1AdjustRegionClosure : public HeapRegionClosure {
55 G1FullCollector* _collector;
56 G1CMBitMap* _bitmap;
57 uint _worker_id;
58 public:
59 G1AdjustRegionClosure(G1FullCollector* collector, uint worker_id) :
60 _collector(collector),
61 _bitmap(collector->mark_bitmap()),
62 _worker_id(worker_id) { }
63
64 bool do_heap_region(HeapRegion* r) {
65 if (UseAltGCForwarding) {
66 return do_heap_region_impl<true>(r);
67 } else {
68 return do_heap_region_impl<false>(r);
69 }
70 }
71
72 private:
73 template <bool ALT_FWD>
74 bool do_heap_region_impl(HeapRegion* r) {
75 G1AdjustClosure<ALT_FWD> cl(_collector);
76 if (r->is_humongous()) {
77 // Special handling for humongous regions to get somewhat better
78 // work distribution.
79 oop obj = cast_to_oop(r->humongous_start_region()->bottom());
80 obj->oop_iterate(&cl, MemRegion(r->bottom(), r->top()));
81 } else if (!r->is_closed_archive() && !r->is_free()) {
82 // Closed archive regions never change references and only contain
83 // references into other closed regions and are always live. Free
84 // regions do not contain objects to iterate. So skip both.
85 G1AdjustLiveClosure<ALT_FWD> adjust(&cl);
86 r->apply_to_marked_objects(_bitmap, &adjust);
87 }
88 return false;
89 }
90 };
91
92 G1FullGCAdjustTask::G1FullGCAdjustTask(G1FullCollector* collector) :
93 G1FullGCTask("G1 Adjust", collector),
94 _root_processor(G1CollectedHeap::heap(), collector->workers()),
95 _references_done(false),
96 _weak_proc_task(collector->workers()),
97 _hrclaimer(collector->workers()) {
98 // Need cleared claim bits for the roots processing
99 ClassLoaderDataGraph::clear_claimed_marks();
100 }
101
102 template <bool ALT_FWD>
103 void G1FullGCAdjustTask::work_impl(uint worker_id) {
104 Ticks start = Ticks::now();
105 ResourceMark rm;
106
107 // Adjust preserved marks first since they are not balanced.
108 G1FullGCMarker* marker = collector()->marker(worker_id);
109 marker->preserved_stack()->adjust_during_full_gc();
110
111 G1AdjustClosure<ALT_FWD> adjust(collector());
112 // Adjust the weak roots.
113 if (!Atomic::cmpxchg(&_references_done, false, true)) {
114 G1CollectedHeap::heap()->ref_processor_stw()->weak_oops_do(&adjust);
115 }
116
117 AlwaysTrueClosure always_alive;
118 _weak_proc_task.work(worker_id, &always_alive, &adjust);
119
120 CLDToOopClosure adjust_cld(&adjust, ClassLoaderData::_claim_strong);
121 CodeBlobToOopClosure adjust_code(&adjust, CodeBlobToOopClosure::FixRelocations);
122 _root_processor.process_all_roots(&adjust, &adjust_cld, &adjust_code);
123
124 // Now adjust pointers region by region
125 G1AdjustRegionClosure blk(collector(), worker_id);
126 G1CollectedHeap::heap()->heap_region_par_iterate_from_worker_offset(&blk, &_hrclaimer, worker_id);
127 log_task("Adjust task", worker_id, start);
128 }
129
130 void G1FullGCAdjustTask::work(uint worker_id) {
131 if (UseAltGCForwarding) {
132 work_impl<true>(worker_id);
133 } else {
134 work_impl<false>(worker_id);
135 }
136 }