1 /*
2 * Copyright (c) 2021, 2022, Red Hat, Inc. 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
26 #include "precompiled.hpp"
27
28 #include "gc/shared/strongRootsScope.hpp"
29 #include "gc/shared/taskTerminator.hpp"
30 #include "gc/shared/workerThread.hpp"
31 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
32 #include "gc/shenandoah/shenandoahGenerationType.hpp"
33 #include "gc/shenandoah/shenandoahMark.inline.hpp"
34 #include "gc/shenandoah/shenandoahReferenceProcessor.hpp"
35 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp"
36 #include "gc/shenandoah/shenandoahSTWMark.hpp"
37 #include "gc/shenandoah/shenandoahVerifier.hpp"
38
39 class ShenandoahSTWMarkTask : public WorkerTask {
40 private:
41 ShenandoahSTWMark* const _mark;
42
43 public:
44 ShenandoahSTWMarkTask(ShenandoahSTWMark* mark);
45 void work(uint worker_id);
46 };
47
48 ShenandoahSTWMarkTask::ShenandoahSTWMarkTask(ShenandoahSTWMark* mark) :
49 WorkerTask("Shenandoah STW mark"),
50 _mark(mark) {
51 }
52
53 void ShenandoahSTWMarkTask::work(uint worker_id) {
54 ShenandoahParallelWorkerSession worker_session(worker_id);
55 _mark->mark_roots(worker_id);
56 _mark->finish_mark(worker_id);
57 }
58
59 ShenandoahSTWMark::ShenandoahSTWMark(bool full_gc) :
60 ShenandoahMark(),
61 _root_scanner(full_gc ? ShenandoahPhaseTimings::full_gc_mark : ShenandoahPhaseTimings::degen_gc_stw_mark),
62 _terminator(ShenandoahHeap::heap()->workers()->active_workers(), ShenandoahHeap::heap()->marking_context()->task_queues()),
63 _full_gc(full_gc) {
64 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a Shenandoah safepoint");
65 }
66
67 void ShenandoahSTWMark::mark() {
68 ShenandoahHeap* const heap = ShenandoahHeap::heap();
69
70 // Arm all nmethods. Even though this is STW mark, some marking code
71 // piggybacks on nmethod barriers for special instances.
72 ShenandoahCodeRoots::arm_nmethods_for_mark();
73
74 // Weak reference processing
75 ShenandoahReferenceProcessor* rp = heap->ref_processor();
76 rp->reset_thread_locals();
77 rp->set_soft_reference_policy(heap->soft_ref_policy()->should_clear_all_soft_refs());
78
79 // Init mark, do not expect forwarded pointers in roots
80 if (ShenandoahVerify) {
81 assert(Thread::current()->is_VM_thread(), "Must be");
82 heap->verifier()->verify_roots_no_forwarded();
83 }
84
85 start_mark();
86
87 uint nworkers = heap->workers()->active_workers();
88 task_queues()->reserve(nworkers);
89
90 TASKQUEUE_STATS_ONLY(task_queues()->reset_taskqueue_stats());
91
92 {
93 // Mark
94 StrongRootsScope scope(nworkers);
95 ShenandoahSTWMarkTask task(this);
96 heap->workers()->run_task(&task);
97
98 assert(task_queues()->is_empty(), "Should be empty");
99 }
100
101 heap->mark_complete_marking_context();
102 end_mark();
103
104 // Mark is finished, can disarm the nmethods now.
105 ShenandoahCodeRoots::disarm_nmethods();
106
107 assert(task_queues()->is_empty(), "Should be empty");
108 TASKQUEUE_STATS_ONLY(task_queues()->print_and_reset_taskqueue_stats(""));
109 }
110
111 void ShenandoahSTWMark::mark_roots(uint worker_id) {
112 ShenandoahReferenceProcessor* rp = ShenandoahHeap::heap()->ref_processor();
113 ShenandoahMarkRefsClosure<NON_GEN> cl(task_queues()->queue(worker_id), rp);
114 _root_scanner.roots_do(&cl, worker_id);
115 }
116
117 void ShenandoahSTWMark::finish_mark(uint worker_id) {
118 ShenandoahPhaseTimings::Phase phase = _full_gc ? ShenandoahPhaseTimings::full_gc_mark : ShenandoahPhaseTimings::degen_gc_stw_mark;
119 ShenandoahWorkerTimingsTracker timer(phase, ShenandoahPhaseTimings::ParallelMark, worker_id);
120 ShenandoahReferenceProcessor* rp = ShenandoahHeap::heap()->ref_processor();
121 StringDedup::Requests requests;
122
123 mark_loop(worker_id, &_terminator, rp, NON_GEN, false /* not cancellable */,
124 ShenandoahStringDedup::is_enabled() ? ALWAYS_DEDUP : NO_DEDUP, &requests);
125 }