1 /*
2 * Copyright (c) 2024, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2017, 2022, Red Hat, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "code/codeCache.hpp"
27 #include "code/nmethod.hpp"
28 #include "gc/shared/classUnloadingContext.hpp"
29 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
30 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
31 #include "gc/shenandoah/shenandoahNMethod.inline.hpp"
32 #include "gc/shenandoah/shenandoahUtils.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "memory/universe.hpp"
35 #include "runtime/atomicAccess.hpp"
36 #include "utilities/powerOfTwo.hpp"
37
38
39 ShenandoahNMethodTable* ShenandoahCodeRoots::_nmethod_table;
40 int ShenandoahCodeRoots::_disarmed_value = 1;
41
42 void ShenandoahCodeRoots::initialize() {
43 _nmethod_table = new ShenandoahNMethodTable();
44 }
45
46 void ShenandoahCodeRoots::register_nmethod(nmethod* nm) {
47 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
48 _nmethod_table->register_nmethod(nm);
49 }
50
51 void ShenandoahCodeRoots::unregister_nmethod(nmethod* nm) {
52 assert_locked_or_safepoint(CodeCache_lock);
53 _nmethod_table->unregister_nmethod(nm);
54 }
55
56 void ShenandoahCodeRoots::arm_nmethods() {
57 BarrierSet::barrier_set()->barrier_set_nmethod()->arm_all_nmethods();
58 }
59
60 class ShenandoahDisarmNMethodClosure : public NMethodClosure {
61 public:
62 virtual void do_nmethod(nmethod* nm) {
63 ShenandoahNMethod::disarm_nmethod(nm);
64 }
65 };
66
67 class ShenandoahDisarmNMethodsTask : public WorkerTask {
68 private:
69 ShenandoahDisarmNMethodClosure _cl;
70 ShenandoahConcurrentNMethodIterator _iterator;
71
72 public:
73 ShenandoahDisarmNMethodsTask() :
74 WorkerTask("Shenandoah Disarm NMethods"),
75 _iterator(ShenandoahCodeRoots::table()) {
76 assert(SafepointSynchronize::is_at_safepoint(), "Only at a safepoint");
77 }
78
79 virtual void work(uint worker_id) {
80 ShenandoahParallelWorkerSession worker_session(worker_id);
81 _iterator.nmethods_do(&_cl);
82 }
83 };
84
85 void ShenandoahCodeRoots::disarm_nmethods() {
86 ShenandoahDisarmNMethodsTask task;
87 ShenandoahHeap::heap()->workers()->run_task(&task);
88 }
89
90 class ShenandoahNMethodUnlinkClosure : public NMethodClosure {
91 private:
92 bool _unloading_occurred;
93 ShenandoahHeap* const _heap;
94 BarrierSetNMethod* const _bs;
95
96 public:
97 ShenandoahNMethodUnlinkClosure(bool unloading_occurred) :
98 _unloading_occurred(unloading_occurred),
99 _heap(ShenandoahHeap::heap()),
100 _bs(ShenandoahBarrierSet::barrier_set()->barrier_set_nmethod()) {}
101
102 virtual void do_nmethod(nmethod* nm) {
103 assert(_heap->is_concurrent_weak_root_in_progress(), "Only this phase");
104
105 ShenandoahNMethod* nm_data = ShenandoahNMethod::gc_data(nm);
106 assert(!nm_data->is_unregistered(), "Should not see unregistered entry");
107
108 if (nm->is_unloading()) {
109 ShenandoahNMethodLocker locker(nm_data->lock());
110 nm->unlink();
111 return;
112 }
113
114 {
115 ShenandoahNMethodLocker locker(nm_data->lock());
116
117 // Heal oops
118 if (_bs->is_armed(nm)) {
119 ShenandoahNMethod::heal_nmethod_metadata(nm_data);
120 // Must remain armed to complete remaining work in nmethod entry barrier
121 assert(_bs->is_armed(nm), "Should remain armed");
122 }
123 }
124
125 // Clear compiled ICs and exception caches
126 ShenandoahNMethodLocker locker(nm_data->ic_lock());
127 nm->unload_nmethod_caches(_unloading_occurred);
128 }
129 };
130
131 class ShenandoahUnlinkTask : public WorkerTask {
132 private:
133 ShenandoahNMethodUnlinkClosure _cl;
134 ShenandoahConcurrentNMethodIterator _iterator;
135
136 public:
137 ShenandoahUnlinkTask(bool unloading_occurred) :
138 WorkerTask("Shenandoah Unlink NMethods"),
139 _cl(unloading_occurred),
140 _iterator(ShenandoahCodeRoots::table()) {}
141
142 virtual void work(uint worker_id) {
143 _iterator.nmethods_do(&_cl);
144 }
145 };
146
147 void ShenandoahCodeRoots::unlink(WorkerThreads* workers, bool unloading_occurred) {
148 assert(ShenandoahHeap::heap()->unload_classes(), "Only when running concurrent class unloading");
149
150 ShenandoahUnlinkTask task(unloading_occurred);
151 workers->run_task(&task);
152 }
153
154 void ShenandoahCodeRoots::purge() {
155 assert(ShenandoahHeap::heap()->unload_classes(), "Only when running concurrent class unloading");
156
157 ClassUnloadingContext::context()->purge_and_free_nmethods();
158 }
159
160 ShenandoahCodeRootsIterator::ShenandoahCodeRootsIterator() :
161 _table_snapshot(nullptr) {
162 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
163 MutexLocker locker(CodeCache_lock, Mutex::_no_safepoint_check_flag);
164 _table_snapshot = ShenandoahCodeRoots::table()->snapshot_for_iteration();
165 }
166
167 ShenandoahCodeRootsIterator::~ShenandoahCodeRootsIterator() {
168 MonitorLocker locker(CodeCache_lock, Mutex::_no_safepoint_check_flag);
169 ShenandoahCodeRoots::table()->finish_iteration(_table_snapshot);
170 _table_snapshot = nullptr;
171 locker.notify_all();
172 }
173
174 void ShenandoahCodeRootsIterator::possibly_parallel_nmethods_do(NMethodClosure *f) {
175 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
176 assert(_table_snapshot != nullptr, "Sanity");
177 _table_snapshot->parallel_nmethods_do(f);
178 }