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/shenandoahEvacOOMHandler.inline.hpp"
31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
32 #include "gc/shenandoah/shenandoahNMethod.inline.hpp"
33 #include "gc/shenandoah/shenandoahUtils.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "memory/universe.hpp"
36 #include "runtime/atomicAccess.hpp"
37 #include "utilities/powerOfTwo.hpp"
38
39
40 ShenandoahNMethodTable* ShenandoahCodeRoots::_nmethod_table;
41 int ShenandoahCodeRoots::_disarmed_value = 1;
42
43 void ShenandoahCodeRoots::initialize() {
44 _nmethod_table = new ShenandoahNMethodTable();
45 }
46
47 void ShenandoahCodeRoots::register_nmethod(nmethod* nm) {
48 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
49 _nmethod_table->register_nmethod(nm);
50 }
51
52 void ShenandoahCodeRoots::unregister_nmethod(nmethod* nm) {
53 assert_locked_or_safepoint(CodeCache_lock);
54 _nmethod_table->unregister_nmethod(nm);
55 }
56
57 void ShenandoahCodeRoots::arm_nmethods() {
58 if (ShenandoahGCStateCheckHotpatch) {
59 char gc_state = ShenandoahHeap::heap()->gc_state();
60 log_info(gc)("Arming nmethods with GC state: %d [%s%s%s%s%s%s%s]",
61 gc_state,
62 ((gc_state & ShenandoahHeap::HAS_FORWARDED) > 0) ? "HAS_FORWARDED " : "",
63 ((gc_state & ShenandoahHeap::MARKING) > 0) ? "MARKING " : "",
64 ((gc_state & ShenandoahHeap::EVACUATION) > 0) ? "EVACUATION " : "",
65 ((gc_state & ShenandoahHeap::UPDATE_REFS) > 0) ? "UPDATE_REFS " : "",
66 ((gc_state & ShenandoahHeap::WEAK_ROOTS) > 0) ? "WEAK_ROOTS " : "",
67 ((gc_state & ShenandoahHeap::YOUNG_MARKING) > 0) ? "YOUNG_MARKING " : "",
68 ((gc_state & ShenandoahHeap::OLD_MARKING) > 0) ? "OLD_MARKING " : ""
69 );
70 }
71 BarrierSet::barrier_set()->barrier_set_nmethod()->arm_all_nmethods();
72 }
73
74 class ShenandoahDisarmNMethodClosure : public NMethodClosure {
75 public:
76 virtual void do_nmethod(nmethod* nm) {
77 ShenandoahNMethod::disarm_nmethod(nm);
78 }
79 };
80
81 class ShenandoahDisarmNMethodsTask : public WorkerTask {
82 private:
83 ShenandoahDisarmNMethodClosure _cl;
84 ShenandoahConcurrentNMethodIterator _iterator;
85
86 public:
87 ShenandoahDisarmNMethodsTask() :
88 WorkerTask("Shenandoah Disarm NMethods"),
89 _iterator(ShenandoahCodeRoots::table()) {}
90
91 virtual void work(uint worker_id) {
92 ShenandoahParallelWorkerSession worker_session(worker_id);
93 _iterator.nmethods_do(&_cl);
94 }
95 };
96
97 void ShenandoahCodeRoots::disarm_nmethods() {
98 ShenandoahDisarmNMethodsTask task;
99 ShenandoahHeap::heap()->workers()->run_task(&task);
100 }
101
102 class ShenandoahNMethodUnlinkClosure : public NMethodClosure {
103 private:
104 bool _unloading_occurred;
105 ShenandoahHeap* const _heap;
106 BarrierSetNMethod* const _bs;
107
108 public:
109 ShenandoahNMethodUnlinkClosure(bool unloading_occurred) :
110 _unloading_occurred(unloading_occurred),
111 _heap(ShenandoahHeap::heap()),
112 _bs(ShenandoahBarrierSet::barrier_set()->barrier_set_nmethod()) {}
113
114 virtual void do_nmethod(nmethod* nm) {
115 assert(_heap->is_concurrent_weak_root_in_progress(), "Only this phase");
116
117 ShenandoahNMethod* nm_data = ShenandoahNMethod::gc_data(nm);
118 assert(!nm_data->is_unregistered(), "Should not see unregistered entry");
119
120 if (nm->is_unloading()) {
121 ShenandoahNMethodLocker locker(nm_data->lock());
122 nm->unlink();
123 return;
124 }
125
126 {
127 ShenandoahNMethodLocker locker(nm_data->lock());
128
129 // Heal oops
130 if (_bs->is_armed(nm)) {
131 ShenandoahEvacOOMScope oom_evac_scope;
132 ShenandoahNMethod::heal_nmethod_metadata(nm_data);
133 // Must remain armed to complete remaining work in nmethod entry barrier
134 assert(_bs->is_armed(nm), "Should remain armed");
135 }
136 }
137
138 // Clear compiled ICs and exception caches
139 ShenandoahNMethodLocker locker(nm_data->ic_lock());
140 nm->unload_nmethod_caches(_unloading_occurred);
141 }
142 };
143
144 class ShenandoahUnlinkTask : public WorkerTask {
145 private:
146 ShenandoahNMethodUnlinkClosure _cl;
147 ShenandoahConcurrentNMethodIterator _iterator;
148
149 public:
150 ShenandoahUnlinkTask(bool unloading_occurred) :
151 WorkerTask("Shenandoah Unlink NMethods"),
152 _cl(unloading_occurred),
153 _iterator(ShenandoahCodeRoots::table()) {}
154
155 virtual void work(uint worker_id) {
156 _iterator.nmethods_do(&_cl);
157 }
158 };
159
160 void ShenandoahCodeRoots::unlink(WorkerThreads* workers, bool unloading_occurred) {
161 assert(ShenandoahHeap::heap()->unload_classes(), "Only when running concurrent class unloading");
162
163 ShenandoahUnlinkTask task(unloading_occurred);
164 workers->run_task(&task);
165 }
166
167 void ShenandoahCodeRoots::purge() {
168 assert(ShenandoahHeap::heap()->unload_classes(), "Only when running concurrent class unloading");
169
170 ClassUnloadingContext::context()->purge_and_free_nmethods();
171 }
172
173 ShenandoahCodeRootsIterator::ShenandoahCodeRootsIterator() :
174 _table_snapshot(nullptr) {
175 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
176 MutexLocker locker(CodeCache_lock, Mutex::_no_safepoint_check_flag);
177 _table_snapshot = ShenandoahCodeRoots::table()->snapshot_for_iteration();
178 }
179
180 ShenandoahCodeRootsIterator::~ShenandoahCodeRootsIterator() {
181 MonitorLocker locker(CodeCache_lock, Mutex::_no_safepoint_check_flag);
182 ShenandoahCodeRoots::table()->finish_iteration(_table_snapshot);
183 _table_snapshot = nullptr;
184 locker.notify_all();
185 }
186
187 void ShenandoahCodeRootsIterator::possibly_parallel_nmethods_do(NMethodClosure *f) {
188 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
189 assert(_table_snapshot != nullptr, "Sanity");
190 _table_snapshot->parallel_nmethods_do(f);
191 }