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