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/events.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 BarrierSet::barrier_set()->barrier_set_nmethod()->arm_all_nmethods();
59 }
60
61 class ShenandoahNMethodUnlinkClosure : public NMethodClosure {
62 private:
63 bool _unloading_occurred;
64 ShenandoahHeap* const _heap;
65 BarrierSetNMethod* const _bs;
66
67 public:
68 ShenandoahNMethodUnlinkClosure(bool unloading_occurred) :
69 _unloading_occurred(unloading_occurred),
70 _heap(ShenandoahHeap::heap()),
71 _bs(ShenandoahBarrierSet::barrier_set()->barrier_set_nmethod()) {}
72
73 virtual void do_nmethod(nmethod* nm) {
74 assert(_heap->is_concurrent_weak_root_in_progress(), "Only this phase");
75
76 ShenandoahNMethod* nm_data = ShenandoahNMethod::gc_data(nm);
77 assert(!nm_data->is_unregistered(), "Should not see unregistered entry");
78
79 if (nm->is_unloading()) {
80 ShenandoahNMethodLocker locker(nm_data->lock());
81 nm->unlink();
82 return;
83 }
84
85 if (_heap->is_evacuation_in_progress()) {
86 ShenandoahNMethodLocker locker(nm_data->lock());
87
88 // Heal oops
89 if (_bs->is_armed(nm)) {
90 ShenandoahNMethod::heal_nmethod_metadata(nm_data);
91 // Must remain armed to complete remaining work in nmethod entry barrier
92 assert(_bs->is_armed(nm), "Should remain armed");
93 }
94 }
95
96 // Clear compiled ICs and exception caches
97 ShenandoahNMethodLocker locker(nm_data->ic_lock());
98 nm->unload_nmethod_caches(_unloading_occurred);
99 }
100 };
101
102 class ShenandoahUnlinkTask : public WorkerTask {
103 private:
104 ShenandoahNMethodUnlinkClosure _cl;
105 ShenandoahConcurrentNMethodIterator _iterator;
106
107 public:
108 ShenandoahUnlinkTask(bool unloading_occurred) :
109 WorkerTask("Shenandoah Unlink NMethods"),
110 _cl(unloading_occurred),
111 _iterator(ShenandoahCodeRoots::table()) {}
112
113 virtual void work(uint worker_id) {
114 _iterator.nmethods_do(&_cl);
115 }
116 };
117
118 void ShenandoahCodeRoots::unlink(WorkerThreads* workers, bool unloading_occurred) {
119 assert(ShenandoahHeap::heap()->unload_classes(), "Only when running concurrent class unloading");
120
121 ShenandoahUnlinkTask task(unloading_occurred);
122 workers->run_task(&task);
123 }
124
125 void ShenandoahCodeRoots::purge() {
126 assert(ShenandoahHeap::heap()->unload_classes(), "Only when running concurrent class unloading");
127
128 ClassUnloadingContext::context()->purge_and_free_nmethods();
129 }
130
131 ShenandoahCodeRootsIterator::ShenandoahCodeRootsIterator() :
132 _table_snapshot(nullptr) {
133 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
134 MutexLocker locker(CodeCache_lock, Mutex::_no_safepoint_check_flag);
135 _table_snapshot = ShenandoahCodeRoots::table()->snapshot_for_iteration();
136 }
137
138 ShenandoahCodeRootsIterator::~ShenandoahCodeRootsIterator() {
139 MonitorLocker locker(CodeCache_lock, Mutex::_no_safepoint_check_flag);
140 ShenandoahCodeRoots::table()->finish_iteration(_table_snapshot);
141 _table_snapshot = nullptr;
142 locker.notify_all();
143 }
144
145 void ShenandoahCodeRootsIterator::possibly_parallel_nmethods_do(NMethodClosure *f) {
146 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
147 assert(_table_snapshot != nullptr, "Sanity");
148 _table_snapshot->parallel_nmethods_do(f);
149 }