1 /*
2 * Copyright (c) 2019, 2021, 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 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHROOTPROCESSOR_INLINE_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHROOTPROCESSOR_INLINE_HPP
27
28 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
29
30 #include "classfile/classLoaderDataGraph.hpp"
31 #include "gc/shared/oopStorageSetParState.inline.hpp"
32 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
33 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
34 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
35 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
36 #include "gc/shenandoah/shenandoahUtils.hpp"
37 #include "memory/resourceArea.hpp"
38 #include "runtime/mutexLocker.hpp"
39 #include "runtime/safepoint.hpp"
40
41 template <bool CONCURRENT>
42 ShenandoahVMWeakRoots<CONCURRENT>::ShenandoahVMWeakRoots(ShenandoahPhaseTimings::Phase phase) :
43 _phase(phase) {
44 }
45
46 template <bool CONCURRENT>
47 template <typename T>
48 void ShenandoahVMWeakRoots<CONCURRENT>::oops_do(T* cl, uint worker_id) {
49 ShenandoahWorkerTimingsTracker timer(_phase, ShenandoahPhaseTimings::VMWeakRoots, worker_id);
50 _weak_roots.oops_do(cl);
51 }
52
53 template <bool CONCURRENT>
54 template <typename IsAlive, typename KeepAlive>
55 void ShenandoahVMWeakRoots<CONCURRENT>::weak_oops_do(IsAlive* is_alive, KeepAlive* keep_alive, uint worker_id) {
56 ShenandoahCleanUpdateWeakOopsClosure<CONCURRENT, IsAlive, KeepAlive> cl(is_alive, keep_alive);
57 ShenandoahWorkerTimingsTracker timer(_phase, ShenandoahPhaseTimings::VMWeakRoots, worker_id);
58 _weak_roots.oops_do(&cl);
59 }
60
61 template <bool CONCURRENT>
62 void ShenandoahVMWeakRoots<CONCURRENT>::report_num_dead() {
63 _weak_roots.report_num_dead();
64 }
65
66 template <bool CONCURRENT>
67 ShenandoahVMRoots<CONCURRENT>::ShenandoahVMRoots(ShenandoahPhaseTimings::Phase phase) :
68 _phase(phase) {
69 }
70
71 template <bool CONCURRENT>
72 template <typename T>
73 void ShenandoahVMRoots<CONCURRENT>::oops_do(T* cl, uint worker_id) {
74 ShenandoahWorkerTimingsTracker timer(_phase, ShenandoahPhaseTimings::VMStrongRoots, worker_id);
75 _strong_roots.oops_do(cl);
76 }
77
78 template <bool CONCURRENT>
79 ShenandoahClassLoaderDataRoots<CONCURRENT>::ShenandoahClassLoaderDataRoots(ShenandoahPhaseTimings::Phase phase, uint n_workers, bool heap_iteration) :
80 _semaphore(worker_count(n_workers)),
81 _phase(phase) {
82 if (heap_iteration) {
83 ClassLoaderDataGraph::clear_claimed_marks(ClassLoaderData::_claim_other);
84 } else {
85 ClassLoaderDataGraph::clear_claimed_marks(ClassLoaderData::_claim_strong);
86 }
87
88 if (CONCURRENT) {
89 ClassLoaderDataGraph_lock->lock();
90 }
91
92 // Non-concurrent mode only runs at safepoints
93 assert(CONCURRENT || SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
94 }
95
96 template <bool CONCURRENT>
97 ShenandoahClassLoaderDataRoots<CONCURRENT>::~ShenandoahClassLoaderDataRoots() {
98 if (CONCURRENT) {
99 ClassLoaderDataGraph_lock->unlock();
100 }
101 }
102
103 template <bool CONCURRENT>
104 void ShenandoahClassLoaderDataRoots<CONCURRENT>::cld_do_impl(CldDo f, CLDClosure* clds, uint worker_id) {
105 if (CONCURRENT) {
106 if (_semaphore.try_acquire()) {
107 ShenandoahWorkerTimingsTracker timer(_phase, ShenandoahPhaseTimings::CLDGRoots, worker_id);
108 f(clds);
109 _semaphore.claim_all();
110 }
111 } else {
112 ShenandoahWorkerTimingsTracker timer(_phase, ShenandoahPhaseTimings::CLDGRoots, worker_id);
113 f(clds);
114 }
115 }
116
117 template <bool CONCURRENT>
118 void ShenandoahClassLoaderDataRoots<CONCURRENT>::always_strong_cld_do(CLDClosure* clds, uint worker_id) {
119 cld_do_impl(&ClassLoaderDataGraph::always_strong_cld_do, clds, worker_id);
120 }
121
122 template <bool CONCURRENT>
123 void ShenandoahClassLoaderDataRoots<CONCURRENT>::cld_do(CLDClosure* clds, uint worker_id) {
124 cld_do_impl(&ClassLoaderDataGraph::cld_do, clds, worker_id);
125 }
126
127 class ShenandoahParallelOopsDoThreadClosure : public ThreadClosure {
128 private:
129 OopClosure* _f;
130 NMethodClosure* _cf;
131 ThreadClosure* _thread_cl;
132 public:
133 ShenandoahParallelOopsDoThreadClosure(OopClosure* f, NMethodClosure* cf, ThreadClosure* thread_cl) :
134 _f(f), _cf(cf), _thread_cl(thread_cl) {}
135
136 void do_thread(Thread* t) {
137 if (_thread_cl != nullptr) {
138 _thread_cl->do_thread(t);
139 }
140 t->oops_do(_f, _cf);
141 }
142 };
143
144 // The rationale for selecting the roots to scan is as follows:
145 // a. With unload_classes = true, we only want to scan the actual strong roots from the
146 // code cache. This will allow us to identify the dead classes, unload them, *and*
147 // invalidate the relevant code cache blobs. This could be only done together with
148 // class unloading.
149 // b. With unload_classes = false, we have to nominally retain all the references from code
150 // cache, because there could be the case of embedded class/oop in the generated code,
151 // which we will never visit during mark. Without code cache invalidation, as in (a),
152 // we risk executing that code cache blob, and crashing.
153 template <typename T>
154 void ShenandoahSTWRootScanner::roots_do(T* oops, uint worker_id) {
155 MarkingNMethodClosure nmethods_cl(oops);
156 CLDToOopClosure clds(oops, ClassLoaderData::_claim_strong);
157 ResourceMark rm;
158
159 if (_unload_classes) {
160 _thread_roots.oops_do(oops, &nmethods_cl, worker_id);
161 _cld_roots.always_strong_cld_do(&clds, worker_id);
162 } else {
163 _thread_roots.oops_do(oops, nullptr, worker_id);
164 _code_roots.nmethods_do(&nmethods_cl, worker_id);
165 _cld_roots.cld_do(&clds, worker_id);
166 }
167
168 _vm_roots.oops_do<T>(oops, worker_id);
169 }
170
171 template <typename IsAlive, typename KeepAlive>
172 void ShenandoahRootUpdater::roots_do(uint worker_id, IsAlive* is_alive, KeepAlive* keep_alive) {
173 ShenandoahNMethodAndDisarmClosure nmethods_and_disarm_Cl(keep_alive);
174 NMethodToOopClosure* codes_cl = static_cast<NMethodToOopClosure*>(&nmethods_and_disarm_Cl);
175
176 CLDToOopClosure clds(keep_alive, ClassLoaderData::_claim_strong);
177
178 // Process light-weight/limited parallel roots then
179 _vm_roots.oops_do(keep_alive, worker_id);
180 _weak_roots.weak_oops_do<IsAlive, KeepAlive>(is_alive, keep_alive, worker_id);
181 _cld_roots.cld_do(&clds, worker_id);
182
183 // Process heavy-weight/fully parallel roots the last
184 _code_roots.nmethods_do(codes_cl, worker_id);
185 _thread_roots.oops_do(keep_alive, nullptr, worker_id);
186 }
187
188 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHROOTPROCESSOR_INLINE_HPP