1 /*
2 * Copyright (c) 2013, 2020, 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 #include "precompiled.hpp"
26 #include "gc/shenandoah/shenandoahAsserts.hpp"
27 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
28 #include "gc/shenandoah/shenandoahBarrierSetClone.inline.hpp"
29 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
30 #include "gc/shenandoah/shenandoahBarrierSetNMethod.hpp"
31 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
32 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp"
33 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
34 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
35 #include "memory/iterator.inline.hpp"
36 #include "runtime/interfaceSupport.inline.hpp"
37 #ifdef COMPILER1
38 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
39 #endif
40 #ifdef COMPILER2
41 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
42 #endif
43
44 class ShenandoahBarrierSetC1;
45 class ShenandoahBarrierSetC2;
46
47 static BarrierSetNMethod* make_barrier_set_nmethod(ShenandoahHeap* heap) {
48 // NMethod barriers are only used when concurrent nmethod unloading is enabled
49 if (!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading()) {
50 return NULL;
51 }
52 return new ShenandoahBarrierSetNMethod(heap);
53 }
54
55 ShenandoahBarrierSet::ShenandoahBarrierSet(ShenandoahHeap* heap) :
56 BarrierSet(make_barrier_set_assembler<ShenandoahBarrierSetAssembler>(),
57 make_barrier_set_c1<ShenandoahBarrierSetC1>(),
58 make_barrier_set_c2<ShenandoahBarrierSetC2>(),
59 make_barrier_set_nmethod(heap),
60 BarrierSet::FakeRtti(BarrierSet::ShenandoahBarrierSet)),
61 _heap(heap),
62 _satb_mark_queue_buffer_allocator("SATB Buffer Allocator", ShenandoahSATBBufferSize),
63 _satb_mark_queue_set(&_satb_mark_queue_buffer_allocator)
64 {
65 }
66
67 ShenandoahBarrierSetAssembler* ShenandoahBarrierSet::assembler() {
68 BarrierSetAssembler* const bsa = BarrierSet::barrier_set()->barrier_set_assembler();
69 return reinterpret_cast<ShenandoahBarrierSetAssembler*>(bsa);
70 }
71
72 void ShenandoahBarrierSet::print_on(outputStream* st) const {
73 st->print("ShenandoahBarrierSet");
74 }
75
76 bool ShenandoahBarrierSet::is_a(BarrierSet::Name bsn) {
77 return bsn == BarrierSet::ShenandoahBarrierSet;
78 }
79
80 bool ShenandoahBarrierSet::is_aligned(HeapWord* hw) {
81 return true;
82 }
83
84 bool ShenandoahBarrierSet::need_load_reference_barrier(DecoratorSet decorators, BasicType type) {
85 if (!ShenandoahLoadRefBarrier) return false;
86 // Only needed for references
87 return is_reference_type(type);
88 }
89
90 bool ShenandoahBarrierSet::use_load_reference_barrier_native(DecoratorSet decorators, BasicType type) {
91 assert(need_load_reference_barrier(decorators, type), "Should be subset of LRB");
92 assert(is_reference_type(type), "Why we here?");
93 // Native load reference barrier is only needed for concurrent root processing
94 if (!ShenandoahConcurrentRoots::can_do_concurrent_roots()) {
95 return false;
96 }
97
98 return (decorators & IN_NATIVE) != 0;
99 }
100
101 bool ShenandoahBarrierSet::need_keep_alive_barrier(DecoratorSet decorators,BasicType type) {
102 if (!ShenandoahSATBBarrier) return false;
103 // Only needed for references
104 if (!is_reference_type(type)) return false;
105
106 bool keep_alive = (decorators & AS_NO_KEEPALIVE) == 0;
107 bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0;
108 bool on_weak_ref = (decorators & (ON_WEAK_OOP_REF | ON_PHANTOM_OOP_REF)) != 0;
109 return (on_weak_ref || unknown) && keep_alive;
110 }
111
112 oop ShenandoahBarrierSet::load_reference_barrier_not_null(oop obj) {
113 if (ShenandoahLoadRefBarrier && _heap->has_forwarded_objects()) {
114 return load_reference_barrier_impl(obj);
115 } else {
116 return obj;
117 }
118 }
119
120 oop ShenandoahBarrierSet::load_reference_barrier(oop obj) {
121 if (obj != NULL) {
122 return load_reference_barrier_not_null(obj);
123 } else {
124 return obj;
125 }
126 }
127
128 oop ShenandoahBarrierSet::load_reference_barrier_impl(oop obj) {
129 assert(ShenandoahLoadRefBarrier, "should be enabled");
130 if (!CompressedOops::is_null(obj)) {
131 bool evac_in_progress = _heap->is_evacuation_in_progress();
132 oop fwd = resolve_forwarded_not_null(obj);
133 if (evac_in_progress &&
134 _heap->in_collection_set(obj) &&
135 obj == fwd) {
136 Thread *t = Thread::current();
137 ShenandoahEvacOOMScope oom_evac_scope;
138 return _heap->evacuate_object(obj, t);
139 } else {
140 return fwd;
141 }
142 } else {
143 return obj;
144 }
145 }
146
147 void ShenandoahBarrierSet::on_thread_create(Thread* thread) {
148 // Create thread local data
149 ShenandoahThreadLocalData::create(thread);
150 }
151
152 void ShenandoahBarrierSet::on_thread_destroy(Thread* thread) {
153 // Destroy thread local data
154 ShenandoahThreadLocalData::destroy(thread);
155 }
156
157 void ShenandoahBarrierSet::on_thread_attach(Thread *thread) {
158 assert(!thread->is_Java_thread() || !SafepointSynchronize::is_at_safepoint(),
159 "We should not be at a safepoint");
160 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
161 assert(!queue.is_active(), "SATB queue should not be active");
162 assert( queue.is_empty(), "SATB queue should be empty");
163 queue.set_active(_satb_mark_queue_set.is_active());
164 if (thread->is_Java_thread()) {
165 ShenandoahThreadLocalData::set_gc_state(thread, _heap->gc_state());
166 ShenandoahThreadLocalData::initialize_gclab(thread);
167 ShenandoahThreadLocalData::set_disarmed_value(thread, ShenandoahCodeRoots::disarmed_value());
168 }
169 }
170
171 void ShenandoahBarrierSet::on_thread_detach(Thread *thread) {
172 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
173 queue.flush();
174 if (thread->is_Java_thread()) {
175 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
176 if (gclab != NULL) {
177 gclab->retire();
178 }
179 }
180 }
181
182 oop ShenandoahBarrierSet::load_reference_barrier_native(oop obj, oop* load_addr) {
183 return load_reference_barrier_native_impl(obj, load_addr);
184 }
185
186 oop ShenandoahBarrierSet::load_reference_barrier_native(oop obj, narrowOop* load_addr) {
187 return load_reference_barrier_native_impl(obj, load_addr);
188 }
189
190 template <class T>
191 oop ShenandoahBarrierSet::load_reference_barrier_native_impl(oop obj, T* load_addr) {
192 if (CompressedOops::is_null(obj)) {
193 return NULL;
194 }
195
196 ShenandoahMarkingContext* const marking_context = _heap->marking_context();
197 if (_heap->is_concurrent_weak_root_in_progress() && !marking_context->is_marked(obj)) {
198 Thread* thr = Thread::current();
199 if (thr->is_Java_thread()) {
200 return NULL;
201 } else {
202 return obj;
203 }
204 }
205
206 oop fwd = load_reference_barrier_not_null(obj);
207 if (load_addr != NULL && fwd != obj) {
208 // Since we are here and we know the load address, update the reference.
209 ShenandoahHeap::cas_oop(fwd, load_addr, obj);
210 }
211
212 return fwd;
213 }
214
215 void ShenandoahBarrierSet::clone_barrier_runtime(oop src) {
216 if (_heap->has_forwarded_objects() || (ShenandoahStoreValEnqueueBarrier && _heap->is_concurrent_mark_in_progress())) {
217 clone_barrier(src);
218 }
219 }
220