1 /*
2 * Copyright (c) 2001, 2018, Oracle and/or its affiliates. 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/g1/g1BarrierSet.inline.hpp"
27 #include "gc/g1/g1BarrierSetAssembler.hpp"
28 #include "gc/g1/g1CardTable.inline.hpp"
29 #include "gc/g1/g1CollectedHeap.inline.hpp"
30 #include "gc/g1/g1ThreadLocalData.hpp"
31 #include "gc/g1/heapRegion.hpp"
32 #include "gc/g1/satbMarkQueue.hpp"
33 #include "logging/log.hpp"
34 #include "oops/access.inline.hpp"
35 #include "oops/compressedOops.inline.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "runtime/mutexLocker.hpp"
38 #include "runtime/thread.inline.hpp"
39 #include "utilities/macros.hpp"
40
41 SATBMarkQueueSet G1BarrierSet::_satb_mark_queue_set;
42 DirtyCardQueueSet G1BarrierSet::_dirty_card_queue_set;
43
44 G1BarrierSet::G1BarrierSet(G1CardTable* card_table) :
45 CardTableBarrierSet(make_barrier_set_assembler<G1BarrierSetAssembler>(),
46 card_table,
47 BarrierSet::FakeRtti(BarrierSet::G1BarrierSet)) {}
48
49 void G1BarrierSet::enqueue(oop pre_val) {
50 // Nulls should have been already filtered.
51 assert(oopDesc::is_oop(pre_val, true), "Error");
52
53 if (!_satb_mark_queue_set.is_active()) return;
54 Thread* thr = Thread::current();
55 if (thr->is_Java_thread()) {
56 G1ThreadLocalData::satb_mark_queue(thr).enqueue(pre_val);
57 } else {
58 MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag);
59 _satb_mark_queue_set.shared_satb_queue()->enqueue(pre_val);
60 }
61 }
62
63 void G1BarrierSet::write_ref_array_pre_oop_entry(oop* dst, size_t length) {
64 G1BarrierSet *bs = barrier_set_cast<G1BarrierSet>(BarrierSet::barrier_set());
65 bs->write_ref_array_pre(dst, length, false);
66 }
67
68 void G1BarrierSet::write_ref_array_pre_narrow_oop_entry(narrowOop* dst, size_t length) {
69 G1BarrierSet *bs = barrier_set_cast<G1BarrierSet>(BarrierSet::barrier_set());
70 bs->write_ref_array_pre(dst, length, false);
71 }
72
73 void G1BarrierSet::write_ref_array_post_entry(HeapWord* dst, size_t length) {
74 G1BarrierSet *bs = barrier_set_cast<G1BarrierSet>(BarrierSet::barrier_set());
75 bs->G1BarrierSet::write_ref_array(dst, length);
76 }
77
78 template <class T> void
79 G1BarrierSet::write_ref_array_pre_work(T* dst, size_t count) {
80 if (!_satb_mark_queue_set.is_active()) return;
81 T* elem_ptr = dst;
82 for (size_t i = 0; i < count; i++, elem_ptr++) {
83 T heap_oop = RawAccess<>::oop_load(elem_ptr);
84 if (!CompressedOops::is_null(heap_oop)) {
85 enqueue(CompressedOops::decode_not_null(heap_oop));
86 }
87 }
88 }
89
90 void G1BarrierSet::write_ref_array_pre(oop* dst, size_t count, bool dest_uninitialized) {
91 if (!dest_uninitialized) {
92 write_ref_array_pre_work(dst, count);
93 }
94 }
95
96 void G1BarrierSet::write_ref_array_pre(narrowOop* dst, size_t count, bool dest_uninitialized) {
97 if (!dest_uninitialized) {
98 write_ref_array_pre_work(dst, count);
99 }
100 }
101
102 void G1BarrierSet::write_ref_field_post_slow(volatile jbyte* byte) {
103 // In the slow path, we know a card is not young
104 assert(*byte != G1CardTable::g1_young_card_val(), "slow path invoked without filtering");
105 OrderAccess::storeload();
106 if (*byte != G1CardTable::dirty_card_val()) {
107 *byte = G1CardTable::dirty_card_val();
108 Thread* thr = Thread::current();
109 if (thr->is_Java_thread()) {
110 G1ThreadLocalData::dirty_card_queue(thr).enqueue(byte);
111 } else {
112 MutexLockerEx x(Shared_DirtyCardQ_lock,
113 Mutex::_no_safepoint_check_flag);
114 _dirty_card_queue_set.shared_dirty_card_queue()->enqueue(byte);
115 }
116 }
117 }
118
119 void G1BarrierSet::invalidate(MemRegion mr) {
120 if (mr.is_empty()) {
121 return;
122 }
123 volatile jbyte* byte = _card_table->byte_for(mr.start());
124 jbyte* last_byte = _card_table->byte_for(mr.last());
125 Thread* thr = Thread::current();
126 // skip all consecutive young cards
127 for (; byte <= last_byte && *byte == G1CardTable::g1_young_card_val(); byte++);
128
129 if (byte <= last_byte) {
130 OrderAccess::storeload();
131 // Enqueue if necessary.
132 if (thr->is_Java_thread()) {
133 for (; byte <= last_byte; byte++) {
134 if (*byte == G1CardTable::g1_young_card_val()) {
135 continue;
136 }
137 if (*byte != G1CardTable::dirty_card_val()) {
138 *byte = G1CardTable::dirty_card_val();
139 G1ThreadLocalData::dirty_card_queue(thr).enqueue(byte);
140 }
141 }
142 } else {
143 MutexLockerEx x(Shared_DirtyCardQ_lock,
144 Mutex::_no_safepoint_check_flag);
145 for (; byte <= last_byte; byte++) {
146 if (*byte == G1CardTable::g1_young_card_val()) {
147 continue;
148 }
149 if (*byte != G1CardTable::dirty_card_val()) {
150 *byte = G1CardTable::dirty_card_val();
151 _dirty_card_queue_set.shared_dirty_card_queue()->enqueue(byte);
152 }
153 }
154 }
155 }
156 }
157
158 void G1BarrierSet::on_thread_create(Thread* thread) {
159 // Create thread local data
160 G1ThreadLocalData::create(thread);
161 }
162
163 void G1BarrierSet::on_thread_destroy(Thread* thread) {
164 // Destroy thread local data
165 G1ThreadLocalData::destroy(thread);
166 }
167
168 void G1BarrierSet::on_thread_attach(JavaThread* thread) {
169 // This method initializes the SATB and dirty card queues before a
170 // JavaThread is added to the Java thread list. Right now, we don't
171 // have to do anything to the dirty card queue (it should have been
172 // activated when the thread was created), but we have to activate
173 // the SATB queue if the thread is created while a marking cycle is
174 // in progress. The activation / de-activation of the SATB queues at
175 // the beginning / end of a marking cycle is done during safepoints
176 // so we have to make sure this method is called outside one to be
177 // able to safely read the active field of the SATB queue set. Right
178 // now, it is called just before the thread is added to the Java
179 // thread list in the Threads::add() method. That method is holding
180 // the Threads_lock which ensures we are outside a safepoint. We
181 // cannot do the obvious and set the active field of the SATB queue
182 // when the thread is created given that, in some cases, safepoints
183 // might happen between the JavaThread constructor being called and the
184 // thread being added to the Java thread list (an example of this is
185 // when the structure for the DestroyJavaVM thread is created).
186 assert(!SafepointSynchronize::is_at_safepoint(), "We should not be at a safepoint");
187 assert(!G1ThreadLocalData::satb_mark_queue(thread).is_active(), "SATB queue should not be active");
188 assert(G1ThreadLocalData::satb_mark_queue(thread).is_empty(), "SATB queue should be empty");
189 assert(G1ThreadLocalData::dirty_card_queue(thread).is_active(), "Dirty card queue should be active");
190
191 // If we are creating the thread during a marking cycle, we should
192 // set the active field of the SATB queue to true.
193 if (_satb_mark_queue_set.is_active()) {
194 G1ThreadLocalData::satb_mark_queue(thread).set_active(true);
195 }
196 }
197
198 void G1BarrierSet::on_thread_detach(JavaThread* thread) {
199 // Flush any deferred card marks, SATB buffers and dirty card queue buffers
200 CardTableBarrierSet::on_thread_detach(thread);
201 G1ThreadLocalData::satb_mark_queue(thread).flush();
202 G1ThreadLocalData::dirty_card_queue(thread).flush();
203 }