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