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