1 /*
2 * Copyright (c) 2001, 2016, 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.hpp"
27 #include "gc/g1/g1BSCodeGen.hpp"
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/c1G1BSCodeGen.hpp"
30 #include "gc/g1/c2G1BSCodeGen.hpp"
31 #include "gc/g1/heapRegion.hpp"
32 #include "gc/g1/satbMarkQueue.hpp"
33 #include "logging/log.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "runtime/interfaceSupport.hpp"
36 #include "runtime/mutexLocker.hpp"
37 #include "runtime/safepoint.hpp"
38 #include "runtime/thread.inline.hpp"
39
40 // Set of all SATB queues.
41 static SATBMarkQueueSet _satb_mark_queue_set;
42 // Set of all dirty card queues.
43 static DirtyCardQueueSet _dirty_card_queue_set;
44
45 // SATB marking queue support
46 SATBMarkQueueSet& G1BarrierSet::satb_mark_queue_set() {
47 return _satb_mark_queue_set;
48 }
49
50 // Dirty card queue support
51 DirtyCardQueueSet& G1BarrierSet::dirty_card_queue_set() {
52 return _dirty_card_queue_set;
53 }
54
55 G1BarrierSet::G1BarrierSet(CardTable* card_table) :
56 CardTableModRefBS(card_table, BarrierSet::FakeRtti(BarrierSet::G1BarrierSet))
57 { }
58
59 void G1BarrierSet::satb_enqueue(oop pre_val) {
60 // Nulls should have been already filtered.
61 assert(pre_val->is_oop(true), "Error");
62
63 if (!_satb_mark_queue_set.is_active()) return;
64 Thread* thr = Thread::current();
65 if (thr->is_Java_thread()) {
66 JavaThread* jt = (JavaThread*)thr;
67 jt->satb_mark_queue().enqueue(pre_val);
68 } else {
69 MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag);
70 _satb_mark_queue_set.shared_satb_queue()->enqueue(pre_val);
71 }
72 }
73
74 void G1BarrierSet::card_enqueue(volatile jbyte* card) {
75 Thread* thr = Thread::current();
76 if (thr->is_Java_thread()) {
77 JavaThread* jt = (JavaThread*)thr;
78 jt->dirty_card_queue().enqueue(card);
79 } else {
80 MutexLockerEx x(Shared_DirtyCardQ_lock,
81 Mutex::_no_safepoint_check_flag);
82 dirty_card_queue_set().shared_dirty_card_queue()->enqueue(card);
83 }
84 }
85
86 BarrierSetCodeGen *G1BarrierSet::make_code_gen() {
87 return new G1BSCodeGen();
88 }
89
90 C1BarrierSetCodeGen* G1BarrierSet::make_c1_code_gen() {
91 return new C1G1BSCodeGen();
92 }
93
94 C2BarrierSetCodeGen* G1BarrierSet::make_c2_code_gen() {
95 return new C2G1BSCodeGen();
96 }
97
98 template <class T> void
99 G1BarrierSet::write_ref_array_pre_work(T* dst, int count) {
100 if (!_satb_mark_queue_set.is_active()) return;
101 T* elem_ptr = dst;
102 for (int i = 0; i < count; i++, elem_ptr++) {
103 T heap_oop = oopDesc::load_heap_oop(elem_ptr);
104 if (!oopDesc::is_null(heap_oop)) {
105 satb_enqueue(oopDesc::decode_heap_oop_not_null(heap_oop));
106 }
107 }
108 }
109
110 void G1BarrierSet::write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {
111 if (!dest_uninitialized) {
112 write_ref_array_pre_work(dst, count);
113 }
114 }
115
116 void G1BarrierSet::write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {
117 if (!dest_uninitialized) {
118 write_ref_array_pre_work(dst, count);
119 }
120 }
121
122 void G1BarrierSet::invalidate(MemRegion mr) {
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 _dirty_card_queue_set.shared_dirty_card_queue()->enqueue(byte);
153 }
154 }
155 }
156 }
157 }
158
159 void G1BarrierSet::write_ref_nmethod_post(nmethod* nm, oop obj) {
160 if (obj != NULL) {
161 G1CollectedHeap* g1h = G1CollectedHeap::heap();
162 HeapRegion* hr = g1h->heap_region_containing(obj);
163 hr->add_strong_code_root(nm);
164 }
165 }
166
167 class G1EnsureLastRefToRegion : public OopClosure {
168 G1CollectedHeap* _g1h;
169 HeapRegion* _hr;
170 oop* _dst;
171
172 bool _value;
173 public:
174 G1EnsureLastRefToRegion(G1CollectedHeap* g1h, HeapRegion* hr, oop* dst) :
175 _g1h(g1h), _hr(hr), _dst(dst), _value(true) {}
176
177 void do_oop(oop* p) {
178 if (_value && p != _dst) {
179 oop obj = oopDesc::load_heap_oop(p);
180 if (obj != NULL) {
181 HeapRegion* hr = _g1h->heap_region_containing(obj);
182 if (hr == _hr) {
183 // Another reference to the same region.
184 _value = false;
185 }
186 }
187 }
188 }
189 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
190 bool value() const { return _value; }
191 };
192
193 void G1BarrierSet::write_ref_nmethod_pre(nmethod* nm, ptrdiff_t offset) {
194 oop* dst = (oop*)(intptr_t(nm) + offset);
195 oop obj = oopDesc::load_heap_oop(dst);
196 if (obj != NULL) {
197 G1CollectedHeap* g1h = G1CollectedHeap::heap();
198 HeapRegion* hr = g1h->heap_region_containing(obj);
199 G1EnsureLastRefToRegion ensure_last_ref(g1h, hr, dst);
200 nm->oops_do(&ensure_last_ref);
201 if (ensure_last_ref.value()) {
202 // Last reference to this region, remove the nmethod from the rset.
203 hr->remove_strong_code_root(nm);
204 }
205 }
206 }
207
208 void G1BarrierSet::on_add_thread(JavaThread* thread) {
209 assert(!SafepointSynchronize::is_at_safepoint(),
210 "we should not be at a safepoint");
211
212 SATBMarkQueue& satb_queue = thread->satb_mark_queue();
213 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
214 // The SATB queue should have been constructed with its active
215 // field set to false.
216 assert(!satb_queue.is_active(), "SATB queue should not be active");
217 assert(satb_queue.is_empty(), "SATB queue should be empty");
218 // If we are creating the thread during a marking cycle, we should
219 // set the active field of the SATB queue to true.
220 if (satb_queue_set.is_active()) {
221 satb_queue.set_active(true);
222 }
223
224 DirtyCardQueue& dirty_queue = thread->dirty_card_queue();
225 // The dirty card queue should have been constructed with its
226 // active field set to true.
227 assert(dirty_queue.is_active(), "dirty card queue should be active");
228 }
229
230 void G1BarrierSet::on_destroy_thread(JavaThread* thread) {
231 CardTableModRefBS::on_destroy_thread(thread);
232 thread->satb_mark_queue().flush();
233 thread->dirty_card_queue().flush();
234 }
235
236 bool G1BarrierSet::is_referent_field(oop base, ptrdiff_t offset) {
237 Klass* k;
238 return offset == java_lang_ref_Reference::referent_offset &&
239 (k = base->klass()) &&
240 InstanceKlass::cast(k)->reference_type() != REF_NONE;
241 }
242
243 // G1 write-barrier pre: executed before a pointer store.
244 JRT_LEAF(void, G1BarrierSet::g1_wb_pre(oopDesc* orig, JavaThread *thread))
245 if (orig == NULL) {
246 assert(false, "should be optimized out");
247 return;
248 }
249 assert(orig->is_oop(true /* ignore mark word */), "Error");
250 // store the original value that was in the field reference
251 thread->satb_mark_queue().enqueue(orig);
252 JRT_END
253
254 // G1 write-barrier post: executed after a pointer store.
255 JRT_LEAF(void, G1BarrierSet::g1_wb_post(void* card_addr, JavaThread* thread))
256 thread->dirty_card_queue().enqueue(card_addr);
257 JRT_END