1 /*
2 * Copyright (c) 2001, 2015, 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/g1CollectedHeap.inline.hpp"
27 #include "gc/g1/g1SATBCardTableModRefBS.hpp"
28 #include "gc/g1/heapRegion.hpp"
29 #include "gc/g1/satbMarkQueue.hpp"
30 #include "gc/shared/memset_with_concurrent_readers.hpp"
31 #include "logging/log.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "runtime/atomic.inline.hpp"
34 #include "runtime/mutexLocker.hpp"
35 #include "runtime/orderAccess.inline.hpp"
36 #include "runtime/thread.inline.hpp"
37
38 G1SATBCardTableModRefBS::G1SATBCardTableModRefBS(
39 MemRegion whole_heap,
40 const BarrierSet::FakeRtti& fake_rtti) :
41 CardTableModRefBS(whole_heap, fake_rtti.add_tag(BarrierSet::G1SATBCT))
42 { }
43
44 void G1SATBCardTableModRefBS::enqueue(oop pre_val) {
45 // Nulls should have been already filtered.
46 assert(pre_val->is_oop(true), "Error");
47
48 if (!JavaThread::satb_mark_queue_set().is_active()) return;
49 Thread* thr = Thread::current();
50 if (thr->is_Java_thread()) {
51 JavaThread* jt = (JavaThread*)thr;
52 jt->satb_mark_queue().enqueue(pre_val);
53 } else {
54 MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag);
55 JavaThread::satb_mark_queue_set().shared_satb_queue()->enqueue(pre_val);
56 }
57 }
58
59 template <class T> void
60 G1SATBCardTableModRefBS::write_ref_array_pre_work(T* dst, int count) {
61 if (!JavaThread::satb_mark_queue_set().is_active()) return;
62 T* elem_ptr = dst;
63 for (int i = 0; i < count; i++, elem_ptr++) {
64 T heap_oop = oopDesc::load_heap_oop(elem_ptr);
65 if (!oopDesc::is_null(heap_oop)) {
66 enqueue(oopDesc::decode_heap_oop_not_null(heap_oop));
67 }
68 }
69 }
70
71 void G1SATBCardTableModRefBS::write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {
72 if (!dest_uninitialized) {
73 write_ref_array_pre_work(dst, count);
74 }
75 }
76 void G1SATBCardTableModRefBS::write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {
77 if (!dest_uninitialized) {
78 write_ref_array_pre_work(dst, count);
79 }
80 }
81
82 bool G1SATBCardTableModRefBS::mark_card_deferred(size_t card_index) {
83 jbyte val = _byte_map[card_index];
84 // It's already processed
85 if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) {
86 return false;
87 }
88
89 if (val == g1_young_gen) {
90 // the card is for a young gen region. We don't need to keep track of all pointers into young
91 return false;
92 }
93
94 // Cached bit can be installed either on a clean card or on a claimed card.
95 jbyte new_val = val;
96 if (val == clean_card_val()) {
97 new_val = (jbyte)deferred_card_val();
98 } else {
99 if (val & claimed_card_val()) {
100 new_val = val | (jbyte)deferred_card_val();
101 }
102 }
103 if (new_val != val) {
104 Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
105 }
106 return true;
107 }
108
109 void G1SATBCardTableModRefBS::g1_mark_as_young(const MemRegion& mr) {
110 jbyte *const first = byte_for(mr.start());
111 jbyte *const last = byte_after(mr.last());
112
113 memset_with_concurrent_readers(first, g1_young_gen, last - first);
114 }
115
116 #ifndef PRODUCT
117 void G1SATBCardTableModRefBS::verify_g1_young_region(MemRegion mr) {
118 verify_region(mr, g1_young_gen, true);
119 }
120 #endif
121
122 void G1SATBCardTableLoggingModRefBSChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
123 // Default value for a clean card on the card table is -1. So we cannot take advantage of the zero_filled parameter.
124 MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords);
125 _card_table->clear(mr);
126 }
127
128 G1SATBCardTableLoggingModRefBS::
129 G1SATBCardTableLoggingModRefBS(MemRegion whole_heap) :
130 G1SATBCardTableModRefBS(whole_heap, BarrierSet::FakeRtti(G1SATBCTLogging)),
131 _dcqs(JavaThread::dirty_card_queue_set()),
132 _listener()
133 {
134 _listener.set_card_table(this);
135 }
136
137 void G1SATBCardTableLoggingModRefBS::initialize(G1RegionToSpaceMapper* mapper) {
138 mapper->set_mapping_changed_listener(&_listener);
139
140 _byte_map_size = mapper->reserved().byte_size();
141
142 _guard_index = cards_required(_whole_heap.word_size()) - 1;
143 _last_valid_index = _guard_index - 1;
144
145 HeapWord* low_bound = _whole_heap.start();
146 HeapWord* high_bound = _whole_heap.end();
147
148 _cur_covered_regions = 1;
149 _covered[0] = _whole_heap;
150
151 _byte_map = (jbyte*) mapper->reserved().start();
152 byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
153 assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
154 assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
155
156 log_trace(barrier)("G1SATBCardTableModRefBS::G1SATBCardTableModRefBS: ");
157 log_trace(barrier)(" &_byte_map[0]: " INTPTR_FORMAT " &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
158 p2i(&_byte_map[0]), p2i(&_byte_map[_last_valid_index]));
159 log_trace(barrier)(" byte_map_base: " INTPTR_FORMAT, p2i(byte_map_base));
160 }
161
162 void
163 G1SATBCardTableLoggingModRefBS::write_ref_field_work(void* field,
164 oop new_val,
165 bool release) {
166 volatile jbyte* byte = byte_for(field);
167 if (*byte == g1_young_gen) {
168 return;
169 }
170 OrderAccess::storeload();
171 if (*byte != dirty_card) {
172 *byte = dirty_card;
173 Thread* thr = Thread::current();
174 if (thr->is_Java_thread()) {
175 JavaThread* jt = (JavaThread*)thr;
176 jt->dirty_card_queue().enqueue(byte);
177 } else {
178 MutexLockerEx x(Shared_DirtyCardQ_lock,
179 Mutex::_no_safepoint_check_flag);
180 _dcqs.shared_dirty_card_queue()->enqueue(byte);
181 }
182 }
183 }
184
185 void
186 G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr, bool whole_heap) {
187 volatile jbyte* byte = byte_for(mr.start());
188 jbyte* last_byte = byte_for(mr.last());
189 Thread* thr = Thread::current();
190 if (whole_heap) {
191 while (byte <= last_byte) {
192 *byte = dirty_card;
193 byte++;
194 }
195 } else {
196 // skip all consecutive young cards
197 for (; byte <= last_byte && *byte == g1_young_gen; byte++);
198
199 if (byte <= last_byte) {
200 OrderAccess::storeload();
201 // Enqueue if necessary.
202 if (thr->is_Java_thread()) {
203 JavaThread* jt = (JavaThread*)thr;
204 for (; byte <= last_byte; byte++) {
205 if (*byte == g1_young_gen) {
206 continue;
207 }
208 if (*byte != dirty_card) {
209 *byte = dirty_card;
210 jt->dirty_card_queue().enqueue(byte);
211 }
212 }
213 } else {
214 MutexLockerEx x(Shared_DirtyCardQ_lock,
215 Mutex::_no_safepoint_check_flag);
216 for (; byte <= last_byte; byte++) {
217 if (*byte == g1_young_gen) {
218 continue;
219 }
220 if (*byte != dirty_card) {
221 *byte = dirty_card;
222 _dcqs.shared_dirty_card_queue()->enqueue(byte);
223 }
224 }
225 }
226 }
227 }
228 }
229
230 void G1SATBCardTableModRefBS::write_ref_nmethod_post(oop* dst, nmethod* nm) {
231 oop obj = oopDesc::load_heap_oop(dst);
232 if (obj != NULL) {
233 G1CollectedHeap* g1h = G1CollectedHeap::heap();
234 HeapRegion* hr = g1h->heap_region_containing(obj);
235 hr->add_strong_code_root(nm);
236 }
237 }
238
239 class G1EnsureLastRefToRegion : public OopClosure {
240 G1CollectedHeap* _g1h;
241 HeapRegion* _hr;
242 oop* _dst;
243
244 bool _value;
245 public:
246 G1EnsureLastRefToRegion(G1CollectedHeap* g1h, HeapRegion* hr, oop* dst) :
247 _g1h(g1h), _hr(hr), _dst(dst), _value(true) {}
248
249 void do_oop(oop* p) {
250 if (_value && p != _dst) {
251 oop obj = oopDesc::load_heap_oop(p);
252 if (obj != NULL) {
253 HeapRegion* hr = _g1h->heap_region_containing(obj);
254 if (hr == _hr) {
255 // Another reference to the same region.
256 _value = false;
257 }
258 }
259 }
260 }
261 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
262 bool value() const { return _value; }
263 };
264
265 void G1SATBCardTableModRefBS::write_ref_nmethod_pre(oop* dst, nmethod* nm) {
266 oop obj = oopDesc::load_heap_oop(dst);
267 if (obj != NULL) {
268 G1CollectedHeap* g1h = G1CollectedHeap::heap();
269 HeapRegion* hr = g1h->heap_region_containing(obj);
270 G1EnsureLastRefToRegion ensure_last_ref(g1h, hr, dst);
271 nm->oops_do(&ensure_last_ref);
272 if (ensure_last_ref.value()) {
273 // Last reference to this region, remove the nmethod from the rset.
274 hr->remove_strong_code_root(nm);
275 }
276 }
277 }