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/g1CollectedHeap.inline.hpp"
27#include "gc/g1/g1SATBCardTableModRefBS.inline.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.hpp"
34#include "runtime/mutexLocker.hpp"
35#include "runtime/orderAccess.inline.hpp"
36#include "runtime/thread.inline.hpp"
37
38G1SATBCardTableModRefBS::G1SATBCardTableModRefBS(
39  MemRegion whole_heap,
40  const BarrierSet::FakeRtti& fake_rtti) :
41  CardTableModRefBS(whole_heap, fake_rtti.add_tag(BarrierSet::G1SATBCT))
42{ }
43
44void 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
59template <class T> void
60G1SATBCardTableModRefBS::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
71void 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}
76void 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
82bool 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  // Cached bit can be installed either on a clean card or on a claimed card.
90  jbyte new_val = val;
91  if (val == clean_card_val()) {
92    new_val = (jbyte)deferred_card_val();
93  } else {
94    if (val & claimed_card_val()) {
95      new_val = val | (jbyte)deferred_card_val();
96    }
97  }
98  if (new_val != val) {
99    Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
100  }
101  return true;
102}
103
104void G1SATBCardTableModRefBS::g1_mark_as_young(const MemRegion& mr) {
105  jbyte *const first = byte_for(mr.start());
106  jbyte *const last = byte_after(mr.last());
107
108  memset_with_concurrent_readers(first, g1_young_gen, last - first);
109}
110
111#ifndef PRODUCT
112void G1SATBCardTableModRefBS::verify_g1_young_region(MemRegion mr) {
113  verify_region(mr, g1_young_gen,  true);
114}
115#endif
116
117void G1SATBCardTableLoggingModRefBSChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
118  // Default value for a clean card on the card table is -1. So we cannot take advantage of the zero_filled parameter.
119  MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords);
120  _card_table->clear(mr);
121}
122
123G1SATBCardTableLoggingModRefBS::
124G1SATBCardTableLoggingModRefBS(MemRegion whole_heap) :
125  G1SATBCardTableModRefBS(whole_heap, BarrierSet::FakeRtti(G1SATBCTLogging)),
126  _dcqs(JavaThread::dirty_card_queue_set()),
127  _listener()
128{
129  _listener.set_card_table(this);
130}
131
132void G1SATBCardTableLoggingModRefBS::initialize(G1RegionToSpaceMapper* mapper) {
133  mapper->set_mapping_changed_listener(&_listener);
134
135  _byte_map_size = mapper->reserved().byte_size();
136
137  _guard_index = cards_required(_whole_heap.word_size()) - 1;
138  _last_valid_index = _guard_index - 1;
139
140  HeapWord* low_bound  = _whole_heap.start();
141  HeapWord* high_bound = _whole_heap.end();
142
143  _cur_covered_regions = 1;
144  _covered[0] = _whole_heap;
145
146  _byte_map = (jbyte*) mapper->reserved().start();
147  byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
148  assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
149  assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
150
151  log_trace(gc, barrier)("G1SATBCardTableModRefBS::G1SATBCardTableModRefBS: ");
152  log_trace(gc, barrier)("    &_byte_map[0]: " INTPTR_FORMAT "  &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
153                         p2i(&_byte_map[0]), p2i(&_byte_map[_last_valid_index]));
154  log_trace(gc, barrier)("    byte_map_base: " INTPTR_FORMAT,  p2i(byte_map_base));
155}
156
157void
158G1SATBCardTableLoggingModRefBS::write_ref_field_work(void* field,
159                                                     oop new_val,
160                                                     bool release) {
161  volatile jbyte* byte = byte_for(field);
162  if (*byte == g1_young_gen) {
163    return;
164  }
165  OrderAccess::storeload();
166  if (*byte != dirty_card) {
167    *byte = dirty_card;
168    Thread* thr = Thread::current();
169    if (thr->is_Java_thread()) {
170      JavaThread* jt = (JavaThread*)thr;
171      jt->dirty_card_queue().enqueue(byte);
172    } else {
173      MutexLockerEx x(Shared_DirtyCardQ_lock,
174                      Mutex::_no_safepoint_check_flag);
175      _dcqs.shared_dirty_card_queue()->enqueue(byte);
176    }
177  }
178}
179
180void
181G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr) {
182  volatile jbyte* byte = byte_for(mr.start());
183  jbyte* last_byte = byte_for(mr.last());
184  Thread* thr = Thread::current();
185    // skip all consecutive young cards
186  for (; byte <= last_byte && *byte == g1_young_gen; byte++);
187
188  if (byte <= last_byte) {
189    OrderAccess::storeload();
190    // Enqueue if necessary.
191    if (thr->is_Java_thread()) {
192      JavaThread* jt = (JavaThread*)thr;
193      for (; byte <= last_byte; byte++) {
194        if (*byte == g1_young_gen) {
195          continue;
196        }
197        if (*byte != dirty_card) {
198          *byte = dirty_card;
199          jt->dirty_card_queue().enqueue(byte);
200        }
201      }
202    } else {
203      MutexLockerEx x(Shared_DirtyCardQ_lock,
204                      Mutex::_no_safepoint_check_flag);
205      for (; byte <= last_byte; byte++) {
206        if (*byte == g1_young_gen) {
207          continue;
208        }
209        if (*byte != dirty_card) {
210          *byte = dirty_card;
211          _dcqs.shared_dirty_card_queue()->enqueue(byte);
212        }
213      }
214    }
215  }
216}
217
218void G1SATBCardTableModRefBS::write_ref_nmethod_post(oop* dst, nmethod* nm) {
219  oop obj = oopDesc::load_heap_oop(dst);
220  if (obj != NULL) {
221    G1CollectedHeap* g1h = G1CollectedHeap::heap();
222    HeapRegion* hr = g1h->heap_region_containing(obj);
223    hr->add_strong_code_root(nm);
224  }
225}
226
227class G1EnsureLastRefToRegion : public OopClosure {
228  G1CollectedHeap* _g1h;
229  HeapRegion* _hr;
230  oop* _dst;
231
232  bool _value;
233public:
234  G1EnsureLastRefToRegion(G1CollectedHeap* g1h, HeapRegion* hr, oop* dst) :
235    _g1h(g1h), _hr(hr), _dst(dst), _value(true) {}
236
237  void do_oop(oop* p) {
238    if (_value && p != _dst) {
239      oop obj = oopDesc::load_heap_oop(p);
240      if (obj != NULL) {
241        HeapRegion* hr = _g1h->heap_region_containing(obj);
242        if (hr == _hr) {
243          // Another reference to the same region.
244          _value = false;
245        }
246      }
247    }
248  }
249  void do_oop(narrowOop* p) { ShouldNotReachHere(); }
250  bool value() const        { return _value;  }
251};
252
253void G1SATBCardTableModRefBS::write_ref_nmethod_pre(oop* dst, nmethod* nm) {
254  oop obj = oopDesc::load_heap_oop(dst);
255  if (obj != NULL) {
256    G1CollectedHeap* g1h = G1CollectedHeap::heap();
257    HeapRegion* hr = g1h->heap_region_containing(obj);
258    G1EnsureLastRefToRegion ensure_last_ref(g1h, hr, dst);
259    nm->oops_do(&ensure_last_ref);
260    if (ensure_last_ref.value()) {
261      // Last reference to this region, remove the nmethod from the rset.
262      hr->remove_strong_code_root(nm);
263    }
264  }
265}
266