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 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 // 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 } 103 104 void 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 112 void G1SATBCardTableModRefBS::verify_g1_young_region(MemRegion mr) { 113 verify_region(mr, g1_young_gen, true); 114 } 115 #endif 116 117 void 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 } 122 123 G1SATBCardTableLoggingModRefBS:: 124 G1SATBCardTableLoggingModRefBS(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 } 131 132 void 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 } 156 157 void 158 G1SATBCardTableLoggingModRefBS::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 } 179 180 void 181 G1SATBCardTableLoggingModRefBS::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 } 217 218 void 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 } 226 227 class G1EnsureLastRefToRegion : public OopClosure { 228 G1CollectedHeap* _g1h; 229 HeapRegion* _hr; 230 oop* _dst; 231 232 bool _value; 233 public: 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 }; 252 253 void 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 }