1 /* 2 * Copyright (c) 2001, 2019, 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/g1BufferNodeList.hpp" 27 #include "gc/g1/g1CardTableEntryClosure.hpp" 28 #include "gc/g1/g1CollectedHeap.inline.hpp" 29 #include "gc/g1/g1DirtyCardQueue.hpp" 30 #include "gc/g1/g1FreeIdSet.hpp" 31 #include "gc/g1/g1RedirtyCardsQueue.hpp" 32 #include "gc/g1/g1RemSet.hpp" 33 #include "gc/g1/g1ThreadLocalData.hpp" 34 #include "gc/g1/heapRegionRemSet.hpp" 35 #include "gc/shared/suspendibleThreadSet.hpp" 36 #include "gc/shared/workgroup.hpp" 37 #include "runtime/atomic.hpp" 38 #include "runtime/flags/flagSetting.hpp" 39 #include "runtime/mutexLocker.hpp" 40 #include "runtime/safepoint.hpp" 41 #include "runtime/thread.inline.hpp" 42 #include "runtime/threadSMR.hpp" 43 44 // Closure used for updating remembered sets and recording references that 45 // point into the collection set while the mutator is running. 46 // Assumed to be only executed concurrently with the mutator. Yields via 47 // SuspendibleThreadSet after every card. 48 class G1RefineCardConcurrentlyClosure: public G1CardTableEntryClosure { 49 public: 50 bool do_card_ptr(CardValue* card_ptr, uint worker_i) { 51 G1CollectedHeap::heap()->rem_set()->refine_card_concurrently(card_ptr, worker_i); 52 53 if (SuspendibleThreadSet::should_yield()) { 54 // Caller will actually yield. 55 return false; 56 } 57 // Otherwise, we finished successfully; return true. 58 return true; 59 } 60 }; 61 62 G1DirtyCardQueue::G1DirtyCardQueue(G1DirtyCardQueueSet* qset) : 63 // Dirty card queues are always active, so we create them with their 64 // active field set to true. 65 PtrQueue(qset, true /* active */) 66 { } 67 68 G1DirtyCardQueue::~G1DirtyCardQueue() { 69 flush(); 70 } 71 72 void G1DirtyCardQueue::handle_completed_buffer() { 73 assert(_buf != NULL, "precondition"); 74 BufferNode* node = BufferNode::make_node_from_buffer(_buf, index()); 75 G1DirtyCardQueueSet* dcqs = dirty_card_qset(); 76 if (dcqs->process_or_enqueue_completed_buffer(node)) { 77 reset(); // Buffer fully processed, reset index. 78 } else { 79 allocate_buffer(); // Buffer enqueued, get a new one. 80 } 81 } 82 83 G1DirtyCardQueueSet::G1DirtyCardQueueSet() : 84 PtrQueueSet(), 85 _cbl_mon(NULL), 86 _completed_buffers_head(NULL), 87 _completed_buffers_tail(NULL), 88 _num_cards(0), 89 _process_cards_threshold(ProcessCardsThresholdNever), 90 _process_completed_buffers(false), 91 _max_cards(MaxCardsUnlimited), 92 _max_cards_padding(0), 93 _free_ids(0, num_par_ids()), 94 _processed_buffers_mut(0), 95 _processed_buffers_rs_thread(0) 96 { 97 _all_active = true; 98 } 99 100 G1DirtyCardQueueSet::~G1DirtyCardQueueSet() { 101 abandon_completed_buffers(); 102 } 103 104 // Determines how many mutator threads can process the buffers in parallel. 105 uint G1DirtyCardQueueSet::num_par_ids() { 106 return (uint)os::initial_active_processor_count(); 107 } 108 109 void G1DirtyCardQueueSet::initialize(Monitor* cbl_mon, 110 BufferNode::Allocator* allocator) { 111 PtrQueueSet::initialize(allocator); 112 assert(_cbl_mon == NULL, "Init order issue?"); 113 _cbl_mon = cbl_mon; 114 } 115 116 void G1DirtyCardQueueSet::handle_zero_index_for_thread(Thread* t) { 117 G1ThreadLocalData::dirty_card_queue(t).handle_zero_index(); 118 } 119 120 void G1DirtyCardQueueSet::enqueue_completed_buffer(BufferNode* cbn) { 121 MonitorLocker ml(_cbl_mon, Mutex::_no_safepoint_check_flag); 122 cbn->set_next(NULL); 123 if (_completed_buffers_tail == NULL) { 124 assert(_completed_buffers_head == NULL, "Well-formedness"); 125 _completed_buffers_head = cbn; 126 _completed_buffers_tail = cbn; 127 } else { 128 _completed_buffers_tail->set_next(cbn); 129 _completed_buffers_tail = cbn; 130 } 131 _num_cards += buffer_size() - cbn->index(); 132 133 if (!process_completed_buffers() && 134 (num_cards() > process_cards_threshold())) { 135 set_process_completed_buffers(true); 136 ml.notify_all(); 137 } 138 verify_num_cards(); 139 } 140 141 BufferNode* G1DirtyCardQueueSet::get_completed_buffer(size_t stop_at) { 142 MutexLocker x(_cbl_mon, Mutex::_no_safepoint_check_flag); 143 144 if (num_cards() <= stop_at) { 145 return NULL; 146 } 147 148 assert(num_cards() > 0, "invariant"); 149 assert(_completed_buffers_head != NULL, "invariant"); 150 assert(_completed_buffers_tail != NULL, "invariant"); 151 152 BufferNode* bn = _completed_buffers_head; 153 _num_cards -= buffer_size() - bn->index(); 154 _completed_buffers_head = bn->next(); 155 if (_completed_buffers_head == NULL) { 156 assert(num_cards() == 0, "invariant"); 157 _completed_buffers_tail = NULL; 158 set_process_completed_buffers(false); 159 } 160 verify_num_cards(); 161 bn->set_next(NULL); 162 return bn; 163 } 164 165 #ifdef ASSERT 166 void G1DirtyCardQueueSet::verify_num_cards() const { 167 size_t actual = 0; 168 BufferNode* cur = _completed_buffers_head; 169 while (cur != NULL) { 170 actual += buffer_size() - cur->index(); 171 cur = cur->next(); 172 } 173 assert(actual == _num_cards, 174 "Num entries in completed buffers should be " SIZE_FORMAT " but are " SIZE_FORMAT, 175 _num_cards, actual); 176 } 177 #endif 178 179 void G1DirtyCardQueueSet::abandon_completed_buffers() { 180 BufferNode* buffers_to_delete = NULL; 181 { 182 MutexLocker x(_cbl_mon, Mutex::_no_safepoint_check_flag); 183 buffers_to_delete = _completed_buffers_head; 184 _completed_buffers_head = NULL; 185 _completed_buffers_tail = NULL; 186 _num_cards = 0; 187 set_process_completed_buffers(false); 188 } 189 while (buffers_to_delete != NULL) { 190 BufferNode* bn = buffers_to_delete; 191 buffers_to_delete = bn->next(); 192 bn->set_next(NULL); 193 deallocate_buffer(bn); 194 } 195 } 196 197 void G1DirtyCardQueueSet::notify_if_necessary() { 198 MonitorLocker ml(_cbl_mon, Mutex::_no_safepoint_check_flag); 199 if (num_cards() > process_cards_threshold()) { 200 set_process_completed_buffers(true); 201 ml.notify_all(); 202 } 203 } 204 205 // Merge lists of buffers. Notify the processing threads. 206 // The source queue is emptied as a result. The queues 207 // must share the monitor. 208 void G1DirtyCardQueueSet::merge_bufferlists(G1RedirtyCardsQueueSet* src) { 209 assert(allocator() == src->allocator(), "precondition"); 210 const G1BufferNodeList from = src->take_all_completed_buffers(); 211 if (from._head == NULL) return; 212 213 MutexLocker x(_cbl_mon, Mutex::_no_safepoint_check_flag); 214 if (_completed_buffers_tail == NULL) { 215 assert(_completed_buffers_head == NULL, "Well-formedness"); 216 _completed_buffers_head = from._head; 217 _completed_buffers_tail = from._tail; 218 } else { 219 assert(_completed_buffers_head != NULL, "Well formedness"); 220 _completed_buffers_tail->set_next(from._head); 221 _completed_buffers_tail = from._tail; 222 } 223 _num_cards += from._entry_count; 224 225 assert(_completed_buffers_head == NULL && _completed_buffers_tail == NULL || 226 _completed_buffers_head != NULL && _completed_buffers_tail != NULL, 227 "Sanity"); 228 verify_num_cards(); 229 } 230 231 bool G1DirtyCardQueueSet::apply_closure_to_buffer(G1CardTableEntryClosure* cl, 232 BufferNode* node, 233 uint worker_i) { 234 if (cl == NULL) return true; 235 bool result = true; 236 void** buf = BufferNode::make_buffer_from_node(node); 237 size_t i = node->index(); 238 size_t limit = buffer_size(); 239 for ( ; i < limit; ++i) { 240 CardTable::CardValue* card_ptr = static_cast<CardTable::CardValue*>(buf[i]); 241 assert(card_ptr != NULL, "invariant"); 242 if (!cl->do_card_ptr(card_ptr, worker_i)) { 243 result = false; // Incomplete processing. 244 break; 245 } 246 } 247 assert(i <= buffer_size(), "invariant"); 248 node->set_index(i); 249 return result; 250 } 251 252 #ifndef ASSERT 253 #define assert_fully_consumed(node, buffer_size) 254 #else 255 #define assert_fully_consumed(node, buffer_size) \ 256 do { \ 257 size_t _afc_index = (node)->index(); \ 258 size_t _afc_size = (buffer_size); \ 259 assert(_afc_index == _afc_size, \ 260 "Buffer was not fully consumed as claimed: index: " \ 261 SIZE_FORMAT ", size: " SIZE_FORMAT, \ 262 _afc_index, _afc_size); \ 263 } while (0) 264 #endif // ASSERT 265 266 bool G1DirtyCardQueueSet::process_or_enqueue_completed_buffer(BufferNode* node) { 267 if (Thread::current()->is_Java_thread()) { 268 // If the number of buffers exceeds the limit, make this Java 269 // thread do the processing itself. We don't lock to access 270 // buffer count or padding; it is fine to be imprecise here. The 271 // add of padding could overflow, which is treated as unlimited. 272 size_t limit = max_cards() + max_cards_padding(); 273 if ((num_cards() > limit) && (limit >= max_cards())) { 274 if (mut_process_buffer(node)) { 275 return true; 276 } 277 } 278 } 279 enqueue_completed_buffer(node); 280 return false; 281 } 282 283 bool G1DirtyCardQueueSet::mut_process_buffer(BufferNode* node) { 284 uint worker_id = _free_ids.claim_par_id(); // temporarily claim an id 285 G1RefineCardConcurrentlyClosure cl; 286 bool result = apply_closure_to_buffer(&cl, node, worker_id); 287 _free_ids.release_par_id(worker_id); // release the id 288 289 if (result) { 290 assert_fully_consumed(node, buffer_size()); 291 Atomic::inc(&_processed_buffers_mut); 292 } 293 return result; 294 } 295 296 bool G1DirtyCardQueueSet::refine_completed_buffer_concurrently(uint worker_i, size_t stop_at) { 297 G1RefineCardConcurrentlyClosure cl; 298 return apply_closure_to_completed_buffer(&cl, worker_i, stop_at, false); 299 } 300 301 bool G1DirtyCardQueueSet::apply_closure_during_gc(G1CardTableEntryClosure* cl, uint worker_i) { 302 assert_at_safepoint(); 303 return apply_closure_to_completed_buffer(cl, worker_i, 0, true); 304 } 305 306 bool G1DirtyCardQueueSet::apply_closure_to_completed_buffer(G1CardTableEntryClosure* cl, 307 uint worker_i, 308 size_t stop_at, 309 bool during_pause) { 310 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause"); 311 BufferNode* nd = get_completed_buffer(stop_at); 312 if (nd == NULL) { 313 return false; 314 } else { 315 if (apply_closure_to_buffer(cl, nd, worker_i)) { 316 assert_fully_consumed(nd, buffer_size()); 317 // Done with fully processed buffer. 318 deallocate_buffer(nd); 319 Atomic::inc(&_processed_buffers_rs_thread); 320 } else { 321 // Return partially processed buffer to the queue. 322 guarantee(!during_pause, "Should never stop early"); 323 enqueue_completed_buffer(nd); 324 } 325 return true; 326 } 327 } 328 329 void G1DirtyCardQueueSet::abandon_logs() { 330 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 331 abandon_completed_buffers(); 332 333 // Since abandon is done only at safepoints, we can safely manipulate 334 // these queues. 335 struct AbandonThreadLogClosure : public ThreadClosure { 336 virtual void do_thread(Thread* t) { 337 G1ThreadLocalData::dirty_card_queue(t).reset(); 338 } 339 } closure; 340 Threads::threads_do(&closure); 341 342 G1BarrierSet::shared_dirty_card_queue().reset(); 343 } 344 345 void G1DirtyCardQueueSet::concatenate_logs() { 346 // Iterate over all the threads, if we find a partial log add it to 347 // the global list of logs. Temporarily turn off the limit on the number 348 // of outstanding buffers. 349 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 350 size_t old_limit = max_cards(); 351 set_max_cards(MaxCardsUnlimited); 352 353 struct ConcatenateThreadLogClosure : public ThreadClosure { 354 virtual void do_thread(Thread* t) { 355 G1DirtyCardQueue& dcq = G1ThreadLocalData::dirty_card_queue(t); 356 if (!dcq.is_empty()) { 357 dcq.flush(); 358 } 359 } 360 } closure; 361 Threads::threads_do(&closure); 362 363 G1BarrierSet::shared_dirty_card_queue().flush(); 364 set_max_cards(old_limit); 365 }