1 /* 2 * Copyright (c) 2001, 2017, 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/dirtyCardQueue.hpp" 27 #include "gc/g1/g1CollectedHeap.inline.hpp" 28 #include "gc/g1/g1RemSet.hpp" 29 #include "gc/g1/heapRegionRemSet.hpp" 30 #include "gc/shared/workgroup.hpp" 31 #include "runtime/atomic.hpp" 32 #include "runtime/mutexLocker.hpp" 33 #include "runtime/safepoint.hpp" 34 #include "runtime/thread.inline.hpp" 35 #include "runtime/threadSMR.hpp" 36 37 // Closure used for updating remembered sets and recording references that 38 // point into the collection set while the mutator is running. 39 // Assumed to be only executed concurrently with the mutator. Yields via 40 // SuspendibleThreadSet after every card. 41 class G1RefineCardConcurrentlyClosure: public CardTableEntryClosure { 42 public: 43 bool do_card_ptr(jbyte* card_ptr, uint worker_i) { 44 G1CollectedHeap::heap()->g1_rem_set()->refine_card_concurrently(card_ptr, worker_i); 45 46 if (SuspendibleThreadSet::should_yield()) { 47 // Caller will actually yield. 48 return false; 49 } 50 // Otherwise, we finished successfully; return true. 51 return true; 52 } 53 }; 54 55 // Represents a set of free small integer ids. 56 class FreeIdSet : public CHeapObj<mtGC> { 57 enum { 58 end_of_list = UINT_MAX, 59 claimed = UINT_MAX - 1 60 }; 61 62 uint _size; 63 Monitor* _mon; 64 65 uint* _ids; 66 uint _hd; 67 uint _waiters; 68 uint _claimed; 69 70 public: 71 FreeIdSet(uint size, Monitor* mon); 72 ~FreeIdSet(); 73 74 // Returns an unclaimed parallel id (waiting for one to be released if 75 // necessary). 76 uint claim_par_id(); 77 78 void release_par_id(uint id); 79 }; 80 81 FreeIdSet::FreeIdSet(uint size, Monitor* mon) : 82 _size(size), _mon(mon), _hd(0), _waiters(0), _claimed(0) 83 { 84 guarantee(size != 0, "must be"); 85 _ids = NEW_C_HEAP_ARRAY(uint, size, mtGC); 86 for (uint i = 0; i < size - 1; i++) { 87 _ids[i] = i+1; 88 } 89 _ids[size-1] = end_of_list; // end of list. 90 } 91 92 FreeIdSet::~FreeIdSet() { 93 FREE_C_HEAP_ARRAY(uint, _ids); 94 } 95 96 uint FreeIdSet::claim_par_id() { 97 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); 98 while (_hd == end_of_list) { 99 _waiters++; 100 _mon->wait(Mutex::_no_safepoint_check_flag); 101 _waiters--; 102 } 103 uint res = _hd; 104 _hd = _ids[res]; 105 _ids[res] = claimed; // For debugging. 106 _claimed++; 107 return res; 108 } 109 110 void FreeIdSet::release_par_id(uint id) { 111 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); 112 assert(_ids[id] == claimed, "Precondition."); 113 _ids[id] = _hd; 114 _hd = id; 115 _claimed--; 116 if (_waiters > 0) { 117 _mon->notify_all(); 118 } 119 } 120 121 DirtyCardQueue::DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent) : 122 // Dirty card queues are always active, so we create them with their 123 // active field set to true. 124 PtrQueue(qset, permanent, true /* active */) 125 { } 126 127 DirtyCardQueue::~DirtyCardQueue() { 128 if (!is_permanent()) { 129 flush(); 130 } 131 } 132 133 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) : 134 PtrQueueSet(notify_when_complete), 135 _shared_dirty_card_queue(this, true /* permanent */), 136 _free_ids(NULL), 137 _processed_buffers_mut(0), _processed_buffers_rs_thread(0) 138 { 139 _all_active = true; 140 } 141 142 // Determines how many mutator threads can process the buffers in parallel. 143 uint DirtyCardQueueSet::num_par_ids() { 144 return (uint)os::initial_active_processor_count(); 145 } 146 147 void DirtyCardQueueSet::initialize(Monitor* cbl_mon, 148 Mutex* fl_lock, 149 int process_completed_threshold, 150 int max_completed_queue, 151 Mutex* lock, 152 DirtyCardQueueSet* fl_owner, 153 bool init_free_ids) { 154 PtrQueueSet::initialize(cbl_mon, 155 fl_lock, 156 process_completed_threshold, 157 max_completed_queue, 158 fl_owner); 159 set_buffer_size(G1UpdateBufferSize); 160 _shared_dirty_card_queue.set_lock(lock); 161 if (init_free_ids) { 162 _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon); 163 } 164 } 165 166 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) { 167 t->dirty_card_queue().handle_zero_index(); 168 } 169 170 bool DirtyCardQueueSet::apply_closure_to_buffer(CardTableEntryClosure* cl, 171 BufferNode* node, 172 bool consume, 173 uint worker_i) { 174 if (cl == NULL) return true; 175 bool result = true; 176 void** buf = BufferNode::make_buffer_from_node(node); 177 size_t i = node->index(); 178 size_t limit = buffer_size(); 179 for ( ; i < limit; ++i) { 180 jbyte* card_ptr = static_cast<jbyte*>(buf[i]); 181 assert(card_ptr != NULL, "invariant"); 182 if (!cl->do_card_ptr(card_ptr, worker_i)) { 183 result = false; // Incomplete processing. 184 break; 185 } 186 } 187 if (consume) { 188 assert(i <= buffer_size(), "invariant"); 189 node->set_index(i); 190 } 191 return result; 192 } 193 194 #ifndef ASSERT 195 #define assert_fully_consumed(node, buffer_size) 196 #else 197 #define assert_fully_consumed(node, buffer_size) \ 198 do { \ 199 size_t _afc_index = (node)->index(); \ 200 size_t _afc_size = (buffer_size); \ 201 assert(_afc_index == _afc_size, \ 202 "Buffer was not fully consumed as claimed: index: " \ 203 SIZE_FORMAT ", size: " SIZE_FORMAT, \ 204 _afc_index, _afc_size); \ 205 } while (0) 206 #endif // ASSERT 207 208 bool DirtyCardQueueSet::mut_process_buffer(BufferNode* node) { 209 guarantee(_free_ids != NULL, "must be"); 210 211 uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id 212 G1RefineCardConcurrentlyClosure cl; 213 bool result = apply_closure_to_buffer(&cl, node, true, worker_i); 214 _free_ids->release_par_id(worker_i); // release the id 215 216 if (result) { 217 assert_fully_consumed(node, buffer_size()); 218 Atomic::inc(&_processed_buffers_mut); 219 } 220 return result; 221 } 222 223 224 BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) { 225 BufferNode* nd = NULL; 226 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); 227 228 if (_n_completed_buffers <= stop_at) { 229 _process_completed = false; 230 return NULL; 231 } 232 233 if (_completed_buffers_head != NULL) { 234 nd = _completed_buffers_head; 235 assert(_n_completed_buffers > 0, "Invariant"); 236 _completed_buffers_head = nd->next(); 237 _n_completed_buffers--; 238 if (_completed_buffers_head == NULL) { 239 assert(_n_completed_buffers == 0, "Invariant"); 240 _completed_buffers_tail = NULL; 241 } 242 } 243 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked()); 244 return nd; 245 } 246 247 bool DirtyCardQueueSet::refine_completed_buffer_concurrently(uint worker_i, size_t stop_at) { 248 G1RefineCardConcurrentlyClosure cl; 249 return apply_closure_to_completed_buffer(&cl, worker_i, stop_at, false); 250 } 251 252 bool DirtyCardQueueSet::apply_closure_during_gc(CardTableEntryClosure* cl, uint worker_i) { 253 assert_at_safepoint(false); 254 return apply_closure_to_completed_buffer(cl, worker_i, 0, true); 255 } 256 257 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl, 258 uint worker_i, 259 size_t stop_at, 260 bool during_pause) { 261 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause"); 262 BufferNode* nd = get_completed_buffer(stop_at); 263 if (nd == NULL) { 264 return false; 265 } else { 266 if (apply_closure_to_buffer(cl, nd, true, worker_i)) { 267 assert_fully_consumed(nd, buffer_size()); 268 // Done with fully processed buffer. 269 deallocate_buffer(nd); 270 Atomic::inc(&_processed_buffers_rs_thread); 271 } else { 272 // Return partially processed buffer to the queue. 273 guarantee(!during_pause, "Should never stop early"); 274 enqueue_complete_buffer(nd); 275 } 276 return true; 277 } 278 } 279 280 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) { 281 BufferNode* nd = _cur_par_buffer_node; 282 while (nd != NULL) { 283 BufferNode* next = nd->next(); 284 BufferNode* actual = Atomic::cmpxchg(next, &_cur_par_buffer_node, nd); 285 if (actual == nd) { 286 bool b = apply_closure_to_buffer(cl, nd, false); 287 guarantee(b, "Should not stop early."); 288 nd = next; 289 } else { 290 nd = actual; 291 } 292 } 293 } 294 295 // Deallocates any completed log buffers 296 void DirtyCardQueueSet::clear() { 297 BufferNode* buffers_to_delete = NULL; 298 { 299 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); 300 while (_completed_buffers_head != NULL) { 301 BufferNode* nd = _completed_buffers_head; 302 _completed_buffers_head = nd->next(); 303 nd->set_next(buffers_to_delete); 304 buffers_to_delete = nd; 305 } 306 _n_completed_buffers = 0; 307 _completed_buffers_tail = NULL; 308 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked()); 309 } 310 while (buffers_to_delete != NULL) { 311 BufferNode* nd = buffers_to_delete; 312 buffers_to_delete = nd->next(); 313 deallocate_buffer(nd); 314 } 315 316 } 317 318 void DirtyCardQueueSet::abandon_logs() { 319 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 320 clear(); 321 // Since abandon is done only at safepoints, we can safely manipulate 322 // these queues. 323 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 324 t->dirty_card_queue().reset(); 325 } 326 shared_dirty_card_queue()->reset(); 327 } 328 329 void DirtyCardQueueSet::concatenate_log(DirtyCardQueue& dcq) { 330 if (!dcq.is_empty()) { 331 dcq.flush(); 332 } 333 } 334 335 void DirtyCardQueueSet::concatenate_logs() { 336 // Iterate over all the threads, if we find a partial log add it to 337 // the global list of logs. Temporarily turn off the limit on the number 338 // of outstanding buffers. 339 int save_max_completed_queue = _max_completed_queue; 340 _max_completed_queue = max_jint; 341 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 342 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 343 concatenate_log(t->dirty_card_queue()); 344 } 345 concatenate_log(_shared_dirty_card_queue); 346 // Restore the completed buffer queue limit. 347 _max_completed_queue = save_max_completed_queue; 348 }