1 /* 2 * Copyright (c) 2001, 2018, 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/g1ThreadLocalData.hpp" 30 #include "gc/g1/heapRegionRemSet.hpp" 31 #include "gc/shared/suspendibleThreadSet.hpp" 32 #include "gc/shared/workgroup.hpp" 33 #include "runtime/atomic.hpp" 34 #include "runtime/flags/flagSetting.hpp" 35 #include "runtime/mutexLocker.hpp" 36 #include "runtime/safepoint.hpp" 37 #include "runtime/thread.inline.hpp" 38 #include "runtime/threadSMR.hpp" 39 40 // Closure used for updating remembered sets and recording references that 41 // point into the collection set while the mutator is running. 42 // Assumed to be only executed concurrently with the mutator. Yields via 43 // SuspendibleThreadSet after every card. 44 class G1RefineCardConcurrentlyClosure: public CardTableEntryClosure { 45 public: 46 bool do_card_ptr(jbyte* card_ptr, uint worker_i) { 47 G1CollectedHeap::heap()->g1_rem_set()->refine_card_concurrently(card_ptr, worker_i); 48 49 if (SuspendibleThreadSet::should_yield()) { 50 // Caller will actually yield. 51 return false; 52 } 53 // Otherwise, we finished successfully; return true. 54 return true; 55 } 56 }; 57 58 // Represents a set of free small integer ids. 59 class FreeIdSet : public CHeapObj<mtGC> { 60 enum { 61 end_of_list = UINT_MAX, 62 claimed = UINT_MAX - 1 63 }; 64 65 uint _size; 66 Monitor* _mon; 67 68 uint* _ids; 69 uint _hd; 70 uint _waiters; 71 uint _claimed; 72 73 public: 74 FreeIdSet(uint size, Monitor* mon); 75 ~FreeIdSet(); 76 77 // Returns an unclaimed parallel id (waiting for one to be released if 78 // necessary). 79 uint claim_par_id(); 80 81 void release_par_id(uint id); 82 }; 83 84 FreeIdSet::FreeIdSet(uint size, Monitor* mon) : 85 _size(size), _mon(mon), _hd(0), _waiters(0), _claimed(0) 86 { 87 guarantee(size != 0, "must be"); 88 _ids = NEW_C_HEAP_ARRAY(uint, size, mtGC); 89 for (uint i = 0; i < size - 1; i++) { 90 _ids[i] = i+1; 91 } 92 _ids[size-1] = end_of_list; // end of list. 93 } 94 95 FreeIdSet::~FreeIdSet() { 96 FREE_C_HEAP_ARRAY(uint, _ids); 97 } 98 99 uint FreeIdSet::claim_par_id() { 100 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); 101 while (_hd == end_of_list) { 102 _waiters++; 103 _mon->wait(Mutex::_no_safepoint_check_flag); 104 _waiters--; 105 } 106 uint res = _hd; 107 _hd = _ids[res]; 108 _ids[res] = claimed; // For debugging. 109 _claimed++; 110 return res; 111 } 112 113 void FreeIdSet::release_par_id(uint id) { 114 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); 115 assert(_ids[id] == claimed, "Precondition."); 116 _ids[id] = _hd; 117 _hd = id; 118 _claimed--; 119 if (_waiters > 0) { 120 _mon->notify_all(); 121 } 122 } 123 124 DirtyCardQueue::DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent) : 125 // Dirty card queues are always active, so we create them with their 126 // active field set to true. 127 PtrQueue(qset, permanent, true /* active */) 128 { } 129 130 DirtyCardQueue::~DirtyCardQueue() { 131 if (!is_permanent()) { 132 flush(); 133 } 134 } 135 136 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) : 137 PtrQueueSet(notify_when_complete), 138 _shared_dirty_card_queue(this, true /* permanent */), 139 _free_ids(NULL), 140 _processed_buffers_mut(0), _processed_buffers_rs_thread(0) 141 { 142 _all_active = true; 143 } 144 145 // Determines how many mutator threads can process the buffers in parallel. 146 uint DirtyCardQueueSet::num_par_ids() { 147 return (uint)os::initial_active_processor_count(); 148 } 149 150 void DirtyCardQueueSet::initialize(Monitor* cbl_mon, 151 BufferNode::Allocator* allocator, 152 Mutex* lock, 153 bool init_free_ids) { 154 PtrQueueSet::initialize(cbl_mon, allocator); 155 _shared_dirty_card_queue.set_lock(lock); 156 if (init_free_ids) { 157 _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon); 158 } 159 } 160 161 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) { 162 G1ThreadLocalData::dirty_card_queue(t).handle_zero_index(); 163 } 164 165 bool DirtyCardQueueSet::apply_closure_to_buffer(CardTableEntryClosure* cl, 166 BufferNode* node, 167 bool consume, 168 uint worker_i) { 169 if (cl == NULL) return true; 170 bool result = true; 171 void** buf = BufferNode::make_buffer_from_node(node); 172 size_t i = node->index(); 173 size_t limit = buffer_size(); 174 for ( ; i < limit; ++i) { 175 jbyte* card_ptr = static_cast<jbyte*>(buf[i]); 176 assert(card_ptr != NULL, "invariant"); 177 if (!cl->do_card_ptr(card_ptr, worker_i)) { 178 result = false; // Incomplete processing. 179 break; 180 } 181 } 182 if (consume) { 183 assert(i <= buffer_size(), "invariant"); 184 node->set_index(i); 185 } 186 return result; 187 } 188 189 #ifndef ASSERT 190 #define assert_fully_consumed(node, buffer_size) 191 #else 192 #define assert_fully_consumed(node, buffer_size) \ 193 do { \ 194 size_t _afc_index = (node)->index(); \ 195 size_t _afc_size = (buffer_size); \ 196 assert(_afc_index == _afc_size, \ 197 "Buffer was not fully consumed as claimed: index: " \ 198 SIZE_FORMAT ", size: " SIZE_FORMAT, \ 199 _afc_index, _afc_size); \ 200 } while (0) 201 #endif // ASSERT 202 203 bool DirtyCardQueueSet::mut_process_buffer(BufferNode* node) { 204 guarantee(_free_ids != NULL, "must be"); 205 206 uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id 207 G1RefineCardConcurrentlyClosure cl; 208 bool result = apply_closure_to_buffer(&cl, node, true, worker_i); 209 _free_ids->release_par_id(worker_i); // release the id 210 211 if (result) { 212 assert_fully_consumed(node, buffer_size()); 213 Atomic::inc(&_processed_buffers_mut); 214 } 215 return result; 216 } 217 218 219 BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) { 220 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); 221 222 if (_n_completed_buffers <= stop_at) { 223 return NULL; 224 } 225 226 assert(_n_completed_buffers > 0, "invariant"); 227 assert(_completed_buffers_head != NULL, "invariant"); 228 assert(_completed_buffers_tail != NULL, "invariant"); 229 230 BufferNode* nd = _completed_buffers_head; 231 _completed_buffers_head = nd->next(); 232 _n_completed_buffers--; 233 if (_completed_buffers_head == NULL) { 234 assert(_n_completed_buffers == 0, "Invariant"); 235 _completed_buffers_tail = NULL; 236 } 237 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked()); 238 return nd; 239 } 240 241 bool DirtyCardQueueSet::refine_completed_buffer_concurrently(uint worker_i, size_t stop_at) { 242 G1RefineCardConcurrentlyClosure cl; 243 return apply_closure_to_completed_buffer(&cl, worker_i, stop_at, false); 244 } 245 246 bool DirtyCardQueueSet::apply_closure_during_gc(CardTableEntryClosure* cl, uint worker_i) { 247 assert_at_safepoint(); 248 return apply_closure_to_completed_buffer(cl, worker_i, 0, true); 249 } 250 251 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl, 252 uint worker_i, 253 size_t stop_at, 254 bool during_pause) { 255 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause"); 256 BufferNode* nd = get_completed_buffer(stop_at); 257 if (nd == NULL) { 258 return false; 259 } else { 260 if (apply_closure_to_buffer(cl, nd, true, worker_i)) { 261 assert_fully_consumed(nd, buffer_size()); 262 // Done with fully processed buffer. 263 deallocate_buffer(nd); 264 Atomic::inc(&_processed_buffers_rs_thread); 265 } else { 266 // Return partially processed buffer to the queue. 267 guarantee(!during_pause, "Should never stop early"); 268 enqueue_complete_buffer(nd); 269 } 270 return true; 271 } 272 } 273 274 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) { 275 BufferNode* nd = _cur_par_buffer_node; 276 while (nd != NULL) { 277 BufferNode* next = nd->next(); 278 BufferNode* actual = Atomic::cmpxchg(next, &_cur_par_buffer_node, nd); 279 if (actual == nd) { 280 bool b = apply_closure_to_buffer(cl, nd, false); 281 guarantee(b, "Should not stop early."); 282 nd = next; 283 } else { 284 nd = actual; 285 } 286 } 287 } 288 289 // Deallocates any completed log buffers 290 void DirtyCardQueueSet::clear() { 291 BufferNode* buffers_to_delete = NULL; 292 { 293 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); 294 while (_completed_buffers_head != NULL) { 295 BufferNode* nd = _completed_buffers_head; 296 _completed_buffers_head = nd->next(); 297 nd->set_next(buffers_to_delete); 298 buffers_to_delete = nd; 299 } 300 _n_completed_buffers = 0; 301 _completed_buffers_tail = NULL; 302 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked()); 303 } 304 while (buffers_to_delete != NULL) { 305 BufferNode* nd = buffers_to_delete; 306 buffers_to_delete = nd->next(); 307 deallocate_buffer(nd); 308 } 309 310 } 311 312 void DirtyCardQueueSet::abandon_logs() { 313 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 314 clear(); 315 // Since abandon is done only at safepoints, we can safely manipulate 316 // these queues. 317 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 318 G1ThreadLocalData::dirty_card_queue(t).reset(); 319 } 320 shared_dirty_card_queue()->reset(); 321 } 322 323 void DirtyCardQueueSet::concatenate_log(DirtyCardQueue& dcq) { 324 if (!dcq.is_empty()) { 325 dcq.flush(); 326 } 327 } 328 329 void DirtyCardQueueSet::concatenate_logs() { 330 // Iterate over all the threads, if we find a partial log add it to 331 // the global list of logs. Temporarily turn off the limit on the number 332 // of outstanding buffers. 333 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 334 SizeTFlagSetting local_max(_max_completed_buffers, 335 MaxCompletedBuffersUnlimited); 336 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 337 concatenate_log(G1ThreadLocalData::dirty_card_queue(t)); 338 } 339 concatenate_log(_shared_dirty_card_queue); 340 }