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/g1BarrierSet.hpp" 28 #include "gc/g1/g1CollectedHeap.inline.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 36 // Represents a set of free small integer ids. 37 class FreeIdSet : public CHeapObj<mtGC> { 38 enum { 39 end_of_list = UINT_MAX, 40 claimed = UINT_MAX - 1 41 }; 42 43 uint _size; 44 Monitor* _mon; 45 46 uint* _ids; 47 uint _hd; 48 uint _waiters; 49 uint _claimed; 50 51 public: 52 FreeIdSet(uint size, Monitor* mon); 53 ~FreeIdSet(); 54 55 // Returns an unclaimed parallel id (waiting for one to be released if 56 // necessary). 57 uint claim_par_id(); 58 59 void release_par_id(uint id); 60 }; 61 62 FreeIdSet::FreeIdSet(uint size, Monitor* mon) : 63 _size(size), _mon(mon), _hd(0), _waiters(0), _claimed(0) 64 { 65 guarantee(size != 0, "must be"); 66 _ids = NEW_C_HEAP_ARRAY(uint, size, mtGC); 67 for (uint i = 0; i < size - 1; i++) { 68 _ids[i] = i+1; 69 } 70 _ids[size-1] = end_of_list; // end of list. 71 } 72 73 FreeIdSet::~FreeIdSet() { 74 FREE_C_HEAP_ARRAY(uint, _ids); 75 } 76 77 uint FreeIdSet::claim_par_id() { 78 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); 79 while (_hd == end_of_list) { 80 _waiters++; 81 _mon->wait(Mutex::_no_safepoint_check_flag); 82 _waiters--; 83 } 84 uint res = _hd; 85 _hd = _ids[res]; 86 _ids[res] = claimed; // For debugging. 87 _claimed++; 88 return res; 89 } 90 91 void FreeIdSet::release_par_id(uint id) { 92 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); 93 assert(_ids[id] == claimed, "Precondition."); 94 _ids[id] = _hd; 95 _hd = id; 96 _claimed--; 97 if (_waiters > 0) { 98 _mon->notify_all(); 99 } 100 } 101 102 DirtyCardQueue::DirtyCardQueue(DirtyCardQueueSet* dcqs, bool permanent) : 103 // Dirty card queues are always active, so we create them with their 104 // active field set to true. 105 PtrQueue(dcqs != NULL ? dcqs : &G1BarrierSet::dirty_card_queue_set(), permanent, true /* active */) 106 { } 107 108 DirtyCardQueue::~DirtyCardQueue() { 109 if (!is_permanent()) { 110 flush(); 111 } 112 } 113 114 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) : 115 PtrQueueSet(notify_when_complete), 116 _mut_process_closure(NULL), 117 _shared_dirty_card_queue(this, true /* permanent */), 118 _free_ids(NULL), 119 _processed_buffers_mut(0), _processed_buffers_rs_thread(0) 120 { 121 _all_active = true; 122 } 123 124 // Determines how many mutator threads can process the buffers in parallel. 125 uint DirtyCardQueueSet::num_par_ids() { 126 return (uint)os::initial_active_processor_count(); 127 } 128 129 void DirtyCardQueueSet::initialize(CardTableEntryClosure* cl, 130 Monitor* cbl_mon, 131 Mutex* fl_lock, 132 int process_completed_threshold, 133 int max_completed_queue, 134 Mutex* lock, 135 DirtyCardQueueSet* fl_owner, 136 bool init_free_ids) { 137 _mut_process_closure = cl; 138 PtrQueueSet::initialize(cbl_mon, 139 fl_lock, 140 process_completed_threshold, 141 max_completed_queue, 142 fl_owner); 143 set_buffer_size(G1UpdateBufferSize); 144 _shared_dirty_card_queue.set_lock(lock); 145 if (init_free_ids) { 146 _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon); 147 } 148 } 149 150 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) { 151 t->dirty_card_queue().handle_zero_index(); 152 } 153 154 bool DirtyCardQueueSet::apply_closure_to_buffer(CardTableEntryClosure* cl, 155 BufferNode* node, 156 bool consume, 157 uint worker_i) { 158 if (cl == NULL) return true; 159 bool result = true; 160 void** buf = BufferNode::make_buffer_from_node(node); 161 size_t limit = DirtyCardQueue::byte_index_to_index(buffer_size()); 162 size_t i = DirtyCardQueue::byte_index_to_index(node->index()); 163 for ( ; i < limit; ++i) { 164 jbyte* card_ptr = static_cast<jbyte*>(buf[i]); 165 assert(card_ptr != NULL, "invariant"); 166 if (!cl->do_card_ptr(card_ptr, worker_i)) { 167 result = false; // Incomplete processing. 168 break; 169 } 170 } 171 if (consume) { 172 size_t new_index = DirtyCardQueue::index_to_byte_index(i); 173 assert(new_index <= buffer_size(), "invariant"); 174 node->set_index(new_index); 175 } 176 return result; 177 } 178 179 #ifndef ASSERT 180 #define assert_fully_consumed(node, buffer_size) 181 #else 182 #define assert_fully_consumed(node, buffer_size) \ 183 do { \ 184 size_t _afc_index = (node)->index(); \ 185 size_t _afc_size = (buffer_size); \ 186 assert(_afc_index == _afc_size, \ 187 "Buffer was not fully consumed as claimed: index: " \ 188 SIZE_FORMAT ", size: " SIZE_FORMAT, \ 189 _afc_index, _afc_size); \ 190 } while (0) 191 #endif // ASSERT 192 193 bool DirtyCardQueueSet::mut_process_buffer(BufferNode* node) { 194 guarantee(_free_ids != NULL, "must be"); 195 196 uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id 197 bool result = apply_closure_to_buffer(_mut_process_closure, node, true, worker_i); 198 _free_ids->release_par_id(worker_i); // release the id 199 200 if (result) { 201 assert_fully_consumed(node, buffer_size()); 202 Atomic::inc(&_processed_buffers_mut); 203 } 204 return result; 205 } 206 207 208 BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) { 209 BufferNode* nd = NULL; 210 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); 211 212 if (_n_completed_buffers <= stop_at) { 213 _process_completed = false; 214 return NULL; 215 } 216 217 if (_completed_buffers_head != NULL) { 218 nd = _completed_buffers_head; 219 assert(_n_completed_buffers > 0, "Invariant"); 220 _completed_buffers_head = nd->next(); 221 _n_completed_buffers--; 222 if (_completed_buffers_head == NULL) { 223 assert(_n_completed_buffers == 0, "Invariant"); 224 _completed_buffers_tail = NULL; 225 } 226 } 227 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked()); 228 return nd; 229 } 230 231 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl, 232 uint worker_i, 233 size_t stop_at, 234 bool during_pause) { 235 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause"); 236 BufferNode* nd = get_completed_buffer(stop_at); 237 if (nd == NULL) { 238 return false; 239 } else { 240 if (apply_closure_to_buffer(cl, nd, true, worker_i)) { 241 assert_fully_consumed(nd, buffer_size()); 242 // Done with fully processed buffer. 243 deallocate_buffer(nd); 244 Atomic::inc(&_processed_buffers_rs_thread); 245 } else { 246 // Return partially processed buffer to the queue. 247 guarantee(!during_pause, "Should never stop early"); 248 enqueue_complete_buffer(nd); 249 } 250 return true; 251 } 252 } 253 254 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) { 255 BufferNode* nd = _cur_par_buffer_node; 256 while (nd != NULL) { 257 BufferNode* next = nd->next(); 258 void* actual = Atomic::cmpxchg_ptr(next, &_cur_par_buffer_node, nd); 259 if (actual == nd) { 260 bool b = apply_closure_to_buffer(cl, nd, false); 261 guarantee(b, "Should not stop early."); 262 nd = next; 263 } else { 264 nd = static_cast<BufferNode*>(actual); 265 } 266 } 267 } 268 269 // Deallocates any completed log buffers 270 void DirtyCardQueueSet::clear() { 271 BufferNode* buffers_to_delete = NULL; 272 { 273 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); 274 while (_completed_buffers_head != NULL) { 275 BufferNode* nd = _completed_buffers_head; 276 _completed_buffers_head = nd->next(); 277 nd->set_next(buffers_to_delete); 278 buffers_to_delete = nd; 279 } 280 _n_completed_buffers = 0; 281 _completed_buffers_tail = NULL; 282 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked()); 283 } 284 while (buffers_to_delete != NULL) { 285 BufferNode* nd = buffers_to_delete; 286 buffers_to_delete = nd->next(); 287 deallocate_buffer(nd); 288 } 289 290 } 291 292 void DirtyCardQueueSet::abandon_logs() { 293 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 294 clear(); 295 // Since abandon is done only at safepoints, we can safely manipulate 296 // these queues. 297 for (JavaThread* t = Threads::first(); t; t = t->next()) { 298 t->dirty_card_queue().reset(); 299 } 300 shared_dirty_card_queue()->reset(); 301 } 302 303 void DirtyCardQueueSet::concatenate_log(DirtyCardQueue& dcq) { 304 if (!dcq.is_empty()) { 305 dcq.flush(); 306 } 307 } 308 309 void DirtyCardQueueSet::concatenate_logs() { 310 // Iterate over all the threads, if we find a partial log add it to 311 // the global list of logs. Temporarily turn off the limit on the number 312 // of outstanding buffers. 313 int save_max_completed_queue = _max_completed_queue; 314 _max_completed_queue = max_jint; 315 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 316 for (JavaThread* t = Threads::first(); t; t = t->next()) { 317 concatenate_log(t->dirty_card_queue()); 318 } 319 concatenate_log(_shared_dirty_card_queue); 320 // Restore the completed buffer queue limit. 321 _max_completed_queue = save_max_completed_queue; 322 }