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/g1CollectedHeap.inline.hpp" 27 #include "gc/g1/g1DirtyCardQueue.hpp" 28 #include "gc/g1/g1FreeIdSet.hpp" 29 #include "gc/g1/g1RemSet.hpp" 30 #include "gc/g1/g1ThreadLocalData.hpp" 31 #include "gc/g1/heapRegionRemSet.hpp" 32 #include "gc/shared/suspendibleThreadSet.hpp" 33 #include "gc/shared/workgroup.hpp" 34 #include "runtime/atomic.hpp" 35 #include "runtime/flags/flagSetting.hpp" 36 #include "runtime/mutexLocker.hpp" 37 #include "runtime/safepoint.hpp" 38 #include "runtime/thread.inline.hpp" 39 #include "runtime/threadSMR.hpp" 40 41 // Closure used for updating remembered sets and recording references that 42 // point into the collection set while the mutator is running. 43 // Assumed to be only executed concurrently with the mutator. Yields via 44 // SuspendibleThreadSet after every card. 45 class G1RefineCardConcurrentlyClosure: public G1CardTableEntryClosure { 46 public: 47 bool do_card_ptr(CardValue* card_ptr, uint worker_i) { 48 G1CollectedHeap::heap()->rem_set()->refine_card_concurrently(card_ptr, worker_i); 49 50 if (SuspendibleThreadSet::should_yield()) { 51 // Caller will actually yield. 52 return false; 53 } 54 // Otherwise, we finished successfully; return true. 55 return true; 56 } 57 }; 58 59 G1DirtyCardQueue::G1DirtyCardQueue(G1DirtyCardQueueSet* qset) : 60 // Dirty card queues are always active, so we create them with their 61 // active field set to true. 62 PtrQueue(qset, true /* active */) 63 { } 64 65 G1DirtyCardQueue::~G1DirtyCardQueue() { 66 flush(); 67 } 68 69 void G1DirtyCardQueue::handle_completed_buffer() { 70 assert(_buf != NULL, "precondition"); 71 BufferNode* node = BufferNode::make_node_from_buffer(_buf, index()); 72 G1DirtyCardQueueSet* dcqs = dirty_card_qset(); 73 if (dcqs->process_or_enqueue_completed_buffer(node)) { 74 reset(); // Buffer fully processed, reset index. 75 } else { 76 allocate_buffer(); // Buffer enqueued, get a new one. 77 } 78 } 79 80 G1DirtyCardQueueSet::G1DirtyCardQueueSet(bool notify_when_complete) : 81 PtrQueueSet(notify_when_complete), 82 _max_completed_buffers(MaxCompletedBuffersUnlimited), 83 _completed_buffers_padding(0), 84 _free_ids(NULL), 85 _processed_buffers_mut(0), 86 _processed_buffers_rs_thread(0), 87 _cur_par_buffer_node(NULL) 88 { 89 _all_active = true; 90 } 91 92 G1DirtyCardQueueSet::~G1DirtyCardQueueSet() { 93 delete _free_ids; 94 } 95 96 // Determines how many mutator threads can process the buffers in parallel. 97 uint G1DirtyCardQueueSet::num_par_ids() { 98 return (uint)os::initial_active_processor_count(); 99 } 100 101 void G1DirtyCardQueueSet::initialize(Monitor* cbl_mon, 102 BufferNode::Allocator* allocator, 103 bool init_free_ids) { 104 PtrQueueSet::initialize(cbl_mon, allocator); 105 if (init_free_ids) { 106 _free_ids = new G1FreeIdSet(0, num_par_ids()); 107 } 108 } 109 110 void G1DirtyCardQueueSet::handle_zero_index_for_thread(Thread* t) { 111 G1ThreadLocalData::dirty_card_queue(t).handle_zero_index(); 112 } 113 114 bool G1DirtyCardQueueSet::apply_closure_to_buffer(G1CardTableEntryClosure* cl, 115 BufferNode* node, 116 bool consume, 117 uint worker_i) { 118 if (cl == NULL) return true; 119 bool result = true; 120 void** buf = BufferNode::make_buffer_from_node(node); 121 size_t i = node->index(); 122 size_t limit = buffer_size(); 123 for ( ; i < limit; ++i) { 124 CardTable::CardValue* card_ptr = static_cast<CardTable::CardValue*>(buf[i]); 125 assert(card_ptr != NULL, "invariant"); 126 if (!cl->do_card_ptr(card_ptr, worker_i)) { 127 result = false; // Incomplete processing. 128 break; 129 } 130 } 131 if (consume) { 132 assert(i <= buffer_size(), "invariant"); 133 node->set_index(i); 134 } 135 return result; 136 } 137 138 #ifndef ASSERT 139 #define assert_fully_consumed(node, buffer_size) 140 #else 141 #define assert_fully_consumed(node, buffer_size) \ 142 do { \ 143 size_t _afc_index = (node)->index(); \ 144 size_t _afc_size = (buffer_size); \ 145 assert(_afc_index == _afc_size, \ 146 "Buffer was not fully consumed as claimed: index: " \ 147 SIZE_FORMAT ", size: " SIZE_FORMAT, \ 148 _afc_index, _afc_size); \ 149 } while (0) 150 #endif // ASSERT 151 152 bool G1DirtyCardQueueSet::process_or_enqueue_completed_buffer(BufferNode* node) { 153 if (Thread::current()->is_Java_thread()) { 154 // If the number of buffers exceeds the limit, make this Java 155 // thread do the processing itself. We don't lock to access 156 // buffer count or padding; it is fine to be imprecise here. The 157 // add of padding could overflow, which is treated as unlimited. 158 size_t max_buffers = max_completed_buffers(); 159 size_t limit = max_buffers + completed_buffers_padding(); 160 if ((completed_buffers_num() > limit) && (limit >= max_buffers)) { 161 if (mut_process_buffer(node)) { 162 return true; 163 } 164 } 165 } 166 enqueue_completed_buffer(node); 167 return false; 168 } 169 170 bool G1DirtyCardQueueSet::mut_process_buffer(BufferNode* node) { 171 guarantee(_free_ids != NULL, "must be"); 172 173 uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id 174 G1RefineCardConcurrentlyClosure cl; 175 bool result = apply_closure_to_buffer(&cl, node, true, worker_i); 176 _free_ids->release_par_id(worker_i); // release the id 177 178 if (result) { 179 assert_fully_consumed(node, buffer_size()); 180 Atomic::inc(&_processed_buffers_mut); 181 } 182 return result; 183 } 184 185 bool G1DirtyCardQueueSet::refine_completed_buffer_concurrently(uint worker_i, size_t stop_at) { 186 G1RefineCardConcurrentlyClosure cl; 187 return apply_closure_to_completed_buffer(&cl, worker_i, stop_at, false); 188 } 189 190 bool G1DirtyCardQueueSet::apply_closure_during_gc(G1CardTableEntryClosure* cl, uint worker_i) { 191 assert_at_safepoint(); 192 return apply_closure_to_completed_buffer(cl, worker_i, 0, true); 193 } 194 195 bool G1DirtyCardQueueSet::apply_closure_to_completed_buffer(G1CardTableEntryClosure* cl, 196 uint worker_i, 197 size_t stop_at, 198 bool during_pause) { 199 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause"); 200 BufferNode* nd = get_completed_buffer(stop_at); 201 if (nd == NULL) { 202 return false; 203 } else { 204 if (apply_closure_to_buffer(cl, nd, true, worker_i)) { 205 assert_fully_consumed(nd, buffer_size()); 206 // Done with fully processed buffer. 207 deallocate_buffer(nd); 208 Atomic::inc(&_processed_buffers_rs_thread); 209 } else { 210 // Return partially processed buffer to the queue. 211 guarantee(!during_pause, "Should never stop early"); 212 enqueue_completed_buffer(nd); 213 } 214 return true; 215 } 216 } 217 218 void G1DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(G1CardTableEntryClosure* cl) { 219 BufferNode* nd = _cur_par_buffer_node; 220 while (nd != NULL) { 221 BufferNode* next = nd->next(); 222 BufferNode* actual = Atomic::cmpxchg(next, &_cur_par_buffer_node, nd); 223 if (actual == nd) { 224 bool b = apply_closure_to_buffer(cl, nd, false); 225 guarantee(b, "Should not stop early."); 226 nd = next; 227 } else { 228 nd = actual; 229 } 230 } 231 } 232 233 void G1DirtyCardQueueSet::abandon_logs() { 234 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 235 abandon_completed_buffers(); 236 237 // Since abandon is done only at safepoints, we can safely manipulate 238 // these queues. 239 struct AbandonThreadLogClosure : public ThreadClosure { 240 virtual void do_thread(Thread* t) { 241 G1ThreadLocalData::dirty_card_queue(t).reset(); 242 } 243 } closure; 244 Threads::threads_do(&closure); 245 246 G1BarrierSet::shared_dirty_card_queue().reset(); 247 } 248 249 void G1DirtyCardQueueSet::concatenate_logs() { 250 // Iterate over all the threads, if we find a partial log add it to 251 // the global list of logs. Temporarily turn off the limit on the number 252 // of outstanding buffers. 253 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 254 size_t old_limit = max_completed_buffers(); 255 set_max_completed_buffers(MaxCompletedBuffersUnlimited); 256 257 struct ConcatenateThreadLogClosure : public ThreadClosure { 258 virtual void do_thread(Thread* t) { 259 G1DirtyCardQueue& dcq = G1ThreadLocalData::dirty_card_queue(t); 260 if (!dcq.is_empty()) { 261 dcq.flush(); 262 } 263 } 264 } closure; 265 Threads::threads_do(&closure); 266 267 G1BarrierSet::shared_dirty_card_queue().flush(); 268 set_max_completed_buffers(old_limit); 269 }