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/dirtyCardQueue.hpp" 27 #include "gc/g1/g1CollectedHeap.inline.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 CardTableEntryClosure { 46 public: 47 bool do_card_ptr(jbyte* card_ptr, uint worker_i) { 48 G1CollectedHeap::heap()->g1_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 DirtyCardQueue::DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent) : 60 // Dirty card queues are always active, so we create them with their 61 // active field set to true. 62 PtrQueue(qset, permanent, true /* active */) 63 { } 64 65 DirtyCardQueue::~DirtyCardQueue() { 66 if (!is_permanent()) { 67 flush(); 68 } 69 } 70 71 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) : 72 PtrQueueSet(notify_when_complete), 73 _shared_dirty_card_queue(this, true /* permanent */), 74 _free_ids(NULL), 75 _processed_buffers_mut(0), 76 _processed_buffers_rs_thread(0), 77 _cur_par_buffer_node(NULL) 78 { 79 _all_active = true; 80 } 81 82 // Determines how many mutator threads can process the buffers in parallel. 83 uint DirtyCardQueueSet::num_par_ids() { 84 return (uint)os::initial_active_processor_count(); 85 } 86 87 void DirtyCardQueueSet::initialize(Monitor* cbl_mon, 88 BufferNode::Allocator* allocator, 89 Mutex* lock, 90 bool init_free_ids) { 91 PtrQueueSet::initialize(cbl_mon, allocator); 92 _shared_dirty_card_queue.set_lock(lock); 93 if (init_free_ids) { 94 _free_ids = new G1FreeIdSet(0, num_par_ids()); 95 } 96 } 97 98 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) { 99 G1ThreadLocalData::dirty_card_queue(t).handle_zero_index(); 100 } 101 102 bool DirtyCardQueueSet::apply_closure_to_buffer(CardTableEntryClosure* cl, 103 BufferNode* node, 104 bool consume, 105 uint worker_i) { 106 if (cl == NULL) return true; 107 bool result = true; 108 void** buf = BufferNode::make_buffer_from_node(node); 109 size_t i = node->index(); 110 size_t limit = buffer_size(); 111 for ( ; i < limit; ++i) { 112 jbyte* card_ptr = static_cast<jbyte*>(buf[i]); 113 assert(card_ptr != NULL, "invariant"); 114 if (!cl->do_card_ptr(card_ptr, worker_i)) { 115 result = false; // Incomplete processing. 116 break; 117 } 118 } 119 if (consume) { 120 assert(i <= buffer_size(), "invariant"); 121 node->set_index(i); 122 } 123 return result; 124 } 125 126 #ifndef ASSERT 127 #define assert_fully_consumed(node, buffer_size) 128 #else 129 #define assert_fully_consumed(node, buffer_size) \ 130 do { \ 131 size_t _afc_index = (node)->index(); \ 132 size_t _afc_size = (buffer_size); \ 133 assert(_afc_index == _afc_size, \ 134 "Buffer was not fully consumed as claimed: index: " \ 135 SIZE_FORMAT ", size: " SIZE_FORMAT, \ 136 _afc_index, _afc_size); \ 137 } while (0) 138 #endif // ASSERT 139 140 bool DirtyCardQueueSet::mut_process_buffer(BufferNode* node) { 141 guarantee(_free_ids != NULL, "must be"); 142 143 uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id 144 G1RefineCardConcurrentlyClosure cl; 145 bool result = apply_closure_to_buffer(&cl, node, true, worker_i); 146 _free_ids->release_par_id(worker_i); // release the id 147 148 if (result) { 149 assert_fully_consumed(node, buffer_size()); 150 Atomic::inc(&_processed_buffers_mut); 151 } 152 return result; 153 } 154 155 bool DirtyCardQueueSet::refine_completed_buffer_concurrently(uint worker_i, size_t stop_at) { 156 G1RefineCardConcurrentlyClosure cl; 157 return apply_closure_to_completed_buffer(&cl, worker_i, stop_at, false); 158 } 159 160 bool DirtyCardQueueSet::apply_closure_during_gc(CardTableEntryClosure* cl, uint worker_i) { 161 assert_at_safepoint(); 162 return apply_closure_to_completed_buffer(cl, worker_i, 0, true); 163 } 164 165 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl, 166 uint worker_i, 167 size_t stop_at, 168 bool during_pause) { 169 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause"); 170 BufferNode* nd = get_completed_buffer(stop_at); 171 if (nd == NULL) { 172 return false; 173 } else { 174 if (apply_closure_to_buffer(cl, nd, true, worker_i)) { 175 assert_fully_consumed(nd, buffer_size()); 176 // Done with fully processed buffer. 177 deallocate_buffer(nd); 178 Atomic::inc(&_processed_buffers_rs_thread); 179 } else { 180 // Return partially processed buffer to the queue. 181 guarantee(!during_pause, "Should never stop early"); 182 enqueue_completed_buffer(nd); 183 } 184 return true; 185 } 186 } 187 188 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) { 189 BufferNode* nd = _cur_par_buffer_node; 190 while (nd != NULL) { 191 BufferNode* next = nd->next(); 192 BufferNode* actual = Atomic::cmpxchg(next, &_cur_par_buffer_node, nd); 193 if (actual == nd) { 194 bool b = apply_closure_to_buffer(cl, nd, false); 195 guarantee(b, "Should not stop early."); 196 nd = next; 197 } else { 198 nd = actual; 199 } 200 } 201 } 202 203 void DirtyCardQueueSet::abandon_logs() { 204 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 205 abandon_completed_buffers(); 206 // Since abandon is done only at safepoints, we can safely manipulate 207 // these queues. 208 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 209 G1ThreadLocalData::dirty_card_queue(t).reset(); 210 } 211 shared_dirty_card_queue()->reset(); 212 } 213 214 void DirtyCardQueueSet::concatenate_log(DirtyCardQueue& dcq) { 215 if (!dcq.is_empty()) { 216 dcq.flush(); 217 } 218 } 219 220 void DirtyCardQueueSet::concatenate_logs() { 221 // Iterate over all the threads, if we find a partial log add it to 222 // the global list of logs. Temporarily turn off the limit on the number 223 // of outstanding buffers. 224 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); 225 size_t old_limit = max_completed_buffers(); 226 set_max_completed_buffers(MaxCompletedBuffersUnlimited); 227 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 228 concatenate_log(G1ThreadLocalData::dirty_card_queue(t)); 229 } 230 concatenate_log(_shared_dirty_card_queue); 231 set_max_completed_buffers(old_limit); 232 }