1 /* 2 * Copyright (c) 2015, 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 27 #include "aot/aotLoader.hpp" 28 #include "classfile/stringTable.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "code/codeCache.hpp" 31 #include "gc/g1/g1BarrierSet.hpp" 32 #include "gc/g1/g1CodeBlobClosure.hpp" 33 #include "gc/g1/g1CollectedHeap.inline.hpp" 34 #include "gc/g1/g1CollectorState.hpp" 35 #include "gc/g1/g1GCPhaseTimes.hpp" 36 #include "gc/g1/g1ParScanThreadState.inline.hpp" 37 #include "gc/g1/g1Policy.hpp" 38 #include "gc/g1/g1RootClosures.hpp" 39 #include "gc/g1/g1RootProcessor.hpp" 40 #include "gc/g1/heapRegion.inline.hpp" 41 #include "gc/shared/oopStorageParState.hpp" 42 #include "gc/shared/referenceProcessor.hpp" 43 #include "gc/shared/weakProcessor.hpp" 44 #include "memory/allocation.inline.hpp" 45 #include "runtime/mutex.hpp" 46 #include "services/management.hpp" 47 #include "utilities/macros.hpp" 48 49 void G1RootProcessor::worker_has_discovered_all_strong_classes() { 50 assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading"); 51 52 uint new_value = (uint)Atomic::add(1, &_n_workers_discovered_strong_classes); 53 if (new_value == n_workers()) { 54 // This thread is last. Notify the others. 55 MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag); 56 _lock.notify_all(); 57 } 58 } 59 60 void G1RootProcessor::wait_until_all_strong_classes_discovered() { 61 assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading"); 62 63 if ((uint)_n_workers_discovered_strong_classes != n_workers()) { 64 MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag); 65 while ((uint)_n_workers_discovered_strong_classes != n_workers()) { 66 _lock.wait(Mutex::_no_safepoint_check_flag, 0, false); 67 } 68 } 69 } 70 71 G1RootProcessor::G1RootProcessor(G1CollectedHeap* g1h, uint n_workers) : 72 _g1h(g1h), 73 _process_strong_tasks(G1RP_PS_NumElements), 74 _srs(n_workers), 75 _lock(Mutex::leaf, "G1 Root Scanning barrier lock", false, Monitor::_safepoint_check_never), 76 _par_state_string(StringTable::weak_storage()), 77 _n_workers_discovered_strong_classes(0) {} 78 79 void G1RootProcessor::evacuate_roots(G1ParScanThreadState* pss, uint worker_i) { 80 G1GCPhaseTimes* phase_times = _g1h->g1_policy()->phase_times(); 81 82 G1EvacPhaseTimesTracker timer(phase_times, pss, G1GCPhaseTimes::ExtRootScan, worker_i); 83 84 G1EvacuationRootClosures* closures = pss->closures(); 85 process_java_roots(closures, phase_times, worker_i); 86 87 // This is the point where this worker thread will not find more strong CLDs/nmethods. 88 // Report this so G1 can synchronize the strong and weak CLDs/nmethods processing. 89 if (closures->trace_metadata()) { 90 worker_has_discovered_all_strong_classes(); 91 } 92 93 process_vm_roots(closures, phase_times, worker_i); 94 process_string_table_roots(closures, phase_times, worker_i); 95 96 { 97 // Now the CM ref_processor roots. 98 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CMRefRoots, worker_i); 99 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_refProcessor_oops_do)) { 100 // We need to treat the discovered reference lists of the 101 // concurrent mark ref processor as roots and keep entries 102 // (which are added by the marking threads) on them live 103 // until they can be processed at the end of marking. 104 _g1h->ref_processor_cm()->weak_oops_do(closures->strong_oops()); 105 } 106 } 107 108 if (closures->trace_metadata()) { 109 { 110 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WaitForStrongCLD, worker_i); 111 // Barrier to make sure all workers passed 112 // the strong CLD and strong nmethods phases. 113 wait_until_all_strong_classes_discovered(); 114 } 115 116 // Now take the complement of the strong CLDs. 117 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WeakCLDRoots, worker_i); 118 assert(closures->second_pass_weak_clds() != NULL, "Should be non-null if we are tracing metadata."); 119 ClassLoaderDataGraph::roots_cld_do(NULL, closures->second_pass_weak_clds()); 120 } else { 121 phase_times->record_time_secs(G1GCPhaseTimes::WaitForStrongCLD, worker_i, 0.0); 122 phase_times->record_time_secs(G1GCPhaseTimes::WeakCLDRoots, worker_i, 0.0); 123 assert(closures->second_pass_weak_clds() == NULL, "Should be null if not tracing metadata."); 124 } 125 126 // During conc marking we have to filter the per-thread SATB buffers 127 // to make sure we remove any oops into the CSet (which will show up 128 // as implicitly live). 129 { 130 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SATBFiltering, worker_i); 131 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_filter_satb_buffers) && _g1h->collector_state()->mark_or_rebuild_in_progress()) { 132 G1BarrierSet::satb_mark_queue_set().filter_thread_buffers(); 133 } 134 } 135 136 _process_strong_tasks.all_tasks_completed(n_workers()); 137 } 138 139 // Adaptor to pass the closures to the strong roots in the VM. 140 class StrongRootsClosures : public G1RootClosures { 141 OopClosure* _roots; 142 CLDClosure* _clds; 143 CodeBlobClosure* _blobs; 144 public: 145 StrongRootsClosures(OopClosure* roots, CLDClosure* clds, CodeBlobClosure* blobs) : 146 _roots(roots), _clds(clds), _blobs(blobs) {} 147 148 OopClosure* weak_oops() { return NULL; } 149 OopClosure* strong_oops() { return _roots; } 150 151 CLDClosure* weak_clds() { return NULL; } 152 CLDClosure* strong_clds() { return _clds; } 153 154 CodeBlobClosure* strong_codeblobs() { return _blobs; } 155 }; 156 157 void G1RootProcessor::process_strong_roots(OopClosure* oops, 158 CLDClosure* clds, 159 CodeBlobClosure* blobs) { 160 StrongRootsClosures closures(oops, clds, blobs); 161 162 process_java_roots(&closures, NULL, 0); 163 process_vm_roots(&closures, NULL, 0); 164 165 _process_strong_tasks.all_tasks_completed(n_workers()); 166 } 167 168 // Adaptor to pass the closures to all the roots in the VM. 169 class AllRootsClosures : public G1RootClosures { 170 OopClosure* _roots; 171 CLDClosure* _clds; 172 public: 173 AllRootsClosures(OopClosure* roots, CLDClosure* clds) : 174 _roots(roots), _clds(clds) {} 175 176 OopClosure* weak_oops() { return _roots; } 177 OopClosure* strong_oops() { return _roots; } 178 179 // By returning the same CLDClosure for both weak and strong CLDs we ensure 180 // that a single walk of the CLDG will invoke the closure on all CLDs i the 181 // system. 182 CLDClosure* weak_clds() { return _clds; } 183 CLDClosure* strong_clds() { return _clds; } 184 185 // We don't want to visit code blobs more than once, so we return NULL for the 186 // strong case and walk the entire code cache as a separate step. 187 CodeBlobClosure* strong_codeblobs() { return NULL; } 188 }; 189 190 void G1RootProcessor::process_all_roots(OopClosure* oops, 191 CLDClosure* clds, 192 CodeBlobClosure* blobs, 193 bool process_string_table) { 194 AllRootsClosures closures(oops, clds); 195 196 process_java_roots(&closures, NULL, 0); 197 process_vm_roots(&closures, NULL, 0); 198 199 if (process_string_table) { 200 process_string_table_roots(&closures, NULL, 0); 201 } 202 process_code_cache_roots(blobs, NULL, 0); 203 204 _process_strong_tasks.all_tasks_completed(n_workers()); 205 } 206 207 void G1RootProcessor::process_all_roots(OopClosure* oops, 208 CLDClosure* clds, 209 CodeBlobClosure* blobs) { 210 process_all_roots(oops, clds, blobs, true); 211 } 212 213 void G1RootProcessor::process_all_roots_no_string_table(OopClosure* oops, 214 CLDClosure* clds, 215 CodeBlobClosure* blobs) { 216 assert(!ClassUnloading, "Should only be used when class unloading is disabled"); 217 process_all_roots(oops, clds, blobs, false); 218 } 219 220 void G1RootProcessor::process_java_roots(G1RootClosures* closures, 221 G1GCPhaseTimes* phase_times, 222 uint worker_i) { 223 // Iterating over the CLDG and the Threads are done early to allow us to 224 // first process the strong CLDs and nmethods and then, after a barrier, 225 // let the thread process the weak CLDs and nmethods. 226 { 227 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CLDGRoots, worker_i); 228 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_ClassLoaderDataGraph_oops_do)) { 229 ClassLoaderDataGraph::roots_cld_do(closures->strong_clds(), closures->weak_clds()); 230 } 231 } 232 233 { 234 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ThreadRoots, worker_i); 235 bool is_par = n_workers() > 1; 236 Threads::possibly_parallel_oops_do(is_par, 237 closures->strong_oops(), 238 closures->strong_codeblobs()); 239 } 240 } 241 242 void G1RootProcessor::process_vm_roots(G1RootClosures* closures, 243 G1GCPhaseTimes* phase_times, 244 uint worker_i) { 245 OopClosure* strong_roots = closures->strong_oops(); 246 OopClosure* weak_roots = closures->weak_oops(); 247 248 { 249 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::UniverseRoots, worker_i); 250 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_Universe_oops_do)) { 251 Universe::oops_do(strong_roots); 252 } 253 } 254 255 { 256 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JNIRoots, worker_i); 257 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_JNIHandles_oops_do)) { 258 JNIHandles::oops_do(strong_roots); 259 } 260 } 261 262 { 263 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ObjectSynchronizerRoots, worker_i); 264 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_ObjectSynchronizer_oops_do)) { 265 ObjectSynchronizer::oops_do(strong_roots); 266 } 267 } 268 269 { 270 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ManagementRoots, worker_i); 271 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_Management_oops_do)) { 272 Management::oops_do(strong_roots); 273 } 274 } 275 276 { 277 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JVMTIRoots, worker_i); 278 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_jvmti_oops_do)) { 279 JvmtiExport::oops_do(strong_roots); 280 } 281 } 282 283 #if INCLUDE_AOT 284 if (UseAOT) { 285 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::AOTCodeRoots, worker_i); 286 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_aot_oops_do)) { 287 AOTLoader::oops_do(strong_roots); 288 } 289 } 290 #endif 291 292 { 293 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SystemDictionaryRoots, worker_i); 294 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_SystemDictionary_oops_do)) { 295 SystemDictionary::roots_oops_do(strong_roots, weak_roots); 296 } 297 } 298 } 299 300 void G1RootProcessor::process_string_table_roots(G1RootClosures* closures, 301 G1GCPhaseTimes* phase_times, 302 uint worker_i) { 303 assert(closures->weak_oops() != NULL, "Should only be called when all roots are processed"); 304 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::StringTableRoots, worker_i); 305 // All threads execute the following. A specific chunk of buckets 306 // from the StringTable are the individual tasks. 307 StringTable::possibly_parallel_oops_do(&_par_state_string, closures->weak_oops()); 308 } 309 310 void G1RootProcessor::process_code_cache_roots(CodeBlobClosure* code_closure, 311 G1GCPhaseTimes* phase_times, 312 uint worker_i) { 313 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_CodeCache_oops_do)) { 314 CodeCache::blobs_do(code_closure); 315 } 316 } 317 318 void G1RootProcessor::process_full_gc_weak_roots(OopClosure* oops) { 319 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_refProcessor_oops_do)) { 320 _g1h->ref_processor_stw()->weak_oops_do(oops); 321 } 322 323 if (!_process_strong_tasks.is_task_claimed(G1RP_PS_weakProcessor_oops_do)) { 324 WeakProcessor::oops_do(oops); 325 } 326 } 327 328 uint G1RootProcessor::n_workers() const { 329 return _srs.n_threads(); 330 }