1 /* 2 * Copyright (c) 2015, 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 "classfile/stringTable.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "code/codeCache.hpp" 30 #include "gc/g1/bufferingOopClosure.hpp" 31 #include "gc/g1/g1CollectedHeap.inline.hpp" 32 #include "gc/g1/g1CollectorPolicy.hpp" 33 #include "gc/g1/g1GCPhaseTimes.hpp" 34 #include "gc/g1/g1RemSet.inline.hpp" 35 #include "gc/g1/g1RootProcessor.hpp" 36 #include "memory/allocation.inline.hpp" 37 #include "runtime/fprofiler.hpp" 38 #include "runtime/mutex.hpp" 39 #include "services/management.hpp" 40 41 class G1CodeBlobClosure : public CodeBlobClosure { 42 class HeapRegionGatheringOopClosure : public OopClosure { 43 G1CollectedHeap* _g1h; 44 OopClosure* _work; 45 nmethod* _nm; 46 47 template <typename T> 48 void do_oop_work(T* p) { 49 _work->do_oop(p); 50 T oop_or_narrowoop = oopDesc::load_heap_oop(p); 51 if (!oopDesc::is_null(oop_or_narrowoop)) { 52 oop o = oopDesc::decode_heap_oop_not_null(oop_or_narrowoop); 53 HeapRegion* hr = _g1h->heap_region_containing_raw(o); 54 assert(!_g1h->obj_in_cs(o) || hr->rem_set()->strong_code_roots_list_contains(_nm), "if o still in CS then evacuation failed and nm must already be in the remset"); 55 hr->add_strong_code_root(_nm); 56 } 57 } 58 59 public: 60 HeapRegionGatheringOopClosure(OopClosure* oc) : _g1h(G1CollectedHeap::heap()), _work(oc), _nm(NULL) {} 61 62 void do_oop(oop* o) { 63 do_oop_work(o); 64 } 65 66 void do_oop(narrowOop* o) { 67 do_oop_work(o); 68 } 69 70 void set_nm(nmethod* nm) { 71 _nm = nm; 72 } 73 }; 74 75 HeapRegionGatheringOopClosure _oc; 76 public: 77 G1CodeBlobClosure(OopClosure* oc) : _oc(oc) {} 78 79 void do_code_blob(CodeBlob* cb) { 80 nmethod* nm = cb->as_nmethod_or_null(); 81 if (nm != NULL) { 82 if (!nm->test_set_oops_do_mark()) { 83 _oc.set_nm(nm); 84 nm->oops_do(&_oc); 85 nm->fix_oop_relocations(); 86 } 87 } 88 } 89 }; 90 91 92 void G1RootProcessor::worker_has_discovered_all_strong_classes() { 93 assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading"); 94 95 uint new_value = (uint)Atomic::add(1, &_n_workers_discovered_strong_classes); 96 if (new_value == n_workers()) { 97 // This thread is last. Notify the others. 98 MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag); 99 _lock.notify_all(); 100 } 101 } 102 103 void G1RootProcessor::wait_until_all_strong_classes_discovered() { 104 assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading"); 105 106 if ((uint)_n_workers_discovered_strong_classes != n_workers()) { 107 MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag); 108 while ((uint)_n_workers_discovered_strong_classes != n_workers()) { 109 _lock.wait(Mutex::_no_safepoint_check_flag, 0, false); 110 } 111 } 112 } 113 114 G1RootProcessor::G1RootProcessor(G1CollectedHeap* g1h, uint n_workers) : 115 _g1h(g1h), 116 _process_strong_tasks(new SubTasksDone(G1RP_PS_NumElements)), 117 _srs(n_workers), 118 _lock(Mutex::leaf, "G1 Root Scanning barrier lock", false, Monitor::_safepoint_check_never), 119 _n_workers_discovered_strong_classes(0) {} 120 121 void G1RootProcessor::evacuate_roots(OopClosure* scan_non_heap_roots, 122 OopClosure* scan_non_heap_weak_roots, 123 CLDClosure* scan_strong_clds, 124 CLDClosure* scan_weak_clds, 125 bool trace_metadata, 126 uint worker_i) { 127 // First scan the shared roots. 128 double ext_roots_start = os::elapsedTime(); 129 G1GCPhaseTimes* phase_times = _g1h->g1_policy()->phase_times(); 130 131 BufferingOopClosure buf_scan_non_heap_roots(scan_non_heap_roots); 132 BufferingOopClosure buf_scan_non_heap_weak_roots(scan_non_heap_weak_roots); 133 134 OopClosure* const weak_roots = &buf_scan_non_heap_weak_roots; 135 OopClosure* const strong_roots = &buf_scan_non_heap_roots; 136 137 // CodeBlobClosures are not interoperable with BufferingOopClosures 138 G1CodeBlobClosure root_code_blobs(scan_non_heap_roots); 139 140 process_java_roots(strong_roots, 141 trace_metadata ? scan_strong_clds : NULL, 142 scan_strong_clds, 143 trace_metadata ? NULL : scan_weak_clds, 144 &root_code_blobs, 145 phase_times, 146 worker_i); 147 148 // This is the point where this worker thread will not find more strong CLDs/nmethods. 149 // Report this so G1 can synchronize the strong and weak CLDs/nmethods processing. 150 if (trace_metadata) { 151 worker_has_discovered_all_strong_classes(); 152 } 153 154 process_vm_roots(strong_roots, weak_roots, phase_times, worker_i); 155 156 { 157 // Now the CM ref_processor roots. 158 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CMRefRoots, worker_i); 159 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_refProcessor_oops_do)) { 160 // We need to treat the discovered reference lists of the 161 // concurrent mark ref processor as roots and keep entries 162 // (which are added by the marking threads) on them live 163 // until they can be processed at the end of marking. 164 _g1h->ref_processor_cm()->weak_oops_do(&buf_scan_non_heap_roots); 165 } 166 } 167 168 if (trace_metadata) { 169 { 170 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WaitForStrongCLD, worker_i); 171 // Barrier to make sure all workers passed 172 // the strong CLD and strong nmethods phases. 173 wait_until_all_strong_classes_discovered(); 174 } 175 176 // Now take the complement of the strong CLDs. 177 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WeakCLDRoots, worker_i); 178 ClassLoaderDataGraph::roots_cld_do(NULL, scan_weak_clds); 179 } else { 180 phase_times->record_time_secs(G1GCPhaseTimes::WaitForStrongCLD, worker_i, 0.0); 181 phase_times->record_time_secs(G1GCPhaseTimes::WeakCLDRoots, worker_i, 0.0); 182 } 183 184 // Finish up any enqueued closure apps (attributed as object copy time). 185 buf_scan_non_heap_roots.done(); 186 buf_scan_non_heap_weak_roots.done(); 187 188 double obj_copy_time_sec = buf_scan_non_heap_roots.closure_app_seconds() 189 + buf_scan_non_heap_weak_roots.closure_app_seconds(); 190 191 phase_times->record_time_secs(G1GCPhaseTimes::ObjCopy, worker_i, obj_copy_time_sec); 192 193 double ext_root_time_sec = os::elapsedTime() - ext_roots_start - obj_copy_time_sec; 194 195 phase_times->record_time_secs(G1GCPhaseTimes::ExtRootScan, worker_i, ext_root_time_sec); 196 197 // During conc marking we have to filter the per-thread SATB buffers 198 // to make sure we remove any oops into the CSet (which will show up 199 // as implicitly live). 200 { 201 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SATBFiltering, worker_i); 202 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_filter_satb_buffers) && _g1h->mark_in_progress()) { 203 JavaThread::satb_mark_queue_set().filter_thread_buffers(); 204 } 205 } 206 207 _process_strong_tasks->all_tasks_completed(n_workers()); 208 } 209 210 void G1RootProcessor::process_strong_roots(OopClosure* oops, 211 CLDClosure* clds, 212 CodeBlobClosure* blobs) { 213 214 process_java_roots(oops, clds, clds, NULL, blobs, NULL, 0); 215 process_vm_roots(oops, NULL, NULL, 0); 216 217 _process_strong_tasks->all_tasks_completed(n_workers()); 218 } 219 220 void G1RootProcessor::process_all_roots(OopClosure* oops, 221 CLDClosure* clds, 222 CodeBlobClosure* blobs) { 223 224 process_java_roots(oops, NULL, clds, clds, NULL, NULL, 0); 225 process_vm_roots(oops, oops, NULL, 0); 226 227 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_CodeCache_oops_do)) { 228 CodeCache::blobs_do(blobs); 229 } 230 231 _process_strong_tasks->all_tasks_completed(n_workers()); 232 } 233 234 void G1RootProcessor::process_java_roots(OopClosure* strong_roots, 235 CLDClosure* thread_stack_clds, 236 CLDClosure* strong_clds, 237 CLDClosure* weak_clds, 238 CodeBlobClosure* strong_code, 239 G1GCPhaseTimes* phase_times, 240 uint worker_i) { 241 assert(thread_stack_clds == NULL || weak_clds == NULL, "There is overlap between those, only one may be set"); 242 // Iterating over the CLDG and the Threads are done early to allow us to 243 // first process the strong CLDs and nmethods and then, after a barrier, 244 // let the thread process the weak CLDs and nmethods. 245 { 246 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CLDGRoots, worker_i); 247 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_ClassLoaderDataGraph_oops_do)) { 248 ClassLoaderDataGraph::roots_cld_do(strong_clds, weak_clds); 249 } 250 } 251 252 { 253 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ThreadRoots, worker_i); 254 bool is_par = n_workers() > 1; 255 Threads::possibly_parallel_oops_do(is_par, strong_roots, thread_stack_clds, strong_code); 256 } 257 } 258 259 void G1RootProcessor::process_vm_roots(OopClosure* strong_roots, 260 OopClosure* weak_roots, 261 G1GCPhaseTimes* phase_times, 262 uint worker_i) { 263 { 264 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::UniverseRoots, worker_i); 265 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_Universe_oops_do)) { 266 Universe::oops_do(strong_roots); 267 } 268 } 269 270 { 271 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JNIRoots, worker_i); 272 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_JNIHandles_oops_do)) { 273 JNIHandles::oops_do(strong_roots); 274 } 275 } 276 277 { 278 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ObjectSynchronizerRoots, worker_i); 279 if (!_process_strong_tasks-> is_task_claimed(G1RP_PS_ObjectSynchronizer_oops_do)) { 280 ObjectSynchronizer::oops_do(strong_roots); 281 } 282 } 283 284 { 285 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::FlatProfilerRoots, worker_i); 286 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_FlatProfiler_oops_do)) { 287 FlatProfiler::oops_do(strong_roots); 288 } 289 } 290 291 { 292 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ManagementRoots, worker_i); 293 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_Management_oops_do)) { 294 Management::oops_do(strong_roots); 295 } 296 } 297 298 { 299 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JVMTIRoots, worker_i); 300 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_jvmti_oops_do)) { 301 JvmtiExport::oops_do(strong_roots); 302 } 303 } 304 305 { 306 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SystemDictionaryRoots, worker_i); 307 if (!_process_strong_tasks->is_task_claimed(G1RP_PS_SystemDictionary_oops_do)) { 308 SystemDictionary::roots_oops_do(strong_roots, weak_roots); 309 } 310 } 311 312 { 313 G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::StringTableRoots, worker_i); 314 // All threads execute the following. A specific chunk of buckets 315 // from the StringTable are the individual tasks. 316 if (weak_roots != NULL) { 317 StringTable::possibly_parallel_oops_do(weak_roots); 318 } 319 } 320 } 321 322 void G1RootProcessor::scan_remembered_sets(G1ParPushHeapRSClosure* scan_rs, 323 OopClosure* scan_non_heap_weak_roots, 324 uint worker_i) { 325 G1CodeBlobClosure scavenge_cs_nmethods(scan_non_heap_weak_roots); 326 327 _g1h->g1_rem_set()->oops_into_collection_set_do(scan_rs, &scavenge_cs_nmethods, worker_i); 328 } 329 330 uint G1RootProcessor::n_workers() const { 331 return _srs.n_threads(); 332 }