Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/g1/concurrentMarkThread.cpp @ 1840:4e0094bc41fa
6983311: G1: LoopTest hangs when run with -XX:+ExplicitInvokesConcurrent
Summary: Clear the concurrent marking "in progress" flag while the FullGCCount_lock is held. This avoids a race that can cause back to back System.gc() calls, when ExplicitGCInvokesConcurrent is enabled, to fail to initiate a marking cycle causing the requesting thread to hang.
Reviewed-by: tonyp, ysr
| author | johnc |
|---|---|
| date | Fri, 01 Oct 2010 18:23:16 -0700 |
| parents | 4e5661ba9d98 |
| children | f95d63e2154a |
| rev | line source |
|---|---|
| 342 | 1 /* |
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2 * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved. |
| 342 | 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 342 | 22 * |
| 23 */ | |
| 24 | |
| 25 #include "incls/_precompiled.incl" | |
| 26 #include "incls/_concurrentMarkThread.cpp.incl" | |
| 27 | |
| 28 // ======= Concurrent Mark Thread ======== | |
| 29 | |
| 30 // The CM thread is created when the G1 garbage collector is used | |
| 31 | |
| 32 SurrogateLockerThread* | |
| 33 ConcurrentMarkThread::_slt = NULL; | |
| 34 | |
| 35 ConcurrentMarkThread::ConcurrentMarkThread(ConcurrentMark* cm) : | |
| 36 ConcurrentGCThread(), | |
| 37 _cm(cm), | |
| 38 _started(false), | |
| 39 _in_progress(false), | |
| 40 _vtime_accum(0.0), | |
| 41 _vtime_mark_accum(0.0), | |
| 42 _vtime_count_accum(0.0) | |
| 43 { | |
| 44 create_and_start(); | |
| 45 } | |
| 46 | |
| 47 class CMCheckpointRootsInitialClosure: public VoidClosure { | |
| 48 | |
| 49 ConcurrentMark* _cm; | |
| 50 public: | |
| 51 | |
| 52 CMCheckpointRootsInitialClosure(ConcurrentMark* cm) : | |
| 53 _cm(cm) {} | |
| 54 | |
| 55 void do_void(){ | |
| 56 _cm->checkpointRootsInitial(); | |
| 57 } | |
| 58 }; | |
| 59 | |
| 60 class CMCheckpointRootsFinalClosure: public VoidClosure { | |
| 61 | |
| 62 ConcurrentMark* _cm; | |
| 63 public: | |
| 64 | |
| 65 CMCheckpointRootsFinalClosure(ConcurrentMark* cm) : | |
| 66 _cm(cm) {} | |
| 67 | |
| 68 void do_void(){ | |
| 69 _cm->checkpointRootsFinal(false); // !clear_all_soft_refs | |
| 70 } | |
| 71 }; | |
| 72 | |
| 73 class CMCleanUp: public VoidClosure { | |
| 74 ConcurrentMark* _cm; | |
| 75 public: | |
| 76 | |
| 77 CMCleanUp(ConcurrentMark* cm) : | |
| 78 _cm(cm) {} | |
| 79 | |
| 80 void do_void(){ | |
| 81 _cm->cleanup(); | |
| 82 } | |
| 83 }; | |
| 84 | |
| 85 | |
| 86 | |
| 87 void ConcurrentMarkThread::run() { | |
| 88 initialize_in_thread(); | |
| 89 _vtime_start = os::elapsedVTime(); | |
| 90 wait_for_universe_init(); | |
| 91 | |
| 92 G1CollectedHeap* g1 = G1CollectedHeap::heap(); | |
| 93 G1CollectorPolicy* g1_policy = g1->g1_policy(); | |
| 94 G1MMUTracker *mmu_tracker = g1_policy->mmu_tracker(); | |
| 95 Thread *current_thread = Thread::current(); | |
| 96 | |
| 97 while (!_should_terminate) { | |
| 98 // wait until started is set. | |
| 99 sleepBeforeNextCycle(); | |
| 100 { | |
| 101 ResourceMark rm; | |
| 102 HandleMark hm; | |
| 103 double cycle_start = os::elapsedVTime(); | |
| 104 double mark_start_sec = os::elapsedTime(); | |
| 105 char verbose_str[128]; | |
| 106 | |
| 107 if (PrintGC) { | |
| 108 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 109 gclog_or_tty->stamp(PrintGCTimeStamps); | |
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110 gclog_or_tty->print_cr("[GC concurrent-mark-start]"); |
| 342 | 111 } |
| 112 | |
| 113 if (!g1_policy->in_young_gc_mode()) { | |
| 114 // this ensures the flag is not set if we bail out of the marking | |
| 115 // cycle; normally the flag is cleared immediately after cleanup | |
| 116 g1->set_marking_complete(); | |
| 117 | |
| 118 if (g1_policy->adaptive_young_list_length()) { | |
| 119 double now = os::elapsedTime(); | |
| 120 double init_prediction_ms = g1_policy->predict_init_time_ms(); | |
| 121 jlong sleep_time_ms = mmu_tracker->when_ms(now, init_prediction_ms); | |
| 122 os::sleep(current_thread, sleep_time_ms, false); | |
| 123 } | |
| 124 | |
| 125 // We don't have to skip here if we've been asked to restart, because | |
| 126 // in the worst case we just enqueue a new VM operation to start a | |
| 127 // marking. Note that the init operation resets has_aborted() | |
| 128 CMCheckpointRootsInitialClosure init_cl(_cm); | |
| 129 strcpy(verbose_str, "GC initial-mark"); | |
| 130 VM_CGC_Operation op(&init_cl, verbose_str); | |
| 131 VMThread::execute(&op); | |
| 132 } | |
| 133 | |
| 134 int iter = 0; | |
| 135 do { | |
| 136 iter++; | |
| 137 if (!cm()->has_aborted()) { | |
| 138 _cm->markFromRoots(); | |
| 139 } | |
| 140 | |
| 141 double mark_end_time = os::elapsedVTime(); | |
| 142 double mark_end_sec = os::elapsedTime(); | |
| 143 _vtime_mark_accum += (mark_end_time - cycle_start); | |
| 144 if (!cm()->has_aborted()) { | |
| 145 if (g1_policy->adaptive_young_list_length()) { | |
| 146 double now = os::elapsedTime(); | |
| 147 double remark_prediction_ms = g1_policy->predict_remark_time_ms(); | |
| 148 jlong sleep_time_ms = mmu_tracker->when_ms(now, remark_prediction_ms); | |
| 149 os::sleep(current_thread, sleep_time_ms, false); | |
| 150 } | |
| 151 | |
| 152 if (PrintGC) { | |
| 153 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 154 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 155 gclog_or_tty->print_cr("[GC concurrent-mark-end, %1.7lf sec]", | |
| 156 mark_end_sec - mark_start_sec); | |
| 157 } | |
| 158 | |
| 159 CMCheckpointRootsFinalClosure final_cl(_cm); | |
| 160 sprintf(verbose_str, "GC remark"); | |
| 161 VM_CGC_Operation op(&final_cl, verbose_str); | |
| 162 VMThread::execute(&op); | |
| 163 } | |
| 164 if (cm()->restart_for_overflow() && | |
| 165 G1TraceMarkStackOverflow) { | |
| 166 gclog_or_tty->print_cr("Restarting conc marking because of MS overflow " | |
| 167 "in remark (restart #%d).", iter); | |
| 168 } | |
| 169 | |
| 170 if (cm()->restart_for_overflow()) { | |
| 171 if (PrintGC) { | |
| 172 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 173 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 174 gclog_or_tty->print_cr("[GC concurrent-mark-restart-for-overflow]"); | |
| 175 } | |
| 176 } | |
| 177 } while (cm()->restart_for_overflow()); | |
| 178 double counting_start_time = os::elapsedVTime(); | |
| 179 | |
| 180 // YSR: These look dubious (i.e. redundant) !!! FIX ME | |
| 181 slt()->manipulatePLL(SurrogateLockerThread::acquirePLL); | |
| 182 slt()->manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL); | |
| 183 | |
| 184 if (!cm()->has_aborted()) { | |
| 185 double count_start_sec = os::elapsedTime(); | |
| 186 if (PrintGC) { | |
| 187 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 188 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 189 gclog_or_tty->print_cr("[GC concurrent-count-start]"); | |
| 190 } | |
| 191 | |
| 192 _sts.join(); | |
| 193 _cm->calcDesiredRegions(); | |
| 194 _sts.leave(); | |
| 195 | |
| 196 if (!cm()->has_aborted()) { | |
| 197 double count_end_sec = os::elapsedTime(); | |
| 198 if (PrintGC) { | |
| 199 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 200 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 201 gclog_or_tty->print_cr("[GC concurrent-count-end, %1.7lf]", | |
| 202 count_end_sec - count_start_sec); | |
| 203 } | |
| 204 } | |
| 205 } | |
| 206 double end_time = os::elapsedVTime(); | |
| 207 _vtime_count_accum += (end_time - counting_start_time); | |
| 208 // Update the total virtual time before doing this, since it will try | |
| 209 // to measure it to get the vtime for this marking. We purposely | |
| 210 // neglect the presumably-short "completeCleanup" phase here. | |
| 211 _vtime_accum = (end_time - _vtime_start); | |
| 212 if (!cm()->has_aborted()) { | |
| 213 if (g1_policy->adaptive_young_list_length()) { | |
| 214 double now = os::elapsedTime(); | |
| 215 double cleanup_prediction_ms = g1_policy->predict_cleanup_time_ms(); | |
| 216 jlong sleep_time_ms = mmu_tracker->when_ms(now, cleanup_prediction_ms); | |
| 217 os::sleep(current_thread, sleep_time_ms, false); | |
| 218 } | |
| 219 | |
| 220 CMCleanUp cl_cl(_cm); | |
| 221 sprintf(verbose_str, "GC cleanup"); | |
| 222 VM_CGC_Operation op(&cl_cl, verbose_str); | |
| 223 VMThread::execute(&op); | |
| 224 } else { | |
| 225 G1CollectedHeap::heap()->set_marking_complete(); | |
| 226 } | |
| 227 | |
| 228 if (!cm()->has_aborted()) { | |
| 229 double cleanup_start_sec = os::elapsedTime(); | |
| 230 if (PrintGC) { | |
| 231 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 232 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 233 gclog_or_tty->print_cr("[GC concurrent-cleanup-start]"); | |
| 234 } | |
| 235 | |
| 236 // Now do the remainder of the cleanup operation. | |
| 237 _sts.join(); | |
| 238 _cm->completeCleanup(); | |
| 239 if (!cm()->has_aborted()) { | |
| 240 g1_policy->record_concurrent_mark_cleanup_completed(); | |
| 241 | |
| 242 double cleanup_end_sec = os::elapsedTime(); | |
| 243 if (PrintGC) { | |
| 244 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 245 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 246 gclog_or_tty->print_cr("[GC concurrent-cleanup-end, %1.7lf]", | |
| 247 cleanup_end_sec - cleanup_start_sec); | |
| 248 } | |
| 249 } | |
| 250 _sts.leave(); | |
| 251 } | |
| 252 // We're done: no more unclean regions coming. | |
| 253 G1CollectedHeap::heap()->set_unclean_regions_coming(false); | |
| 254 | |
| 255 if (cm()->has_aborted()) { | |
| 256 if (PrintGC) { | |
| 257 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 258 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 259 gclog_or_tty->print_cr("[GC concurrent-mark-abort]"); | |
| 260 } | |
| 261 } | |
| 262 | |
| 263 // we now want to allow clearing of the marking bitmap to be | |
| 264 // suspended by a collection pause. | |
| 265 _sts.join(); | |
| 266 _cm->clearNextBitmap(); | |
| 267 _sts.leave(); | |
| 268 } | |
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269 |
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270 // Update the number of full collections that have been |
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271 // completed. This will also notify the FullGCCount_lock in case a |
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272 // Java thread is waiting for a full GC to happen (e.g., it |
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273 // called System.gc() with +ExplicitGCInvokesConcurrent). |
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274 g1->increment_full_collections_completed(true /* outer */); |
| 342 | 275 } |
| 276 assert(_should_terminate, "just checking"); | |
| 277 | |
| 278 terminate(); | |
| 279 } | |
| 280 | |
| 281 | |
| 282 void ConcurrentMarkThread::yield() { | |
| 283 _sts.yield("Concurrent Mark"); | |
| 284 } | |
| 285 | |
| 286 void ConcurrentMarkThread::stop() { | |
| 287 // it is ok to take late safepoints here, if needed | |
| 288 MutexLockerEx mu(Terminator_lock); | |
| 289 _should_terminate = true; | |
| 290 while (!_has_terminated) { | |
| 291 Terminator_lock->wait(); | |
| 292 } | |
| 293 } | |
| 294 | |
| 1019 | 295 void ConcurrentMarkThread::print() const { |
| 296 print_on(tty); | |
| 297 } | |
| 298 | |
| 299 void ConcurrentMarkThread::print_on(outputStream* st) const { | |
| 300 st->print("\"G1 Main Concurrent Mark GC Thread\" "); | |
| 301 Thread::print_on(st); | |
| 302 st->cr(); | |
| 342 | 303 } |
| 304 | |
| 305 void ConcurrentMarkThread::sleepBeforeNextCycle() { | |
| 306 // We join here because we don't want to do the "shouldConcurrentMark()" | |
| 307 // below while the world is otherwise stopped. | |
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308 assert(!in_progress(), "should have been cleared"); |
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309 |
| 342 | 310 MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); |
| 311 while (!started()) { | |
| 312 CGC_lock->wait(Mutex::_no_safepoint_check_flag); | |
| 313 } | |
| 314 set_in_progress(); | |
| 315 clear_started(); | |
| 316 } | |
| 317 | |
| 318 // Note: this method, although exported by the ConcurrentMarkSweepThread, | |
| 319 // which is a non-JavaThread, can only be called by a JavaThread. | |
| 320 // Currently this is done at vm creation time (post-vm-init) by the | |
| 321 // main/Primordial (Java)Thread. | |
| 322 // XXX Consider changing this in the future to allow the CMS thread | |
| 323 // itself to create this thread? | |
| 324 void ConcurrentMarkThread::makeSurrogateLockerThread(TRAPS) { | |
| 325 assert(_slt == NULL, "SLT already created"); | |
| 326 _slt = SurrogateLockerThread::make(THREAD); | |
| 327 } |