rev 60598 : imported patch 8247928-refactor-concurrent-mark-thread

   1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
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  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).
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  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
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  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoaderDataGraph.hpp"
  27 #include "gc/g1/g1Analytics.hpp"
  28 #include "gc/g1/g1CollectedHeap.inline.hpp"
  29 #include "gc/g1/g1ConcurrentMark.inline.hpp"
  30 #include "gc/g1/g1ConcurrentMarkThread.inline.hpp"
  31 #include "gc/g1/g1MMUTracker.hpp"
  32 #include "gc/g1/g1Policy.hpp"
  33 #include "gc/g1/g1RemSet.hpp"
  34 #include "gc/g1/g1Trace.hpp"
  35 #include "gc/g1/g1VMOperations.hpp"
  36 #include "gc/shared/concurrentGCBreakpoints.hpp"
  37 #include "gc/shared/gcId.hpp"
  38 #include "gc/shared/gcTraceTime.inline.hpp"
  39 #include "gc/shared/suspendibleThreadSet.hpp"
  40 #include "logging/log.hpp"
  41 #include "memory/resourceArea.hpp"
  42 #include "runtime/handles.inline.hpp"
  43 #include "runtime/vmThread.hpp"
  44 #include "utilities/debug.hpp"
  45 #include "utilities/ticks.hpp"

  46 
  47 G1ConcurrentMarkThread::G1ConcurrentMarkThread(G1ConcurrentMark* cm) :
  48   ConcurrentGCThread(),
  49   _vtime_start(0.0),
  50   _vtime_accum(0.0),

  51   _cm(cm),
  52   _state(Idle)
  53 {
  54   set_name("G1 Main Marker");
  55   create_and_start();
  56 }
  57 
  58 class CMRemark : public VoidClosure {
  59   G1ConcurrentMark* _cm;
  60 public:
  61   CMRemark(G1ConcurrentMark* cm) : _cm(cm) {}
  62 
  63   void do_void(){
  64     _cm->remark();
  65   }
  66 };
  67 
  68 class CMCleanup : public VoidClosure {
  69   G1ConcurrentMark* _cm;
  70 public:
  71   CMCleanup(G1ConcurrentMark* cm) : _cm(cm) {}
  72 
  73   void do_void(){
  74     _cm->cleanup();
  75   }
  76 };
  77 
  78 double G1ConcurrentMarkThread::mmu_delay_end(G1Policy* policy, bool remark) {
  79   // There are 3 reasons to use SuspendibleThreadSetJoiner.
  80   // 1. To avoid concurrency problem.
  81   //    - G1MMUTracker::add_pause(), when_sec() and its variation(when_ms() etc..) can be called
  82   //      concurrently from ConcurrentMarkThread and VMThread.
  83   // 2. If currently a gc is running, but it has not yet updated the MMU,
  84   //    we will not forget to consider that pause in the MMU calculation.
  85   // 3. If currently a gc is running, ConcurrentMarkThread will wait it to be finished.
  86   //    And then sleep for predicted amount of time by delay_to_keep_mmu().
  87   SuspendibleThreadSetJoiner sts_join;
  88 
  89   const G1Analytics* analytics = policy->analytics();
  90   double prediction_ms = remark ? analytics->predict_remark_time_ms()
  91                                 : analytics->predict_cleanup_time_ms();
  92   double prediction = prediction_ms / MILLIUNITS;
  93   G1MMUTracker *mmu_tracker = policy->mmu_tracker();
  94   double now = os::elapsedTime();
  95   return now + mmu_tracker->when_sec(now, prediction);
  96 }
  97 
  98 void G1ConcurrentMarkThread::delay_to_keep_mmu(bool remark) {
  99   G1Policy* policy = G1CollectedHeap::heap()->policy();
 100 
 101   if (policy->use_adaptive_young_list_length()) {
 102     double delay_end_sec = mmu_delay_end(policy, remark);
 103     // Wait for timeout or thread termination request.
 104     MonitorLocker ml(CGC_lock, Monitor::_no_safepoint_check_flag);
 105     while (!_cm->has_aborted() && !should_terminate()) {
 106       double sleep_time_sec = (delay_end_sec - os::elapsedTime());
 107       jlong sleep_time_ms = ceil(sleep_time_sec * MILLIUNITS);
 108       if (sleep_time_ms <= 0) {
 109         break;                  // Passed end time.
 110       } else if (ml.wait(sleep_time_ms, Monitor::_no_safepoint_check_flag)) {
 111         break;                  // Timeout => reached end time.


 112       }
 113       // Other (possibly spurious) wakeup.  Retry with updated sleep time.
 114     }
 115   }
 116 }
 117 
 118 class G1ConcPhaseTimer : public GCTraceConcTimeImpl<LogLevel::Info, LOG_TAGS(gc, marking)> {
 119   G1ConcurrentMark* _cm;
 120   const char* _t;
 121  public:
 122   G1ConcPhaseTimer(G1ConcurrentMark* cm, const char* title) :
 123     GCTraceConcTimeImpl<LogLevel::Info,  LogTag::_gc, LogTag::_marking>(title),
 124     _cm(cm)
 125   {
 126     _cm->gc_timer_cm()->register_gc_concurrent_start(title);
 127   }
 128 
 129   ~G1ConcPhaseTimer() {
 130     _cm->gc_timer_cm()->register_gc_concurrent_end();
 131   }
 132 };
 133 
 134 void G1ConcurrentMarkThread::run_service() {
 135   _vtime_start = os::elapsedVTime();
 136 



 137   while (!should_terminate()) {
 138     if (wait_for_next_cycle()) {


 139       break;
 140     }
 141 
 142     GCIdMark gc_id_mark;
 143     GCTraceConcTime(Info, gc) tt("Concurrent Cycle");
 144 
 145     concurrent_cycle_start();
 146     full_concurrent_cycle_do();
 147     concurrent_cycle_end();
 148 
 149     _vtime_accum = (os::elapsedVTime() - _vtime_start);
 150   }
 151   _cm->root_regions()->cancel_scan();
 152 }
 153 
 154 void G1ConcurrentMarkThread::stop_service() {
 155   MutexLocker ml(CGC_lock, Mutex::_no_safepoint_check_flag);
 156   CGC_lock->notify_all();
 157 }
 158 
 159 bool G1ConcurrentMarkThread::wait_for_next_cycle() {
 160   assert(!in_progress(), "should have been cleared");
 161 
 162   MonitorLocker ml(CGC_lock, Mutex::_no_safepoint_check_flag);
 163   while (!started() && !should_terminate()) {
 164     ml.wait();
 165   }
 166 
 167   if (started()) {
 168     set_in_progress();
 169   }
 170 
 171   return should_terminate();
 172 }





 173 
 174 bool G1ConcurrentMarkThread::phase_clear_cld_claimed_marks() {
 175   G1ConcPhaseTimer p(_cm, "Concurrent Clear Claimed Marks");
 176   ClassLoaderDataGraph::clear_claimed_marks();
 177   return _cm->has_aborted();
 178 }
 179 
 180 bool G1ConcurrentMarkThread::phase_scan_root_regions() {
 181   G1ConcPhaseTimer p(_cm, "Concurrent Scan Root Regions");
 182   _cm->scan_root_regions();
 183   return _cm->has_aborted();
 184 }


 185 
 186 bool G1ConcurrentMarkThread::phase_mark_from_roots() {









 187   ConcurrentGCBreakpoints::at("AFTER MARKING STARTED");
 188   G1ConcPhaseTimer p(_cm, "Concurrent Mark From Roots");
 189   _cm->mark_from_roots();
 190   return _cm->has_aborted();
 191 }


 192 
 193 bool G1ConcurrentMarkThread::phase_preclean() {
 194   G1ConcPhaseTimer p(_cm, "Concurrent Preclean");
 195   _cm->preclean();
 196   return _cm->has_aborted();
 197 }


 198 
 199 bool G1ConcurrentMarkThread::phase_delay_to_keep_mmu_before_remark() {
 200   delay_to_keep_mmu(true /* remark */);
 201   return _cm->has_aborted();
 202 }




 203 
 204 bool G1ConcurrentMarkThread::phase_remark(bool& has_overflown) {
 205   ConcurrentGCBreakpoints::at("BEFORE MARKING COMPLETED");




 206   CMRemark cl(_cm);
 207   VM_G1Concurrent op(&cl, "Pause Remark");
 208   VMThread::execute(&op);
 209   has_overflown = _cm->has_overflown();
 210   return _cm->has_aborted();
 211 }







 212 
 213 bool G1ConcurrentMarkThread::phase_rebuild_remembered_sets() {
 214   G1ConcPhaseTimer p(_cm, "Concurrent Rebuild Remembered Sets");
 215   _cm->rebuild_rem_set_concurrently();
 216   return _cm->has_aborted();
 217 }
 218 
 219 bool G1ConcurrentMarkThread::phase_delay_to_keep_mmu_before_cleanup() {
 220   delay_to_keep_mmu(false /* cleanup */);
 221   return _cm->has_aborted();
 222 }




 223 
 224 bool G1ConcurrentMarkThread::phase_cleanup() {
 225   CMCleanup cl(_cm);
 226   VM_G1Concurrent op(&cl, "Pause Cleanup");
 227   VMThread::execute(&op);
 228   return _cm->has_aborted();
 229 }
 230 
 231 bool G1ConcurrentMarkThread::phase_clear_bitmap_for_next_mark() {




 232   G1ConcPhaseTimer p(_cm, "Concurrent Cleanup for Next Mark");
 233   _cm->cleanup_for_next_mark();
 234   return _cm->has_aborted();
 235 }
 236 
 237 void G1ConcurrentMarkThread::concurrent_cycle_start() {
 238   _cm->concurrent_cycle_start();
 239 }
 240 
 241 void G1ConcurrentMarkThread::full_concurrent_cycle_do() {
 242   HandleMark hm(Thread::current());
 243   ResourceMark rm;
 244 
 245   // Phase 1: Clear CLD claimed marks.
 246   phase_clear_cld_claimed_marks();
 247 
 248   // Do not return before the scan root regions phase as a GC waits for a
 249   // notification from it.
 250 
 251   // Phase 2: Scan root regions.
 252   if (phase_scan_root_regions()) return;
 253 
 254   Ticks mark_start = Ticks::now();
 255   log_info(gc, marking)("Concurrent Mark (%.3fs)", mark_start.seconds());
 256 
 257   bool needs_restart;
 258   uint iter = 1;
 259   do {
 260    // Phase 3: Mark From Roots.
 261     if (phase_mark_from_roots()) return;
 262 
 263     // Phase 4: Preclean (optional)
 264     if (G1UseReferencePrecleaning) {
 265       if (phase_preclean()) return;
 266     }
 267 
 268     // Phase 5: Wait for Remark.
 269     if (phase_delay_to_keep_mmu_before_remark()) return;
 270 
 271     // Phase 6: Remark pause
 272     if (phase_remark(needs_restart)) return;
 273     if (needs_restart) {
 274       log_info(gc, marking)("Concurrent Mark Restart for Mark Stack Overflow (iteration #%u)",
 275                             iter++);
 276     }
 277   } while (needs_restart);
 278 
 279   Ticks mark_end = Ticks::now();
 280   log_info(gc, marking)("Concurrent Mark (%.3fs, %.3fs) %.3fms",
 281                         mark_start.seconds(), mark_end.seconds(),
 282                         (mark_end - mark_start).seconds() * 1000.0);
 283 
 284   // Phase 7: Rebuild remembered sets.
 285   if (phase_rebuild_remembered_sets()) return;
 286 
 287   // Phase 8: Wait for Cleanup.
 288   if (phase_delay_to_keep_mmu_before_cleanup()) return;
 289 
 290   // Phase 9: Cleanup pause
 291   if (phase_cleanup()) return;
 292 
 293   // Phase 10: Clear bitmap for next mark.
 294   phase_clear_bitmap_for_next_mark();
 295 }
 296 
 297 void G1ConcurrentMarkThread::concurrent_cycle_end() {
 298   // Update the number of full collections that have been
 299   // completed. This will also notify the G1OldGCCount_lock in case a
 300   // Java thread is waiting for a full GC to happen (e.g., it
 301   // called System.gc() with +ExplicitGCInvokesConcurrent).

 302   SuspendibleThreadSetJoiner sts_join;
 303   G1CollectedHeap::heap()->increment_old_marking_cycles_completed(true /* concurrent */,
 304                                                                   !_cm->has_aborted());
 305 
 306   _cm->concurrent_cycle_end();
 307   ConcurrentGCBreakpoints::notify_active_to_idle();
























 308 }
--- EOF ---