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src/share/vm/gc/cms/vmCMSOperations.cpp

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rev 11747 : [mq]: per.hotspot.patch


  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/cms/concurrentMarkSweepGeneration.inline.hpp"
  27 #include "gc/cms/concurrentMarkSweepThread.hpp"
  28 #include "gc/cms/vmCMSOperations.hpp"
  29 #include "gc/shared/gcLocker.inline.hpp"
  30 #include "gc/shared/gcTimer.hpp"
  31 #include "gc/shared/gcTraceTime.inline.hpp"
  32 #include "gc/shared/isGCActiveMark.hpp"
  33 #include "runtime/interfaceSupport.hpp"
  34 #include "runtime/os.hpp"
  35 #include "utilities/dtrace.hpp"
  36 
  37 //////////////////////////////////////////////////////////
  38 // Methods in abstract class VM_CMS_Operation
  39 //////////////////////////////////////////////////////////
  40 void VM_CMS_Operation::acquire_pending_list_lock() {
  41   _pending_list_locker.lock();
  42 }
  43 
  44 void VM_CMS_Operation::release_and_notify_pending_list_lock() {
  45   _pending_list_locker.unlock();
  46 }
  47 
  48 void VM_CMS_Operation::verify_before_gc() {
  49   if (VerifyBeforeGC &&
  50       GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) {
  51     GCTraceTime(Info, gc, phases, verify) tm("Verify Before", _collector->_gc_timer_cm);
  52     HandleMark hm;
  53     FreelistLocker x(_collector);
  54     MutexLockerEx  y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
  55     GenCollectedHeap::heap()->prepare_for_verify();
  56     Universe::verify();
  57   }
  58 }
  59 
  60 void VM_CMS_Operation::verify_after_gc() {
  61   if (VerifyAfterGC &&
  62       GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) {
  63     GCTraceTime(Info, gc, phases, verify) tm("Verify After", _collector->_gc_timer_cm);
  64     HandleMark hm;
  65     FreelistLocker x(_collector);
  66     MutexLockerEx  y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
  67     Universe::verify();
  68   }
  69 }
  70 
  71 bool VM_CMS_Operation::lost_race() const {
  72   if (CMSCollector::abstract_state() == CMSCollector::Idling) {
  73     // We lost a race to a foreground collection
  74     // -- there's nothing to do
  75     return true;
  76   }
  77   assert(CMSCollector::abstract_state() == legal_state(),
  78          "Inconsistent collector state?");
  79   return false;
  80 }
  81 
  82 bool VM_CMS_Operation::doit_prologue() {
  83   assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
  84   assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
  85   assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
  86          "Possible deadlock");
  87 
  88   if (needs_pending_list_lock()) {
  89     acquire_pending_list_lock();
  90   }
  91   // Get the Heap_lock after the pending_list_lock.
  92   Heap_lock->lock();
  93   if (lost_race()) {
  94     assert(_prologue_succeeded == false, "Initialized in c'tor");
  95     Heap_lock->unlock();
  96     if (needs_pending_list_lock()) {
  97       release_and_notify_pending_list_lock();
  98     }
  99   } else {
 100     _prologue_succeeded = true;
 101   }
 102   return _prologue_succeeded;
 103 }
 104 
 105 void VM_CMS_Operation::doit_epilogue() {
 106   assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
 107   assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
 108   assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
 109          "Possible deadlock");
 110 
 111   // Release the Heap_lock first.
 112   Heap_lock->unlock();
 113   if (needs_pending_list_lock()) {
 114     release_and_notify_pending_list_lock();
 115   }

 116 }
 117 
 118 //////////////////////////////////////////////////////////
 119 // Methods in class VM_CMS_Initial_Mark
 120 //////////////////////////////////////////////////////////
 121 void VM_CMS_Initial_Mark::doit() {
 122   if (lost_race()) {
 123     // Nothing to do.
 124     return;
 125   }
 126   HS_PRIVATE_CMS_INITMARK_BEGIN();
 127   GCIdMark gc_id_mark(_gc_id);
 128 
 129   _collector->_gc_timer_cm->register_gc_pause_start("Initial Mark");
 130 
 131   GenCollectedHeap* gch = GenCollectedHeap::heap();
 132   GCCauseSetter gccs(gch, GCCause::_cms_initial_mark);
 133 
 134   VM_CMS_Operation::verify_before_gc();
 135 


 213   assert(thr != NULL, "Unexpected tid");
 214   if (!thr->is_Java_thread()) {
 215     assert(thr->is_VM_thread(), "Expected to be evaluated by VM thread");
 216     GenCollectedHeap* gch = GenCollectedHeap::heap();
 217     if (_gc_count_before != gch->total_collections()) {
 218       // No need to do a young gc, we'll just nudge the CMS thread
 219       // in the doit() method above, to be executed soon.
 220       assert(_gc_count_before < gch->total_collections(),
 221              "total_collections() should be monotonically increasing");
 222       return false;  // no need for foreground young gc
 223     }
 224   }
 225   return true;       // may still need foreground young gc
 226 }
 227 
 228 
 229 void VM_GenCollectFullConcurrent::doit_epilogue() {
 230   Thread* thr = Thread::current();
 231   assert(thr->is_Java_thread(), "just checking");
 232   JavaThread* jt = (JavaThread*)thr;
 233   // Release the Heap_lock first.



 234   Heap_lock->unlock();
 235   release_and_notify_pending_list_lock();
 236 
 237   // It is fine to test whether completed collections has
 238   // exceeded our request count without locking because
 239   // the completion count is monotonically increasing;
 240   // this will break for very long-running apps when the
 241   // count overflows and wraps around. XXX fix me !!!
 242   // e.g. at the rate of 1 full gc per ms, this could
 243   // overflow in about 1000 years.
 244   GenCollectedHeap* gch = GenCollectedHeap::heap();
 245   if (_gc_cause != GCCause::_gc_locker &&
 246       gch->total_full_collections_completed() <= _full_gc_count_before) {
 247     // maybe we should change the condition to test _gc_cause ==
 248     // GCCause::_java_lang_system_gc or GCCause::_dcmd_gc_run,
 249     // instead of _gc_cause != GCCause::_gc_locker
 250     assert(GCCause::is_user_requested_gc(_gc_cause),
 251            "the only way to get here if this was a System.gc()-induced GC");
 252     assert(ExplicitGCInvokesConcurrent, "Error");
 253     // Now, wait for witnessing concurrent gc cycle to complete,
 254     // but do so in native mode, because we want to lock the
 255     // FullGCEvent_lock, which may be needed by the VM thread


  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/cms/concurrentMarkSweepGeneration.inline.hpp"
  27 #include "gc/cms/concurrentMarkSweepThread.hpp"
  28 #include "gc/cms/vmCMSOperations.hpp"
  29 #include "gc/shared/gcLocker.inline.hpp"
  30 #include "gc/shared/gcTimer.hpp"
  31 #include "gc/shared/gcTraceTime.inline.hpp"
  32 #include "gc/shared/isGCActiveMark.hpp"
  33 #include "runtime/interfaceSupport.hpp"
  34 #include "runtime/os.hpp"
  35 #include "utilities/dtrace.hpp"
  36 
  37 //////////////////////////////////////////////////////////
  38 // Methods in abstract class VM_CMS_Operation
  39 //////////////////////////////////////////////////////////








  40 void VM_CMS_Operation::verify_before_gc() {
  41   if (VerifyBeforeGC &&
  42       GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) {
  43     GCTraceTime(Info, gc, phases, verify) tm("Verify Before", _collector->_gc_timer_cm);
  44     HandleMark hm;
  45     FreelistLocker x(_collector);
  46     MutexLockerEx  y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
  47     GenCollectedHeap::heap()->prepare_for_verify();
  48     Universe::verify();
  49   }
  50 }
  51 
  52 void VM_CMS_Operation::verify_after_gc() {
  53   if (VerifyAfterGC &&
  54       GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) {
  55     GCTraceTime(Info, gc, phases, verify) tm("Verify After", _collector->_gc_timer_cm);
  56     HandleMark hm;
  57     FreelistLocker x(_collector);
  58     MutexLockerEx  y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
  59     Universe::verify();
  60   }
  61 }
  62 
  63 bool VM_CMS_Operation::lost_race() const {
  64   if (CMSCollector::abstract_state() == CMSCollector::Idling) {
  65     // We lost a race to a foreground collection
  66     // -- there's nothing to do
  67     return true;
  68   }
  69   assert(CMSCollector::abstract_state() == legal_state(),
  70          "Inconsistent collector state?");
  71   return false;
  72 }
  73 
  74 bool VM_CMS_Operation::doit_prologue() {
  75   assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
  76   assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
  77   assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
  78          "Possible deadlock");
  79 




  80   Heap_lock->lock();
  81   if (lost_race()) {
  82     assert(_prologue_succeeded == false, "Initialized in c'tor");
  83     Heap_lock->unlock();



  84   } else {
  85     _prologue_succeeded = true;
  86   }
  87   return _prologue_succeeded;
  88 }
  89 
  90 void VM_CMS_Operation::doit_epilogue() {
  91   assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
  92   assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
  93   assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
  94          "Possible deadlock");
  95 
  96   if (Universe::has_reference_pending_list()) {
  97     Heap_lock->notify_all();


  98   }
  99   Heap_lock->unlock();
 100 }
 101 
 102 //////////////////////////////////////////////////////////
 103 // Methods in class VM_CMS_Initial_Mark
 104 //////////////////////////////////////////////////////////
 105 void VM_CMS_Initial_Mark::doit() {
 106   if (lost_race()) {
 107     // Nothing to do.
 108     return;
 109   }
 110   HS_PRIVATE_CMS_INITMARK_BEGIN();
 111   GCIdMark gc_id_mark(_gc_id);
 112 
 113   _collector->_gc_timer_cm->register_gc_pause_start("Initial Mark");
 114 
 115   GenCollectedHeap* gch = GenCollectedHeap::heap();
 116   GCCauseSetter gccs(gch, GCCause::_cms_initial_mark);
 117 
 118   VM_CMS_Operation::verify_before_gc();
 119 


 197   assert(thr != NULL, "Unexpected tid");
 198   if (!thr->is_Java_thread()) {
 199     assert(thr->is_VM_thread(), "Expected to be evaluated by VM thread");
 200     GenCollectedHeap* gch = GenCollectedHeap::heap();
 201     if (_gc_count_before != gch->total_collections()) {
 202       // No need to do a young gc, we'll just nudge the CMS thread
 203       // in the doit() method above, to be executed soon.
 204       assert(_gc_count_before < gch->total_collections(),
 205              "total_collections() should be monotonically increasing");
 206       return false;  // no need for foreground young gc
 207     }
 208   }
 209   return true;       // may still need foreground young gc
 210 }
 211 
 212 
 213 void VM_GenCollectFullConcurrent::doit_epilogue() {
 214   Thread* thr = Thread::current();
 215   assert(thr->is_Java_thread(), "just checking");
 216   JavaThread* jt = (JavaThread*)thr;
 217 
 218   if (Universe::has_reference_pending_list()) {
 219     Heap_lock->notify_all();
 220   }
 221   Heap_lock->unlock();

 222 
 223   // It is fine to test whether completed collections has
 224   // exceeded our request count without locking because
 225   // the completion count is monotonically increasing;
 226   // this will break for very long-running apps when the
 227   // count overflows and wraps around. XXX fix me !!!
 228   // e.g. at the rate of 1 full gc per ms, this could
 229   // overflow in about 1000 years.
 230   GenCollectedHeap* gch = GenCollectedHeap::heap();
 231   if (_gc_cause != GCCause::_gc_locker &&
 232       gch->total_full_collections_completed() <= _full_gc_count_before) {
 233     // maybe we should change the condition to test _gc_cause ==
 234     // GCCause::_java_lang_system_gc or GCCause::_dcmd_gc_run,
 235     // instead of _gc_cause != GCCause::_gc_locker
 236     assert(GCCause::is_user_requested_gc(_gc_cause),
 237            "the only way to get here if this was a System.gc()-induced GC");
 238     assert(ExplicitGCInvokesConcurrent, "Error");
 239     // Now, wait for witnessing concurrent gc cycle to complete,
 240     // but do so in native mode, because we want to lock the
 241     // FullGCEvent_lock, which may be needed by the VM thread
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