jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp@4947ee68d19c (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp@4947ee68d19c (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp

Thu, 06 Jan 2011 23:50:02 -0800

author: ysr
date: Thu, 06 Jan 2011 23:50:02 -0800
changeset 2452: 4947ee68d19c
parent 2314: f95d63e2154a
child 2647: a181f3a124dd
permissions: -rw-r--r--

7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
Summary: The recorded _sweep_limit may not necessarily remain a block boundary as the old generation expands during a concurrent cycle. Terminal actions inside the sweep closure need to be aware of this as they cross over the limit.
Reviewed-by: johnc, minqi

 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
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  */
 #include "precompiled.hpp"
 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.inline.hpp"
 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
 #include "gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp"
 #include "gc_implementation/shared/isGCActiveMark.hpp"
 #include "memory/gcLocker.inline.hpp"
 #include "runtime/interfaceSupport.hpp"
 #include "utilities/dtrace.hpp"
 HS_DTRACE_PROBE_DECL(hs_private, cms__initmark__begin);
 HS_DTRACE_PROBE_DECL(hs_private, cms__initmark__end);
 HS_DTRACE_PROBE_DECL(hs_private, cms__remark__begin);
 HS_DTRACE_PROBE_DECL(hs_private, cms__remark__end);
 //////////////////////////////////////////////////////////
 // Methods in abstract class VM_CMS_Operation
 //////////////////////////////////////////////////////////
 void VM_CMS_Operation::acquire_pending_list_lock() {
   // The caller may block while communicating
   // with the SLT thread in order to acquire/release the PLL.
   ConcurrentMarkSweepThread::slt()->
     manipulatePLL(SurrogateLockerThread::acquirePLL);
 }
 void VM_CMS_Operation::release_and_notify_pending_list_lock() {
   // The caller may block while communicating
   // with the SLT thread in order to acquire/release the PLL.
   ConcurrentMarkSweepThread::slt()->
     manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL);
 }
 void VM_CMS_Operation::verify_before_gc() {
   if (VerifyBeforeGC &&
       GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) {
     HandleMark hm;
     FreelistLocker x(_collector);
     MutexLockerEx  y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
     Universe::heap()->prepare_for_verify();
     Universe::verify(true);
   }
 }
 void VM_CMS_Operation::verify_after_gc() {
   if (VerifyAfterGC &&
       GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) {
     HandleMark hm;
     FreelistLocker x(_collector);
     MutexLockerEx  y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
     Universe::verify(true);
   }
 }
 bool VM_CMS_Operation::lost_race() const {
   if (CMSCollector::abstract_state() == CMSCollector::Idling) {
     // We lost a race to a foreground collection
     // -- there's nothing to do
     return true;
   }
   assert(CMSCollector::abstract_state() == legal_state(),
          "Inconsistent collector state?");
   return false;
 }
 bool VM_CMS_Operation::doit_prologue() {
   assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
   assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
   assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
          "Possible deadlock");
   if (needs_pll()) {
     acquire_pending_list_lock();
   }
   // Get the Heap_lock after the pending_list_lock.
   Heap_lock->lock();
   if (lost_race()) {
     assert(_prologue_succeeded == false, "Initialized in c'tor");
     Heap_lock->unlock();
     if (needs_pll()) {
       release_and_notify_pending_list_lock();
     }
   } else {
     _prologue_succeeded = true;
   }
   return _prologue_succeeded;
 }
 void VM_CMS_Operation::doit_epilogue() {
   assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
   assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
   assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
          "Possible deadlock");
   // Release the Heap_lock first.
   Heap_lock->unlock();
   if (needs_pll()) {
     release_and_notify_pending_list_lock();
   }
 }
 //////////////////////////////////////////////////////////
 // Methods in class VM_CMS_Initial_Mark
 //////////////////////////////////////////////////////////
 void VM_CMS_Initial_Mark::doit() {
   if (lost_race()) {
     // Nothing to do.
     return;
   }
   HS_DTRACE_PROBE(hs_private, cms__initmark__begin);
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   GCCauseSetter gccs(gch, GCCause::_cms_initial_mark);
   VM_CMS_Operation::verify_before_gc();
   IsGCActiveMark x; // stop-world GC active
   _collector->do_CMS_operation(CMSCollector::CMS_op_checkpointRootsInitial);
   VM_CMS_Operation::verify_after_gc();
   HS_DTRACE_PROBE(hs_private, cms__initmark__end);
 }
 //////////////////////////////////////////////////////////
 // Methods in class VM_CMS_Final_Remark_Operation
 //////////////////////////////////////////////////////////
 void VM_CMS_Final_Remark::doit() {
   if (lost_race()) {
     // Nothing to do.
     return;
   }
   HS_DTRACE_PROBE(hs_private, cms__remark__begin);
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   GCCauseSetter gccs(gch, GCCause::_cms_final_remark);
   VM_CMS_Operation::verify_before_gc();
   IsGCActiveMark x; // stop-world GC active
   _collector->do_CMS_operation(CMSCollector::CMS_op_checkpointRootsFinal);
   VM_CMS_Operation::verify_after_gc();
   HS_DTRACE_PROBE(hs_private, cms__remark__end);
 }
 // VM operation to invoke a concurrent collection of a
 // GenCollectedHeap heap.
 void VM_GenCollectFullConcurrent::doit() {
   assert(Thread::current()->is_VM_thread(), "Should be VM thread");
   assert(GCLockerInvokesConcurrent || ExplicitGCInvokesConcurrent, "Unexpected");
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   if (_gc_count_before == gch->total_collections()) {
     // The "full" of do_full_collection call below "forces"
     // a collection; the second arg, 0, below ensures that
     // only the young gen is collected. XXX In the future,
     // we'll probably need to have something in this interface
     // to say do this only if we are sure we will not bail
     // out to a full collection in this attempt, but that's
     // for the future.
     assert(SafepointSynchronize::is_at_safepoint(),
       "We can only be executing this arm of if at a safepoint");
     GCCauseSetter gccs(gch, _gc_cause);
     gch->do_full_collection(gch->must_clear_all_soft_refs(),
 /* collect only youngest gen */);
   } // Else no need for a foreground young gc
   assert((_gc_count_before < gch->total_collections()) ||
          (GC_locker::is_active() /* gc may have been skipped */
           && (_gc_count_before == gch->total_collections())),
          "total_collections() should be monotonically increasing");
   MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
   if (gch->total_full_collections() == _full_gc_count_before) {
     // Disable iCMS until the full collection is done.
     CMSCollector::disable_icms();
     // In case CMS thread was in icms_wait(), wake it up.
     CMSCollector::start_icms();
     // Nudge the CMS thread to start a concurrent collection.
     CMSCollector::request_full_gc(_full_gc_count_before);
   } else {
     FullGCCount_lock->notify_all();  // Inform the Java thread its work is done
   }
 }
 bool VM_GenCollectFullConcurrent::evaluate_at_safepoint() const {
   Thread* thr = Thread::current();
   assert(thr != NULL, "Unexpected tid");
   if (!thr->is_Java_thread()) {
     assert(thr->is_VM_thread(), "Expected to be evaluated by VM thread");
     GenCollectedHeap* gch = GenCollectedHeap::heap();
     if (_gc_count_before != gch->total_collections()) {
       // No need to do a young gc, we'll just nudge the CMS thread
       // in the doit() method above, to be executed soon.
       assert(_gc_count_before < gch->total_collections(),
              "total_collections() should be monotnically increasing");
       return false;  // no need for foreground young gc
     }
   }
   return true;       // may still need foreground young gc
 }
 void VM_GenCollectFullConcurrent::doit_epilogue() {
   Thread* thr = Thread::current();
   assert(thr->is_Java_thread(), "just checking");
   JavaThread* jt = (JavaThread*)thr;
   // Release the Heap_lock first.
   Heap_lock->unlock();
   release_and_notify_pending_list_lock();
   // It is fine to test whether completed collections has
   // exceeded our request count without locking because
   // the completion count is monotonically increasing;
   // this will break for very long-running apps when the
   // count overflows and wraps around. XXX fix me !!!
   // e.g. at the rate of 1 full gc per ms, this could
   // overflow in about 1000 years.
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   if (_gc_cause != GCCause::_gc_locker &&
       gch->total_full_collections_completed() <= _full_gc_count_before) {
     // maybe we should change the condition to test _gc_cause ==
     // GCCause::_java_lang_system_gc, instead of
     // _gc_cause != GCCause::_gc_locker
     assert(_gc_cause == GCCause::_java_lang_system_gc,
            "the only way to get here if this was a System.gc()-induced GC");
     assert(ExplicitGCInvokesConcurrent, "Error");
     // Now, wait for witnessing concurrent gc cycle to complete,
     // but do so in native mode, because we want to lock the
     // FullGCEvent_lock, which may be needed by the VM thread
     // or by the CMS thread, so we do not want to be suspended
     // while holding that lock.
     ThreadToNativeFromVM native(jt);
     MutexLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
     // Either a concurrent or a stop-world full gc is sufficient
     // witness to our request.
     while (gch->total_full_collections_completed() <= _full_gc_count_before) {
       FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
     }
   }
   // Enable iCMS back.
   CMSCollector::enable_icms();
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp@4947ee68d19c (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp