src/hotspot/share/gc/g1/g1RootProcessor.cpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2015, 2018, 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.
  *
  */

 #include "precompiled.hpp"

 #include "aot/aotLoader.hpp"
 #include "classfile/stringTable.hpp"
 #include "classfile/systemDictionary.hpp"
 #include "code/codeCache.hpp"
 #include "gc/g1/g1BarrierSet.hpp"
 #include "gc/g1/g1CodeBlobClosure.hpp"
 #include "gc/g1/g1CollectedHeap.inline.hpp"
 #include "gc/g1/g1CollectorState.hpp"
 #include "gc/g1/g1GCPhaseTimes.hpp"
 #include "gc/g1/g1ParScanThreadState.inline.hpp"
 #include "gc/g1/g1Policy.hpp"
 #include "gc/g1/g1RootClosures.hpp"
 #include "gc/g1/g1RootProcessor.hpp"
 #include "gc/g1/heapRegion.inline.hpp"
 #include "gc/shared/oopStorageParState.hpp"
 #include "gc/shared/referenceProcessor.hpp"
 #include "gc/shared/weakProcessor.hpp"
 #include "memory/allocation.inline.hpp"
 #include "runtime/mutex.hpp"
 #include "services/management.hpp"
 #include "utilities/macros.hpp"

 void G1RootProcessor::worker_has_discovered_all_strong_classes() {
   assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading");

   uint new_value = (uint)Atomic::add(1, &_n_workers_discovered_strong_classes);
   if (new_value == n_workers()) {
     // This thread is last. Notify the others.
     MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag);
     _lock.notify_all();
   }
 }

 void G1RootProcessor::wait_until_all_strong_classes_discovered() {
   assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading");

   if ((uint)_n_workers_discovered_strong_classes != n_workers()) {
     MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag);
     while ((uint)_n_workers_discovered_strong_classes != n_workers()) {
       _lock.wait(Mutex::_no_safepoint_check_flag, 0, false);
     }
   }
 }

 G1RootProcessor::G1RootProcessor(G1CollectedHeap* g1h, uint n_workers) :
     _g1h(g1h),
     _process_strong_tasks(G1RP_PS_NumElements),
     _srs(n_workers),
     _lock(Mutex::leaf, "G1 Root Scanning barrier lock", false, Monitor::_safepoint_check_never),
     _par_state_string(StringTable::weak_storage()),
     _n_workers_discovered_strong_classes(0) {}

 void G1RootProcessor::evacuate_roots(G1ParScanThreadState* pss, uint worker_i) {
   G1GCPhaseTimes* phase_times = _g1h->g1_policy()->phase_times();

   G1EvacPhaseTimesTracker timer(phase_times, pss, G1GCPhaseTimes::ExtRootScan, worker_i);

   G1EvacuationRootClosures* closures = pss->closures();
   process_java_roots(closures, phase_times, worker_i);

   // This is the point where this worker thread will not find more strong CLDs/nmethods.
   // Report this so G1 can synchronize the strong and weak CLDs/nmethods processing.
   if (closures->trace_metadata()) {
     worker_has_discovered_all_strong_classes();
   }

   process_vm_roots(closures, phase_times, worker_i);
   process_string_table_roots(closures, phase_times, worker_i);

   {
     // Now the CM ref_processor roots.
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CMRefRoots, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_refProcessor_oops_do)) {
       // We need to treat the discovered reference lists of the
       // concurrent mark ref processor as roots and keep entries
       // (which are added by the marking threads) on them live
       // until they can be processed at the end of marking.
       _g1h->ref_processor_cm()->weak_oops_do(closures->strong_oops());
     }
   }

   if (closures->trace_metadata()) {
     {
       G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WaitForStrongCLD, worker_i);
       // Barrier to make sure all workers passed
       // the strong CLD and strong nmethods phases.
       wait_until_all_strong_classes_discovered();
     }

     // Now take the complement of the strong CLDs.
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WeakCLDRoots, worker_i);
     assert(closures->second_pass_weak_clds() != NULL, "Should be non-null if we are tracing metadata.");
     ClassLoaderDataGraph::roots_cld_do(NULL, closures->second_pass_weak_clds());
   } else {
     phase_times->record_time_secs(G1GCPhaseTimes::WaitForStrongCLD, worker_i, 0.0);
     phase_times->record_time_secs(G1GCPhaseTimes::WeakCLDRoots, worker_i, 0.0);
     assert(closures->second_pass_weak_clds() == NULL, "Should be null if not tracing metadata.");
   }

   // During conc marking we have to filter the per-thread SATB buffers
   // to make sure we remove any oops into the CSet (which will show up
   // as implicitly live).
   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SATBFiltering, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_filter_satb_buffers) && _g1h->collector_state()->mark_or_rebuild_in_progress()) {
       G1BarrierSet::satb_mark_queue_set().filter_thread_buffers();
     }
   }

   _process_strong_tasks.all_tasks_completed(n_workers());
 }

 // Adaptor to pass the closures to the strong roots in the VM.
 class StrongRootsClosures : public G1RootClosures {
   OopClosure* _roots;
   CLDClosure* _clds;
   CodeBlobClosure* _blobs;
 public:
   StrongRootsClosures(OopClosure* roots, CLDClosure* clds, CodeBlobClosure* blobs) :
       _roots(roots), _clds(clds), _blobs(blobs) {}

   OopClosure* weak_oops()   { return NULL; }
   OopClosure* strong_oops() { return _roots; }

   CLDClosure* weak_clds()        { return NULL; }
   CLDClosure* strong_clds()      { return _clds; }

   CodeBlobClosure* strong_codeblobs() { return _blobs; }
 };

 void G1RootProcessor::process_strong_roots(OopClosure* oops,
                                            CLDClosure* clds,
                                            CodeBlobClosure* blobs) {
   StrongRootsClosures closures(oops, clds, blobs);

   process_java_roots(&closures, NULL, 0);
   process_vm_roots(&closures, NULL, 0);

   _process_strong_tasks.all_tasks_completed(n_workers());
 }

 // Adaptor to pass the closures to all the roots in the VM.
 class AllRootsClosures : public G1RootClosures {
   OopClosure* _roots;
   CLDClosure* _clds;
 public:
   AllRootsClosures(OopClosure* roots, CLDClosure* clds) :
       _roots(roots), _clds(clds) {}

   OopClosure* weak_oops() { return _roots; }
   OopClosure* strong_oops() { return _roots; }

   // By returning the same CLDClosure for both weak and strong CLDs we ensure
   // that a single walk of the CLDG will invoke the closure on all CLDs i the
   // system.
   CLDClosure* weak_clds() { return _clds; }
   CLDClosure* strong_clds() { return _clds; }

   // We don't want to visit code blobs more than once, so we return NULL for the
   // strong case and walk the entire code cache as a separate step.
   CodeBlobClosure* strong_codeblobs() { return NULL; }
 };

 void G1RootProcessor::process_all_roots(OopClosure* oops,
                                         CLDClosure* clds,
                                         CodeBlobClosure* blobs,
                                         bool process_string_table) {
   AllRootsClosures closures(oops, clds);

   process_java_roots(&closures, NULL, 0);
   process_vm_roots(&closures, NULL, 0);

   if (process_string_table) {
     process_string_table_roots(&closures, NULL, 0);
   }
   process_code_cache_roots(blobs, NULL, 0);

   _process_strong_tasks.all_tasks_completed(n_workers());
 }

 void G1RootProcessor::process_all_roots(OopClosure* oops,
                                         CLDClosure* clds,
                                         CodeBlobClosure* blobs) {
   process_all_roots(oops, clds, blobs, true);
 }

 void G1RootProcessor::process_all_roots_no_string_table(OopClosure* oops,
                                                         CLDClosure* clds,
                                                         CodeBlobClosure* blobs) {
   assert(!ClassUnloading, "Should only be used when class unloading is disabled");
   process_all_roots(oops, clds, blobs, false);
 }

 void G1RootProcessor::process_java_roots(G1RootClosures* closures,
                                          G1GCPhaseTimes* phase_times,
                                          uint worker_i) {
   // Iterating over the CLDG and the Threads are done early to allow us to
   // first process the strong CLDs and nmethods and then, after a barrier,
   // let the thread process the weak CLDs and nmethods.
   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CLDGRoots, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_ClassLoaderDataGraph_oops_do)) {
       ClassLoaderDataGraph::roots_cld_do(closures->strong_clds(), closures->weak_clds());
     }
   }

   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ThreadRoots, worker_i);
     bool is_par = n_workers() > 1;
     Threads::possibly_parallel_oops_do(is_par,
                                        closures->strong_oops(),
                                        closures->strong_codeblobs());
   }
 }

 void G1RootProcessor::process_vm_roots(G1RootClosures* closures,
                                        G1GCPhaseTimes* phase_times,
                                        uint worker_i) {
   OopClosure* strong_roots = closures->strong_oops();

   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::UniverseRoots, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_Universe_oops_do)) {
       Universe::oops_do(strong_roots);
     }
   }

   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JNIRoots, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_JNIHandles_oops_do)) {
       JNIHandles::oops_do(strong_roots);
     }
   }

   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ObjectSynchronizerRoots, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_ObjectSynchronizer_oops_do)) {
       ObjectSynchronizer::oops_do(strong_roots);
     }
   }

   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ManagementRoots, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_Management_oops_do)) {
       Management::oops_do(strong_roots);
     }
   }

   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JVMTIRoots, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_jvmti_oops_do)) {
       JvmtiExport::oops_do(strong_roots);
     }
   }

 #if INCLUDE_AOT
   if (UseAOT) {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::AOTCodeRoots, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_aot_oops_do)) {
         AOTLoader::oops_do(strong_roots);
     }
   }
 #endif

   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SystemDictionaryRoots, worker_i);
     if (!_process_strong_tasks.is_task_claimed(G1RP_PS_SystemDictionary_oops_do)) {
       SystemDictionary::oops_do(strong_roots);
     }
   }
 }

 void G1RootProcessor::process_string_table_roots(G1RootClosures* closures,
                                                  G1GCPhaseTimes* phase_times,
                                                  uint worker_i) {
   assert(closures->weak_oops() != NULL, "Should only be called when all roots are processed");
   G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::StringTableRoots, worker_i);
   // All threads execute the following. A specific chunk of buckets
   // from the StringTable are the individual tasks.
   StringTable::possibly_parallel_oops_do(&_par_state_string, closures->weak_oops());
 }

 void G1RootProcessor::process_code_cache_roots(CodeBlobClosure* code_closure,
                                                G1GCPhaseTimes* phase_times,
                                                uint worker_i) {
   if (!_process_strong_tasks.is_task_claimed(G1RP_PS_CodeCache_oops_do)) {
     CodeCache::blobs_do(code_closure);
   }
 }

 void G1RootProcessor::process_full_gc_weak_roots(OopClosure* oops) {
   if (!_process_strong_tasks.is_task_claimed(G1RP_PS_refProcessor_oops_do)) {
     _g1h->ref_processor_stw()->weak_oops_do(oops);
   }

   if (!_process_strong_tasks.is_task_claimed(G1RP_PS_weakProcessor_oops_do)) {
     WeakProcessor::oops_do(oops);
   }
 }

 uint G1RootProcessor::n_workers() const {
   return _srs.n_threads();
 }
	/*
	* Copyright (c) 2015, 2018, 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.
	*
	*/

	#include "precompiled.hpp"

	#include "aot/aotLoader.hpp"
	#include "classfile/stringTable.hpp"
	#include "classfile/systemDictionary.hpp"
	#include "code/codeCache.hpp"
	#include "gc/g1/g1BarrierSet.hpp"
	#include "gc/g1/g1CodeBlobClosure.hpp"
	#include "gc/g1/g1CollectedHeap.inline.hpp"
	#include "gc/g1/g1CollectorState.hpp"
	#include "gc/g1/g1GCPhaseTimes.hpp"
	#include "gc/g1/g1ParScanThreadState.inline.hpp"
	#include "gc/g1/g1Policy.hpp"
	#include "gc/g1/g1RootClosures.hpp"
	#include "gc/g1/g1RootProcessor.hpp"
	#include "gc/g1/heapRegion.inline.hpp"
	#include "gc/shared/oopStorageParState.hpp"
	#include "gc/shared/referenceProcessor.hpp"
	#include "gc/shared/weakProcessor.hpp"
	#include "memory/allocation.inline.hpp"
	#include "runtime/mutex.hpp"
	#include "services/management.hpp"
	#include "utilities/macros.hpp"

	void G1RootProcessor::worker_has_discovered_all_strong_classes() {
	assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading");

	uint new_value = (uint)Atomic::add(1, &_n_workers_discovered_strong_classes);
	if (new_value == n_workers()) {
	// This thread is last. Notify the others.
	MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag);
	_lock.notify_all();
	}
	}

	void G1RootProcessor::wait_until_all_strong_classes_discovered() {
	assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading");

	if ((uint)_n_workers_discovered_strong_classes != n_workers()) {
	MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag);
	while ((uint)_n_workers_discovered_strong_classes != n_workers()) {
	_lock.wait(Mutex::_no_safepoint_check_flag, 0, false);
	}
	}
	}

	G1RootProcessor::G1RootProcessor(G1CollectedHeap* g1h, uint n_workers) :
	_g1h(g1h),
	_process_strong_tasks(G1RP_PS_NumElements),
	_srs(n_workers),
	_lock(Mutex::leaf, "G1 Root Scanning barrier lock", false, Monitor::_safepoint_check_never),
	_par_state_string(StringTable::weak_storage()),
	_n_workers_discovered_strong_classes(0) {}

	void G1RootProcessor::evacuate_roots(G1ParScanThreadState* pss, uint worker_i) {
	G1GCPhaseTimes* phase_times = _g1h->g1_policy()->phase_times();

	G1EvacPhaseTimesTracker timer(phase_times, pss, G1GCPhaseTimes::ExtRootScan, worker_i);

	G1EvacuationRootClosures* closures = pss->closures();
	process_java_roots(closures, phase_times, worker_i);

	// This is the point where this worker thread will not find more strong CLDs/nmethods.
	// Report this so G1 can synchronize the strong and weak CLDs/nmethods processing.
	if (closures->trace_metadata()) {
	worker_has_discovered_all_strong_classes();
	}

	process_vm_roots(closures, phase_times, worker_i);
	process_string_table_roots(closures, phase_times, worker_i);

	{
	// Now the CM ref_processor roots.
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CMRefRoots, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_refProcessor_oops_do)) {
	// We need to treat the discovered reference lists of the
	// concurrent mark ref processor as roots and keep entries
	// (which are added by the marking threads) on them live
	// until they can be processed at the end of marking.
	_g1h->ref_processor_cm()->weak_oops_do(closures->strong_oops());
	}
	}

	if (closures->trace_metadata()) {
	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WaitForStrongCLD, worker_i);
	// Barrier to make sure all workers passed
	// the strong CLD and strong nmethods phases.
	wait_until_all_strong_classes_discovered();
	}

	// Now take the complement of the strong CLDs.
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WeakCLDRoots, worker_i);
	assert(closures->second_pass_weak_clds() != NULL, "Should be non-null if we are tracing metadata.");
	ClassLoaderDataGraph::roots_cld_do(NULL, closures->second_pass_weak_clds());
	} else {
	phase_times->record_time_secs(G1GCPhaseTimes::WaitForStrongCLD, worker_i, 0.0);
	phase_times->record_time_secs(G1GCPhaseTimes::WeakCLDRoots, worker_i, 0.0);
	assert(closures->second_pass_weak_clds() == NULL, "Should be null if not tracing metadata.");
	}

	// During conc marking we have to filter the per-thread SATB buffers
	// to make sure we remove any oops into the CSet (which will show up
	// as implicitly live).
	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SATBFiltering, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_filter_satb_buffers) && _g1h->collector_state()->mark_or_rebuild_in_progress()) {
	G1BarrierSet::satb_mark_queue_set().filter_thread_buffers();
	}
	}

	_process_strong_tasks.all_tasks_completed(n_workers());
	}

	// Adaptor to pass the closures to the strong roots in the VM.
	class StrongRootsClosures : public G1RootClosures {
	OopClosure* _roots;
	CLDClosure* _clds;
	CodeBlobClosure* _blobs;
	public:
	StrongRootsClosures(OopClosure* roots, CLDClosure* clds, CodeBlobClosure* blobs) :
	_roots(roots), _clds(clds), _blobs(blobs) {}

	OopClosure* weak_oops() { return NULL; }
	OopClosure* strong_oops() { return _roots; }

	CLDClosure* weak_clds() { return NULL; }
	CLDClosure* strong_clds() { return _clds; }

	CodeBlobClosure* strong_codeblobs() { return _blobs; }
	};

	void G1RootProcessor::process_strong_roots(OopClosure* oops,
	CLDClosure* clds,
	CodeBlobClosure* blobs) {
	StrongRootsClosures closures(oops, clds, blobs);

	process_java_roots(&closures, NULL, 0);
	process_vm_roots(&closures, NULL, 0);

	_process_strong_tasks.all_tasks_completed(n_workers());
	}

	// Adaptor to pass the closures to all the roots in the VM.
	class AllRootsClosures : public G1RootClosures {
	OopClosure* _roots;
	CLDClosure* _clds;
	public:
	AllRootsClosures(OopClosure* roots, CLDClosure* clds) :
	_roots(roots), _clds(clds) {}

	OopClosure* weak_oops() { return _roots; }
	OopClosure* strong_oops() { return _roots; }

	// By returning the same CLDClosure for both weak and strong CLDs we ensure
	// that a single walk of the CLDG will invoke the closure on all CLDs i the
	// system.
	CLDClosure* weak_clds() { return _clds; }
	CLDClosure* strong_clds() { return _clds; }

	// We don't want to visit code blobs more than once, so we return NULL for the
	// strong case and walk the entire code cache as a separate step.
	CodeBlobClosure* strong_codeblobs() { return NULL; }
	};

	void G1RootProcessor::process_all_roots(OopClosure* oops,
	CLDClosure* clds,
	CodeBlobClosure* blobs,
	bool process_string_table) {
	AllRootsClosures closures(oops, clds);

	process_java_roots(&closures, NULL, 0);
	process_vm_roots(&closures, NULL, 0);

	if (process_string_table) {
	process_string_table_roots(&closures, NULL, 0);
	}
	process_code_cache_roots(blobs, NULL, 0);

	_process_strong_tasks.all_tasks_completed(n_workers());
	}

	void G1RootProcessor::process_all_roots(OopClosure* oops,
	CLDClosure* clds,
	CodeBlobClosure* blobs) {
	process_all_roots(oops, clds, blobs, true);
	}

	void G1RootProcessor::process_all_roots_no_string_table(OopClosure* oops,
	CLDClosure* clds,
	CodeBlobClosure* blobs) {
	assert(!ClassUnloading, "Should only be used when class unloading is disabled");
	process_all_roots(oops, clds, blobs, false);
	}

	void G1RootProcessor::process_java_roots(G1RootClosures* closures,
	G1GCPhaseTimes* phase_times,
	uint worker_i) {
	// Iterating over the CLDG and the Threads are done early to allow us to
	// first process the strong CLDs and nmethods and then, after a barrier,
	// let the thread process the weak CLDs and nmethods.
	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CLDGRoots, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_ClassLoaderDataGraph_oops_do)) {
	ClassLoaderDataGraph::roots_cld_do(closures->strong_clds(), closures->weak_clds());
	}
	}

	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ThreadRoots, worker_i);
	bool is_par = n_workers() > 1;
	Threads::possibly_parallel_oops_do(is_par,
	closures->strong_oops(),
	closures->strong_codeblobs());
	}
	}

	void G1RootProcessor::process_vm_roots(G1RootClosures* closures,
	G1GCPhaseTimes* phase_times,
	uint worker_i) {
	OopClosure* strong_roots = closures->strong_oops();

	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::UniverseRoots, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_Universe_oops_do)) {
	Universe::oops_do(strong_roots);
	}
	}

	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JNIRoots, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_JNIHandles_oops_do)) {
	JNIHandles::oops_do(strong_roots);
	}
	}

	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ObjectSynchronizerRoots, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_ObjectSynchronizer_oops_do)) {
	ObjectSynchronizer::oops_do(strong_roots);
	}
	}

	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ManagementRoots, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_Management_oops_do)) {
	Management::oops_do(strong_roots);
	}
	}

	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JVMTIRoots, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_jvmti_oops_do)) {
	JvmtiExport::oops_do(strong_roots);
	}
	}

	#if INCLUDE_AOT
	if (UseAOT) {
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::AOTCodeRoots, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_aot_oops_do)) {
	AOTLoader::oops_do(strong_roots);
	}
	}
	#endif

	{
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SystemDictionaryRoots, worker_i);
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_SystemDictionary_oops_do)) {
	SystemDictionary::oops_do(strong_roots);
	}
	}
	}

	void G1RootProcessor::process_string_table_roots(G1RootClosures* closures,
	G1GCPhaseTimes* phase_times,
	uint worker_i) {
	assert(closures->weak_oops() != NULL, "Should only be called when all roots are processed");
	G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::StringTableRoots, worker_i);
	// All threads execute the following. A specific chunk of buckets
	// from the StringTable are the individual tasks.
	StringTable::possibly_parallel_oops_do(&_par_state_string, closures->weak_oops());
	}

	void G1RootProcessor::process_code_cache_roots(CodeBlobClosure* code_closure,
	G1GCPhaseTimes* phase_times,
	uint worker_i) {
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_CodeCache_oops_do)) {
	CodeCache::blobs_do(code_closure);
	}
	}

	void G1RootProcessor::process_full_gc_weak_roots(OopClosure* oops) {
	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_refProcessor_oops_do)) {
	_g1h->ref_processor_stw()->weak_oops_do(oops);
	}

	if (!_process_strong_tasks.is_task_claimed(G1RP_PS_weakProcessor_oops_do)) {
	WeakProcessor::oops_do(oops);
	}
	}

	uint G1RootProcessor::n_workers() const {
	return _srs.n_threads();
	}