src/share/vm/services/memoryManager.cpp - platform/external/jetbrains/jdk8u_hotspot - Git at Google

 /*
  * Copyright (c) 2003, 2013, 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 "classfile/systemDictionary.hpp"
 #include "classfile/vmSymbols.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/javaCalls.hpp"
 #include "runtime/orderAccess.inline.hpp"
 #include "services/lowMemoryDetector.hpp"
 #include "services/management.hpp"
 #include "services/memoryManager.hpp"
 #include "services/memoryPool.hpp"
 #include "services/memoryService.hpp"
 #include "services/gcNotifier.hpp"
 #include "utilities/dtrace.hpp"

 #ifndef USDT2
 HS_DTRACE_PROBE_DECL8(hotspot, mem__pool__gc__begin, char*, int, char*, int,
   size_t, size_t, size_t, size_t);
 HS_DTRACE_PROBE_DECL8(hotspot, mem__pool__gc__end, char*, int, char*, int,
   size_t, size_t, size_t, size_t);
 #endif /* !USDT2 */

 MemoryManager::MemoryManager() {
   _num_pools = 0;
   (void)const_cast<instanceOop&>(_memory_mgr_obj = NULL);
 }

 void MemoryManager::add_pool(MemoryPool* pool) {
   assert(_num_pools < MemoryManager::max_num_pools, "_num_pools exceeds the max");
   if (_num_pools < MemoryManager::max_num_pools) {
     _pools[_num_pools] = pool;
     _num_pools++;
   }
   pool->add_manager(this);
 }

 MemoryManager* MemoryManager::get_code_cache_memory_manager() {
   return (MemoryManager*) new CodeCacheMemoryManager();
 }

 MemoryManager* MemoryManager::get_metaspace_memory_manager() {
   return (MemoryManager*) new MetaspaceMemoryManager();
 }

 GCMemoryManager* MemoryManager::get_copy_memory_manager() {
   return (GCMemoryManager*) new CopyMemoryManager();
 }

 GCMemoryManager* MemoryManager::get_msc_memory_manager() {
   return (GCMemoryManager*) new MSCMemoryManager();
 }

 GCMemoryManager* MemoryManager::get_parnew_memory_manager() {
   return (GCMemoryManager*) new ParNewMemoryManager();
 }

 GCMemoryManager* MemoryManager::get_cms_memory_manager() {
   return (GCMemoryManager*) new CMSMemoryManager();
 }

 GCMemoryManager* MemoryManager::get_psScavenge_memory_manager() {
   return (GCMemoryManager*) new PSScavengeMemoryManager();
 }

 GCMemoryManager* MemoryManager::get_psMarkSweep_memory_manager() {
   return (GCMemoryManager*) new PSMarkSweepMemoryManager();
 }

 GCMemoryManager* MemoryManager::get_g1YoungGen_memory_manager() {
   return (GCMemoryManager*) new G1YoungGenMemoryManager();
 }

 GCMemoryManager* MemoryManager::get_g1OldGen_memory_manager() {
   return (GCMemoryManager*) new G1OldGenMemoryManager();
 }

 instanceOop MemoryManager::get_memory_manager_instance(TRAPS) {
   // Must do an acquire so as to force ordering of subsequent
   // loads from anything _memory_mgr_obj points to or implies.
   instanceOop mgr_obj = (instanceOop)OrderAccess::load_ptr_acquire(&_memory_mgr_obj);
   if (mgr_obj == NULL) {
     // It's ok for more than one thread to execute the code up to the locked region.
     // Extra manager instances will just be gc'ed.
     Klass* k = Management::sun_management_ManagementFactory_klass(CHECK_0);
     instanceKlassHandle ik(THREAD, k);

     Handle mgr_name = java_lang_String::create_from_str(name(), CHECK_0);

     JavaValue result(T_OBJECT);
     JavaCallArguments args;
     args.push_oop(mgr_name);    // Argument 1

     Symbol* method_name = NULL;
     Symbol* signature = NULL;
     if (is_gc_memory_manager()) {
       method_name = vmSymbols::createGarbageCollector_name();
       signature = vmSymbols::createGarbageCollector_signature();
       args.push_oop(Handle());      // Argument 2 (for future extension)
     } else {
       method_name = vmSymbols::createMemoryManager_name();
       signature = vmSymbols::createMemoryManager_signature();
     }

     JavaCalls::call_static(&result,
                            ik,
                            method_name,
                            signature,
                            &args,
                            CHECK_0);

     instanceOop m = (instanceOop) result.get_jobject();
     instanceHandle mgr(THREAD, m);

     {
       // Get lock before setting _memory_mgr_obj
       // since another thread may have created the instance
       MutexLocker ml(Management_lock);

       // Check if another thread has created the management object.  We reload
       // _memory_mgr_obj here because some other thread may have initialized
       // it while we were executing the code before the lock.
       //
       // The lock has done an acquire, so the load can't float above it, but
       // we need to do a load_acquire as above.
       mgr_obj = (instanceOop)OrderAccess::load_ptr_acquire(&_memory_mgr_obj);
       if (mgr_obj != NULL) {
          return mgr_obj;
       }

       // Get the address of the object we created via call_special.
       mgr_obj = mgr();

       // Use store barrier to make sure the memory accesses associated
       // with creating the management object are visible before publishing
       // its address.  The unlock will publish the store to _memory_mgr_obj
       // because it does a release first.
       OrderAccess::release_store_ptr(&_memory_mgr_obj, mgr_obj);
     }
   }

   return mgr_obj;
 }

 void MemoryManager::oops_do(OopClosure* f) {
   f->do_oop((oop*) &_memory_mgr_obj);
 }

 GCStatInfo::GCStatInfo(int num_pools) {
   // initialize the arrays for memory usage
   _before_gc_usage_array = (MemoryUsage*) NEW_C_HEAP_ARRAY(MemoryUsage, num_pools, mtInternal);
   _after_gc_usage_array  = (MemoryUsage*) NEW_C_HEAP_ARRAY(MemoryUsage, num_pools, mtInternal);
   _usage_array_size = num_pools;
   clear();
 }

 GCStatInfo::~GCStatInfo() {
   FREE_C_HEAP_ARRAY(MemoryUsage*, _before_gc_usage_array, mtInternal);
   FREE_C_HEAP_ARRAY(MemoryUsage*, _after_gc_usage_array, mtInternal);
 }

 void GCStatInfo::set_gc_usage(int pool_index, MemoryUsage usage, bool before_gc) {
   MemoryUsage* gc_usage_array;
   if (before_gc) {
     gc_usage_array = _before_gc_usage_array;
   } else {
     gc_usage_array = _after_gc_usage_array;
   }
   gc_usage_array[pool_index] = usage;
 }

 void GCStatInfo::clear() {
   _index = 0;
   _start_time = 0L;
   _end_time = 0L;
   size_t len = _usage_array_size * sizeof(MemoryUsage);
   memset(_before_gc_usage_array, 0, len);
   memset(_after_gc_usage_array, 0, len);
 }


 GCMemoryManager::GCMemoryManager() : MemoryManager() {
   _num_collections = 0;
   _last_gc_stat = NULL;
   _last_gc_lock = new Mutex(Mutex::leaf, "_last_gc_lock", true);
   _current_gc_stat = NULL;
   _num_gc_threads = 1;
   _notification_enabled = false;
 }

 GCMemoryManager::~GCMemoryManager() {
   delete _last_gc_stat;
   delete _last_gc_lock;
   delete _current_gc_stat;
 }

 void GCMemoryManager::initialize_gc_stat_info() {
   assert(MemoryService::num_memory_pools() > 0, "should have one or more memory pools");
   _last_gc_stat = new(ResourceObj::C_HEAP, mtGC) GCStatInfo(MemoryService::num_memory_pools());
   _current_gc_stat = new(ResourceObj::C_HEAP, mtGC) GCStatInfo(MemoryService::num_memory_pools());
   // tracking concurrent collections we need two objects: one to update, and one to
   // hold the publicly available "last (completed) gc" information.
 }

 void GCMemoryManager::gc_begin(bool recordGCBeginTime, bool recordPreGCUsage,
                                bool recordAccumulatedGCTime) {
   assert(_last_gc_stat != NULL && _current_gc_stat != NULL, "Just checking");
   if (recordAccumulatedGCTime) {
     _accumulated_timer.start();
   }
   // _num_collections now increases in gc_end, to count completed collections
   if (recordGCBeginTime) {
     _current_gc_stat->set_index(_num_collections+1);
     _current_gc_stat->set_start_time(Management::timestamp());
   }

   if (recordPreGCUsage) {
     // Keep memory usage of all memory pools
     for (int i = 0; i < MemoryService::num_memory_pools(); i++) {
       MemoryPool* pool = MemoryService::get_memory_pool(i);
       MemoryUsage usage = pool->get_memory_usage();
       _current_gc_stat->set_before_gc_usage(i, usage);
 #ifndef USDT2
       HS_DTRACE_PROBE8(hotspot, mem__pool__gc__begin,
         name(), strlen(name()),
         pool->name(), strlen(pool->name()),
         usage.init_size(), usage.used(),
         usage.committed(), usage.max_size());
 #else /* USDT2 */
       HOTSPOT_MEM_POOL_GC_BEGIN(
         (char *) name(), strlen(name()),
         (char *) pool->name(), strlen(pool->name()),
         usage.init_size(), usage.used(),
         usage.committed(), usage.max_size());
 #endif /* USDT2 */
     }
   }
 }

 // A collector MUST, even if it does not complete for some reason,
 // make a TraceMemoryManagerStats object where countCollection is true,
 // to ensure the current gc stat is placed in _last_gc_stat.
 void GCMemoryManager::gc_end(bool recordPostGCUsage,
                              bool recordAccumulatedGCTime,
                              bool recordGCEndTime, bool countCollection,
                              GCCause::Cause cause) {
   if (recordAccumulatedGCTime) {
     _accumulated_timer.stop();
   }
   if (recordGCEndTime) {
     _current_gc_stat->set_end_time(Management::timestamp());
   }

   if (recordPostGCUsage) {
     int i;
     // keep the last gc statistics for all memory pools
     for (i = 0; i < MemoryService::num_memory_pools(); i++) {
       MemoryPool* pool = MemoryService::get_memory_pool(i);
       MemoryUsage usage = pool->get_memory_usage();

 #ifndef USDT2
       HS_DTRACE_PROBE8(hotspot, mem__pool__gc__end,
         name(), strlen(name()),
         pool->name(), strlen(pool->name()),
         usage.init_size(), usage.used(),
         usage.committed(), usage.max_size());
 #else /* USDT2 */
       HOTSPOT_MEM_POOL_GC_END(
         (char *) name(), strlen(name()),
         (char *) pool->name(), strlen(pool->name()),
         usage.init_size(), usage.used(),
         usage.committed(), usage.max_size());
 #endif /* USDT2 */

       _current_gc_stat->set_after_gc_usage(i, usage);
     }

     // Set last collection usage of the memory pools managed by this collector
     for (i = 0; i < num_memory_pools(); i++) {
       MemoryPool* pool = get_memory_pool(i);
       MemoryUsage usage = pool->get_memory_usage();

       // Compare with GC usage threshold
       pool->set_last_collection_usage(usage);
       LowMemoryDetector::detect_after_gc_memory(pool);
     }
   }

   if (countCollection) {
     _num_collections++;
     // alternately update two objects making one public when complete
     {
       MutexLockerEx ml(_last_gc_lock, Mutex::_no_safepoint_check_flag);
       GCStatInfo *tmp = _last_gc_stat;
       _last_gc_stat = _current_gc_stat;
       _current_gc_stat = tmp;
       // reset the current stat for diagnosability purposes
       _current_gc_stat->clear();
     }

     if (is_notification_enabled()) {
       bool isMajorGC = this == MemoryService::get_major_gc_manager();
       GCNotifier::pushNotification(this, isMajorGC ? "end of major GC" : "end of minor GC",
                                    GCCause::to_string(cause));
     }
   }
 }

 size_t GCMemoryManager::get_last_gc_stat(GCStatInfo* dest) {
   MutexLockerEx ml(_last_gc_lock, Mutex::_no_safepoint_check_flag);
   if (_last_gc_stat->gc_index() != 0) {
     dest->set_index(_last_gc_stat->gc_index());
     dest->set_start_time(_last_gc_stat->start_time());
     dest->set_end_time(_last_gc_stat->end_time());
     assert(dest->usage_array_size() == _last_gc_stat->usage_array_size(),
            "Must have same array size");
     size_t len = dest->usage_array_size() * sizeof(MemoryUsage);
     memcpy(dest->before_gc_usage_array(), _last_gc_stat->before_gc_usage_array(), len);
     memcpy(dest->after_gc_usage_array(), _last_gc_stat->after_gc_usage_array(), len);
   }
   return _last_gc_stat->gc_index();
 }
	/*
	* Copyright (c) 2003, 2013, 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 "classfile/systemDictionary.hpp"
	#include "classfile/vmSymbols.hpp"
	#include "oops/oop.inline.hpp"
	#include "runtime/handles.inline.hpp"
	#include "runtime/javaCalls.hpp"
	#include "runtime/orderAccess.inline.hpp"
	#include "services/lowMemoryDetector.hpp"
	#include "services/management.hpp"
	#include "services/memoryManager.hpp"
	#include "services/memoryPool.hpp"
	#include "services/memoryService.hpp"
	#include "services/gcNotifier.hpp"
	#include "utilities/dtrace.hpp"

	#ifndef USDT2
	HS_DTRACE_PROBE_DECL8(hotspot, mem__pool__gc__begin, char, int, char, int,
	size_t, size_t, size_t, size_t);
	HS_DTRACE_PROBE_DECL8(hotspot, mem__pool__gc__end, char, int, char, int,
	size_t, size_t, size_t, size_t);
	#endif /* !USDT2 */

	MemoryManager::MemoryManager() {
	_num_pools = 0;
	(void)const_cast<instanceOop&>(_memory_mgr_obj = NULL);
	}

	void MemoryManager::add_pool(MemoryPool* pool) {
	assert(_num_pools < MemoryManager::max_num_pools, "_num_pools exceeds the max");
	if (_num_pools < MemoryManager::max_num_pools) {
	_pools[_num_pools] = pool;
	_num_pools++;
	}
	pool->add_manager(this);
	}

	MemoryManager* MemoryManager::get_code_cache_memory_manager() {
	return (MemoryManager*) new CodeCacheMemoryManager();
	}

	MemoryManager* MemoryManager::get_metaspace_memory_manager() {
	return (MemoryManager*) new MetaspaceMemoryManager();
	}

	GCMemoryManager* MemoryManager::get_copy_memory_manager() {
	return (GCMemoryManager*) new CopyMemoryManager();
	}

	GCMemoryManager* MemoryManager::get_msc_memory_manager() {
	return (GCMemoryManager*) new MSCMemoryManager();
	}

	GCMemoryManager* MemoryManager::get_parnew_memory_manager() {
	return (GCMemoryManager*) new ParNewMemoryManager();
	}

	GCMemoryManager* MemoryManager::get_cms_memory_manager() {
	return (GCMemoryManager*) new CMSMemoryManager();
	}

	GCMemoryManager* MemoryManager::get_psScavenge_memory_manager() {
	return (GCMemoryManager*) new PSScavengeMemoryManager();
	}

	GCMemoryManager* MemoryManager::get_psMarkSweep_memory_manager() {
	return (GCMemoryManager*) new PSMarkSweepMemoryManager();
	}

	GCMemoryManager* MemoryManager::get_g1YoungGen_memory_manager() {
	return (GCMemoryManager*) new G1YoungGenMemoryManager();
	}

	GCMemoryManager* MemoryManager::get_g1OldGen_memory_manager() {
	return (GCMemoryManager*) new G1OldGenMemoryManager();
	}

	instanceOop MemoryManager::get_memory_manager_instance(TRAPS) {
	// Must do an acquire so as to force ordering of subsequent
	// loads from anything _memory_mgr_obj points to or implies.
	instanceOop mgr_obj = (instanceOop)OrderAccess::load_ptr_acquire(&_memory_mgr_obj);
	if (mgr_obj == NULL) {
	// It's ok for more than one thread to execute the code up to the locked region.
	// Extra manager instances will just be gc'ed.
	Klass* k = Management::sun_management_ManagementFactory_klass(CHECK_0);
	instanceKlassHandle ik(THREAD, k);

	Handle mgr_name = java_lang_String::create_from_str(name(), CHECK_0);

	JavaValue result(T_OBJECT);
	JavaCallArguments args;
	args.push_oop(mgr_name); // Argument 1

	Symbol* method_name = NULL;
	Symbol* signature = NULL;
	if (is_gc_memory_manager()) {
	method_name = vmSymbols::createGarbageCollector_name();
	signature = vmSymbols::createGarbageCollector_signature();
	args.push_oop(Handle()); // Argument 2 (for future extension)
	} else {
	method_name = vmSymbols::createMemoryManager_name();
	signature = vmSymbols::createMemoryManager_signature();
	}

	JavaCalls::call_static(&result,
	ik,
	method_name,
	signature,
	&args,
	CHECK_0);

	instanceOop m = (instanceOop) result.get_jobject();
	instanceHandle mgr(THREAD, m);

	{
	// Get lock before setting _memory_mgr_obj
	// since another thread may have created the instance
	MutexLocker ml(Management_lock);

	// Check if another thread has created the management object. We reload
	// _memory_mgr_obj here because some other thread may have initialized
	// it while we were executing the code before the lock.
	//
	// The lock has done an acquire, so the load can't float above it, but
	// we need to do a load_acquire as above.
	mgr_obj = (instanceOop)OrderAccess::load_ptr_acquire(&_memory_mgr_obj);
	if (mgr_obj != NULL) {
	return mgr_obj;
	}

	// Get the address of the object we created via call_special.
	mgr_obj = mgr();

	// Use store barrier to make sure the memory accesses associated
	// with creating the management object are visible before publishing
	// its address. The unlock will publish the store to _memory_mgr_obj
	// because it does a release first.
	OrderAccess::release_store_ptr(&_memory_mgr_obj, mgr_obj);
	}
	}

	return mgr_obj;
	}

	void MemoryManager::oops_do(OopClosure* f) {
	f->do_oop((oop*) &_memory_mgr_obj);
	}

	GCStatInfo::GCStatInfo(int num_pools) {
	// initialize the arrays for memory usage
	_before_gc_usage_array = (MemoryUsage*) NEW_C_HEAP_ARRAY(MemoryUsage, num_pools, mtInternal);
	_after_gc_usage_array = (MemoryUsage*) NEW_C_HEAP_ARRAY(MemoryUsage, num_pools, mtInternal);
	_usage_array_size = num_pools;
	clear();
	}

	GCStatInfo::~GCStatInfo() {
	FREE_C_HEAP_ARRAY(MemoryUsage*, _before_gc_usage_array, mtInternal);
	FREE_C_HEAP_ARRAY(MemoryUsage*, _after_gc_usage_array, mtInternal);
	}

	void GCStatInfo::set_gc_usage(int pool_index, MemoryUsage usage, bool before_gc) {
	MemoryUsage* gc_usage_array;
	if (before_gc) {
	gc_usage_array = _before_gc_usage_array;
	} else {
	gc_usage_array = _after_gc_usage_array;
	}
	gc_usage_array[pool_index] = usage;
	}

	void GCStatInfo::clear() {
	_index = 0;
	_start_time = 0L;
	_end_time = 0L;
	size_t len = _usage_array_size * sizeof(MemoryUsage);
	memset(_before_gc_usage_array, 0, len);
	memset(_after_gc_usage_array, 0, len);
	}


	GCMemoryManager::GCMemoryManager() : MemoryManager() {
	_num_collections = 0;
	_last_gc_stat = NULL;
	_last_gc_lock = new Mutex(Mutex::leaf, "_last_gc_lock", true);
	_current_gc_stat = NULL;
	_num_gc_threads = 1;
	_notification_enabled = false;
	}

	GCMemoryManager::~GCMemoryManager() {
	delete _last_gc_stat;
	delete _last_gc_lock;
	delete _current_gc_stat;
	}

	void GCMemoryManager::initialize_gc_stat_info() {
	assert(MemoryService::num_memory_pools() > 0, "should have one or more memory pools");
	_last_gc_stat = new(ResourceObj::C_HEAP, mtGC) GCStatInfo(MemoryService::num_memory_pools());
	_current_gc_stat = new(ResourceObj::C_HEAP, mtGC) GCStatInfo(MemoryService::num_memory_pools());
	// tracking concurrent collections we need two objects: one to update, and one to
	// hold the publicly available "last (completed) gc" information.
	}

	void GCMemoryManager::gc_begin(bool recordGCBeginTime, bool recordPreGCUsage,
	bool recordAccumulatedGCTime) {
	assert(_last_gc_stat != NULL && _current_gc_stat != NULL, "Just checking");
	if (recordAccumulatedGCTime) {
	_accumulated_timer.start();
	}
	// _num_collections now increases in gc_end, to count completed collections
	if (recordGCBeginTime) {
	_current_gc_stat->set_index(_num_collections+1);
	_current_gc_stat->set_start_time(Management::timestamp());
	}

	if (recordPreGCUsage) {
	// Keep memory usage of all memory pools
	for (int i = 0; i < MemoryService::num_memory_pools(); i++) {
	MemoryPool* pool = MemoryService::get_memory_pool(i);
	MemoryUsage usage = pool->get_memory_usage();
	_current_gc_stat->set_before_gc_usage(i, usage);
	#ifndef USDT2
	HS_DTRACE_PROBE8(hotspot, mem__pool__gc__begin,
	name(), strlen(name()),
	pool->name(), strlen(pool->name()),
	usage.init_size(), usage.used(),
	usage.committed(), usage.max_size());
	#else /* USDT2 */
	HOTSPOT_MEM_POOL_GC_BEGIN(
	(char *) name(), strlen(name()),
	(char *) pool->name(), strlen(pool->name()),
	usage.init_size(), usage.used(),
	usage.committed(), usage.max_size());
	#endif /* USDT2 */
	}
	}
	}

	// A collector MUST, even if it does not complete for some reason,
	// make a TraceMemoryManagerStats object where countCollection is true,
	// to ensure the current gc stat is placed in _last_gc_stat.
	void GCMemoryManager::gc_end(bool recordPostGCUsage,
	bool recordAccumulatedGCTime,
	bool recordGCEndTime, bool countCollection,
	GCCause::Cause cause) {
	if (recordAccumulatedGCTime) {
	_accumulated_timer.stop();
	}
	if (recordGCEndTime) {
	_current_gc_stat->set_end_time(Management::timestamp());
	}

	if (recordPostGCUsage) {
	int i;
	// keep the last gc statistics for all memory pools
	for (i = 0; i < MemoryService::num_memory_pools(); i++) {
	MemoryPool* pool = MemoryService::get_memory_pool(i);
	MemoryUsage usage = pool->get_memory_usage();

	#ifndef USDT2
	HS_DTRACE_PROBE8(hotspot, mem__pool__gc__end,
	name(), strlen(name()),
	pool->name(), strlen(pool->name()),
	usage.init_size(), usage.used(),
	usage.committed(), usage.max_size());
	#else /* USDT2 */
	HOTSPOT_MEM_POOL_GC_END(
	(char *) name(), strlen(name()),
	(char *) pool->name(), strlen(pool->name()),
	usage.init_size(), usage.used(),
	usage.committed(), usage.max_size());
	#endif /* USDT2 */

	_current_gc_stat->set_after_gc_usage(i, usage);
	}

	// Set last collection usage of the memory pools managed by this collector
	for (i = 0; i < num_memory_pools(); i++) {
	MemoryPool* pool = get_memory_pool(i);
	MemoryUsage usage = pool->get_memory_usage();

	// Compare with GC usage threshold
	pool->set_last_collection_usage(usage);
	LowMemoryDetector::detect_after_gc_memory(pool);
	}
	}

	if (countCollection) {
	_num_collections++;
	// alternately update two objects making one public when complete
	{
	MutexLockerEx ml(_last_gc_lock, Mutex::_no_safepoint_check_flag);
	GCStatInfo *tmp = _last_gc_stat;
	_last_gc_stat = _current_gc_stat;
	_current_gc_stat = tmp;
	// reset the current stat for diagnosability purposes
	_current_gc_stat->clear();
	}

	if (is_notification_enabled()) {
	bool isMajorGC = this == MemoryService::get_major_gc_manager();
	GCNotifier::pushNotification(this, isMajorGC ? "end of major GC" : "end of minor GC",
	GCCause::to_string(cause));
	}
	}
	}

	size_t GCMemoryManager::get_last_gc_stat(GCStatInfo* dest) {
	MutexLockerEx ml(_last_gc_lock, Mutex::_no_safepoint_check_flag);
	if (_last_gc_stat->gc_index() != 0) {
	dest->set_index(_last_gc_stat->gc_index());
	dest->set_start_time(_last_gc_stat->start_time());
	dest->set_end_time(_last_gc_stat->end_time());
	assert(dest->usage_array_size() == _last_gc_stat->usage_array_size(),
	"Must have same array size");
	size_t len = dest->usage_array_size() * sizeof(MemoryUsage);
	memcpy(dest->before_gc_usage_array(), _last_gc_stat->before_gc_usage_array(), len);
	memcpy(dest->after_gc_usage_array(), _last_gc_stat->after_gc_usage_array(), len);
	}
	return _last_gc_stat->gc_index();
	}