src/hotspot/share/gc/g1/g1MonitoringSupport.cpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2011, 2019, 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 "gc/g1/g1CollectedHeap.inline.hpp"
 #include "gc/g1/g1MonitoringSupport.hpp"
 #include "gc/g1/g1Policy.hpp"
 #include "gc/g1/g1MemoryPool.hpp"
 #include "gc/shared/hSpaceCounters.hpp"
 #include "memory/metaspaceCounters.hpp"
 #include "services/memoryPool.hpp"

 class G1GenerationCounters : public GenerationCounters {
 protected:
   G1MonitoringSupport* _g1mm;

 public:
   G1GenerationCounters(G1MonitoringSupport* g1mm,
                        const char* name, int ordinal, int spaces,
                        size_t min_capacity, size_t max_capacity,
                        size_t curr_capacity)
   : GenerationCounters(name, ordinal, spaces, min_capacity,
                        max_capacity, curr_capacity), _g1mm(g1mm) { }
 };

 class G1YoungGenerationCounters : public G1GenerationCounters {
 public:
   // We pad the capacity three times given that the young generation
   // contains three spaces (eden and two survivors).
   G1YoungGenerationCounters(G1MonitoringSupport* g1mm, const char* name, size_t max_size)
   : G1GenerationCounters(g1mm, name, 0 /* ordinal */, 3 /* spaces */,
                          G1MonitoringSupport::pad_capacity(0, 3) /* min_capacity */,
                          G1MonitoringSupport::pad_capacity(max_size, 3),
                          G1MonitoringSupport::pad_capacity(0, 3) /* curr_capacity */) {
     if (UsePerfData) {
       update_all();
     }
   }

   virtual void update_all() {
     size_t committed =
               G1MonitoringSupport::pad_capacity(_g1mm->young_gen_committed(), 3);
     _current_size->set_value(committed);
   }
 };

 class G1OldGenerationCounters : public G1GenerationCounters {
 public:
   G1OldGenerationCounters(G1MonitoringSupport* g1mm, const char* name, size_t max_size)
   : G1GenerationCounters(g1mm, name, 1 /* ordinal */, 1 /* spaces */,
                          G1MonitoringSupport::pad_capacity(0) /* min_capacity */,
                          G1MonitoringSupport::pad_capacity(max_size),
                          G1MonitoringSupport::pad_capacity(0) /* curr_capacity */) {
     if (UsePerfData) {
       update_all();
     }
   }

   virtual void update_all() {
     size_t committed =
               G1MonitoringSupport::pad_capacity(_g1mm->old_gen_committed());
     _current_size->set_value(committed);
   }
 };

 G1MonitoringSupport::G1MonitoringSupport(G1CollectedHeap* g1h) :
   _g1h(g1h),
   _incremental_memory_manager("G1 Young Generation", "end of minor GC"),
   _full_gc_memory_manager("G1 Old Generation", "end of major GC"),
   _eden_space_pool(NULL),
   _survivor_space_pool(NULL),
   _old_gen_pool(NULL),
   _incremental_collection_counters(NULL),
   _full_collection_counters(NULL),
   _conc_collection_counters(NULL),
   _young_gen_counters(NULL),
   _old_gen_counters(NULL),
   _old_space_counters(NULL),
   _eden_space_counters(NULL),
   _from_space_counters(NULL),
   _to_space_counters(NULL),

   _overall_committed(0),
   _overall_used(0),
   _young_gen_committed(0),
   _old_gen_committed(0),

   _eden_space_committed(0),
   _eden_space_used(0),
   _survivor_space_committed(0),
   _survivor_space_used(0),
   _old_gen_used(0) {

   recalculate_sizes();

   // Counters for garbage collections
   //
   //  name "collector.0".  In a generational collector this would be the
   // young generation collection.
   _incremental_collection_counters =
     new CollectorCounters("G1 young collection pauses", 0);
   //   name "collector.1".  In a generational collector this would be the
   // old generation collection.
   _full_collection_counters =
     new CollectorCounters("G1 full collection pauses", 1);
   //   name "collector.2".  In a generational collector this would be the
   // STW phases in concurrent collection.
   _conc_collection_counters =
     new CollectorCounters("G1 concurrent cycle pauses", 2);

   // "Generation" and "Space" counters.
   //
   //  name "generation.1" This is logically the old generation in
   // generational GC terms.  The "1, 1" parameters are for
   // the n-th generation (=1) with 1 space.
   // Counters are created from minCapacity, maxCapacity, and capacity
   _old_gen_counters = new G1OldGenerationCounters(this, "old", _g1h->max_capacity());

   //  name  "generation.1.space.0"
   // Counters are created from maxCapacity, capacity, initCapacity,
   // and used.
   _old_space_counters = new HSpaceCounters(_old_gen_counters->name_space(),
     "space", 0 /* ordinal */,
     pad_capacity(g1h->max_capacity()) /* max_capacity */,
     pad_capacity(_old_gen_committed) /* init_capacity */);

   //   Young collection set
   //  name "generation.0".  This is logically the young generation.
   //  The "0, 3" are parameters for the n-th generation (=0) with 3 spaces.
   // See  _old_collection_counters for additional counters
   _young_gen_counters = new G1YoungGenerationCounters(this, "young", _g1h->max_capacity());

   const char* young_collection_name_space = _young_gen_counters->name_space();

   //  name "generation.0.space.0"
   // See _old_space_counters for additional counters
   _eden_space_counters = new HSpaceCounters(young_collection_name_space,
     "eden", 0 /* ordinal */,
     pad_capacity(g1h->max_capacity()) /* max_capacity */,
     pad_capacity(_eden_space_committed) /* init_capacity */);

   //  name "generation.0.space.1"
   // See _old_space_counters for additional counters
   // Set the arguments to indicate that this survivor space is not used.
   _from_space_counters = new HSpaceCounters(young_collection_name_space,
     "s0", 1 /* ordinal */,
     pad_capacity(0) /* max_capacity */,
     pad_capacity(0) /* init_capacity */);
   // Given that this survivor space is not used, we update it here
   // once to reflect that its used space is 0 so that we don't have to
   // worry about updating it again later.
   if (UsePerfData) {
     _from_space_counters->update_used(0);
   }

   //  name "generation.0.space.2"
   // See _old_space_counters for additional counters
   _to_space_counters = new HSpaceCounters(young_collection_name_space,
     "s1", 2 /* ordinal */,
     pad_capacity(g1h->max_capacity()) /* max_capacity */,
     pad_capacity(_survivor_space_committed) /* init_capacity */);
 }

 G1MonitoringSupport::~G1MonitoringSupport() {
   delete _eden_space_pool;
   delete _survivor_space_pool;
   delete _old_gen_pool;
 }

 void G1MonitoringSupport::initialize_serviceability() {
   _eden_space_pool = new G1EdenPool(_g1h, _eden_space_committed);
   _survivor_space_pool = new G1SurvivorPool(_g1h, _survivor_space_committed);
   _old_gen_pool = new G1OldGenPool(_g1h, _old_gen_committed, _g1h->max_capacity());

   _full_gc_memory_manager.add_pool(_eden_space_pool);
   _full_gc_memory_manager.add_pool(_survivor_space_pool);
   _full_gc_memory_manager.add_pool(_old_gen_pool);

   _incremental_memory_manager.add_pool(_eden_space_pool);
   _incremental_memory_manager.add_pool(_survivor_space_pool);
   _incremental_memory_manager.add_pool(_old_gen_pool, false /* always_affected_by_gc */);
 }

 MemoryUsage G1MonitoringSupport::memory_usage() {
   MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);
   return MemoryUsage(InitialHeapSize, _overall_used, _overall_committed, _g1h->max_capacity());
 }

 GrowableArray<GCMemoryManager*> G1MonitoringSupport::memory_managers() {
   GrowableArray<GCMemoryManager*> memory_managers(2);
   memory_managers.append(&_incremental_memory_manager);
   memory_managers.append(&_full_gc_memory_manager);
   return memory_managers;
 }

 GrowableArray<MemoryPool*> G1MonitoringSupport::memory_pools() {
   GrowableArray<MemoryPool*> memory_pools(3);
   memory_pools.append(_eden_space_pool);
   memory_pools.append(_survivor_space_pool);
   memory_pools.append(_old_gen_pool);
   return memory_pools;
 }

 void G1MonitoringSupport::recalculate_sizes() {
   assert_heap_locked_or_at_safepoint(true);

   MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);
   // Recalculate all the sizes from scratch.

   uint young_list_length = _g1h->young_regions_count();
   uint survivor_list_length = _g1h->survivor_regions_count();
   assert(young_list_length >= survivor_list_length, "invariant");
   uint eden_list_length = young_list_length - survivor_list_length;
   // Max length includes any potential extensions to the young gen
   // we'll do when the GC locker is active.
   uint young_list_max_length = _g1h->policy()->young_list_max_length();
   assert(young_list_max_length >= survivor_list_length, "invariant");
   uint eden_list_max_length = young_list_max_length - survivor_list_length;

   _overall_used = _g1h->used_unlocked();
   _eden_space_used = (size_t) eden_list_length * HeapRegion::GrainBytes;
   _survivor_space_used = (size_t) survivor_list_length * HeapRegion::GrainBytes;
   _old_gen_used = subtract_up_to_zero(_overall_used, _eden_space_used + _survivor_space_used);

   // First calculate the committed sizes that can be calculated independently.
   _survivor_space_committed = _survivor_space_used;
   _old_gen_committed = HeapRegion::align_up_to_region_byte_size(_old_gen_used);

   // Next, start with the overall committed size.
   _overall_committed = _g1h->capacity();
   size_t committed = _overall_committed;

   // Remove the committed size we have calculated so far (for the
   // survivor and old space).
   assert(committed >= (_survivor_space_committed + _old_gen_committed), "sanity");
   committed -= _survivor_space_committed + _old_gen_committed;

   // Next, calculate and remove the committed size for the eden.
   _eden_space_committed = (size_t) eden_list_max_length * HeapRegion::GrainBytes;
   // Somewhat defensive: be robust in case there are inaccuracies in
   // the calculations
   _eden_space_committed = MIN2(_eden_space_committed, committed);
   committed -= _eden_space_committed;

   // Finally, give the rest to the old space...
   _old_gen_committed += committed;
   // ..and calculate the young gen committed.
   _young_gen_committed = _eden_space_committed + _survivor_space_committed;

   assert(_overall_committed ==
          (_eden_space_committed + _survivor_space_committed + _old_gen_committed),
          "the committed sizes should add up");
   // Somewhat defensive: cap the eden used size to make sure it
   // never exceeds the committed size.
   _eden_space_used = MIN2(_eden_space_used, _eden_space_committed);
   // _survivor_committed and _old_committed are calculated in terms of
   // the corresponding _*_used value, so the next two conditions
   // should hold.
   assert(_survivor_space_used <= _survivor_space_committed, "post-condition");
   assert(_old_gen_used <= _old_gen_committed, "post-condition");
 }

 void G1MonitoringSupport::update_sizes() {
   recalculate_sizes();
   if (UsePerfData) {
     _eden_space_counters->update_capacity(pad_capacity(_eden_space_committed));
     _eden_space_counters->update_used(_eden_space_used);
    // only the "to" survivor space is active, so we don't need to
     // update the counters for the "from" survivor space
     _to_space_counters->update_capacity(pad_capacity(_survivor_space_committed));
     _to_space_counters->update_used(_survivor_space_used);
     _old_space_counters->update_capacity(pad_capacity(_old_gen_committed));
     _old_space_counters->update_used(_old_gen_used);

     _young_gen_counters->update_all();
     _old_gen_counters->update_all();

     MetaspaceCounters::update_performance_counters();
     CompressedClassSpaceCounters::update_performance_counters();
   }
 }

 void G1MonitoringSupport::update_eden_size() {
   // Recalculate everything - this should be fast enough and we are sure that we do not
   // miss anything.
   recalculate_sizes();
   if (UsePerfData) {
     _eden_space_counters->update_used(_eden_space_used);
   }
 }

 MemoryUsage G1MonitoringSupport::eden_space_memory_usage(size_t initial_size, size_t max_size) {
   MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);

   return MemoryUsage(initial_size,
                      _eden_space_used,
                      _eden_space_committed,
                      max_size);
 }

 MemoryUsage G1MonitoringSupport::survivor_space_memory_usage(size_t initial_size, size_t max_size) {
   MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);

   return MemoryUsage(initial_size,
                      _survivor_space_used,
                      _survivor_space_committed,
                      max_size);
 }

 MemoryUsage G1MonitoringSupport::old_gen_memory_usage(size_t initial_size, size_t max_size) {
   MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);

   return MemoryUsage(initial_size,
                      _old_gen_used,
                      _old_gen_committed,
                      max_size);
 }

 G1MonitoringScope::G1MonitoringScope(G1MonitoringSupport* g1mm, bool full_gc, bool all_memory_pools_affected) :
   _tcs(full_gc ? g1mm->_full_collection_counters : g1mm->_incremental_collection_counters),
   _tms(full_gc ? &g1mm->_full_gc_memory_manager : &g1mm->_incremental_memory_manager,
        G1CollectedHeap::heap()->gc_cause(), all_memory_pools_affected) {
 }
	/*
	* Copyright (c) 2011, 2019, 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 "gc/g1/g1CollectedHeap.inline.hpp"
	#include "gc/g1/g1MonitoringSupport.hpp"
	#include "gc/g1/g1Policy.hpp"
	#include "gc/g1/g1MemoryPool.hpp"
	#include "gc/shared/hSpaceCounters.hpp"
	#include "memory/metaspaceCounters.hpp"
	#include "services/memoryPool.hpp"

	class G1GenerationCounters : public GenerationCounters {
	protected:
	G1MonitoringSupport* _g1mm;

	public:
	G1GenerationCounters(G1MonitoringSupport* g1mm,
	const char* name, int ordinal, int spaces,
	size_t min_capacity, size_t max_capacity,
	size_t curr_capacity)
	: GenerationCounters(name, ordinal, spaces, min_capacity,
	max_capacity, curr_capacity), _g1mm(g1mm) { }
	};

	class G1YoungGenerationCounters : public G1GenerationCounters {
	public:
	// We pad the capacity three times given that the young generation
	// contains three spaces (eden and two survivors).
	G1YoungGenerationCounters(G1MonitoringSupport* g1mm, const char* name, size_t max_size)
	: G1GenerationCounters(g1mm, name, 0 /* ordinal /, 3 / spaces */,
	G1MonitoringSupport::pad_capacity(0, 3) /* min_capacity */,
	G1MonitoringSupport::pad_capacity(max_size, 3),
	G1MonitoringSupport::pad_capacity(0, 3) /* curr_capacity */) {
	if (UsePerfData) {
	update_all();
	}
	}

	virtual void update_all() {
	size_t committed =
	G1MonitoringSupport::pad_capacity(_g1mm->young_gen_committed(), 3);
	_current_size->set_value(committed);
	}
	};

	class G1OldGenerationCounters : public G1GenerationCounters {
	public:
	G1OldGenerationCounters(G1MonitoringSupport* g1mm, const char* name, size_t max_size)
	: G1GenerationCounters(g1mm, name, 1 /* ordinal /, 1 / spaces */,
	G1MonitoringSupport::pad_capacity(0) /* min_capacity */,
	G1MonitoringSupport::pad_capacity(max_size),
	G1MonitoringSupport::pad_capacity(0) /* curr_capacity */) {
	if (UsePerfData) {
	update_all();
	}
	}

	virtual void update_all() {
	size_t committed =
	G1MonitoringSupport::pad_capacity(_g1mm->old_gen_committed());
	_current_size->set_value(committed);
	}
	};

	G1MonitoringSupport::G1MonitoringSupport(G1CollectedHeap* g1h) :
	_g1h(g1h),
	_incremental_memory_manager("G1 Young Generation", "end of minor GC"),
	_full_gc_memory_manager("G1 Old Generation", "end of major GC"),
	_eden_space_pool(NULL),
	_survivor_space_pool(NULL),
	_old_gen_pool(NULL),
	_incremental_collection_counters(NULL),
	_full_collection_counters(NULL),
	_conc_collection_counters(NULL),
	_young_gen_counters(NULL),
	_old_gen_counters(NULL),
	_old_space_counters(NULL),
	_eden_space_counters(NULL),
	_from_space_counters(NULL),
	_to_space_counters(NULL),

	_overall_committed(0),
	_overall_used(0),
	_young_gen_committed(0),
	_old_gen_committed(0),

	_eden_space_committed(0),
	_eden_space_used(0),
	_survivor_space_committed(0),
	_survivor_space_used(0),
	_old_gen_used(0) {

	recalculate_sizes();

	// Counters for garbage collections
	//
	// name "collector.0". In a generational collector this would be the
	// young generation collection.
	_incremental_collection_counters =
	new CollectorCounters("G1 young collection pauses", 0);
	// name "collector.1". In a generational collector this would be the
	// old generation collection.
	_full_collection_counters =
	new CollectorCounters("G1 full collection pauses", 1);
	// name "collector.2". In a generational collector this would be the
	// STW phases in concurrent collection.
	_conc_collection_counters =
	new CollectorCounters("G1 concurrent cycle pauses", 2);

	// "Generation" and "Space" counters.
	//
	// name "generation.1" This is logically the old generation in
	// generational GC terms. The "1, 1" parameters are for
	// the n-th generation (=1) with 1 space.
	// Counters are created from minCapacity, maxCapacity, and capacity
	_old_gen_counters = new G1OldGenerationCounters(this, "old", _g1h->max_capacity());

	// name "generation.1.space.0"
	// Counters are created from maxCapacity, capacity, initCapacity,
	// and used.
	_old_space_counters = new HSpaceCounters(_old_gen_counters->name_space(),
	"space", 0 /* ordinal */,
	pad_capacity(g1h->max_capacity()) /* max_capacity */,
	pad_capacity(_old_gen_committed) /* init_capacity */);

	// Young collection set
	// name "generation.0". This is logically the young generation.
	// The "0, 3" are parameters for the n-th generation (=0) with 3 spaces.
	// See _old_collection_counters for additional counters
	_young_gen_counters = new G1YoungGenerationCounters(this, "young", _g1h->max_capacity());

	const char* young_collection_name_space = _young_gen_counters->name_space();

	// name "generation.0.space.0"
	// See _old_space_counters for additional counters
	_eden_space_counters = new HSpaceCounters(young_collection_name_space,
	"eden", 0 /* ordinal */,
	pad_capacity(g1h->max_capacity()) /* max_capacity */,
	pad_capacity(_eden_space_committed) /* init_capacity */);

	// name "generation.0.space.1"
	// See _old_space_counters for additional counters
	// Set the arguments to indicate that this survivor space is not used.
	_from_space_counters = new HSpaceCounters(young_collection_name_space,
	"s0", 1 /* ordinal */,
	pad_capacity(0) /* max_capacity */,
	pad_capacity(0) /* init_capacity */);
	// Given that this survivor space is not used, we update it here
	// once to reflect that its used space is 0 so that we don't have to
	// worry about updating it again later.
	if (UsePerfData) {
	_from_space_counters->update_used(0);
	}

	// name "generation.0.space.2"
	// See _old_space_counters for additional counters
	_to_space_counters = new HSpaceCounters(young_collection_name_space,
	"s1", 2 /* ordinal */,
	pad_capacity(g1h->max_capacity()) /* max_capacity */,
	pad_capacity(_survivor_space_committed) /* init_capacity */);
	}

	G1MonitoringSupport::~G1MonitoringSupport() {
	delete _eden_space_pool;
	delete _survivor_space_pool;
	delete _old_gen_pool;
	}

	void G1MonitoringSupport::initialize_serviceability() {
	_eden_space_pool = new G1EdenPool(_g1h, _eden_space_committed);
	_survivor_space_pool = new G1SurvivorPool(_g1h, _survivor_space_committed);
	_old_gen_pool = new G1OldGenPool(_g1h, _old_gen_committed, _g1h->max_capacity());

	_full_gc_memory_manager.add_pool(_eden_space_pool);
	_full_gc_memory_manager.add_pool(_survivor_space_pool);
	_full_gc_memory_manager.add_pool(_old_gen_pool);

	_incremental_memory_manager.add_pool(_eden_space_pool);
	_incremental_memory_manager.add_pool(_survivor_space_pool);
	_incremental_memory_manager.add_pool(_old_gen_pool, false /* always_affected_by_gc */);
	}

	MemoryUsage G1MonitoringSupport::memory_usage() {
	MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);
	return MemoryUsage(InitialHeapSize, _overall_used, _overall_committed, _g1h->max_capacity());
	}

	GrowableArray<GCMemoryManager*> G1MonitoringSupport::memory_managers() {
	GrowableArray<GCMemoryManager*> memory_managers(2);
	memory_managers.append(&_incremental_memory_manager);
	memory_managers.append(&_full_gc_memory_manager);
	return memory_managers;
	}

	GrowableArray<MemoryPool*> G1MonitoringSupport::memory_pools() {
	GrowableArray<MemoryPool*> memory_pools(3);
	memory_pools.append(_eden_space_pool);
	memory_pools.append(_survivor_space_pool);
	memory_pools.append(_old_gen_pool);
	return memory_pools;
	}

	void G1MonitoringSupport::recalculate_sizes() {
	assert_heap_locked_or_at_safepoint(true);

	MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);
	// Recalculate all the sizes from scratch.

	uint young_list_length = _g1h->young_regions_count();
	uint survivor_list_length = _g1h->survivor_regions_count();
	assert(young_list_length >= survivor_list_length, "invariant");
	uint eden_list_length = young_list_length - survivor_list_length;
	// Max length includes any potential extensions to the young gen
	// we'll do when the GC locker is active.
	uint young_list_max_length = _g1h->policy()->young_list_max_length();
	assert(young_list_max_length >= survivor_list_length, "invariant");
	uint eden_list_max_length = young_list_max_length - survivor_list_length;

	_overall_used = _g1h->used_unlocked();
	_eden_space_used = (size_t) eden_list_length * HeapRegion::GrainBytes;
	_survivor_space_used = (size_t) survivor_list_length * HeapRegion::GrainBytes;
	_old_gen_used = subtract_up_to_zero(_overall_used, _eden_space_used + _survivor_space_used);

	// First calculate the committed sizes that can be calculated independently.
	_survivor_space_committed = _survivor_space_used;
	_old_gen_committed = HeapRegion::align_up_to_region_byte_size(_old_gen_used);

	// Next, start with the overall committed size.
	_overall_committed = _g1h->capacity();
	size_t committed = _overall_committed;

	// Remove the committed size we have calculated so far (for the
	// survivor and old space).
	assert(committed >= (_survivor_space_committed + _old_gen_committed), "sanity");
	committed -= _survivor_space_committed + _old_gen_committed;

	// Next, calculate and remove the committed size for the eden.
	_eden_space_committed = (size_t) eden_list_max_length * HeapRegion::GrainBytes;
	// Somewhat defensive: be robust in case there are inaccuracies in
	// the calculations
	_eden_space_committed = MIN2(_eden_space_committed, committed);
	committed -= _eden_space_committed;

	// Finally, give the rest to the old space...
	_old_gen_committed += committed;
	// ..and calculate the young gen committed.
	_young_gen_committed = _eden_space_committed + _survivor_space_committed;

	assert(_overall_committed ==
	(_eden_space_committed + _survivor_space_committed + _old_gen_committed),
	"the committed sizes should add up");
	// Somewhat defensive: cap the eden used size to make sure it
	// never exceeds the committed size.
	_eden_space_used = MIN2(_eden_space_used, _eden_space_committed);
	// _survivor_committed and _old_committed are calculated in terms of
	// the corresponding _*_used value, so the next two conditions
	// should hold.
	assert(_survivor_space_used <= _survivor_space_committed, "post-condition");
	assert(_old_gen_used <= _old_gen_committed, "post-condition");
	}

	void G1MonitoringSupport::update_sizes() {
	recalculate_sizes();
	if (UsePerfData) {
	_eden_space_counters->update_capacity(pad_capacity(_eden_space_committed));
	_eden_space_counters->update_used(_eden_space_used);
	// only the "to" survivor space is active, so we don't need to
	// update the counters for the "from" survivor space
	_to_space_counters->update_capacity(pad_capacity(_survivor_space_committed));
	_to_space_counters->update_used(_survivor_space_used);
	_old_space_counters->update_capacity(pad_capacity(_old_gen_committed));
	_old_space_counters->update_used(_old_gen_used);

	_young_gen_counters->update_all();
	_old_gen_counters->update_all();

	MetaspaceCounters::update_performance_counters();
	CompressedClassSpaceCounters::update_performance_counters();
	}
	}

	void G1MonitoringSupport::update_eden_size() {
	// Recalculate everything - this should be fast enough and we are sure that we do not
	// miss anything.
	recalculate_sizes();
	if (UsePerfData) {
	_eden_space_counters->update_used(_eden_space_used);
	}
	}

	MemoryUsage G1MonitoringSupport::eden_space_memory_usage(size_t initial_size, size_t max_size) {
	MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);

	return MemoryUsage(initial_size,
	_eden_space_used,
	_eden_space_committed,
	max_size);
	}

	MemoryUsage G1MonitoringSupport::survivor_space_memory_usage(size_t initial_size, size_t max_size) {
	MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);

	return MemoryUsage(initial_size,
	_survivor_space_used,
	_survivor_space_committed,
	max_size);
	}

	MemoryUsage G1MonitoringSupport::old_gen_memory_usage(size_t initial_size, size_t max_size) {
	MutexLockerEx x(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);

	return MemoryUsage(initial_size,
	_old_gen_used,
	_old_gen_committed,
	max_size);
	}

	G1MonitoringScope::G1MonitoringScope(G1MonitoringSupport* g1mm, bool full_gc, bool all_memory_pools_affected) :
	_tcs(full_gc ? g1mm->_full_collection_counters : g1mm->_incremental_collection_counters),
	_tms(full_gc ? &g1mm->_full_gc_memory_manager : &g1mm->_incremental_memory_manager,
	G1CollectedHeap::heap()->gc_cause(), all_memory_pools_affected) {
	}