src/share/vm/gc_implementation/parallelScavenge/psOldGen.cpp - platform/external/jetbrains/jdk8u_hotspot - Git at Google

 /*
  * Copyright (c) 2001, 2014, 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_implementation/parallelScavenge/parallelScavengeHeap.hpp"
 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
 #include "gc_implementation/shared/spaceDecorator.hpp"
 #include "memory/cardTableModRefBS.hpp"
 #include "memory/gcLocker.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/java.hpp"

 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC

 inline const char* PSOldGen::select_name() {
   return UseParallelOldGC ? "ParOldGen" : "PSOldGen";
 }

 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,
                    size_t initial_size, size_t min_size, size_t max_size,
                    const char* perf_data_name, int level):
   _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
   _max_gen_size(max_size)
 {
   initialize(rs, alignment, perf_data_name, level);
 }

 PSOldGen::PSOldGen(size_t initial_size,
                    size_t min_size, size_t max_size,
                    const char* perf_data_name, int level):
   _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
   _max_gen_size(max_size)
 {}

 void PSOldGen::initialize(ReservedSpace rs, size_t alignment,
                           const char* perf_data_name, int level) {
   initialize_virtual_space(rs, alignment);
   initialize_work(perf_data_name, level);

   // The old gen can grow to gen_size_limit().  _reserve reflects only
   // the current maximum that can be committed.
   assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");

   initialize_performance_counters(perf_data_name, level);
 }

 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {

   _virtual_space = new PSVirtualSpace(rs, alignment);
   if (!_virtual_space->expand_by(_init_gen_size)) {
     vm_exit_during_initialization("Could not reserve enough space for "
                                   "object heap");
   }
 }

 void PSOldGen::initialize_work(const char* perf_data_name, int level) {
   //
   // Basic memory initialization
   //

   MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),
     heap_word_size(_max_gen_size));
   assert(limit_reserved.byte_size() == _max_gen_size,
     "word vs bytes confusion");
   //
   // Object start stuff
   //

   start_array()->initialize(limit_reserved);

   _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
                         (HeapWord*)virtual_space()->high_boundary());

   //
   // Card table stuff
   //

   MemRegion cmr((HeapWord*)virtual_space()->low(),
                 (HeapWord*)virtual_space()->high());
   if (ZapUnusedHeapArea) {
     // Mangle newly committed space immediately rather than
     // waiting for the initialization of the space even though
     // mangling is related to spaces.  Doing it here eliminates
     // the need to carry along information that a complete mangling
     // (bottom to end) needs to be done.
     SpaceMangler::mangle_region(cmr);
   }

   Universe::heap()->barrier_set()->resize_covered_region(cmr);

   CardTableModRefBS* _ct = (CardTableModRefBS*)Universe::heap()->barrier_set();
   assert (_ct->kind() == BarrierSet::CardTableModRef, "Sanity");

   // Verify that the start and end of this generation is the start of a card.
   // If this wasn't true, a single card could span more than one generation,
   // which would cause problems when we commit/uncommit memory, and when we
   // clear and dirty cards.
   guarantee(_ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
   if (_reserved.end() != Universe::heap()->reserved_region().end()) {
     // Don't check at the very end of the heap as we'll assert that we're probing off
     // the end if we try.
     guarantee(_ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
   }

   //
   // ObjectSpace stuff
   //

   _object_space = new MutableSpace(virtual_space()->alignment());

   if (_object_space == NULL)
     vm_exit_during_initialization("Could not allocate an old gen space");

   object_space()->initialize(cmr,
                              SpaceDecorator::Clear,
                              SpaceDecorator::Mangle);

   _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);

   if (_object_mark_sweep == NULL)
     vm_exit_during_initialization("Could not complete allocation of old generation");

   // Update the start_array
   start_array()->set_covered_region(cmr);
 }

 void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) {
   // Generation Counters, generation 'level', 1 subspace
   _gen_counters = new PSGenerationCounters(perf_data_name, level, 1,
                                            virtual_space());
   _space_counters = new SpaceCounters(perf_data_name, 0,
                                       virtual_space()->reserved_size(),
                                       _object_space, _gen_counters);
 }

 // Assume that the generation has been allocated if its
 // reserved size is not 0.
 bool  PSOldGen::is_allocated() {
   return virtual_space()->reserved_size() != 0;
 }

 void PSOldGen::precompact() {
   ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
   assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

   // Reset start array first.
   start_array()->reset();

   object_mark_sweep()->precompact();

   // Now compact the young gen
   heap->young_gen()->precompact();
 }

 void PSOldGen::adjust_pointers() {
   object_mark_sweep()->adjust_pointers();
 }

 void PSOldGen::compact() {
   object_mark_sweep()->compact(ZapUnusedHeapArea);
 }

 size_t PSOldGen::contiguous_available() const {
   return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
 }

 // Allocation. We report all successful allocations to the size policy
 // Note that the perm gen does not use this method, and should not!
 HeapWord* PSOldGen::allocate(size_t word_size) {
   assert_locked_or_safepoint(Heap_lock);
   HeapWord* res = allocate_noexpand(word_size);

   if (res == NULL) {
     res = expand_and_allocate(word_size);
   }

   // Allocations in the old generation need to be reported
   if (res != NULL) {
     ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
     heap->size_policy()->tenured_allocation(word_size);
   }

   return res;
 }

 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
   expand(word_size*HeapWordSize);
   if (GCExpandToAllocateDelayMillis > 0) {
     os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
   }
   return allocate_noexpand(word_size);
 }

 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
   expand(word_size*HeapWordSize);
   if (GCExpandToAllocateDelayMillis > 0) {
     os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
   }
   return cas_allocate_noexpand(word_size);
 }

 void PSOldGen::expand(size_t bytes) {
   if (bytes == 0) {
     return;
   }
   MutexLocker x(ExpandHeap_lock);
   const size_t alignment = virtual_space()->alignment();
   size_t aligned_bytes  = align_size_up(bytes, alignment);
   size_t aligned_expand_bytes = align_size_up(MinHeapDeltaBytes, alignment);

   if (UseNUMA) {
     // With NUMA we use round-robin page allocation for the old gen. Expand by at least
     // providing a page per lgroup. Alignment is larger or equal to the page size.
     aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
   }
   if (aligned_bytes == 0){
     // The alignment caused the number of bytes to wrap.  An expand_by(0) will
     // return true with the implication that and expansion was done when it
     // was not.  A call to expand implies a best effort to expand by "bytes"
     // but not a guarantee.  Align down to give a best effort.  This is likely
     // the most that the generation can expand since it has some capacity to
     // start with.
     aligned_bytes = align_size_down(bytes, alignment);
   }

   bool success = false;
   if (aligned_expand_bytes > aligned_bytes) {
     success = expand_by(aligned_expand_bytes);
   }
   if (!success) {
     success = expand_by(aligned_bytes);
   }
   if (!success) {
     success = expand_to_reserved();
   }

   if (PrintGC && Verbose) {
     if (success && GC_locker::is_active_and_needs_gc()) {
       gclog_or_tty->print_cr("Garbage collection disabled, expanded heap instead");
     }
   }
 }

 bool PSOldGen::expand_by(size_t bytes) {
   assert_lock_strong(ExpandHeap_lock);
   assert_locked_or_safepoint(Heap_lock);
   if (bytes == 0) {
     return true;  // That's what virtual_space()->expand_by(0) would return
   }
   bool result = virtual_space()->expand_by(bytes);
   if (result) {
     if (ZapUnusedHeapArea) {
       // We need to mangle the newly expanded area. The memregion spans
       // end -> new_end, we assume that top -> end is already mangled.
       // Do the mangling before post_resize() is called because
       // the space is available for allocation after post_resize();
       HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
       assert(object_space()->end() < virtual_space_high,
         "Should be true before post_resize()");
       MemRegion mangle_region(object_space()->end(), virtual_space_high);
       // Note that the object space has not yet been updated to
       // coincede with the new underlying virtual space.
       SpaceMangler::mangle_region(mangle_region);
     }
     post_resize();
     if (UsePerfData) {
       _space_counters->update_capacity();
       _gen_counters->update_all();
     }
   }

   if (result && Verbose && PrintGC) {
     size_t new_mem_size = virtual_space()->committed_size();
     size_t old_mem_size = new_mem_size - bytes;
     gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "
                                        SIZE_FORMAT "K to "
                                        SIZE_FORMAT "K",
                     name(), old_mem_size/K, bytes/K, new_mem_size/K);
   }

   return result;
 }

 bool PSOldGen::expand_to_reserved() {
   assert_lock_strong(ExpandHeap_lock);
   assert_locked_or_safepoint(Heap_lock);

   bool result = true;
   const size_t remaining_bytes = virtual_space()->uncommitted_size();
   if (remaining_bytes > 0) {
     result = expand_by(remaining_bytes);
     DEBUG_ONLY(if (!result) warning("grow to reserve failed"));
   }
   return result;
 }

 void PSOldGen::shrink(size_t bytes) {
   assert_lock_strong(ExpandHeap_lock);
   assert_locked_or_safepoint(Heap_lock);

   size_t size = align_size_down(bytes, virtual_space()->alignment());
   if (size > 0) {
     assert_lock_strong(ExpandHeap_lock);
     virtual_space()->shrink_by(bytes);
     post_resize();

     if (Verbose && PrintGC) {
       size_t new_mem_size = virtual_space()->committed_size();
       size_t old_mem_size = new_mem_size + bytes;
       gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by "
                                          SIZE_FORMAT "K to "
                                          SIZE_FORMAT "K",
                       name(), old_mem_size/K, bytes/K, new_mem_size/K);
     }
   }
 }

 void PSOldGen::resize(size_t desired_free_space) {
   const size_t alignment = virtual_space()->alignment();
   const size_t size_before = virtual_space()->committed_size();
   size_t new_size = used_in_bytes() + desired_free_space;
   if (new_size < used_in_bytes()) {
     // Overflowed the addition.
     new_size = gen_size_limit();
   }
   // Adjust according to our min and max
   new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());

   assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
   new_size = align_size_up(new_size, alignment);

   const size_t current_size = capacity_in_bytes();

   if (PrintAdaptiveSizePolicy && Verbose) {
     gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "
       "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
       " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
       " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
       desired_free_space, used_in_bytes(), new_size, current_size,
       gen_size_limit(), min_gen_size());
   }

   if (new_size == current_size) {
     // No change requested
     return;
   }
   if (new_size > current_size) {
     size_t change_bytes = new_size - current_size;
     expand(change_bytes);
   } else {
     size_t change_bytes = current_size - new_size;
     // shrink doesn't grab this lock, expand does. Is that right?
     MutexLocker x(ExpandHeap_lock);
     shrink(change_bytes);
   }

   if (PrintAdaptiveSizePolicy) {
     ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
     assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
     gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "
                   "collection: %d "
                   "(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
                   heap->total_collections(),
                   size_before, virtual_space()->committed_size());
   }
 }

 // NOTE! We need to be careful about resizing. During a GC, multiple
 // allocators may be active during heap expansion. If we allow the
 // heap resizing to become visible before we have correctly resized
 // all heap related data structures, we may cause program failures.
 void PSOldGen::post_resize() {
   // First construct a memregion representing the new size
   MemRegion new_memregion((HeapWord*)virtual_space()->low(),
     (HeapWord*)virtual_space()->high());
   size_t new_word_size = new_memregion.word_size();

   start_array()->set_covered_region(new_memregion);
   Universe::heap()->barrier_set()->resize_covered_region(new_memregion);

   // ALWAYS do this last!!
   object_space()->initialize(new_memregion,
                              SpaceDecorator::DontClear,
                              SpaceDecorator::DontMangle);

   assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
     "Sanity");
 }

 size_t PSOldGen::gen_size_limit() {
   return _max_gen_size;
 }

 void PSOldGen::reset_after_change() {
   ShouldNotReachHere();
   return;
 }

 size_t PSOldGen::available_for_expansion() {
   ShouldNotReachHere();
   return 0;
 }

 size_t PSOldGen::available_for_contraction() {
   ShouldNotReachHere();
   return 0;
 }

 void PSOldGen::print() const { print_on(tty);}
 void PSOldGen::print_on(outputStream* st) const {
   st->print(" %-15s", name());
   if (PrintGCDetails && Verbose) {
     st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,
                 capacity_in_bytes(), used_in_bytes());
   } else {
     st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
                 capacity_in_bytes()/K, used_in_bytes()/K);
   }
   st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
                 virtual_space()->low_boundary(),
                 virtual_space()->high(),
                 virtual_space()->high_boundary());

   st->print("  object"); object_space()->print_on(st);
 }

 void PSOldGen::print_used_change(size_t prev_used) const {
   gclog_or_tty->print(" [%s:", name());
   gclog_or_tty->print(" "  SIZE_FORMAT "K"
                       "->" SIZE_FORMAT "K"
                       "("  SIZE_FORMAT "K)",
                       prev_used / K, used_in_bytes() / K,
                       capacity_in_bytes() / K);
   gclog_or_tty->print("]");
 }

 void PSOldGen::update_counters() {
   if (UsePerfData) {
     _space_counters->update_all();
     _gen_counters->update_all();
   }
 }

 #ifndef PRODUCT

 void PSOldGen::space_invariants() {
   assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
     "Space invariant");
   assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
     "Space invariant");
   assert(virtual_space()->low_boundary() <= virtual_space()->low(),
     "Space invariant");
   assert(virtual_space()->high_boundary() >= virtual_space()->high(),
     "Space invariant");
   assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
     "Space invariant");
   assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
     "Space invariant");
   assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
     "Space invariant");
 }
 #endif

 void PSOldGen::verify() {
   object_space()->verify();
 }
 class VerifyObjectStartArrayClosure : public ObjectClosure {
   PSOldGen* _gen;
   ObjectStartArray* _start_array;

  public:
   VerifyObjectStartArrayClosure(PSOldGen* gen, ObjectStartArray* start_array) :
     _gen(gen), _start_array(start_array) { }

   virtual void do_object(oop obj) {
     HeapWord* test_addr = (HeapWord*)obj + 1;
     guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");
     guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");
   }
 };

 void PSOldGen::verify_object_start_array() {
   VerifyObjectStartArrayClosure check( this, &_start_array );
   object_iterate(&check);
 }

 #ifndef PRODUCT
 void PSOldGen::record_spaces_top() {
   assert(ZapUnusedHeapArea, "Not mangling unused space");
   object_space()->set_top_for_allocations();
 }
 #endif
	/*
	* Copyright (c) 2001, 2014, 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_implementation/parallelScavenge/parallelScavengeHeap.hpp"
	#include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
	#include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
	#include "gc_implementation/parallelScavenge/psOldGen.hpp"
	#include "gc_implementation/shared/spaceDecorator.hpp"
	#include "memory/cardTableModRefBS.hpp"
	#include "memory/gcLocker.inline.hpp"
	#include "oops/oop.inline.hpp"
	#include "runtime/java.hpp"

	PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC

	inline const char* PSOldGen::select_name() {
	return UseParallelOldGC ? "ParOldGen" : "PSOldGen";
	}

	PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,
	size_t initial_size, size_t min_size, size_t max_size,
	const char* perf_data_name, int level):
	_name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
	_max_gen_size(max_size)
	{
	initialize(rs, alignment, perf_data_name, level);
	}

	PSOldGen::PSOldGen(size_t initial_size,
	size_t min_size, size_t max_size,
	const char* perf_data_name, int level):
	_name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
	_max_gen_size(max_size)
	{}

	void PSOldGen::initialize(ReservedSpace rs, size_t alignment,
	const char* perf_data_name, int level) {
	initialize_virtual_space(rs, alignment);
	initialize_work(perf_data_name, level);

	// The old gen can grow to gen_size_limit(). _reserve reflects only
	// the current maximum that can be committed.
	assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");

	initialize_performance_counters(perf_data_name, level);
	}

	void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {

	_virtual_space = new PSVirtualSpace(rs, alignment);
	if (!_virtual_space->expand_by(_init_gen_size)) {
	vm_exit_during_initialization("Could not reserve enough space for "
	"object heap");
	}
	}

	void PSOldGen::initialize_work(const char* perf_data_name, int level) {
	//
	// Basic memory initialization
	//

	MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),
	heap_word_size(_max_gen_size));
	assert(limit_reserved.byte_size() == _max_gen_size,
	"word vs bytes confusion");
	//
	// Object start stuff
	//

	start_array()->initialize(limit_reserved);

	_reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
	(HeapWord*)virtual_space()->high_boundary());

	//
	// Card table stuff
	//

	MemRegion cmr((HeapWord*)virtual_space()->low(),
	(HeapWord*)virtual_space()->high());
	if (ZapUnusedHeapArea) {
	// Mangle newly committed space immediately rather than
	// waiting for the initialization of the space even though
	// mangling is related to spaces. Doing it here eliminates
	// the need to carry along information that a complete mangling
	// (bottom to end) needs to be done.
	SpaceMangler::mangle_region(cmr);
	}

	Universe::heap()->barrier_set()->resize_covered_region(cmr);

	CardTableModRefBS* _ct = (CardTableModRefBS*)Universe::heap()->barrier_set();
	assert (_ct->kind() == BarrierSet::CardTableModRef, "Sanity");

	// Verify that the start and end of this generation is the start of a card.
	// If this wasn't true, a single card could span more than one generation,
	// which would cause problems when we commit/uncommit memory, and when we
	// clear and dirty cards.
	guarantee(_ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
	if (_reserved.end() != Universe::heap()->reserved_region().end()) {
	// Don't check at the very end of the heap as we'll assert that we're probing off
	// the end if we try.
	guarantee(_ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
	}

	//
	// ObjectSpace stuff
	//

	_object_space = new MutableSpace(virtual_space()->alignment());

	if (_object_space == NULL)
	vm_exit_during_initialization("Could not allocate an old gen space");

	object_space()->initialize(cmr,
	SpaceDecorator::Clear,
	SpaceDecorator::Mangle);

	_object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);

	if (_object_mark_sweep == NULL)
	vm_exit_during_initialization("Could not complete allocation of old generation");

	// Update the start_array
	start_array()->set_covered_region(cmr);
	}

	void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) {
	// Generation Counters, generation 'level', 1 subspace
	_gen_counters = new PSGenerationCounters(perf_data_name, level, 1,
	virtual_space());
	_space_counters = new SpaceCounters(perf_data_name, 0,
	virtual_space()->reserved_size(),
	_object_space, _gen_counters);
	}

	// Assume that the generation has been allocated if its
	// reserved size is not 0.
	bool PSOldGen::is_allocated() {
	return virtual_space()->reserved_size() != 0;
	}

	void PSOldGen::precompact() {
	ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
	assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

	// Reset start array first.
	start_array()->reset();

	object_mark_sweep()->precompact();

	// Now compact the young gen
	heap->young_gen()->precompact();
	}

	void PSOldGen::adjust_pointers() {
	object_mark_sweep()->adjust_pointers();
	}

	void PSOldGen::compact() {
	object_mark_sweep()->compact(ZapUnusedHeapArea);
	}

	size_t PSOldGen::contiguous_available() const {
	return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
	}

	// Allocation. We report all successful allocations to the size policy
	// Note that the perm gen does not use this method, and should not!
	HeapWord* PSOldGen::allocate(size_t word_size) {
	assert_locked_or_safepoint(Heap_lock);
	HeapWord* res = allocate_noexpand(word_size);

	if (res == NULL) {
	res = expand_and_allocate(word_size);
	}

	// Allocations in the old generation need to be reported
	if (res != NULL) {
	ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
	heap->size_policy()->tenured_allocation(word_size);
	}

	return res;
	}

	HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
	expand(word_size*HeapWordSize);
	if (GCExpandToAllocateDelayMillis > 0) {
	os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
	}
	return allocate_noexpand(word_size);
	}

	HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
	expand(word_size*HeapWordSize);
	if (GCExpandToAllocateDelayMillis > 0) {
	os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
	}
	return cas_allocate_noexpand(word_size);
	}

	void PSOldGen::expand(size_t bytes) {
	if (bytes == 0) {
	return;
	}
	MutexLocker x(ExpandHeap_lock);
	const size_t alignment = virtual_space()->alignment();
	size_t aligned_bytes = align_size_up(bytes, alignment);
	size_t aligned_expand_bytes = align_size_up(MinHeapDeltaBytes, alignment);

	if (UseNUMA) {
	// With NUMA we use round-robin page allocation for the old gen. Expand by at least
	// providing a page per lgroup. Alignment is larger or equal to the page size.
	aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
	}
	if (aligned_bytes == 0){
	// The alignment caused the number of bytes to wrap. An expand_by(0) will
	// return true with the implication that and expansion was done when it
	// was not. A call to expand implies a best effort to expand by "bytes"
	// but not a guarantee. Align down to give a best effort. This is likely
	// the most that the generation can expand since it has some capacity to
	// start with.
	aligned_bytes = align_size_down(bytes, alignment);
	}

	bool success = false;
	if (aligned_expand_bytes > aligned_bytes) {
	success = expand_by(aligned_expand_bytes);
	}
	if (!success) {
	success = expand_by(aligned_bytes);
	}
	if (!success) {
	success = expand_to_reserved();
	}

	if (PrintGC && Verbose) {
	if (success && GC_locker::is_active_and_needs_gc()) {
	gclog_or_tty->print_cr("Garbage collection disabled, expanded heap instead");
	}
	}
	}

	bool PSOldGen::expand_by(size_t bytes) {
	assert_lock_strong(ExpandHeap_lock);
	assert_locked_or_safepoint(Heap_lock);
	if (bytes == 0) {
	return true; // That's what virtual_space()->expand_by(0) would return
	}
	bool result = virtual_space()->expand_by(bytes);
	if (result) {
	if (ZapUnusedHeapArea) {
	// We need to mangle the newly expanded area. The memregion spans
	// end -> new_end, we assume that top -> end is already mangled.
	// Do the mangling before post_resize() is called because
	// the space is available for allocation after post_resize();
	HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
	assert(object_space()->end() < virtual_space_high,
	"Should be true before post_resize()");
	MemRegion mangle_region(object_space()->end(), virtual_space_high);
	// Note that the object space has not yet been updated to
	// coincede with the new underlying virtual space.
	SpaceMangler::mangle_region(mangle_region);
	}
	post_resize();
	if (UsePerfData) {
	_space_counters->update_capacity();
	_gen_counters->update_all();
	}
	}

	if (result && Verbose && PrintGC) {
	size_t new_mem_size = virtual_space()->committed_size();
	size_t old_mem_size = new_mem_size - bytes;
	gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "
	SIZE_FORMAT "K to "
	SIZE_FORMAT "K",
	name(), old_mem_size/K, bytes/K, new_mem_size/K);
	}

	return result;
	}

	bool PSOldGen::expand_to_reserved() {
	assert_lock_strong(ExpandHeap_lock);
	assert_locked_or_safepoint(Heap_lock);

	bool result = true;
	const size_t remaining_bytes = virtual_space()->uncommitted_size();
	if (remaining_bytes > 0) {
	result = expand_by(remaining_bytes);
	DEBUG_ONLY(if (!result) warning("grow to reserve failed"));
	}
	return result;
	}

	void PSOldGen::shrink(size_t bytes) {
	assert_lock_strong(ExpandHeap_lock);
	assert_locked_or_safepoint(Heap_lock);

	size_t size = align_size_down(bytes, virtual_space()->alignment());
	if (size > 0) {
	assert_lock_strong(ExpandHeap_lock);
	virtual_space()->shrink_by(bytes);
	post_resize();

	if (Verbose && PrintGC) {
	size_t new_mem_size = virtual_space()->committed_size();
	size_t old_mem_size = new_mem_size + bytes;
	gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by "
	SIZE_FORMAT "K to "
	SIZE_FORMAT "K",
	name(), old_mem_size/K, bytes/K, new_mem_size/K);
	}
	}
	}

	void PSOldGen::resize(size_t desired_free_space) {
	const size_t alignment = virtual_space()->alignment();
	const size_t size_before = virtual_space()->committed_size();
	size_t new_size = used_in_bytes() + desired_free_space;
	if (new_size < used_in_bytes()) {
	// Overflowed the addition.
	new_size = gen_size_limit();
	}
	// Adjust according to our min and max
	new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());

	assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
	new_size = align_size_up(new_size, alignment);

	const size_t current_size = capacity_in_bytes();

	if (PrintAdaptiveSizePolicy && Verbose) {
	gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "
	"desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
	" new size: " SIZE_FORMAT " current size " SIZE_FORMAT
	" gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
	desired_free_space, used_in_bytes(), new_size, current_size,
	gen_size_limit(), min_gen_size());
	}

	if (new_size == current_size) {
	// No change requested
	return;
	}
	if (new_size > current_size) {
	size_t change_bytes = new_size - current_size;
	expand(change_bytes);
	} else {
	size_t change_bytes = current_size - new_size;
	// shrink doesn't grab this lock, expand does. Is that right?
	MutexLocker x(ExpandHeap_lock);
	shrink(change_bytes);
	}

	if (PrintAdaptiveSizePolicy) {
	ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
	assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
	gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "
	"collection: %d "
	"(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
	heap->total_collections(),
	size_before, virtual_space()->committed_size());
	}
	}

	// NOTE! We need to be careful about resizing. During a GC, multiple
	// allocators may be active during heap expansion. If we allow the
	// heap resizing to become visible before we have correctly resized
	// all heap related data structures, we may cause program failures.
	void PSOldGen::post_resize() {
	// First construct a memregion representing the new size
	MemRegion new_memregion((HeapWord*)virtual_space()->low(),
	(HeapWord*)virtual_space()->high());
	size_t new_word_size = new_memregion.word_size();

	start_array()->set_covered_region(new_memregion);
	Universe::heap()->barrier_set()->resize_covered_region(new_memregion);

	// ALWAYS do this last!!
	object_space()->initialize(new_memregion,
	SpaceDecorator::DontClear,
	SpaceDecorator::DontMangle);

	assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
	"Sanity");
	}

	size_t PSOldGen::gen_size_limit() {
	return _max_gen_size;
	}

	void PSOldGen::reset_after_change() {
	ShouldNotReachHere();
	return;
	}

	size_t PSOldGen::available_for_expansion() {
	ShouldNotReachHere();
	return 0;
	}

	size_t PSOldGen::available_for_contraction() {
	ShouldNotReachHere();
	return 0;
	}

	void PSOldGen::print() const { print_on(tty);}
	void PSOldGen::print_on(outputStream* st) const {
	st->print(" %-15s", name());
	if (PrintGCDetails && Verbose) {
	st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,
	capacity_in_bytes(), used_in_bytes());
	} else {
	st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
	capacity_in_bytes()/K, used_in_bytes()/K);
	}
	st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
	virtual_space()->low_boundary(),
	virtual_space()->high(),
	virtual_space()->high_boundary());

	st->print(" object"); object_space()->print_on(st);
	}

	void PSOldGen::print_used_change(size_t prev_used) const {
	gclog_or_tty->print(" [%s:", name());
	gclog_or_tty->print(" " SIZE_FORMAT "K"
	"->" SIZE_FORMAT "K"
	"(" SIZE_FORMAT "K)",
	prev_used / K, used_in_bytes() / K,
	capacity_in_bytes() / K);
	gclog_or_tty->print("]");
	}

	void PSOldGen::update_counters() {
	if (UsePerfData) {
	_space_counters->update_all();
	_gen_counters->update_all();
	}
	}

	#ifndef PRODUCT

	void PSOldGen::space_invariants() {
	assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
	"Space invariant");
	assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
	"Space invariant");
	assert(virtual_space()->low_boundary() <= virtual_space()->low(),
	"Space invariant");
	assert(virtual_space()->high_boundary() >= virtual_space()->high(),
	"Space invariant");
	assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
	"Space invariant");
	assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
	"Space invariant");
	assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
	"Space invariant");
	}
	#endif

	void PSOldGen::verify() {
	object_space()->verify();
	}
	class VerifyObjectStartArrayClosure : public ObjectClosure {
	PSOldGen* _gen;
	ObjectStartArray* _start_array;

	public:
	VerifyObjectStartArrayClosure(PSOldGen* gen, ObjectStartArray* start_array) :
	_gen(gen), _start_array(start_array) { }

	virtual void do_object(oop obj) {
	HeapWord* test_addr = (HeapWord*)obj + 1;
	guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");
	guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");
	}
	};

	void PSOldGen::verify_object_start_array() {
	VerifyObjectStartArrayClosure check( this, &_start_array );
	object_iterate(&check);
	}

	#ifndef PRODUCT
	void PSOldGen::record_spaces_top() {
	assert(ZapUnusedHeapArea, "Not mangling unused space");
	object_space()->set_top_for_allocations();
	}
	#endif