src/hotspot/share/gc/g1/g1Allocator.cpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2014, 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/g1Allocator.inline.hpp"
 #include "gc/g1/g1AllocRegion.inline.hpp"
 #include "gc/g1/g1EvacStats.inline.hpp"
 #include "gc/g1/g1EvacuationInfo.hpp"
 #include "gc/g1/g1CollectedHeap.inline.hpp"
 #include "gc/g1/g1Policy.hpp"
 #include "gc/g1/heapRegion.inline.hpp"
 #include "gc/g1/heapRegionSet.inline.hpp"
 #include "gc/g1/heapRegionType.hpp"
 #include "utilities/align.hpp"

 G1Allocator::G1Allocator(G1CollectedHeap* heap) :
   _g1h(heap),
   _survivor_is_full(false),
   _old_is_full(false),
   _mutator_alloc_region(),
   _survivor_gc_alloc_region(heap->alloc_buffer_stats(G1HeapRegionAttr::Young)),
   _old_gc_alloc_region(heap->alloc_buffer_stats(G1HeapRegionAttr::Old)),
   _retained_old_gc_alloc_region(NULL) {
 }

 void G1Allocator::init_mutator_alloc_region() {
   assert(_mutator_alloc_region.get() == NULL, "pre-condition");
   _mutator_alloc_region.init();
 }

 void G1Allocator::release_mutator_alloc_region() {
   _mutator_alloc_region.release();
   assert(_mutator_alloc_region.get() == NULL, "post-condition");
 }

 bool G1Allocator::is_retained_old_region(HeapRegion* hr) {
   return _retained_old_gc_alloc_region == hr;
 }

 void G1Allocator::reuse_retained_old_region(G1EvacuationInfo& evacuation_info,
                                             OldGCAllocRegion* old,
                                             HeapRegion** retained_old) {
   HeapRegion* retained_region = *retained_old;
   *retained_old = NULL;
   assert(retained_region == NULL || !retained_region->is_archive(),
          "Archive region should not be alloc region (index %u)", retained_region->hrm_index());

   // We will discard the current GC alloc region if:
   // a) it's in the collection set (it can happen!),
   // b) it's already full (no point in using it),
   // c) it's empty (this means that it was emptied during
   // a cleanup and it should be on the free list now), or
   // d) it's humongous (this means that it was emptied
   // during a cleanup and was added to the free list, but
   // has been subsequently used to allocate a humongous
   // object that may be less than the region size).
   if (retained_region != NULL &&
       !retained_region->in_collection_set() &&
       !(retained_region->top() == retained_region->end()) &&
       !retained_region->is_empty() &&
       !retained_region->is_humongous()) {
     // The retained region was added to the old region set when it was
     // retired. We have to remove it now, since we don't allow regions
     // we allocate to in the region sets. We'll re-add it later, when
     // it's retired again.
     _g1h->old_set_remove(retained_region);
     old->set(retained_region);
     _g1h->hr_printer()->reuse(retained_region);
     evacuation_info.set_alloc_regions_used_before(retained_region->used());
   }
 }

 void G1Allocator::init_gc_alloc_regions(G1EvacuationInfo& evacuation_info) {
   assert_at_safepoint_on_vm_thread();

   _survivor_is_full = false;
   _old_is_full = false;

   _survivor_gc_alloc_region.init();
   _old_gc_alloc_region.init();
   reuse_retained_old_region(evacuation_info,
                             &_old_gc_alloc_region,
                             &_retained_old_gc_alloc_region);
 }

 void G1Allocator::release_gc_alloc_regions(G1EvacuationInfo& evacuation_info) {
   evacuation_info.set_allocation_regions(survivor_gc_alloc_region()->count() +
                                          old_gc_alloc_region()->count());
   survivor_gc_alloc_region()->release();
   // If we have an old GC alloc region to release, we'll save it in
   // _retained_old_gc_alloc_region. If we don't
   // _retained_old_gc_alloc_region will become NULL. This is what we
   // want either way so no reason to check explicitly for either
   // condition.
   _retained_old_gc_alloc_region = old_gc_alloc_region()->release();
 }

 void G1Allocator::abandon_gc_alloc_regions() {
   assert(survivor_gc_alloc_region()->get() == NULL, "pre-condition");
   assert(old_gc_alloc_region()->get() == NULL, "pre-condition");
   _retained_old_gc_alloc_region = NULL;
 }

 bool G1Allocator::survivor_is_full() const {
   return _survivor_is_full;
 }

 bool G1Allocator::old_is_full() const {
   return _old_is_full;
 }

 void G1Allocator::set_survivor_full() {
   _survivor_is_full = true;
 }

 void G1Allocator::set_old_full() {
   _old_is_full = true;
 }

 size_t G1Allocator::unsafe_max_tlab_alloc() {
   // Return the remaining space in the cur alloc region, but not less than
   // the min TLAB size.

   // Also, this value can be at most the humongous object threshold,
   // since we can't allow tlabs to grow big enough to accommodate
   // humongous objects.

   HeapRegion* hr = mutator_alloc_region()->get();
   size_t max_tlab = _g1h->max_tlab_size() * wordSize;
   if (hr == NULL) {
     return max_tlab;
   } else {
     return MIN2(MAX2(hr->free(), (size_t) MinTLABSize), max_tlab);
   }
 }

 size_t G1Allocator::used_in_alloc_regions() {
   assert(Heap_lock->owner() != NULL, "Should be owned on this thread's behalf.");
   return mutator_alloc_region()->used_in_alloc_regions();
 }


 HeapWord* G1Allocator::par_allocate_during_gc(G1HeapRegionAttr dest,
                                               size_t word_size) {
   size_t temp = 0;
   HeapWord* result = par_allocate_during_gc(dest, word_size, word_size, &temp);
   assert(result == NULL || temp == word_size,
          "Requested " SIZE_FORMAT " words, but got " SIZE_FORMAT " at " PTR_FORMAT,
          word_size, temp, p2i(result));
   return result;
 }

 HeapWord* G1Allocator::par_allocate_during_gc(G1HeapRegionAttr dest,
                                               size_t min_word_size,
                                               size_t desired_word_size,
                                               size_t* actual_word_size) {
   switch (dest.type()) {
     case G1HeapRegionAttr::Young:
       return survivor_attempt_allocation(min_word_size, desired_word_size, actual_word_size);
     case G1HeapRegionAttr::Old:
       return old_attempt_allocation(min_word_size, desired_word_size, actual_word_size);
     default:
       ShouldNotReachHere();
       return NULL; // Keep some compilers happy
   }
 }

 HeapWord* G1Allocator::survivor_attempt_allocation(size_t min_word_size,
                                                    size_t desired_word_size,
                                                    size_t* actual_word_size) {
   assert(!_g1h->is_humongous(desired_word_size),
          "we should not be seeing humongous-size allocations in this path");

   HeapWord* result = survivor_gc_alloc_region()->attempt_allocation(min_word_size,
                                                                     desired_word_size,
                                                                     actual_word_size);
   if (result == NULL && !survivor_is_full()) {
     MutexLocker x(FreeList_lock, Mutex::_no_safepoint_check_flag);
     result = survivor_gc_alloc_region()->attempt_allocation_locked(min_word_size,
                                                                    desired_word_size,
                                                                    actual_word_size);
     if (result == NULL) {
       set_survivor_full();
     }
   }
   if (result != NULL) {
     _g1h->dirty_young_block(result, *actual_word_size);
   }
   return result;
 }

 HeapWord* G1Allocator::old_attempt_allocation(size_t min_word_size,
                                               size_t desired_word_size,
                                               size_t* actual_word_size) {
   assert(!_g1h->is_humongous(desired_word_size),
          "we should not be seeing humongous-size allocations in this path");

   HeapWord* result = old_gc_alloc_region()->attempt_allocation(min_word_size,
                                                                desired_word_size,
                                                                actual_word_size);
   if (result == NULL && !old_is_full()) {
     MutexLocker x(FreeList_lock, Mutex::_no_safepoint_check_flag);
     result = old_gc_alloc_region()->attempt_allocation_locked(min_word_size,
                                                               desired_word_size,
                                                               actual_word_size);
     if (result == NULL) {
       set_old_full();
     }
   }
   return result;
 }

 uint G1PLABAllocator::calc_survivor_alignment_bytes() {
   assert(SurvivorAlignmentInBytes >= ObjectAlignmentInBytes, "sanity");
   if (SurvivorAlignmentInBytes == ObjectAlignmentInBytes) {
     // No need to align objects in the survivors differently, return 0
     // which means "survivor alignment is not used".
     return 0;
   } else {
     assert(SurvivorAlignmentInBytes > 0, "sanity");
     return SurvivorAlignmentInBytes;
   }
 }

 G1PLABAllocator::G1PLABAllocator(G1Allocator* allocator) :
   _g1h(G1CollectedHeap::heap()),
   _allocator(allocator),
   _surviving_alloc_buffer(_g1h->desired_plab_sz(G1HeapRegionAttr::Young)),
   _tenured_alloc_buffer(_g1h->desired_plab_sz(G1HeapRegionAttr::Old)),
   _survivor_alignment_bytes(calc_survivor_alignment_bytes()) {
   for (uint state = 0; state < G1HeapRegionAttr::Num; state++) {
     _direct_allocated[state] = 0;
     _alloc_buffers[state] = NULL;
   }
   _alloc_buffers[G1HeapRegionAttr::Young] = &_surviving_alloc_buffer;
   _alloc_buffers[G1HeapRegionAttr::Old]  = &_tenured_alloc_buffer;
 }

 bool G1PLABAllocator::may_throw_away_buffer(size_t const allocation_word_sz, size_t const buffer_size) const {
   return (allocation_word_sz * 100 < buffer_size * ParallelGCBufferWastePct);
 }

 HeapWord* G1PLABAllocator::allocate_direct_or_new_plab(G1HeapRegionAttr dest,
                                                        size_t word_sz,
                                                        bool* plab_refill_failed) {
   size_t plab_word_size = _g1h->desired_plab_sz(dest);
   size_t required_in_plab = PLAB::size_required_for_allocation(word_sz);

   // Only get a new PLAB if the allocation fits and it would not waste more than
   // ParallelGCBufferWastePct in the existing buffer.
   if ((required_in_plab <= plab_word_size) &&
     may_throw_away_buffer(required_in_plab, plab_word_size)) {

     PLAB* alloc_buf = alloc_buffer(dest);
     alloc_buf->retire();

     size_t actual_plab_size = 0;
     HeapWord* buf = _allocator->par_allocate_during_gc(dest,
                                                        required_in_plab,
                                                        plab_word_size,
                                                        &actual_plab_size);

     assert(buf == NULL || ((actual_plab_size >= required_in_plab) && (actual_plab_size <= plab_word_size)),
            "Requested at minimum " SIZE_FORMAT ", desired " SIZE_FORMAT " words, but got " SIZE_FORMAT " at " PTR_FORMAT,
            required_in_plab, plab_word_size, actual_plab_size, p2i(buf));

     if (buf != NULL) {
       alloc_buf->set_buf(buf, actual_plab_size);

       HeapWord* const obj = alloc_buf->allocate(word_sz);
       assert(obj != NULL, "PLAB should have been big enough, tried to allocate "
                           SIZE_FORMAT " requiring " SIZE_FORMAT " PLAB size " SIZE_FORMAT,
                           word_sz, required_in_plab, plab_word_size);
       return obj;
     }
     // Otherwise.
     *plab_refill_failed = true;
   }
   // Try direct allocation.
   HeapWord* result = _allocator->par_allocate_during_gc(dest, word_sz);
   if (result != NULL) {
     _direct_allocated[dest.type()] += word_sz;
   }
   return result;
 }

 void G1PLABAllocator::undo_allocation(G1HeapRegionAttr dest, HeapWord* obj, size_t word_sz) {
   alloc_buffer(dest)->undo_allocation(obj, word_sz);
 }

 void G1PLABAllocator::flush_and_retire_stats() {
   for (uint state = 0; state < G1HeapRegionAttr::Num; state++) {
     PLAB* const buf = _alloc_buffers[state];
     if (buf != NULL) {
       G1EvacStats* stats = _g1h->alloc_buffer_stats(state);
       buf->flush_and_retire_stats(stats);
       stats->add_direct_allocated(_direct_allocated[state]);
       _direct_allocated[state] = 0;
     }
   }
 }

 size_t G1PLABAllocator::waste() const {
   size_t result = 0;
   for (uint state = 0; state < G1HeapRegionAttr::Num; state++) {
     PLAB * const buf = _alloc_buffers[state];
     if (buf != NULL) {
       result += buf->waste();
     }
   }
   return result;
 }

 size_t G1PLABAllocator::undo_waste() const {
   size_t result = 0;
   for (uint state = 0; state < G1HeapRegionAttr::Num; state++) {
     PLAB * const buf = _alloc_buffers[state];
     if (buf != NULL) {
       result += buf->undo_waste();
     }
   }
   return result;
 }

 bool G1ArchiveAllocator::_archive_check_enabled = false;
 G1ArchiveRegionMap G1ArchiveAllocator::_closed_archive_region_map;
 G1ArchiveRegionMap G1ArchiveAllocator::_open_archive_region_map;

 G1ArchiveAllocator* G1ArchiveAllocator::create_allocator(G1CollectedHeap* g1h, bool open) {
   // Create the archive allocator, and also enable archive object checking
   // in mark-sweep, since we will be creating archive regions.
   G1ArchiveAllocator* result =  new G1ArchiveAllocator(g1h, open);
   enable_archive_object_check();
   return result;
 }

 bool G1ArchiveAllocator::alloc_new_region() {
   // Allocate the highest free region in the reserved heap,
   // and add it to our list of allocated regions. It is marked
   // archive and added to the old set.
   HeapRegion* hr = _g1h->alloc_highest_free_region();
   if (hr == NULL) {
     return false;
   }
   assert(hr->is_empty(), "expected empty region (index %u)", hr->hrm_index());
   if (_open) {
     hr->set_open_archive();
   } else {
     hr->set_closed_archive();
   }
   _g1h->policy()->remset_tracker()->update_at_allocate(hr);
   _g1h->archive_set_add(hr);
   _g1h->hr_printer()->alloc(hr);
   _allocated_regions.append(hr);
   _allocation_region = hr;

   // Set up _bottom and _max to begin allocating in the lowest
   // min_region_size'd chunk of the allocated G1 region.
   _bottom = hr->bottom();
   _max = _bottom + HeapRegion::min_region_size_in_words();

   // Tell mark-sweep that objects in this region are not to be marked.
   set_range_archive(MemRegion(_bottom, HeapRegion::GrainWords), _open);

   // Since we've modified the old set, call update_sizes.
   _g1h->g1mm()->update_sizes();
   return true;
 }

 HeapWord* G1ArchiveAllocator::archive_mem_allocate(size_t word_size) {
   assert(word_size != 0, "size must not be zero");
   if (_allocation_region == NULL) {
     if (!alloc_new_region()) {
       return NULL;
     }
   }
   HeapWord* old_top = _allocation_region->top();
   assert(_bottom >= _allocation_region->bottom(),
          "inconsistent allocation state: " PTR_FORMAT " < " PTR_FORMAT,
          p2i(_bottom), p2i(_allocation_region->bottom()));
   assert(_max <= _allocation_region->end(),
          "inconsistent allocation state: " PTR_FORMAT " > " PTR_FORMAT,
          p2i(_max), p2i(_allocation_region->end()));
   assert(_bottom <= old_top && old_top <= _max,
          "inconsistent allocation state: expected "
          PTR_FORMAT " <= " PTR_FORMAT " <= " PTR_FORMAT,
          p2i(_bottom), p2i(old_top), p2i(_max));

   // Allocate the next word_size words in the current allocation chunk.
   // If allocation would cross the _max boundary, insert a filler and begin
   // at the base of the next min_region_size'd chunk. Also advance to the next
   // chunk if we don't yet cross the boundary, but the remainder would be too
   // small to fill.
   HeapWord* new_top = old_top + word_size;
   size_t remainder = pointer_delta(_max, new_top);
   if ((new_top > _max) ||
       ((new_top < _max) && (remainder < CollectedHeap::min_fill_size()))) {
     if (old_top != _max) {
       size_t fill_size = pointer_delta(_max, old_top);
       CollectedHeap::fill_with_object(old_top, fill_size);
       _summary_bytes_used += fill_size * HeapWordSize;
     }
     _allocation_region->set_top(_max);
     old_top = _bottom = _max;

     // Check if we've just used up the last min_region_size'd chunk
     // in the current region, and if so, allocate a new one.
     if (_bottom != _allocation_region->end()) {
       _max = _bottom + HeapRegion::min_region_size_in_words();
     } else {
       if (!alloc_new_region()) {
         return NULL;
       }
       old_top = _allocation_region->bottom();
     }
   }
   _allocation_region->set_top(old_top + word_size);
   _summary_bytes_used += word_size * HeapWordSize;

   return old_top;
 }

 void G1ArchiveAllocator::complete_archive(GrowableArray<MemRegion>* ranges,
                                           size_t end_alignment_in_bytes) {
   assert((end_alignment_in_bytes >> LogHeapWordSize) < HeapRegion::min_region_size_in_words(),
          "alignment " SIZE_FORMAT " too large", end_alignment_in_bytes);
   assert(is_aligned(end_alignment_in_bytes, HeapWordSize),
          "alignment " SIZE_FORMAT " is not HeapWord (%u) aligned", end_alignment_in_bytes, HeapWordSize);

   // If we've allocated nothing, simply return.
   if (_allocation_region == NULL) {
     return;
   }

   // If an end alignment was requested, insert filler objects.
   if (end_alignment_in_bytes != 0) {
     HeapWord* currtop = _allocation_region->top();
     HeapWord* newtop = align_up(currtop, end_alignment_in_bytes);
     size_t fill_size = pointer_delta(newtop, currtop);
     if (fill_size != 0) {
       if (fill_size < CollectedHeap::min_fill_size()) {
         // If the required fill is smaller than we can represent,
         // bump up to the next aligned address. We know we won't exceed the current
         // region boundary because the max supported alignment is smaller than the min
         // region size, and because the allocation code never leaves space smaller than
         // the min_fill_size at the top of the current allocation region.
         newtop = align_up(currtop + CollectedHeap::min_fill_size(),
                           end_alignment_in_bytes);
         fill_size = pointer_delta(newtop, currtop);
       }
       HeapWord* fill = archive_mem_allocate(fill_size);
       CollectedHeap::fill_with_objects(fill, fill_size);
     }
   }

   // Loop through the allocated regions, and create MemRegions summarizing
   // the allocated address range, combining contiguous ranges. Add the
   // MemRegions to the GrowableArray provided by the caller.
   int index = _allocated_regions.length() - 1;
   assert(_allocated_regions.at(index) == _allocation_region,
          "expected region %u at end of array, found %u",
          _allocation_region->hrm_index(), _allocated_regions.at(index)->hrm_index());
   HeapWord* base_address = _allocation_region->bottom();
   HeapWord* top = base_address;

   while (index >= 0) {
     HeapRegion* next = _allocated_regions.at(index);
     HeapWord* new_base = next->bottom();
     HeapWord* new_top = next->top();
     if (new_base != top) {
       ranges->append(MemRegion(base_address, pointer_delta(top, base_address)));
       base_address = new_base;
     }
     top = new_top;
     index = index - 1;
   }

   assert(top != base_address, "zero-sized range, address " PTR_FORMAT, p2i(base_address));
   ranges->append(MemRegion(base_address, pointer_delta(top, base_address)));
   _allocated_regions.clear();
   _allocation_region = NULL;
 };
	/*
	* Copyright (c) 2014, 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/g1Allocator.inline.hpp"
	#include "gc/g1/g1AllocRegion.inline.hpp"
	#include "gc/g1/g1EvacStats.inline.hpp"
	#include "gc/g1/g1EvacuationInfo.hpp"
	#include "gc/g1/g1CollectedHeap.inline.hpp"
	#include "gc/g1/g1Policy.hpp"
	#include "gc/g1/heapRegion.inline.hpp"
	#include "gc/g1/heapRegionSet.inline.hpp"
	#include "gc/g1/heapRegionType.hpp"
	#include "utilities/align.hpp"

	G1Allocator::G1Allocator(G1CollectedHeap* heap) :
	_g1h(heap),
	_survivor_is_full(false),
	_old_is_full(false),
	_mutator_alloc_region(),
	_survivor_gc_alloc_region(heap->alloc_buffer_stats(G1HeapRegionAttr::Young)),
	_old_gc_alloc_region(heap->alloc_buffer_stats(G1HeapRegionAttr::Old)),
	_retained_old_gc_alloc_region(NULL) {
	}

	void G1Allocator::init_mutator_alloc_region() {
	assert(_mutator_alloc_region.get() == NULL, "pre-condition");
	_mutator_alloc_region.init();
	}

	void G1Allocator::release_mutator_alloc_region() {
	_mutator_alloc_region.release();
	assert(_mutator_alloc_region.get() == NULL, "post-condition");
	}

	bool G1Allocator::is_retained_old_region(HeapRegion* hr) {
	return _retained_old_gc_alloc_region == hr;
	}

	void G1Allocator::reuse_retained_old_region(G1EvacuationInfo& evacuation_info,
	OldGCAllocRegion* old,
	HeapRegion** retained_old) {
	HeapRegion* retained_region = *retained_old;
	*retained_old = NULL;
	assert(retained_region == NULL \|\| !retained_region->is_archive(),
	"Archive region should not be alloc region (index %u)", retained_region->hrm_index());

	// We will discard the current GC alloc region if:
	// a) it's in the collection set (it can happen!),
	// b) it's already full (no point in using it),
	// c) it's empty (this means that it was emptied during
	// a cleanup and it should be on the free list now), or
	// d) it's humongous (this means that it was emptied
	// during a cleanup and was added to the free list, but
	// has been subsequently used to allocate a humongous
	// object that may be less than the region size).
	if (retained_region != NULL &&
	!retained_region->in_collection_set() &&
	!(retained_region->top() == retained_region->end()) &&
	!retained_region->is_empty() &&
	!retained_region->is_humongous()) {
	// The retained region was added to the old region set when it was
	// retired. We have to remove it now, since we don't allow regions
	// we allocate to in the region sets. We'll re-add it later, when
	// it's retired again.
	_g1h->old_set_remove(retained_region);
	old->set(retained_region);
	_g1h->hr_printer()->reuse(retained_region);
	evacuation_info.set_alloc_regions_used_before(retained_region->used());
	}
	}

	void G1Allocator::init_gc_alloc_regions(G1EvacuationInfo& evacuation_info) {
	assert_at_safepoint_on_vm_thread();

	_survivor_is_full = false;
	_old_is_full = false;

	_survivor_gc_alloc_region.init();
	_old_gc_alloc_region.init();
	reuse_retained_old_region(evacuation_info,
	&_old_gc_alloc_region,
	&_retained_old_gc_alloc_region);
	}

	void G1Allocator::release_gc_alloc_regions(G1EvacuationInfo& evacuation_info) {
	evacuation_info.set_allocation_regions(survivor_gc_alloc_region()->count() +
	old_gc_alloc_region()->count());
	survivor_gc_alloc_region()->release();
	// If we have an old GC alloc region to release, we'll save it in
	// _retained_old_gc_alloc_region. If we don't
	// _retained_old_gc_alloc_region will become NULL. This is what we
	// want either way so no reason to check explicitly for either
	// condition.
	_retained_old_gc_alloc_region = old_gc_alloc_region()->release();
	}

	void G1Allocator::abandon_gc_alloc_regions() {
	assert(survivor_gc_alloc_region()->get() == NULL, "pre-condition");
	assert(old_gc_alloc_region()->get() == NULL, "pre-condition");
	_retained_old_gc_alloc_region = NULL;
	}

	bool G1Allocator::survivor_is_full() const {
	return _survivor_is_full;
	}

	bool G1Allocator::old_is_full() const {
	return _old_is_full;
	}

	void G1Allocator::set_survivor_full() {
	_survivor_is_full = true;
	}

	void G1Allocator::set_old_full() {
	_old_is_full = true;
	}

	size_t G1Allocator::unsafe_max_tlab_alloc() {
	// Return the remaining space in the cur alloc region, but not less than
	// the min TLAB size.

	// Also, this value can be at most the humongous object threshold,
	// since we can't allow tlabs to grow big enough to accommodate
	// humongous objects.

	HeapRegion* hr = mutator_alloc_region()->get();
	size_t max_tlab = _g1h->max_tlab_size() * wordSize;
	if (hr == NULL) {
	return max_tlab;
	} else {
	return MIN2(MAX2(hr->free(), (size_t) MinTLABSize), max_tlab);
	}
	}

	size_t G1Allocator::used_in_alloc_regions() {
	assert(Heap_lock->owner() != NULL, "Should be owned on this thread's behalf.");
	return mutator_alloc_region()->used_in_alloc_regions();
	}


	HeapWord* G1Allocator::par_allocate_during_gc(G1HeapRegionAttr dest,
	size_t word_size) {
	size_t temp = 0;
	HeapWord* result = par_allocate_during_gc(dest, word_size, word_size, &temp);
	assert(result == NULL \|\| temp == word_size,
	"Requested " SIZE_FORMAT " words, but got " SIZE_FORMAT " at " PTR_FORMAT,
	word_size, temp, p2i(result));
	return result;
	}

	HeapWord* G1Allocator::par_allocate_during_gc(G1HeapRegionAttr dest,
	size_t min_word_size,
	size_t desired_word_size,
	size_t* actual_word_size) {
	switch (dest.type()) {
	case G1HeapRegionAttr::Young:
	return survivor_attempt_allocation(min_word_size, desired_word_size, actual_word_size);
	case G1HeapRegionAttr::Old:
	return old_attempt_allocation(min_word_size, desired_word_size, actual_word_size);
	default:
	ShouldNotReachHere();
	return NULL; // Keep some compilers happy
	}
	}

	HeapWord* G1Allocator::survivor_attempt_allocation(size_t min_word_size,
	size_t desired_word_size,
	size_t* actual_word_size) {
	assert(!_g1h->is_humongous(desired_word_size),
	"we should not be seeing humongous-size allocations in this path");

	HeapWord* result = survivor_gc_alloc_region()->attempt_allocation(min_word_size,
	desired_word_size,
	actual_word_size);
	if (result == NULL && !survivor_is_full()) {
	MutexLocker x(FreeList_lock, Mutex::_no_safepoint_check_flag);
	result = survivor_gc_alloc_region()->attempt_allocation_locked(min_word_size,
	desired_word_size,
	actual_word_size);
	if (result == NULL) {
	set_survivor_full();
	}
	}
	if (result != NULL) {
	_g1h->dirty_young_block(result, *actual_word_size);
	}
	return result;
	}

	HeapWord* G1Allocator::old_attempt_allocation(size_t min_word_size,
	size_t desired_word_size,
	size_t* actual_word_size) {
	assert(!_g1h->is_humongous(desired_word_size),
	"we should not be seeing humongous-size allocations in this path");

	HeapWord* result = old_gc_alloc_region()->attempt_allocation(min_word_size,
	desired_word_size,
	actual_word_size);
	if (result == NULL && !old_is_full()) {
	MutexLocker x(FreeList_lock, Mutex::_no_safepoint_check_flag);
	result = old_gc_alloc_region()->attempt_allocation_locked(min_word_size,
	desired_word_size,
	actual_word_size);
	if (result == NULL) {
	set_old_full();
	}
	}
	return result;
	}

	uint G1PLABAllocator::calc_survivor_alignment_bytes() {
	assert(SurvivorAlignmentInBytes >= ObjectAlignmentInBytes, "sanity");
	if (SurvivorAlignmentInBytes == ObjectAlignmentInBytes) {
	// No need to align objects in the survivors differently, return 0
	// which means "survivor alignment is not used".
	return 0;
	} else {
	assert(SurvivorAlignmentInBytes > 0, "sanity");
	return SurvivorAlignmentInBytes;
	}
	}

	G1PLABAllocator::G1PLABAllocator(G1Allocator* allocator) :
	_g1h(G1CollectedHeap::heap()),
	_allocator(allocator),
	_surviving_alloc_buffer(_g1h->desired_plab_sz(G1HeapRegionAttr::Young)),
	_tenured_alloc_buffer(_g1h->desired_plab_sz(G1HeapRegionAttr::Old)),
	_survivor_alignment_bytes(calc_survivor_alignment_bytes()) {
	for (uint state = 0; state < G1HeapRegionAttr::Num; state++) {
	_direct_allocated[state] = 0;
	_alloc_buffers[state] = NULL;
	}
	_alloc_buffers[G1HeapRegionAttr::Young] = &_surviving_alloc_buffer;
	_alloc_buffers[G1HeapRegionAttr::Old] = &_tenured_alloc_buffer;
	}

	bool G1PLABAllocator::may_throw_away_buffer(size_t const allocation_word_sz, size_t const buffer_size) const {
	return (allocation_word_sz * 100 < buffer_size * ParallelGCBufferWastePct);
	}

	HeapWord* G1PLABAllocator::allocate_direct_or_new_plab(G1HeapRegionAttr dest,
	size_t word_sz,
	bool* plab_refill_failed) {
	size_t plab_word_size = _g1h->desired_plab_sz(dest);
	size_t required_in_plab = PLAB::size_required_for_allocation(word_sz);

	// Only get a new PLAB if the allocation fits and it would not waste more than
	// ParallelGCBufferWastePct in the existing buffer.
	if ((required_in_plab <= plab_word_size) &&
	may_throw_away_buffer(required_in_plab, plab_word_size)) {

	PLAB* alloc_buf = alloc_buffer(dest);
	alloc_buf->retire();

	size_t actual_plab_size = 0;
	HeapWord* buf = _allocator->par_allocate_during_gc(dest,
	required_in_plab,
	plab_word_size,
	&actual_plab_size);

	assert(buf == NULL \|\| ((actual_plab_size >= required_in_plab) && (actual_plab_size <= plab_word_size)),
	"Requested at minimum " SIZE_FORMAT ", desired " SIZE_FORMAT " words, but got " SIZE_FORMAT " at " PTR_FORMAT,
	required_in_plab, plab_word_size, actual_plab_size, p2i(buf));

	if (buf != NULL) {
	alloc_buf->set_buf(buf, actual_plab_size);

	HeapWord* const obj = alloc_buf->allocate(word_sz);
	assert(obj != NULL, "PLAB should have been big enough, tried to allocate "
	SIZE_FORMAT " requiring " SIZE_FORMAT " PLAB size " SIZE_FORMAT,
	word_sz, required_in_plab, plab_word_size);
	return obj;
	}
	// Otherwise.
	*plab_refill_failed = true;
	}
	// Try direct allocation.
	HeapWord* result = _allocator->par_allocate_during_gc(dest, word_sz);
	if (result != NULL) {
	_direct_allocated[dest.type()] += word_sz;
	}
	return result;
	}

	void G1PLABAllocator::undo_allocation(G1HeapRegionAttr dest, HeapWord* obj, size_t word_sz) {
	alloc_buffer(dest)->undo_allocation(obj, word_sz);
	}

	void G1PLABAllocator::flush_and_retire_stats() {
	for (uint state = 0; state < G1HeapRegionAttr::Num; state++) {
	PLAB* const buf = _alloc_buffers[state];
	if (buf != NULL) {
	G1EvacStats* stats = _g1h->alloc_buffer_stats(state);
	buf->flush_and_retire_stats(stats);
	stats->add_direct_allocated(_direct_allocated[state]);
	_direct_allocated[state] = 0;
	}
	}
	}

	size_t G1PLABAllocator::waste() const {
	size_t result = 0;
	for (uint state = 0; state < G1HeapRegionAttr::Num; state++) {
	PLAB * const buf = _alloc_buffers[state];
	if (buf != NULL) {
	result += buf->waste();
	}
	}
	return result;
	}

	size_t G1PLABAllocator::undo_waste() const {
	size_t result = 0;
	for (uint state = 0; state < G1HeapRegionAttr::Num; state++) {
	PLAB * const buf = _alloc_buffers[state];
	if (buf != NULL) {
	result += buf->undo_waste();
	}
	}
	return result;
	}

	bool G1ArchiveAllocator::_archive_check_enabled = false;
	G1ArchiveRegionMap G1ArchiveAllocator::_closed_archive_region_map;
	G1ArchiveRegionMap G1ArchiveAllocator::_open_archive_region_map;

	G1ArchiveAllocator* G1ArchiveAllocator::create_allocator(G1CollectedHeap* g1h, bool open) {
	// Create the archive allocator, and also enable archive object checking
	// in mark-sweep, since we will be creating archive regions.
	G1ArchiveAllocator* result = new G1ArchiveAllocator(g1h, open);
	enable_archive_object_check();
	return result;
	}

	bool G1ArchiveAllocator::alloc_new_region() {
	// Allocate the highest free region in the reserved heap,
	// and add it to our list of allocated regions. It is marked
	// archive and added to the old set.
	HeapRegion* hr = _g1h->alloc_highest_free_region();
	if (hr == NULL) {
	return false;
	}
	assert(hr->is_empty(), "expected empty region (index %u)", hr->hrm_index());
	if (_open) {
	hr->set_open_archive();
	} else {
	hr->set_closed_archive();
	}
	_g1h->policy()->remset_tracker()->update_at_allocate(hr);
	_g1h->archive_set_add(hr);
	_g1h->hr_printer()->alloc(hr);
	_allocated_regions.append(hr);
	_allocation_region = hr;

	// Set up _bottom and _max to begin allocating in the lowest
	// min_region_size'd chunk of the allocated G1 region.
	_bottom = hr->bottom();
	_max = _bottom + HeapRegion::min_region_size_in_words();

	// Tell mark-sweep that objects in this region are not to be marked.
	set_range_archive(MemRegion(_bottom, HeapRegion::GrainWords), _open);

	// Since we've modified the old set, call update_sizes.
	_g1h->g1mm()->update_sizes();
	return true;
	}

	HeapWord* G1ArchiveAllocator::archive_mem_allocate(size_t word_size) {
	assert(word_size != 0, "size must not be zero");
	if (_allocation_region == NULL) {
	if (!alloc_new_region()) {
	return NULL;
	}
	}
	HeapWord* old_top = _allocation_region->top();
	assert(_bottom >= _allocation_region->bottom(),
	"inconsistent allocation state: " PTR_FORMAT " < " PTR_FORMAT,
	p2i(_bottom), p2i(_allocation_region->bottom()));
	assert(_max <= _allocation_region->end(),
	"inconsistent allocation state: " PTR_FORMAT " > " PTR_FORMAT,
	p2i(_max), p2i(_allocation_region->end()));
	assert(_bottom <= old_top && old_top <= _max,
	"inconsistent allocation state: expected "
	PTR_FORMAT " <= " PTR_FORMAT " <= " PTR_FORMAT,
	p2i(_bottom), p2i(old_top), p2i(_max));

	// Allocate the next word_size words in the current allocation chunk.
	// If allocation would cross the _max boundary, insert a filler and begin
	// at the base of the next min_region_size'd chunk. Also advance to the next
	// chunk if we don't yet cross the boundary, but the remainder would be too
	// small to fill.
	HeapWord* new_top = old_top + word_size;
	size_t remainder = pointer_delta(_max, new_top);
	if ((new_top > _max) \|\|
	((new_top < _max) && (remainder < CollectedHeap::min_fill_size()))) {
	if (old_top != _max) {
	size_t fill_size = pointer_delta(_max, old_top);
	CollectedHeap::fill_with_object(old_top, fill_size);
	_summary_bytes_used += fill_size * HeapWordSize;
	}
	_allocation_region->set_top(_max);
	old_top = _bottom = _max;

	// Check if we've just used up the last min_region_size'd chunk
	// in the current region, and if so, allocate a new one.
	if (_bottom != _allocation_region->end()) {
	_max = _bottom + HeapRegion::min_region_size_in_words();
	} else {
	if (!alloc_new_region()) {
	return NULL;
	}
	old_top = _allocation_region->bottom();
	}
	}
	_allocation_region->set_top(old_top + word_size);
	_summary_bytes_used += word_size * HeapWordSize;

	return old_top;
	}

	void G1ArchiveAllocator::complete_archive(GrowableArray<MemRegion>* ranges,
	size_t end_alignment_in_bytes) {
	assert((end_alignment_in_bytes >> LogHeapWordSize) < HeapRegion::min_region_size_in_words(),
	"alignment " SIZE_FORMAT " too large", end_alignment_in_bytes);
	assert(is_aligned(end_alignment_in_bytes, HeapWordSize),
	"alignment " SIZE_FORMAT " is not HeapWord (%u) aligned", end_alignment_in_bytes, HeapWordSize);

	// If we've allocated nothing, simply return.
	if (_allocation_region == NULL) {
	return;
	}

	// If an end alignment was requested, insert filler objects.
	if (end_alignment_in_bytes != 0) {
	HeapWord* currtop = _allocation_region->top();
	HeapWord* newtop = align_up(currtop, end_alignment_in_bytes);
	size_t fill_size = pointer_delta(newtop, currtop);
	if (fill_size != 0) {
	if (fill_size < CollectedHeap::min_fill_size()) {
	// If the required fill is smaller than we can represent,
	// bump up to the next aligned address. We know we won't exceed the current
	// region boundary because the max supported alignment is smaller than the min
	// region size, and because the allocation code never leaves space smaller than
	// the min_fill_size at the top of the current allocation region.
	newtop = align_up(currtop + CollectedHeap::min_fill_size(),
	end_alignment_in_bytes);
	fill_size = pointer_delta(newtop, currtop);
	}
	HeapWord* fill = archive_mem_allocate(fill_size);
	CollectedHeap::fill_with_objects(fill, fill_size);
	}
	}

	// Loop through the allocated regions, and create MemRegions summarizing
	// the allocated address range, combining contiguous ranges. Add the
	// MemRegions to the GrowableArray provided by the caller.
	int index = _allocated_regions.length() - 1;
	assert(_allocated_regions.at(index) == _allocation_region,
	"expected region %u at end of array, found %u",
	_allocation_region->hrm_index(), _allocated_regions.at(index)->hrm_index());
	HeapWord* base_address = _allocation_region->bottom();
	HeapWord* top = base_address;

	while (index >= 0) {
	HeapRegion* next = _allocated_regions.at(index);
	HeapWord* new_base = next->bottom();
	HeapWord* new_top = next->top();
	if (new_base != top) {
	ranges->append(MemRegion(base_address, pointer_delta(top, base_address)));
	base_address = new_base;
	}
	top = new_top;
	index = index - 1;
	}

	assert(top != base_address, "zero-sized range, address " PTR_FORMAT, p2i(base_address));
	ranges->append(MemRegion(base_address, pointer_delta(top, base_address)));
	_allocated_regions.clear();
	_allocation_region = NULL;
	};