/*

 * Copyright (c) 2014, 2015, 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/g1CollectedHeap.inline.hpp"

#include "gc/g1/g1CollectorPolicy.hpp"

#include "gc/g1/g1MarkSweep.hpp"

#include "gc/g1/heapRegion.inline.hpp"

#include "gc/g1/heapRegionSet.inline.hpp"

G1DefaultAllocator::G1DefaultAllocator(G1CollectedHeap* heap) :

  G1Allocator(heap),

  _retained_old_gc_alloc_region(NULL),

  _survivor_gc_alloc_region(heap->alloc_buffer_stats(InCSetState::Young)),

  _old_gc_alloc_region(heap->alloc_buffer_stats(InCSetState::Old)) {

}

void G1DefaultAllocator::init_mutator_alloc_region() {

  assert(_mutator_alloc_region.get() == NULL, "pre-condition");

  _mutator_alloc_region.init();

}

void G1DefaultAllocator::release_mutator_alloc_region() {

  _mutator_alloc_region.release();

  assert(_mutator_alloc_region.get() == NULL, "post-condition");

}

void G1Allocator::reuse_retained_old_region(EvacuationInfo& 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()) {

    retained_region->record_timestamp();

    // 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);

    bool during_im = _g1h->collector_state()->during_initial_mark_pause();

    retained_region->note_start_of_copying(during_im);

    old->set(retained_region);

    _g1h->hr_printer()->reuse(retained_region);

    evacuation_info.set_alloc_regions_used_before(retained_region->used());

  }

}

void G1DefaultAllocator::init_gc_alloc_regions(EvacuationInfo& evacuation_info) {

  assert_at_safepoint(true /* should_be_vm_thread */);

  _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 G1DefaultAllocator::release_gc_alloc_regions(EvacuationInfo& evacuation_info) {

  AllocationContext_t context = AllocationContext::current();

  evacuation_info.set_allocation_regions(survivor_gc_alloc_region(context)->count() +

                                         old_gc_alloc_region(context)->count());

  survivor_gc_alloc_region(context)->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(context)->release();

  if (_retained_old_gc_alloc_region != NULL) {

    _retained_old_gc_alloc_region->record_retained_region();

  }

}

void G1DefaultAllocator::abandon_gc_alloc_regions() {

  assert(survivor_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");

  assert(old_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");

  _retained_old_gc_alloc_region = NULL;

}

G1PLAB::G1PLAB(size_t gclab_word_size) :

  PLAB(gclab_word_size), _retired(true) { }

size_t G1Allocator::unsafe_max_tlab_alloc(AllocationContext_t context) {

  // 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(context)->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);

  }

}

HeapWord* G1Allocator::par_allocate_during_gc(InCSetState dest,

                                              size_t word_size,

                                              AllocationContext_t context) {

  size_t temp = 0;

  HeapWord* result = par_allocate_during_gc(dest, word_size, word_size, &temp, context);

  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(InCSetState dest,

                                              size_t min_word_size,

                                              size_t desired_word_size,

                                              size_t* actual_word_size,

                                              AllocationContext_t context) {

  switch (dest.value()) {

    case InCSetState::Young:

      return survivor_attempt_allocation(min_word_size, desired_word_size, actual_word_size, context);

    case InCSetState::Old:

      return old_attempt_allocation(min_word_size, desired_word_size, actual_word_size, context);

    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,

                                                   AllocationContext_t context) {

  assert(!_g1h->is_humongous(desired_word_size),

         "we should not be seeing humongous-size allocations in this path");

  HeapWord* result = survivor_gc_alloc_region(context)->attempt_allocation(min_word_size,

                                                                           desired_word_size,

                                                                           actual_word_size,

                                                                           false /* bot_updates */);

  if (result == NULL && !survivor_is_full(context)) {

    MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);

    result = survivor_gc_alloc_region(context)->attempt_allocation_locked(min_word_size,

                                                                          desired_word_size,

                                                                          actual_word_size,

                                                                          false /* bot_updates */);

    if (result == NULL) {

      set_survivor_full(context);

    }

  }

  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,

                                              AllocationContext_t context) {

  assert(!_g1h->is_humongous(desired_word_size),

         "we should not be seeing humongous-size allocations in this path");

  HeapWord* result = old_gc_alloc_region(context)->attempt_allocation(min_word_size,

                                                                      desired_word_size,

                                                                      actual_word_size,

                                                                      true /* bot_updates */);

  if (result == NULL && !old_is_full(context)) {

    MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);

    result = old_gc_alloc_region(context)->attempt_allocation_locked(min_word_size,

                                                                     desired_word_size,

                                                                     actual_word_size,

                                                                     true /* bot_updates */);

    if (result == NULL) {

      set_old_full(context);

    }

  }

  return result;

}

G1PLABAllocator::G1PLABAllocator(G1Allocator* allocator) :

  _g1h(G1CollectedHeap::heap()),

  _allocator(allocator),

  _survivor_alignment_bytes(calc_survivor_alignment_bytes()) {

  for (size_t i = 0; i < ARRAY_SIZE(_direct_allocated); i++) {

    _direct_allocated[i] = 0;

  }

}

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(InCSetState dest,

                                                       size_t word_sz,

                                                       AllocationContext_t context,

                                                       bool* plab_refill_failed) {

  size_t plab_word_size = G1CollectedHeap::heap()->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)) {

    G1PLAB* alloc_buf = alloc_buffer(dest, context);

    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,

                                                       context);

    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, context);

  if (result != NULL) {

    _direct_allocated[dest.value()] += word_sz;

  }

  return result;

}

void G1PLABAllocator::undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz, AllocationContext_t context) {

  alloc_buffer(dest, context)->undo_allocation(obj, word_sz);

}

G1DefaultPLABAllocator::G1DefaultPLABAllocator(G1Allocator* allocator) :

  G1PLABAllocator(allocator),

  _surviving_alloc_buffer(_g1h->desired_plab_sz(InCSetState::Young)),

  _tenured_alloc_buffer(_g1h->desired_plab_sz(InCSetState::Old)) {

  for (uint state = 0; state < InCSetState::Num; state++) {

    _alloc_buffers[state] = NULL;

  }

  _alloc_buffers[InCSetState::Young] = &_surviving_alloc_buffer;

  _alloc_buffers[InCSetState::Old]  = &_tenured_alloc_buffer;

}

void G1DefaultPLABAllocator::flush_and_retire_stats() {

  for (uint state = 0; state < InCSetState::Num; state++) {

    G1PLAB* 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;

    }

  }

}

void G1DefaultPLABAllocator::waste(size_t& wasted, size_t& undo_wasted) {

  wasted = 0;

  undo_wasted = 0;

  for (uint state = 0; state < InCSetState::Num; state++) {

    G1PLAB * const buf = _alloc_buffers[state];

    if (buf != NULL) {

      wasted += buf->waste();

      undo_wasted += buf->undo_waste();

    }

  }

}

G1ArchiveAllocator* G1ArchiveAllocator::create_allocator(G1CollectedHeap* g1h) {

  // 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);

  G1MarkSweep::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());

  hr->set_archive();

  _g1h->old_set_add(hr);

  _g1h->hr_printer()->alloc(hr, G1HRPrinter::Archive);

  _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.

  G1MarkSweep::set_range_archive(MemRegion(_bottom, HeapRegion::GrainWords), true);

  // 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_size_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 = (HeapWord*)align_pointer_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 = (HeapWord*)align_pointer_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;

};