/*

 * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved.

 *

 * 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 "memory/allocation.hpp"

#include "gc/shenandoah/shenandoahHeapRegionSet.inline.hpp"

#include "gc/shenandoah/shenandoahHeap.inline.hpp"

#include "gc/shenandoah/shenandoahHeapRegion.hpp"

#include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"

#include "gc/shenandoah/shenandoahTraversalGC.hpp"

#include "gc/shared/space.inline.hpp"

#include "memory/iterator.inline.hpp"

#include "memory/resourceArea.hpp"

#include "memory/universe.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/java.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/os.hpp"

#include "runtime/safepoint.hpp"

size_t ShenandoahHeapRegion::RegionCount = 0;

size_t ShenandoahHeapRegion::RegionSizeBytes = 0;

size_t ShenandoahHeapRegion::RegionSizeWords = 0;

size_t ShenandoahHeapRegion::RegionSizeBytesShift = 0;

size_t ShenandoahHeapRegion::RegionSizeWordsShift = 0;

size_t ShenandoahHeapRegion::RegionSizeBytesMask = 0;

size_t ShenandoahHeapRegion::RegionSizeWordsMask = 0;

size_t ShenandoahHeapRegion::HumongousThresholdBytes = 0;

size_t ShenandoahHeapRegion::HumongousThresholdWords = 0;

size_t ShenandoahHeapRegion::MaxTLABSizeBytes = 0;

size_t ShenandoahHeapRegion::MaxTLABSizeWords = 0;

ShenandoahHeapRegion::PaddedAllocSeqNum ShenandoahHeapRegion::_alloc_seq_num;

ShenandoahHeapRegion::ShenandoahHeapRegion(ShenandoahHeap* heap, HeapWord* start,

                                           size_t size_words, size_t index, bool committed) :

  _heap(heap),

  _reserved(MemRegion(start, size_words)),

  _region_number(index),

  _new_top(NULL),

  _critical_pins(0),

  _empty_time(os::elapsedTime()),

  _state(committed ? _empty_committed : _empty_uncommitted),

  _tlab_allocs(0),

  _gclab_allocs(0),

  _shared_allocs(0),

  _seqnum_first_alloc_mutator(0),

  _seqnum_first_alloc_gc(0),

  _seqnum_last_alloc_mutator(0),

  _seqnum_last_alloc_gc(0),

  _live_data(0) {

  ContiguousSpace::initialize(_reserved, true, committed);

}

size_t ShenandoahHeapRegion::region_number() const {

  return _region_number;

}

void ShenandoahHeapRegion::report_illegal_transition(const char *method) {

  ResourceMark rm;

  stringStream ss;

  ss.print("Illegal region state transition from \"%s\", at %s\n  ", region_state_to_string(_state), method);

  print_on(&ss);

  fatal("%s", ss.as_string());

}

void ShenandoahHeapRegion::make_regular_allocation() {

  _heap->assert_heaplock_owned_by_current_thread();

  switch (_state) {

    case _empty_uncommitted:

      do_commit();

    case _empty_committed:

      _state = _regular;

    case _regular:

    case _pinned:

      return;

    default:

      report_illegal_transition("regular allocation");

  }

}

void ShenandoahHeapRegion::make_regular_bypass() {

  _heap->assert_heaplock_owned_by_current_thread();

  assert (_heap->is_full_gc_in_progress() || _heap->is_degenerated_gc_in_progress(),

          "only for full or degen GC");

  switch (_state) {

    case _empty_uncommitted:

      do_commit();

    case _empty_committed:

    case _cset:

    case _humongous_start:

    case _humongous_cont:

      _state = _regular;

      return;

    case _pinned_cset:

      _state = _pinned;

      return;

    case _regular:

    case _pinned:

      return;

    default:

      report_illegal_transition("regular bypass");

  }

}

void ShenandoahHeapRegion::make_humongous_start() {

  _heap->assert_heaplock_owned_by_current_thread();

  switch (_state) {

    case _empty_uncommitted:

      do_commit();

    case _empty_committed:

      _state = _humongous_start;

      return;

    default:

      report_illegal_transition("humongous start allocation");

  }

}

void ShenandoahHeapRegion::make_humongous_start_bypass() {

  _heap->assert_heaplock_owned_by_current_thread();

  assert (_heap->is_full_gc_in_progress(), "only for full GC");

  switch (_state) {

    case _empty_committed:

    case _regular:

    case _humongous_start:

    case _humongous_cont:

      _state = _humongous_start;

      return;

    default:

      report_illegal_transition("humongous start bypass");

  }

}

void ShenandoahHeapRegion::make_humongous_cont() {

  _heap->assert_heaplock_owned_by_current_thread();

  switch (_state) {

    case _empty_uncommitted:

      do_commit();

    case _empty_committed:

      _state = _humongous_cont;

      return;

    default:

      report_illegal_transition("humongous continuation allocation");

  }

}

void ShenandoahHeapRegion::make_humongous_cont_bypass() {

  _heap->assert_heaplock_owned_by_current_thread();

  assert (_heap->is_full_gc_in_progress(), "only for full GC");

  switch (_state) {

    case _empty_committed:

    case _regular:

    case _humongous_start:

    case _humongous_cont:

      _state = _humongous_cont;

      return;

    default:

      report_illegal_transition("humongous continuation bypass");

  }

}

void ShenandoahHeapRegion::make_pinned() {

  _heap->assert_heaplock_owned_by_current_thread();

  switch (_state) {

    case _regular:

      assert (_critical_pins == 0, "sanity");

      _state = _pinned;

    case _pinned_cset:

    case _pinned:

      _critical_pins++;

      return;

    case _humongous_start:

      assert (_critical_pins == 0, "sanity");

      _state = _pinned_humongous_start;

    case _pinned_humongous_start:

      _critical_pins++;

      return;

    case _cset:

      guarantee(_heap->cancelled_gc(), "only valid when evac has been cancelled");

      assert (_critical_pins == 0, "sanity");

      _state = _pinned_cset;

      _critical_pins++;

      return;

    default:

      report_illegal_transition("pinning");

  }

}

void ShenandoahHeapRegion::make_unpinned() {

  _heap->assert_heaplock_owned_by_current_thread();

  switch (_state) {

    case _pinned:

      assert (_critical_pins > 0, "sanity");

      _critical_pins--;

      if (_critical_pins == 0) {

        _state = _regular;

      }

      return;

    case _regular:

    case _humongous_start:

      assert (_critical_pins == 0, "sanity");

      return;

    case _pinned_cset:

      guarantee(_heap->cancelled_gc(), "only valid when evac has been cancelled");

      assert (_critical_pins > 0, "sanity");

      _critical_pins--;

      if (_critical_pins == 0) {

        _state = _cset;

      }

      return;

    case _pinned_humongous_start:

      assert (_critical_pins > 0, "sanity");

      _critical_pins--;

      if (_critical_pins == 0) {

        _state = _humongous_start;

      }

      return;

    default:

      report_illegal_transition("unpinning");

  }

}

void ShenandoahHeapRegion::make_cset() {

  _heap->assert_heaplock_owned_by_current_thread();

  switch (_state) {

    case _regular:

      _state = _cset;

    case _cset:

      return;

    default:

      report_illegal_transition("cset");

  }

}

void ShenandoahHeapRegion::make_trash() {

  _heap->assert_heaplock_owned_by_current_thread();

  switch (_state) {

    case _cset:

      // Reclaiming cset regions

    case _humongous_start:

    case _humongous_cont:

      // Reclaiming humongous regions

    case _regular:

      // Immediate region reclaim

      _state = _trash;

      return;

    default:

      report_illegal_transition("trashing");

  }

}

void ShenandoahHeapRegion::make_trash_immediate() {

  make_trash();

  // On this path, we know there are no marked objects in the region,

  // tell marking context about it to bypass bitmap resets.

  _heap->complete_marking_context()->reset_top_bitmap(this);

}

void ShenandoahHeapRegion::make_empty() {

  _heap->assert_heaplock_owned_by_current_thread();

  switch (_state) {

    case _trash:

      _state = _empty_committed;

      _empty_time = os::elapsedTime();

      return;

    default:

      report_illegal_transition("emptying");

  }

}

void ShenandoahHeapRegion::make_uncommitted() {

  _heap->assert_heaplock_owned_by_current_thread();

  switch (_state) {

    case _empty_committed:

      do_uncommit();

      _state = _empty_uncommitted;

      return;

    default:

      report_illegal_transition("uncommiting");

  }

}

void ShenandoahHeapRegion::make_committed_bypass() {

  _heap->assert_heaplock_owned_by_current_thread();

  assert (_heap->is_full_gc_in_progress(), "only for full GC");

  switch (_state) {

    case _empty_uncommitted:

      do_commit();

      _state = _empty_committed;

      return;

    default:

      report_illegal_transition("commit bypass");

  }

}

void ShenandoahHeapRegion::clear_live_data() {

  OrderAccess::release_store_fence<size_t>(&_live_data, 0);

}

void ShenandoahHeapRegion::reset_alloc_metadata() {

  _tlab_allocs = 0;

  _gclab_allocs = 0;

  _shared_allocs = 0;

  _seqnum_first_alloc_mutator = 0;

  _seqnum_last_alloc_mutator = 0;

  _seqnum_first_alloc_gc = 0;

  _seqnum_last_alloc_gc = 0;

}

void ShenandoahHeapRegion::reset_alloc_metadata_to_shared() {

  if (used() > 0) {

    _tlab_allocs = 0;

    _gclab_allocs = 0;

    _shared_allocs = used() >> LogHeapWordSize;

    uint64_t next = _alloc_seq_num.value++;

    _seqnum_first_alloc_mutator = next;

    _seqnum_last_alloc_mutator = next;

    _seqnum_first_alloc_gc = 0;

    _seqnum_last_alloc_gc = 0;

  } else {

    reset_alloc_metadata();

  }

}

size_t ShenandoahHeapRegion::get_shared_allocs() const {

  return _shared_allocs * HeapWordSize;

}

size_t ShenandoahHeapRegion::get_tlab_allocs() const {

  return _tlab_allocs * HeapWordSize;

}

size_t ShenandoahHeapRegion::get_gclab_allocs() const {

  return _gclab_allocs * HeapWordSize;

}

void ShenandoahHeapRegion::set_live_data(size_t s) {

  assert(Thread::current()->is_VM_thread(), "by VM thread");

  _live_data = (s >> LogHeapWordSize);

}

size_t ShenandoahHeapRegion::get_live_data_words() const {

  return OrderAccess::load_acquire(&_live_data);

}

size_t ShenandoahHeapRegion::get_live_data_bytes() const {

  return get_live_data_words() * HeapWordSize;

}

bool ShenandoahHeapRegion::has_live() const {

  return get_live_data_words() != 0;

}

size_t ShenandoahHeapRegion::garbage() const {

  assert(used() >= get_live_data_bytes(), "Live Data must be a subset of used() live: " SIZE_FORMAT " used: " SIZE_FORMAT,

         get_live_data_bytes(), used());

  size_t result = used() - get_live_data_bytes();

  return result;

}

void ShenandoahHeapRegion::print_on(outputStream* st) const {

  st->print("|");

  st->print(SIZE_FORMAT_W(5), this->_region_number);

  switch (_state) {

    case _empty_uncommitted:

      st->print("|EU ");

      break;

    case _empty_committed:

      st->print("|EC ");

      break;

    case _regular:

      st->print("|R  ");

      break;

    case _humongous_start:

      st->print("|H  ");

      break;

    case _pinned_humongous_start:

      st->print("|HP ");

      break;

    case _humongous_cont:

      st->print("|HC ");

      break;

    case _cset:

      st->print("|CS ");

      break;

    case _trash:

      st->print("|T  ");

      break;

    case _pinned:

      st->print("|P  ");

      break;

    case _pinned_cset:

      st->print("|CSP");

      break;

    default:

      ShouldNotReachHere();

  }

  st->print("|BTE " INTPTR_FORMAT_W(12) ", " INTPTR_FORMAT_W(12) ", " INTPTR_FORMAT_W(12),

            p2i(bottom()), p2i(top()), p2i(end()));

  st->print("|TAMS " INTPTR_FORMAT_W(12),

            p2i(_heap->marking_context()->top_at_mark_start(const_cast<ShenandoahHeapRegion*>(this))));

  st->print("|U " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(used()),                proper_unit_for_byte_size(used()));

  st->print("|T " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_tlab_allocs()),     proper_unit_for_byte_size(get_tlab_allocs()));

  st->print("|G " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_gclab_allocs()),    proper_unit_for_byte_size(get_gclab_allocs()));

  st->print("|S " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_shared_allocs()),   proper_unit_for_byte_size(get_shared_allocs()));

  st->print("|L " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_live_data_bytes()), proper_unit_for_byte_size(get_live_data_bytes()));

  st->print("|CP " SIZE_FORMAT_W(3), _critical_pins);

  st->print("|SN " UINT64_FORMAT_X_W(12) ", " UINT64_FORMAT_X_W(8) ", " UINT64_FORMAT_X_W(8) ", " UINT64_FORMAT_X_W(8),

            seqnum_first_alloc_mutator(), seqnum_last_alloc_mutator(),

            seqnum_first_alloc_gc(), seqnum_last_alloc_gc());

  st->cr();

}

void ShenandoahHeapRegion::oop_iterate(OopIterateClosure* blk) {

  if (!is_active()) return;

  if (is_humongous()) {

    oop_iterate_humongous(blk);

  } else {

    oop_iterate_objects(blk);

  }

}

void ShenandoahHeapRegion::oop_iterate_objects(OopIterateClosure* blk) {

  assert(! is_humongous(), "no humongous region here");

  HeapWord* t = top();

  // Could call objects iterate, but this is easier.

  while (obj_addr < t) {

    oop obj = oop(obj_addr);

  }

}

void ShenandoahHeapRegion::oop_iterate_humongous(OopIterateClosure* blk) {

  assert(is_humongous(), "only humongous region here");

  // Find head.

  ShenandoahHeapRegion* r = humongous_start_region();

  assert(r->is_humongous_start(), "need humongous head here");

  obj->oop_iterate(blk, MemRegion(bottom(), top()));

}

ShenandoahHeapRegion* ShenandoahHeapRegion::humongous_start_region() const {

  assert(is_humongous(), "Must be a part of the humongous region");

  size_t reg_num = region_number();

  ShenandoahHeapRegion* r = const_cast<ShenandoahHeapRegion*>(this);

  while (!r->is_humongous_start()) {

    assert(reg_num > 0, "Sanity");

    reg_num --;

    r = _heap->get_region(reg_num);

    assert(r->is_humongous(), "Must be a part of the humongous region");

  }

  assert(r->is_humongous_start(), "Must be");

  return r;

}

void ShenandoahHeapRegion::recycle() {

  ContiguousSpace::clear(false);

  if (ZapUnusedHeapArea) {

    ContiguousSpace::mangle_unused_area_complete();

  }

  clear_live_data();

  reset_alloc_metadata();

  _heap->marking_context()->reset_top_at_mark_start(this);

  make_empty();

}

HeapWord* ShenandoahHeapRegion::block_start_const(const void* p) const {

  assert(MemRegion(bottom(), end()).contains(p),

         "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")",

         p2i(p), p2i(bottom()), p2i(end()));

  if (p >= top()) {

    return top();

  } else {

    HeapWord* cur = last;

    while (cur <= p) {

      last = cur;

    }

    shenandoah_assert_correct(NULL, oop(last));

    return last;

  }

}

void ShenandoahHeapRegion::setup_sizes(size_t initial_heap_size, size_t max_heap_size) {

  // Absolute minimums we should not ever break.

  static const size_t MIN_REGION_SIZE = 256*K;

  if (FLAG_IS_DEFAULT(ShenandoahMinRegionSize)) {

    FLAG_SET_DEFAULT(ShenandoahMinRegionSize, MIN_REGION_SIZE);

  }

  size_t region_size;