/*

 * Copyright (c) 2001, 2012, 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/g1/g1BlockOffsetTable.inline.hpp"

#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"

#include "gc_implementation/g1/g1OopClosures.inline.hpp"

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

#include "gc_implementation/g1/heapRegionRemSet.hpp"

#include "gc_implementation/g1/heapRegionSeq.inline.hpp"

#include "memory/genOopClosures.inline.hpp"

#include "memory/iterator.hpp"

#include "oops/oop.inline.hpp"

int    HeapRegion::LogOfHRGrainBytes = 0;

int    HeapRegion::LogOfHRGrainWords = 0;

size_t HeapRegion::GrainBytes        = 0;

size_t HeapRegion::GrainWords        = 0;

size_t HeapRegion::CardsPerRegion    = 0;

HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,

                                 HeapRegion* hr, ExtendedOopClosure* cl,

                                 CardTableModRefBS::PrecisionStyle precision,

                                 FilterKind fk) :

  ContiguousSpaceDCTOC(hr, cl, precision, NULL),

  _hr(hr), _fk(fk), _g1(g1) { }

FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,

                                                   OopClosure* oc) :

  _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }

class VerifyLiveClosure: public OopClosure {

private:

  G1CollectedHeap* _g1h;

  CardTableModRefBS* _bs;

  oop _containing_obj;

  bool _failures;

  int _n_failures;

  VerifyOption _vo;

public:

  // _vo == UsePrevMarking -> use "prev" marking information,

  // _vo == UseNextMarking -> use "next" marking information,

  // _vo == UseMarkWord    -> use mark word from object header.

  VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :

    _g1h(g1h), _bs(NULL), _containing_obj(NULL),

    _failures(false), _n_failures(0), _vo(vo)

  {

    BarrierSet* bs = _g1h->barrier_set();

    if (bs->is_a(BarrierSet::CardTableModRef))

      _bs = (CardTableModRefBS*)bs;

  }

  void set_containing_obj(oop obj) {

    _containing_obj = obj;

  }

  bool failures() { return _failures; }

  int n_failures() { return _n_failures; }

  virtual void do_oop(narrowOop* p) { do_oop_work(p); }

  virtual void do_oop(      oop* p) { do_oop_work(p); }

  void print_object(outputStream* out, oop obj) {

#ifdef PRODUCT

    Klass* k = obj->klass();

    const char* class_name = InstanceKlass::cast(k)->external_name();

    out->print_cr("class name %s", class_name);

#else // PRODUCT

    obj->print_on(out);

#endif // PRODUCT

  }

  template <class T>

  void do_oop_work(T* p) {

    assert(_containing_obj != NULL, "Precondition");

    assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),

           "Precondition");

    T heap_oop = oopDesc::load_heap_oop(p);

    if (!oopDesc::is_null(heap_oop)) {

      oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);

      bool failed = false;

      if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {

        MutexLockerEx x(ParGCRareEvent_lock,

                        Mutex::_no_safepoint_check_flag);

        if (!_failures) {

          gclog_or_tty->print_cr("");

          gclog_or_tty->print_cr("----------");

        }

        if (!_g1h->is_in_closed_subset(obj)) {

          HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);

          gclog_or_tty->print_cr("Field "PTR_FORMAT

                                 " of live obj "PTR_FORMAT" in region "

                                 "["PTR_FORMAT", "PTR_FORMAT")",

                                 p, (void*) _containing_obj,

                                 from->bottom(), from->end());

          print_object(gclog_or_tty, _containing_obj);

          gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",

                                 (void*) obj);

        } else {

          HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);

          HeapRegion* to   = _g1h->heap_region_containing((HeapWord*)obj);

          gclog_or_tty->print_cr("Field "PTR_FORMAT

                                 " of live obj "PTR_FORMAT" in region "

                                 "["PTR_FORMAT", "PTR_FORMAT")",

                                 p, (void*) _containing_obj,

                                 from->bottom(), from->end());

          print_object(gclog_or_tty, _containing_obj);

          gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "

                                 "["PTR_FORMAT", "PTR_FORMAT")",

                                 (void*) obj, to->bottom(), to->end());

          print_object(gclog_or_tty, obj);

        }

        gclog_or_tty->print_cr("----------");

        gclog_or_tty->flush();

        _failures = true;

        failed = true;

        _n_failures++;

      }

      if (!_g1h->full_collection() || G1VerifyRSetsDuringFullGC) {

        HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);

        HeapRegion* to   = _g1h->heap_region_containing(obj);

        if (from != NULL && to != NULL &&

            from != to &&

            !to->isHumongous()) {

          jbyte cv_obj = *_bs->byte_for_const(_containing_obj);

          jbyte cv_field = *_bs->byte_for_const(p);

          const jbyte dirty = CardTableModRefBS::dirty_card_val();

          bool is_bad = !(from->is_young()

                          || to->rem_set()->contains_reference(p)

                          || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed

                              (_containing_obj->is_objArray() ?

                                  cv_field == dirty

                               : cv_obj == dirty || cv_field == dirty));

          if (is_bad) {

            MutexLockerEx x(ParGCRareEvent_lock,

                            Mutex::_no_safepoint_check_flag);

            if (!_failures) {

              gclog_or_tty->print_cr("");

              gclog_or_tty->print_cr("----------");

            }

            gclog_or_tty->print_cr("Missing rem set entry:");

            gclog_or_tty->print_cr("Field "PTR_FORMAT" "

                                   "of obj "PTR_FORMAT", "

                                   "in region "HR_FORMAT,

                                   p, (void*) _containing_obj,

                                   HR_FORMAT_PARAMS(from));

            _containing_obj->print_on(gclog_or_tty);

            gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "

                                   "in region "HR_FORMAT,

                                   (void*) obj,

                                   HR_FORMAT_PARAMS(to));

            obj->print_on(gclog_or_tty);

            gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",

                          cv_obj, cv_field);

            gclog_or_tty->print_cr("----------");

            gclog_or_tty->flush();

            _failures = true;

            if (!failed) _n_failures++;

          }

        }

      }

    }

  }

};

template<class ClosureType>

HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,

                               HeapRegion* hr,

                               HeapWord* cur, HeapWord* top) {

  oop cur_oop = oop(cur);

  int oop_size = cur_oop->size();

  HeapWord* next_obj = cur + oop_size;

  while (next_obj < top) {

    // Keep filtering the remembered set.

    if (!g1h->is_obj_dead(cur_oop, hr)) {

      // Bottom lies entirely below top, so we can call the

      // non-memRegion version of oop_iterate below.

      cur_oop->oop_iterate(cl);

    }

    cur = next_obj;

    cur_oop = oop(cur);

    oop_size = cur_oop->size();

    next_obj = cur + oop_size;

  }

  return cur;

}

void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,

                                              HeapWord* bottom,

                                              HeapWord* top,

                                              ExtendedOopClosure* cl) {

  G1CollectedHeap* g1h = _g1;

  int oop_size;

  ExtendedOopClosure* cl2 = NULL;

  FilterIntoCSClosure intoCSFilt(this, g1h, cl);

  FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);

  switch (_fk) {

  case NoFilterKind:          cl2 = cl; break;

  case IntoCSFilterKind:      cl2 = &intoCSFilt; break;

  case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;

  default:                    ShouldNotReachHere();

  }

  // Start filtering what we add to the remembered set. If the object is

  // not considered dead, either because it is marked (in the mark bitmap)

  // or it was allocated after marking finished, then we add it. Otherwise

  // we can safely ignore the object.

  if (!g1h->is_obj_dead(oop(bottom), _hr)) {

    oop_size = oop(bottom)->oop_iterate(cl2, mr);

  } else {

    oop_size = oop(bottom)->size();

  }

  bottom += oop_size;

  if (bottom < top) {

    // We replicate the loop below for several kinds of possible filters.

    switch (_fk) {

    case NoFilterKind:

      bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);

      break;

    case IntoCSFilterKind: {

      FilterIntoCSClosure filt(this, g1h, cl);

      bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);

      break;

    }

    case OutOfRegionFilterKind: {

      FilterOutOfRegionClosure filt(_hr, cl);

      bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);

      break;

    }

    default:

      ShouldNotReachHere();

    }

    // Last object. Need to do dead-obj filtering here too.

    if (!g1h->is_obj_dead(oop(bottom), _hr)) {

      oop(bottom)->oop_iterate(cl2, mr);

    }

  }

}

// Minimum region size; we won't go lower than that.

// We might want to decrease this in the future, to deal with small

// heaps a bit more efficiently.

#define MIN_REGION_SIZE  (      1024 * 1024 )

// Maximum region size; we don't go higher than that. There's a good

// reason for having an upper bound. We don't want regions to get too

// large, otherwise cleanup's effectiveness would decrease as there

// will be fewer opportunities to find totally empty regions after

// marking.

#define MAX_REGION_SIZE  ( 32 * 1024 * 1024 )

// The automatic region size calculation will try to have around this

// many regions in the heap (based on the min heap size).

#define TARGET_REGION_NUMBER          2048

void HeapRegion::setup_heap_region_size(uintx min_heap_size) {

  // region_size in bytes

  uintx region_size = G1HeapRegionSize;

  if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {

    // We base the automatic calculation on the min heap size. This

    // can be problematic if the spread between min and max is quite

    // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on

    // the max size, the region size might be way too large for the

    // min size. Either way, some users might have to set the region

    // size manually for some -Xms / -Xmx combos.

    region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,

                       (uintx) MIN_REGION_SIZE);

  }

  int region_size_log = log2_long((jlong) region_size);

  // Recalculate the region size to make sure it's a power of

  // 2. This means that region_size is the largest power of 2 that's

  // <= what we've calculated so far.

  region_size = ((uintx)1 << region_size_log);

  // Now make sure that we don't go over or under our limits.

  if (region_size < MIN_REGION_SIZE) {

    region_size = MIN_REGION_SIZE;

  } else if (region_size > MAX_REGION_SIZE) {

    region_size = MAX_REGION_SIZE;

  }

  // And recalculate the log.

  region_size_log = log2_long((jlong) region_size);

  // Now, set up the globals.

  guarantee(LogOfHRGrainBytes == 0, "we should only set it once");

  LogOfHRGrainBytes = region_size_log;

  guarantee(LogOfHRGrainWords == 0, "we should only set it once");

  LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;

  guarantee(GrainBytes == 0, "we should only set it once");

  // The cast to int is safe, given that we've bounded region_size by

  // MIN_REGION_SIZE and MAX_REGION_SIZE.

  GrainBytes = (size_t)region_size;

  guarantee(GrainWords == 0, "we should only set it once");

  GrainWords = GrainBytes >> LogHeapWordSize;

  guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");

  guarantee(CardsPerRegion == 0, "we should only set it once");

  CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;

}

void HeapRegion::reset_after_compaction() {

  G1OffsetTableContigSpace::reset_after_compaction();

  // After a compaction the mark bitmap is invalid, so we must

  // treat all objects as being inside the unmarked area.

  zero_marked_bytes();

  init_top_at_mark_start();

}

void HeapRegion::hr_clear(bool par, bool clear_space) {

  assert(_humongous_type == NotHumongous,

         "we should have already filtered out humongous regions");

  assert(_humongous_start_region == NULL,

         "we should have already filtered out humongous regions");

  assert(_end == _orig_end,

         "we should have already filtered out humongous regions");

  _in_collection_set = false;

  set_young_index_in_cset(-1);

  uninstall_surv_rate_group();

  set_young_type(NotYoung);

  reset_pre_dummy_top();

  if (!par) {

    // If this is parallel, this will be done later.

    HeapRegionRemSet* hrrs = rem_set();

    if (hrrs != NULL) hrrs->clear();

    _claimed = InitialClaimValue;

  }

  zero_marked_bytes();

  _offsets.resize(HeapRegion::GrainWords);

  init_top_at_mark_start();

  if (clear_space) clear(SpaceDecorator::Mangle);

}

void HeapRegion::par_clear() {

  assert(used() == 0, "the region should have been already cleared");

  assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");

  HeapRegionRemSet* hrrs = rem_set();

  hrrs->clear();

  CardTableModRefBS* ct_bs =

                   (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();

  ct_bs->clear(MemRegion(bottom(), end()));

}

void HeapRegion::calc_gc_efficiency() {

  // GC efficiency is the ratio of how much space would be

  // reclaimed over how long we predict it would take to reclaim it.

  G1CollectedHeap* g1h = G1CollectedHeap::heap();

  G1CollectorPolicy* g1p = g1h->g1_policy();

  // Retrieve a prediction of the elapsed time for this region for

  // a mixed gc because the region will only be evacuated during a

  // mixed gc.

  double region_elapsed_time_ms =

    g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);

  _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;

}

void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {

  assert(!isHumongous(), "sanity / pre-condition");

  assert(end() == _orig_end,

         "Should be normal before the humongous object allocation");

  assert(top() == bottom(), "should be empty");

  assert(bottom() <= new_top && new_top <= new_end, "pre-condition");

  _humongous_type = StartsHumongous;

  _humongous_start_region = this;

  set_end(new_end);

  _offsets.set_for_starts_humongous(new_top);

}

void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {

  assert(!isHumongous(), "sanity / pre-condition");

  assert(end() == _orig_end,

         "Should be normal before the humongous object allocation");

  assert(top() == bottom(), "should be empty");

  assert(first_hr->startsHumongous(), "pre-condition");

  _humongous_type = ContinuesHumongous;

  _humongous_start_region = first_hr;

}

void HeapRegion::set_notHumongous() {

  assert(isHumongous(), "pre-condition");

  if (startsHumongous()) {

    assert(top() <= end(), "pre-condition");

    set_end(_orig_end);

    if (top() > end()) {

      // at least one "continues humongous" region after it

      set_top(end());

    }

  } else {

    // continues humongous

    assert(end() == _orig_end, "sanity");

  }

  assert(capacity() == HeapRegion::GrainBytes, "pre-condition");

  _humongous_type = NotHumongous;

  _humongous_start_region = NULL;

}

bool HeapRegion::claimHeapRegion(jint claimValue) {

  jint current = _claimed;

  if (current != claimValue) {

    jint res = Atomic::cmpxchg(claimValue, &_claimed, current);

    if (res == current) {

      return true;

    }

  }

  return false;

}

HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {

  HeapWord* low = addr;

  HeapWord* high = end();

  while (low < high) {

    size_t diff = pointer_delta(high, low);

    // Must add one below to bias toward the high amount.  Otherwise, if

  // "high" were at the desired value, and "low" were one less, we

    // would not converge on "high".  This is not symmetric, because

    // we set "high" to a block start, which might be the right one,

    // which we don't do for "low".

    HeapWord* middle = low + (diff+1)/2;

    if (middle == high) return high;

    HeapWord* mid_bs = block_start_careful(middle);

    if (mid_bs < addr) {

      low = middle;

    } else {

      high = mid_bs;

    }

  }

  assert(low == high && low >= addr, "Didn't work.");

  return low;

}

#ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away

#pragma warning( disable:4355 ) // 'this' : used in base member initializer list

#endif // _MSC_VER

HeapRegion::HeapRegion(uint hrs_index,

                       G1BlockOffsetSharedArray* sharedOffsetArray,

                       MemRegion mr) :

    G1OffsetTableContigSpace(sharedOffsetArray, mr),

    _hrs_index(hrs_index),

    _humongous_type(NotHumongous), _humongous_start_region(NULL),

    _in_collection_set(false),

    _next_in_special_set(NULL), _orig_end(NULL),

    _claimed(InitialClaimValue), _evacuation_failed(false),

    _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),

    _young_type(NotYoung), _next_young_region(NULL),

    _next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false),

#ifdef ASSERT

    _containing_set(NULL),

#endif // ASSERT

     _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),

    _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),

    _predicted_bytes_to_copy(0)

{

  _orig_end = mr.end();