/*

 * Copyright (c) 2001, 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.

 *

 */

#ifndef SHARE_VM_GC_G1_CONCURRENTMARK_INLINE_HPP

#define SHARE_VM_GC_G1_CONCURRENTMARK_INLINE_HPP

#include "gc/g1/concurrentMark.hpp"

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

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

// Utility routine to set an exclusive range of cards on the given

// card liveness bitmap

inline void ConcurrentMark::set_card_bitmap_range(BitMap* card_bm,

                                                  BitMap::idx_t start_idx,

                                                  BitMap::idx_t end_idx,

                                                  bool is_par) {

  // Set the exclusive bit range [start_idx, end_idx).

  assert((end_idx - start_idx) > 0, "at least one card");

  assert(end_idx <= card_bm->size(), "sanity");

  // Silently clip the end index

  end_idx = MIN2(end_idx, card_bm->size());

  // For small ranges use a simple loop; otherwise use set_range or

  // use par_at_put_range (if parallel). The range is made up of the

  // cards that are spanned by an object/mem region so 8 cards will

  // allow up to object sizes up to 4K to be handled using the loop.

  if ((end_idx - start_idx) <= 8) {

    for (BitMap::idx_t i = start_idx; i < end_idx; i += 1) {

      if (is_par) {

        card_bm->par_set_bit(i);

      } else {

        card_bm->set_bit(i);

      }

    }

  } else {

    // Note BitMap::par_at_put_range() and BitMap::set_range() are exclusive.

    if (is_par) {

      card_bm->par_at_put_range(start_idx, end_idx, true);

    } else {

      card_bm->set_range(start_idx, end_idx);

    }

  }

}

// Returns the index in the liveness accounting card bitmap

// for the given address

inline BitMap::idx_t ConcurrentMark::card_bitmap_index_for(HeapWord* addr) {

  // Below, the term "card num" means the result of shifting an address

  // by the card shift -- address 0 corresponds to card number 0.  One

  // must subtract the card num of the bottom of the heap to obtain a

  // card table index.

  intptr_t card_num = intptr_t(uintptr_t(addr) >> CardTableModRefBS::card_shift);

  return card_num - heap_bottom_card_num();

}

// Counts the given memory region in the given task/worker

// counting data structures.

inline void ConcurrentMark::count_region(MemRegion mr, HeapRegion* hr,

                                         size_t* marked_bytes_array,

                                         BitMap* task_card_bm) {

  G1CollectedHeap* g1h = _g1h;

  CardTableModRefBS* ct_bs = g1h->g1_barrier_set();

  HeapWord* start = mr.start();

  HeapWord* end = mr.end();

  size_t region_size_bytes = mr.byte_size();

  uint index = hr->hrm_index();

  assert(!hr->is_continues_humongous(), "should not be HC region");

  assert(hr == g1h->heap_region_containing(start), "sanity");

  assert(hr == g1h->heap_region_containing(mr.last()), "sanity");

  assert(marked_bytes_array != NULL, "pre-condition");

  assert(task_card_bm != NULL, "pre-condition");

  // Add to the task local marked bytes for this region.

  marked_bytes_array[index] += region_size_bytes;

  BitMap::idx_t start_idx = card_bitmap_index_for(start);

  BitMap::idx_t end_idx = card_bitmap_index_for(end);

  // Note: if we're looking at the last region in heap - end

  // could be actually just beyond the end of the heap; end_idx

  // will then correspond to a (non-existent) card that is also

  // just beyond the heap.

  if (g1h->is_in_g1_reserved(end) && !ct_bs->is_card_aligned(end)) {

    // end of region is not card aligned - increment to cover

    // all the cards spanned by the region.

    end_idx += 1;

  }

  // The card bitmap is task/worker specific => no need to use

  // the 'par' BitMap routines.

  // Set bits in the exclusive bit range [start_idx, end_idx).

  set_card_bitmap_range(task_card_bm, start_idx, end_idx, false /* is_par */);

}

// Counts the given memory region in the task/worker counting

// data structures for the given worker id.

inline void ConcurrentMark::count_region(MemRegion mr,

                                         HeapRegion* hr,

                                         uint worker_id) {

  size_t* marked_bytes_array = count_marked_bytes_array_for(worker_id);

  BitMap* task_card_bm = count_card_bitmap_for(worker_id);

  count_region(mr, hr, marked_bytes_array, task_card_bm);

}

// Counts the given object in the given task/worker counting data structures.

inline void ConcurrentMark::count_object(oop obj,

                                         HeapRegion* hr,

                                         size_t* marked_bytes_array,

                                         BitMap* task_card_bm) {

  MemRegion mr((HeapWord*)obj, obj->size());

  count_region(mr, hr, marked_bytes_array, task_card_bm);

}

// Attempts to mark the given object and, if successful, counts

// the object in the given task/worker counting structures.

inline bool ConcurrentMark::par_mark_and_count(oop obj,

                                               HeapRegion* hr,

                                               size_t* marked_bytes_array,

                                               BitMap* task_card_bm) {

  HeapWord* addr = (HeapWord*)obj;

  if (_nextMarkBitMap->parMark(addr)) {

    // Update the task specific count data for the object.

    count_object(obj, hr, marked_bytes_array, task_card_bm);

    return true;

  }

  return false;

}

// Attempts to mark the given object and, if successful, counts

// the object in the task/worker counting structures for the

// given worker id.

inline bool ConcurrentMark::par_mark_and_count(oop obj,

                                               size_t word_size,

                                               HeapRegion* hr,

                                               uint worker_id) {

  HeapWord* addr = (HeapWord*)obj;

  if (_nextMarkBitMap->parMark(addr)) {

    MemRegion mr(addr, word_size);

    count_region(mr, hr, worker_id);

    return true;

  }

  return false;

}

inline bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) {

  HeapWord* start_addr = MAX2(startWord(), mr.start());

  HeapWord* end_addr = MIN2(endWord(), mr.end());

  if (end_addr > start_addr) {

    // Right-open interval [start-offset, end-offset).

    BitMap::idx_t start_offset = heapWordToOffset(start_addr);

    BitMap::idx_t end_offset = heapWordToOffset(end_addr);

    start_offset = _bm.get_next_one_offset(start_offset, end_offset);

    while (start_offset < end_offset) {

      if (!cl->do_bit(start_offset)) {

        return false;

      }

      HeapWord* next_addr = MIN2(nextObject(offsetToHeapWord(start_offset)), end_addr);

      BitMap::idx_t next_offset = heapWordToOffset(next_addr);

      start_offset = _bm.get_next_one_offset(next_offset, end_offset);

    }

  }

  return true;

}

inline bool CMBitMapRO::iterate(BitMapClosure* cl) {

  MemRegion mr(startWord(), sizeInWords());

  return iterate(cl, mr);

}

#define check_mark(addr)                                                       \

  assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize),      \

         "outside underlying space?");                                         \

  assert(G1CollectedHeap::heap()->is_in_exact(addr),                           \

         err_msg("Trying to access not available bitmap " PTR_FORMAT           \

                 " corresponding to " PTR_FORMAT " (%u)",                      \

                 p2i(this), p2i(addr), G1CollectedHeap::heap()->addr_to_region(addr)));

inline void CMBitMap::mark(HeapWord* addr) {

  check_mark(addr);

  _bm.set_bit(heapWordToOffset(addr));

}

inline void CMBitMap::clear(HeapWord* addr) {

  check_mark(addr);

  _bm.clear_bit(heapWordToOffset(addr));

}

inline bool CMBitMap::parMark(HeapWord* addr) {

  check_mark(addr);

  return _bm.par_set_bit(heapWordToOffset(addr));

}

inline bool CMBitMap::parClear(HeapWord* addr) {

  check_mark(addr);

  return _bm.par_clear_bit(heapWordToOffset(addr));

}

#undef check_mark

inline void CMTask::push(oop obj) {

  HeapWord* objAddr = (HeapWord*) obj;

  assert(_g1h->is_in_g1_reserved(objAddr), "invariant");

  assert(!_g1h->is_on_master_free_list(

              _g1h->heap_region_containing((HeapWord*) objAddr)), "invariant");

  assert(!_g1h->is_obj_ill(obj), "invariant");

  assert(_nextMarkBitMap->isMarked(objAddr), "invariant");

  if (_cm->verbose_high()) {

    gclog_or_tty->print_cr("[%u] pushing " PTR_FORMAT, _worker_id, p2i((void*) obj));

  }

  if (!_task_queue->push(obj)) {

    // The local task queue looks full. We need to push some entries

    // to the global stack.

    if (_cm->verbose_medium()) {

      gclog_or_tty->print_cr("[%u] task queue overflow, "

                             "moving entries to the global stack",

                             _worker_id);

    }

    move_entries_to_global_stack();

    // this should succeed since, even if we overflow the global

    // stack, we should have definitely removed some entries from the

    // local queue. So, there must be space on it.

    bool success = _task_queue->push(obj);

    assert(success, "invariant");

  }

  statsOnly( size_t tmp_size = (size_t)_task_queue->size();

             if (tmp_size > _local_max_size) {

               _local_max_size = tmp_size;

             }

             ++_local_pushes );

}

inline bool CMTask::is_below_finger(oop obj, HeapWord* global_finger) const {

  // If obj is above the global finger, then the mark bitmap scan

  // will find it later, and no push is needed.  Similarly, if we have

  // a current region and obj is between the local finger and the

  // end of the current region, then no push is needed.  The tradeoff

  // of checking both vs only checking the global finger is that the

  // local check will be more accurate and so result in fewer pushes,

  // but may also be a little slower.

  HeapWord* objAddr = (HeapWord*)obj;

  if (_finger != NULL) {

    // We have a current region.

    // Finger and region values are all NULL or all non-NULL.  We

    // use _finger to check since we immediately use its value.

    assert(_curr_region != NULL, "invariant");

    assert(_region_limit != NULL, "invariant");

    assert(_region_limit <= global_finger, "invariant");

    // True if obj is less than the local finger, or is between

    // the region limit and the global finger.

    if (objAddr < _finger) {

      return true;

    } else if (objAddr < _region_limit) {

      return false;

    } // Else check global finger.

  }

  // Check global finger.

  return objAddr < global_finger;

}

inline void CMTask::make_reference_grey(oop obj, HeapRegion* hr) {

  if (_cm->par_mark_and_count(obj, hr, _marked_bytes_array, _card_bm)) {

    if (_cm->verbose_high()) {

      gclog_or_tty->print_cr("[%u] marked object " PTR_FORMAT,

                             _worker_id, p2i(obj));

    }

    // No OrderAccess:store_load() is needed. It is implicit in the

    // CAS done in CMBitMap::parMark() call in the routine above.

    HeapWord* global_finger = _cm->finger();

    // We only need to push a newly grey object on the mark

    // stack if it is in a section of memory the mark bitmap

    // scan has already examined.  Mark bitmap scanning

    // maintains progress "fingers" for determining that.

    //

    // Notice that the global finger might be moving forward

    // concurrently. This is not a problem. In the worst case, we

    // mark the object while it is above the global finger and, by

    // the time we read the global finger, it has moved forward

    // past this object. In this case, the object will probably

    // be visited when a task is scanning the region and will also

    // be pushed on the stack. So, some duplicate work, but no

    // correctness problems.

    if (is_below_finger(obj, global_finger)) {

      if (obj->is_typeArray()) {

        // Immediately process arrays of primitive types, rather

        // than pushing on the mark stack.  This keeps us from

        // adding humongous objects to the mark stack that might

        // be reclaimed before the entry is processed - see

        // selection of candidates for eager reclaim of humongous

        // objects.  The cost of the additional type test is

        // mitigated by avoiding a trip through the mark stack,

        // by only doing a bookkeeping update and avoiding the

        // actual scan of the object - a typeArray contains no

        // references, and the metadata is built-in.

        process_grey_object<false>(obj);

      } else {

        if (_cm->verbose_high()) {

          gclog_or_tty->print_cr("[%u] below a finger (local: " PTR_FORMAT

                                 ", global: " PTR_FORMAT ") pushing "

                                 PTR_FORMAT " on mark stack",

                                 _worker_id, p2i(_finger),

                                 p2i(global_finger), p2i(obj));

        }

        push(obj);

      }

    }

  }

}

inline void CMTask::deal_with_reference(oop obj) {

  if (_cm->verbose_high()) {

    gclog_or_tty->print_cr("[%u] we're dealing with reference = " PTR_FORMAT,

                           _worker_id, p2i((void*) obj));

  }

  increment_refs_reached();

  HeapWord* objAddr = (HeapWord*) obj;

  assert(obj->is_oop_or_null(true /* ignore mark word */), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(obj)));

  if (_g1h->is_in_g1_reserved(objAddr)) {

    assert(obj != NULL, "null check is implicit");

    if (!_nextMarkBitMap->isMarked(objAddr)) {

      // Only get the containing region if the object is not marked on the

      // bitmap (otherwise, it's a waste of time since we won't do

      // anything with it).

      HeapRegion* hr = _g1h->heap_region_containing_raw(obj);

      if (!hr->obj_allocated_since_next_marking(obj)) {

        make_reference_grey(obj, hr);

      }

    }

  }

}

inline void ConcurrentMark::markPrev(oop p) {

  assert(!_prevMarkBitMap->isMarked((HeapWord*) p), "sanity");

  // Note we are overriding the read-only view of the prev map here, via

  // the cast.

  ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p);

}

inline void ConcurrentMark::grayRoot(oop obj, size_t word_size,

                                     uint worker_id, HeapRegion* hr) {

  assert(obj != NULL, "pre-condition");

  HeapWord* addr = (HeapWord*) obj;

  if (hr == NULL) {

    hr = _g1h->heap_region_containing_raw(addr);

  } else {

    assert(hr->is_in(addr), "pre-condition");

  }

  assert(hr != NULL, "sanity");

  // Given that we're looking for a region that contains an object

  // header it's impossible to get back a HC region.

  assert(!hr->is_continues_humongous(), "sanity");

  // We cannot assert that word_size == obj->size() given that obj

  // might not be in a consistent state (another thread might be in

  // the process of copying it). So the best thing we can do is to

  // assert that word_size is under an upper bound which is its

  // containing region's capacity.

  assert(word_size * HeapWordSize <= hr->capacity(),

         err_msg("size: " SIZE_FORMAT " capacity: " SIZE_FORMAT " " HR_FORMAT,

                 word_size * HeapWordSize, hr->capacity(),

                 HR_FORMAT_PARAMS(hr)));

  if (addr < hr->next_top_at_mark_start()) {

    if (!_nextMarkBitMap->isMarked(addr)) {

      par_mark_and_count(obj, word_size, hr, worker_id);

    }

  }

}

#endif // SHARE_VM_GC_G1_CONCURRENTMARK_INLINE_HPP