/*

 * Copyright (c) 2001, 2017, 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_G1CONCURRENTMARK_INLINE_HPP

#define SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP

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

#include "gc/g1/g1ConcurrentMark.hpp"

#include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"

#include "gc/g1/g1ConcurrentMarkObjArrayProcessor.inline.hpp"

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

#include "utilities/bitMap.inline.hpp"

inline bool G1ConcurrentMark::mark_in_next_bitmap(oop const obj) {

  HeapRegion* const hr = _g1h->heap_region_containing(obj);

  return mark_in_next_bitmap(hr, obj);

}

inline bool G1ConcurrentMark::mark_in_next_bitmap(HeapRegion* const hr, oop const obj) {

  assert(hr != NULL, "just checking");

  assert(hr->is_in_reserved(obj), "Attempting to mark object at " PTR_FORMAT " that is not contained in the given region %u", p2i(obj), hr->hrm_index());

  if (hr->obj_allocated_since_next_marking(obj)) {

    return false;

  }

  // Some callers may have stale objects to mark above nTAMS after humongous reclaim.

  // Can't assert that this is a valid object at this point, since it might be in the process of being copied by another thread.

  assert(!hr->is_continues_humongous(), "Should not try to mark object " PTR_FORMAT " in Humongous continues region %u above nTAMS " PTR_FORMAT, p2i(obj), hr->hrm_index(), p2i(hr->next_top_at_mark_start()));

  HeapWord* const obj_addr = (HeapWord*)obj;

  // Dirty read to avoid CAS.

  if (_nextMarkBitMap->is_marked(obj_addr)) {

    return false;

  }

  return _nextMarkBitMap->par_mark(obj_addr);

}

#ifndef PRODUCT

template<typename Fn>

inline void G1CMMarkStack::iterate(Fn fn) const {

  assert_at_safepoint(true);

  size_t num_chunks = 0;

  TaskQueueEntryChunk* cur = _chunk_list;

  while (cur != NULL) {

    guarantee(num_chunks <= _chunks_in_chunk_list, "Found " SIZE_FORMAT " oop chunks which is more than there should be", num_chunks);

    for (size_t i = 0; i < EntriesPerChunk; ++i) {

      if (cur->data[i].is_null()) {

        break;

      }

      fn(cur->data[i]);

    }

    cur = cur->next;

    num_chunks++;

  }

}

#endif

// It scans an object and visits its children.

inline void G1CMTask::scan_task_entry(G1TaskQueueEntry task_entry) { process_grey_task_entry<true>(task_entry); }

inline void G1CMTask::push(G1TaskQueueEntry task_entry) {

  assert(task_entry.is_array_slice() || _g1h->is_in_g1_reserved(task_entry.obj()), "invariant");

  assert(task_entry.is_array_slice() || !_g1h->is_on_master_free_list(

              _g1h->heap_region_containing(task_entry.obj())), "invariant");

  assert(task_entry.is_array_slice() || !_g1h->is_obj_ill(task_entry.obj()), "invariant");  // FIXME!!!

  assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()), "invariant");

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

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

    // to the global stack.

    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(task_entry);

    assert(success, "invariant");

  }

}

inline bool G1CMTask::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;

}

template<bool scan>

inline void G1CMTask::process_grey_task_entry(G1TaskQueueEntry task_entry) {

  assert(scan || (task_entry.is_oop() && task_entry.obj()->is_typeArray()), "Skipping scan of grey non-typeArray");

  assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()),

         "Any stolen object should be a slice or marked");

  if (scan) {

    if (task_entry.is_array_slice()) {

      _words_scanned += _objArray_processor.process_slice(task_entry.slice());

    } else {

      oop obj = task_entry.obj();

      if (G1CMObjArrayProcessor::should_be_sliced(obj)) {

        _words_scanned += _objArray_processor.process_obj(obj);

      } else {

        _words_scanned += obj->oop_iterate_size(_cm_oop_closure);;

      }

    }

  }

  check_limits();

}

inline size_t G1CMTask::scan_objArray(objArrayOop obj, MemRegion mr) {

  obj->oop_iterate(_cm_oop_closure, mr);

  return mr.word_size();

}

inline void G1CMTask::make_reference_grey(oop obj) {

  if (!_cm->mark_in_next_bitmap(obj)) {

    return;

  }

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

  // CAS done in G1CMBitMap::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)) {

    G1TaskQueueEntry entry = G1TaskQueueEntry::from_oop(obj);

    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_task_entry<false>(entry);

    } else {

      push(entry);

    }

  }

}

inline void G1CMTask::deal_with_reference(oop obj) {

  increment_refs_reached();

  if (obj == NULL) {

    return;

  }

  make_reference_grey(obj);

}

inline void G1ConcurrentMark::markPrev(oop p) {

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

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

}

bool G1ConcurrentMark::isPrevMarked(oop p) const {

  assert(p != NULL && oopDesc::is_oop(p), "expected an oop");

  return _prevMarkBitMap->is_marked((HeapWord*)p);

}

inline bool G1ConcurrentMark::do_yield_check() {

  if (SuspendibleThreadSet::should_yield()) {

    SuspendibleThreadSet::yield();

    return true;

  } else {

    return false;

  }

}

#endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP