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 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * 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.

 *

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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP

#define SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP

#include "gc_implementation/g1/g1ParScanThreadState.hpp"

#include "gc_implementation/g1/g1RemSet.inline.hpp"

#include "oops/oop.inline.hpp"

template <class T> void G1ParScanThreadState::do_oop_evac(T* p, HeapRegion* from) {

  assert(!oopDesc::is_null(oopDesc::load_decode_heap_oop(p)),

         "Reference should not be NULL here as such are never pushed to the task queue.");

  oop obj = oopDesc::load_decode_heap_oop_not_null(p);

  // Although we never intentionally push references outside of the collection

  // set, due to (benign) races in the claim mechanism during RSet scanning more

  // than one thread might claim the same card. So the same card may be

  // processed multiple times. So redo this check.

  G1CollectedHeap::in_cset_state_t in_cset_state = _g1h->in_cset_state(obj);

  if (in_cset_state == G1CollectedHeap::InCSet) {

    oop forwardee;

    if (obj->is_forwarded()) {

      forwardee = obj->forwardee();

    } else {

      forwardee = copy_to_survivor_space(obj);

    }

    oopDesc::encode_store_heap_oop(p, forwardee);

  } else if (in_cset_state == G1CollectedHeap::IsHumongous) {

    _g1h->set_humongous_is_live(obj);

  } else {

    assert(in_cset_state == G1CollectedHeap::InNeither,

           err_msg("In_cset_state must be InNeither here, but is %d", in_cset_state));

  }

  assert(obj != NULL, "Must be");

  update_rs(from, p, queue_num());

}

inline void G1ParScanThreadState::do_oop_partial_array(oop* p) {

  assert(has_partial_array_mask(p), "invariant");

  oop from_obj = clear_partial_array_mask(p);

  assert(Universe::heap()->is_in_reserved(from_obj), "must be in heap.");

  assert(from_obj->is_objArray(), "must be obj array");

  objArrayOop from_obj_array = objArrayOop(from_obj);

  // The from-space object contains the real length.

  int length                 = from_obj_array->length();

  assert(from_obj->is_forwarded(), "must be forwarded");

  oop to_obj                 = from_obj->forwardee();

  assert(from_obj != to_obj, "should not be chunking self-forwarded objects");

  objArrayOop to_obj_array   = objArrayOop(to_obj);

  // We keep track of the next start index in the length field of the

  // to-space object.

  int next_index             = to_obj_array->length();

  assert(0 <= next_index && next_index < length,

         err_msg("invariant, next index: %d, length: %d", next_index, length));

  int start                  = next_index;

  int end                    = length;

  int remainder              = end - start;

  // We'll try not to push a range that's smaller than ParGCArrayScanChunk.

  if (remainder > 2 * ParGCArrayScanChunk) {

    end = start + ParGCArrayScanChunk;

    to_obj_array->set_length(end);

    // Push the remainder before we process the range in case another

    // worker has run out of things to do and can steal it.

    oop* from_obj_p = set_partial_array_mask(from_obj);

    push_on_queue(from_obj_p);

  } else {

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

    // We'll process the final range for this object. Restore the length

    // so that the heap remains parsable in case of evacuation failure.

    to_obj_array->set_length(end);

  }

  _scanner.set_region(_g1h->heap_region_containing_raw(to_obj));

  // Process indexes [start,end). It will also process the header

  // along with the first chunk (i.e., the chunk with start == 0).

  // Note that at this point the length field of to_obj_array is not

  // correct given that we are using it to keep track of the next

  // start index. oop_iterate_range() (thankfully!) ignores the length

  // field and only relies on the start / end parameters.  It does

  // however return the size of the object which will be incorrect. So

  // we have to ignore it even if we wanted to use it.

  to_obj_array->oop_iterate_range(&_scanner, start, end);

}

template <class T> inline void G1ParScanThreadState::deal_with_reference(T* ref_to_scan) {

  if (!has_partial_array_mask(ref_to_scan)) {

    // Note: we can use "raw" versions of "region_containing" because

    // "obj_to_scan" is definitely in the heap, and is not in a

    // humongous region.

    HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan);

    do_oop_evac(ref_to_scan, r);

  } else {

    do_oop_partial_array((oop*)ref_to_scan);

  }

}

inline void G1ParScanThreadState::dispatch_reference(StarTask ref) {

  assert(verify_task(ref), "sanity");

  if (ref.is_narrow()) {

    deal_with_reference((narrowOop*)ref);

  } else {

    deal_with_reference((oop*)ref);

  }

}

void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues) {

  StarTask stolen_task;

  while (task_queues->steal(queue_num(), hash_seed(), stolen_task)) {

    assert(verify_task(stolen_task), "sanity");

    dispatch_reference(stolen_task);

    // We've just processed a reference and we might have made

    // available new entries on the queues. So we have to make sure

    // we drain the queues as necessary.

    trim_queue();

  }

}

#endif /* SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP */