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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.

  *

  * 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

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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> inline void G1ParScanThreadState::immediate_rs_update(HeapRegion* from, T* p, int tid) {

   if (!from->is_survivor()) {

     _g1_rem->par_write_ref(from, p, tid);

   }

 }

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

   if (G1DeferredRSUpdate) {

     deferred_rs_update(from, p, tid);

   } else {

     immediate_rs_update(from, p, tid);

   }

 }

 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 */