1 /*

     2  * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.

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

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  */

    23 

    24 #ifndef SHARE_GC_Z_ZREFERENCEPROCESSOR_HPP

    25 #define SHARE_GC_Z_ZREFERENCEPROCESSOR_HPP

    26 

    27 #include "gc/shared/referenceDiscoverer.hpp"

    28 #include "gc/z/zValue.hpp"

    29 

    30 class ReferencePolicy;

    31 class ZWorkers;

    32 

    33 class ZReferenceProcessor : public ReferenceDiscoverer {

    34   friend class ZReferenceProcessorTask;

    35 

    36 private:

    37   static const size_t reference_type_count = REF_PHANTOM + 1;

    38   typedef size_t Counters[reference_type_count];

    39 

    40   ZWorkers* const      _workers;

    41   ReferencePolicy*     _soft_reference_policy;

    42   ZPerWorker<Counters> _encountered_count;

    43   ZPerWorker<Counters> _discovered_count;

    44   ZPerWorker<Counters> _enqueued_count;

    45   ZPerWorker<oop>      _discovered_list;

    46   ZContended<oop>      _pending_list;

    47   oop*                 _pending_list_tail;

    48 

    49   void update_soft_reference_clock() const;

    50 

    51   ReferenceType reference_type(oop obj) const;

    52   const char* reference_type_name(ReferenceType type) const;

    53   volatile oop* reference_referent_addr(oop obj) const;

    54   oop reference_referent(oop obj) const;

    55   bool is_reference_inactive(oop obj) const;

    56   bool is_referent_alive_or_null(oop obj, ReferenceType type) const;

    57   bool is_referent_softly_alive(oop obj, ReferenceType type) const;

    58   bool should_drop_reference(oop obj, ReferenceType type) const;

    59   bool should_mark_referent(ReferenceType type) const;

    60   bool should_clear_referent(ReferenceType type) const;

    61   void keep_referent_alive(oop obj, ReferenceType type) const;

    62 

    63   void discover(oop obj, ReferenceType type);

    64   oop drop(oop obj, ReferenceType type);

    65   oop* keep(oop obj, ReferenceType type);

    66 

    67   bool is_empty() const;

    68 

    69   void work();

    70   void collect_statistics();

    71 

    72 public:

    73   ZReferenceProcessor(ZWorkers* workers);

    74 

    75   void set_soft_reference_policy(bool clear);

    76   void reset_statistics();

    77 

    78   virtual bool discover_reference(oop reference, ReferenceType type);

    79   void process_references();

    80   void enqueue_references();

    81 };

    82 

    83 #endif // SHARE_GC_Z_ZREFERENCEPROCESSOR_HPP