1 /*

     2  * Copyright (c) 2015, 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 

    25 #ifndef SHARE_VM_GC_G1_YOUNGLIST_HPP

    26 #define SHARE_VM_GC_G1_YOUNGLIST_HPP

    27 

    28 #include "memory/allocation.hpp"

    29 #include "runtime/globals.hpp"

    30 

    31 class YoungList : public CHeapObj<mtGC> {

    32 private:

    33   G1CollectedHeap* _g1h;

    34 

    35   HeapRegion* _head;

    36 

    37   HeapRegion* _survivor_head;

    38   HeapRegion* _survivor_tail;

    39 

    40   HeapRegion* _curr;

    41 

    42   uint        _length;

    43   uint        _survivor_length;

    44 

    45   size_t      _last_sampled_rs_lengths;

    46   size_t      _sampled_rs_lengths;

    47 

    48   void         empty_list(HeapRegion* list);

    49 

    50 public:

    51   YoungList(G1CollectedHeap* g1h);

    52 

    53   void         push_region(HeapRegion* hr);

    54   void         add_survivor_region(HeapRegion* hr);

    55 

    56   void         empty_list();

    57   bool         is_empty() { return _length == 0; }

    58   uint         length() { return _length; }

    59   uint         eden_length() { return length() - survivor_length(); }

    60   uint         survivor_length() { return _survivor_length; }

    61 

    62   // Currently we do not keep track of the used byte sum for the

    63   // young list and the survivors and it'd be quite a lot of work to

    64   // do so. When we'll eventually replace the young list with

    65   // instances of HeapRegionLinkedList we'll get that for free. So,

    66   // we'll report the more accurate information then.

    67   size_t       eden_used_bytes() {

    68     assert(length() >= survivor_length(), "invariant");

    69     return (size_t) eden_length() * HeapRegion::GrainBytes;

    70   }

    71   size_t       survivor_used_bytes() {

    72     return (size_t) survivor_length() * HeapRegion::GrainBytes;

    73   }

    74 

    75   void rs_length_sampling_init();

    76   bool rs_length_sampling_more();

    77   void rs_length_sampling_next();

    78 

    79   void reset_sampled_info() {

    80     _last_sampled_rs_lengths =   0;

    81   }

    82   size_t sampled_rs_lengths() { return _last_sampled_rs_lengths; }

    83 

    84   // for development purposes

    85   void reset_auxilary_lists();

    86   void clear() { _head = NULL; _length = 0; }

    87 

    88   void clear_survivors() {

    89     _survivor_head    = NULL;

    90     _survivor_tail    = NULL;

    91     _survivor_length  = 0;

    92   }

    93 

    94   HeapRegion* first_region() { return _head; }

    95   HeapRegion* first_survivor_region() { return _survivor_head; }

    96   HeapRegion* last_survivor_region() { return _survivor_tail; }

    97 

    98   // debugging

    99   bool          check_list_well_formed();

   100   bool          check_list_empty(bool check_sample = true);

   101   void          print();

   102 };

   103 

   104 #endif // SHARE_VM_GC_G1_YOUNGLIST_HPP