1 /*

     2  * Copyright (c) 2001, 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 

    25 #ifndef SHARE_GC_CMS_CMSCARDTABLE_HPP

    26 #define SHARE_GC_CMS_CMSCARDTABLE_HPP

    27 

    28 #include "gc/shared/cardTableRS.hpp"

    29 #include "utilities/globalDefinitions.hpp"

    30 

    31 class DirtyCardToOopClosure;

    32 class MemRegion;

    33 class OopsInGenClosure;

    34 class Space;

    35 

    36 class CMSCardTable : public CardTableRS {

    37 private:

    38   // Returns the number of chunks necessary to cover "mr".

    39   size_t chunks_to_cover(MemRegion mr);

    40 

    41   // Returns the index of the chunk in a stride which

    42   // covers the given address.

    43   uintptr_t addr_to_chunk_index(const void* addr);

    44 

    45   // Initializes "lowest_non_clean" to point to the array for the region

    46   // covering "sp", and "lowest_non_clean_base_chunk_index" to the chunk

    47   // index of the corresponding to the first element of that array.

    48   // Ensures that these arrays are of sufficient size, allocating if necessary.

    49   // May be called by several threads concurrently.

    50   void get_LNC_array_for_space(Space* sp,

    51                                CardValue**& lowest_non_clean,

    52                                uintptr_t& lowest_non_clean_base_chunk_index,

    53                                size_t& lowest_non_clean_chunk_size);

    54 

    55   // Apply cl, which must either itself apply dcto_cl or be dcto_cl,

    56   // to the cards in the stride (of n_strides) within the given space.

    57   void process_stride(Space* sp,

    58                       MemRegion used,

    59                       jint stride, int n_strides,

    60                       OopsInGenClosure* cl,

    61                       CardTableRS* ct,

    62                       CardValue** lowest_non_clean,

    63                       uintptr_t lowest_non_clean_base_chunk_index,

    64                       size_t lowest_non_clean_chunk_size);

    65 

    66   // Makes sure that chunk boundaries are handled appropriately, by

    67   // adjusting the min_done of dcto_cl, and by using a special card-table

    68   // value to indicate how min_done should be set.

    69   void process_chunk_boundaries(Space* sp,

    70                                 DirtyCardToOopClosure* dcto_cl,

    71                                 MemRegion chunk_mr,

    72                                 MemRegion used,

    73                                 CardValue** lowest_non_clean,

    74                                 uintptr_t lowest_non_clean_base_chunk_index,

    75                                 size_t    lowest_non_clean_chunk_size);

    76 

    77   virtual void verify_used_region_at_save_marks(Space* sp) const NOT_DEBUG_RETURN;

    78 

    79 protected:

    80   // Work method used to implement non_clean_card_iterate_possibly_parallel()

    81   // above in the parallel case.

    82   virtual void non_clean_card_iterate_parallel_work(Space* sp, MemRegion mr,

    83                                                     OopsInGenClosure* cl, CardTableRS* ct,

    84                                                     uint n_threads);

    85 

    86 public:

    87   CMSCardTable(MemRegion whole_heap);

    88 };

    89 

    90 #endif // SHARE_GC_CMS_CMSCARDTABLE_HPP