1 /*

     2  * Copyright (c) 2019, SAP SE. All rights reserved.

     3  * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

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

     5  *

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

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

     8  * published by the Free Software Foundation.

     9  *

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

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

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

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

    14  * accompanied this code).

    15  *

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

    17  * 2 along with this work; if not, write to the Free Software Foundation,

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

    19  *

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

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

    22  * questions.

    23  *

    24  */

    25 

    26 #ifndef SHARE_MEMORY_METASPACE_CHUNKLEVEL_HPP

    27 #define SHARE_MEMORY_METASPACE_CHUNKLEVEL_HPP

    28 

    29 #include "utilities/globalDefinitions.hpp"

    30 

    31 // Constants for the chunk levels and some utility functions.

    32 

    33 class outputStream;

    34 

    35 namespace metaspace {

    36 

    37 // Metachunk level (must be signed)

    38 typedef signed char chklvl_t;

    39 

    40 #define CHKLVL_FORMAT "lv%.2d"

    41 

    42 // Chunks are managed by a binary buddy allocator.

    43 

    44 // Chunk sizes range from 1K to 4MB (64bit).

    45 //

    46 // Reasoning: .... TODO explain

    47 

    48 // Each chunk has a level; the level corresponds to its position in the tree

    49 // and describes its size.

    50 //

    51 // The largest chunks are called root chunks, of 4MB in size, and have level 0.

    52 // From there on it goes:

    53 //

    54 // size    level

    55 // 4MB     0

    56 // 2MB     1

    57 // 1MB     2

    58 // 512K    3

    59 // 256K    4

    60 // 128K    5

    61 // 64K     6

    62 // 32K     7

    63 // 16K     8

    64 // 8K      9

    65 // 4K      10

    66 // 2K      11

    67 // 1K      12

    68 

    69 namespace chklvl {

    70 

    71 static const size_t   MAX_CHUNK_BYTE_SIZE    = 4 * M;

    72 static const int      NUM_CHUNK_LEVELS       = 13;

    73 static const size_t   MIN_CHUNK_BYTE_SIZE    = (MAX_CHUNK_BYTE_SIZE >> (size_t)NUM_CHUNK_LEVELS);

    74 

    75 static const size_t   MIN_CHUNK_WORD_SIZE    = MIN_CHUNK_BYTE_SIZE / sizeof(MetaWord);

    76 static const size_t   MAX_CHUNK_WORD_SIZE    = MAX_CHUNK_BYTE_SIZE / sizeof(MetaWord);

    77 

    78 static const chklvl_t ROOT_CHUNK_LEVEL       = 0;

    79 

    80 static const chklvl_t HIGHEST_CHUNK_LEVEL    = NUM_CHUNK_LEVELS - 1;

    81 static const chklvl_t LOWEST_CHUNK_LEVEL     = 0;

    82 

    83 static const chklvl_t INVALID_CHUNK_LEVEL    = (chklvl_t) -1;

    84 

    85 inline bool is_valid_level(chklvl_t level) {

    86   return level >= LOWEST_CHUNK_LEVEL &&

    87          level <= HIGHEST_CHUNK_LEVEL;

    88 }

    89 

    90 inline void check_valid_level(chklvl_t lvl) {

    91   assert(is_valid_level(lvl), "invalid level (%d)", (int)lvl);

    92 }

    93 

    94 // Given a level return the chunk size, in words.

    95 inline size_t word_size_for_level(chklvl_t level) {

    96   check_valid_level(level);

    97   return (MAX_CHUNK_BYTE_SIZE >> level) / BytesPerWord;

    98 }

    99 

   100 // Given an arbitrary word size smaller than the highest chunk size,

   101 // return the highest chunk level able to hold this size.

   102 // Returns INVALID_CHUNK_LEVEL if no fitting level can be found.

   103 chklvl_t level_fitting_word_size(size_t word_size);

   104 

   105 // Shorthands to refer to exact sizes

   106 static const chklvl_t CHUNK_LEVEL_4M =     ROOT_CHUNK_LEVEL;

   107 static const chklvl_t CHUNK_LEVEL_2M =    (ROOT_CHUNK_LEVEL + 1);

   108 static const chklvl_t CHUNK_LEVEL_1M =    (ROOT_CHUNK_LEVEL + 2);

   109 static const chklvl_t CHUNK_LEVEL_512K =  (ROOT_CHUNK_LEVEL + 3);

   110 static const chklvl_t CHUNK_LEVEL_256K =  (ROOT_CHUNK_LEVEL + 4);

   111 static const chklvl_t CHUNK_LEVEL_128K =  (ROOT_CHUNK_LEVEL + 5);

   112 static const chklvl_t CHUNK_LEVEL_64K =   (ROOT_CHUNK_LEVEL + 6);

   113 static const chklvl_t CHUNK_LEVEL_32K =   (ROOT_CHUNK_LEVEL + 7);

   114 static const chklvl_t CHUNK_LEVEL_16K =   (ROOT_CHUNK_LEVEL + 8);

   115 static const chklvl_t CHUNK_LEVEL_8K =    (ROOT_CHUNK_LEVEL + 9);

   116 static const chklvl_t CHUNK_LEVEL_4K =    (ROOT_CHUNK_LEVEL + 10);

   117 static const chklvl_t CHUNK_LEVEL_2K =    (ROOT_CHUNK_LEVEL + 11);

   118 static const chklvl_t CHUNK_LEVEL_1K =    (ROOT_CHUNK_LEVEL + 12);

   119 

   120 STATIC_ASSERT(CHUNK_LEVEL_1K == HIGHEST_CHUNK_LEVEL);

   121 

   122 /////////////////////////////////////////////////////////

   123 // print helpers

   124 void print_chunk_size(outputStream* st, chklvl_t lvl);

   125 

   126 

   127 } // namespace chklvl

   128 

   129 } // namespace metaspace

   130 

   131 #endif // SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP