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dekker.one
1/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
2/*
3 * Main authors:
4 * Christian Schulte <schulte@gecode.org>
5 *
6 * Bugfixes provided by:
7 * Zandra Norman
8 *
9 * Copyright:
10 * Christian Schulte, 2008
11 *
12 * This file is part of Gecode, the generic constraint
13 * development environment:
14 * http://www.gecode.org
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining
17 * a copy of this software and associated documentation files (the
18 * "Software"), to deal in the Software without restriction, including
19 * without limitation the rights to use, copy, modify, merge, publish,
20 * distribute, sublicense, and/or sell copies of the Software, and to
21 * permit persons to whom the Software is furnished to do so, subject to
22 * the following conditions:
23 *
24 * The above copyright notice and this permission notice shall be
25 * included in all copies or substantial portions of the Software.
26 *
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
28 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
29 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
30 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
31 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
32 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
33 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
34 *
35 */
36
37#ifndef GECODE_FREELIST_SIZE_MAX32
38#define GECODE_FREELIST_SIZE_MAX32 3
39#endif
40#ifndef GECODE_FREELIST_SIZE_MAX64
41#define GECODE_FREELIST_SIZE_MAX64 3
42#endif
43
44namespace Gecode { namespace Kernel {
45
46 /**
47 * \brief Parameters defining memory management policy for spaces
48 * \ingroup FuncMemSpace
49 */
50 namespace MemoryConfig {
51 /**
52 * \brief How many heap chunks should be cached at most
53 */
54 const unsigned int n_hc_cache = 4*4;
55
56 /**
57 * \brief Minimal size of a heap chunk requested from the OS
58 */
59 const size_t hcsz_min = 1024;
60 /**
61 * \brief Maximal size of a heap chunk requested from the OS
62 *
63 * Maximal is not strictly true, if a contiguous memory chunk is
64 * requested that exceeds \a hcsz_max, a chunk will be allocated
65 * that fits that request.
66 */
67 const size_t hcsz_max = 32 * 1024;
68 /**
69 * \brief Increment ratio for chunk size
70 *
71 * If a space has requested \a hcsz_inc_ratio chunks of heap memory,
72 * the chunk size is doubled.
73 */
74 const int hcsz_inc_ratio = 8;
75 /**
76 * \brief Decrement ratio for chunk size
77 *
78 * When a space is cloned, the new clone normally inherits the
79 * current chunk size from the original space. However, if the
80 * original space has requested less than \a hcsz_dec_ratio
81 * heap chunks of the current chunk size, the current chunk size
82 * for the clone is halfed.
83 */
84 const int hcsz_dec_ratio = 8;
85
86 /**
87 * \brief Unit size for free lists
88 *
89 * The unit size (given as binary logarithm) defines how big
90 * a unit of memory for free lists is. Also, it defines the
91 * alignment. Sizes of free list objects must be multiples of
92 * the unit size.
93 *
94 * Currently, for 32 bit machines, the unit size is 4 bytes.
95 * For 64 bit machines, it is 8 bytes.
96 */
97 const int fl_unit_size = ((sizeof(void*) == 4) ? 2 : 3);
98 /**
99 * \brief Minimal size for free list element
100 *
101 * The minimal size is given in the number of free list units.
102 *
103 * Currently, for 32 bit machines, the minimal size is 8 bytes.
104 * For 64 bit machines, it is 16 bytes.
105 */
106 const int fl_size_min = ((sizeof(void*) == 4) ? 2 : 2);
107 /**
108 * \brief Maximal size for free list element
109 *
110 * The maximal size is given in the number of free list units.
111 *
112 * Currently, for 32 bit machines, the maximal size is 12 bytes.
113 * For 64 bit machines, it is 24 bytes.
114 */
115 const int fl_size_max = ((sizeof(void*) == 4) ? GECODE_FREELIST_SIZE_MAX32 : GECODE_FREELIST_SIZE_MAX64);
116 /**
117 * \brief Number of free lists elements to allocate
118 *
119 * When a request for a free list element can not be fulfilled, as
120 * the free list is empty and there is also no reusable memory
121 * available, allocate \a fl_refill free list elements.
122 */
123 const int fl_refill = 8;
124 /**
125 * \brief Memory alignment
126 *
127 * Memory alignment is controlled by the macro GECODE_MEMORY_ALIGNMENT.
128 * If it is not defined, it assumed to be 8. Otherwise, the defined
129 * value is used.
130 */
131#ifndef GECODE_MEMORY_ALIGNMENT
132#define GECODE_MEMORY_ALIGNMENT static_cast<size_t>(8U)
133#endif
134 /**
135 * \brief Size of region area
136 *
137 * The region area can be used in a stack fashion through access
138 * from a space. If the a request exceeds the current free space,
139 * memory will be allocated from the heap.
140 */
141 const size_t region_area_size = 32 * 1024;
142
143 /// Align size \a s to the required alignment \a a
144 void align(size_t& s, size_t a = GECODE_MEMORY_ALIGNMENT);
145
146 /*
147 * Alignment
148 *
149 */
150 forceinline void
151 align(size_t& s, size_t a) {
152 s += ((a - (s & (a - 1))) & (a - 1));
153 }
154
155 }
156
157}}
158
159// STATISTICS: kernel-memory