[176] | 1 | // -*- C++ -*- |
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| 2 | |
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| 3 | /* |
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| 4 | |
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| 5 | Heap Layers: An Extensible Memory Allocation Infrastructure |
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| 6 | |
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| 7 | Copyright (C) 2000-2003 by Emery Berger |
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| 8 | http://www.cs.umass.edu/~emery |
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| 9 | emery@cs.umass.edu |
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| 10 | |
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| 11 | This program is free software; you can redistribute it and/or modify |
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| 12 | it under the terms of the GNU General Public License as published by |
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| 13 | the Free Software Foundation; either version 2 of the License, or |
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| 14 | (at your option) any later version. |
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| 15 | |
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| 16 | This program is distributed in the hope that it will be useful, |
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| 17 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 19 | GNU General Public License for more details. |
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| 20 | |
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| 21 | You should have received a copy of the GNU General Public License |
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| 22 | along with this program; if not, write to the Free Software |
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| 23 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 24 | |
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| 25 | */ |
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| 26 | |
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| 27 | #ifndef _KINGSLEYHEAP_H_ |
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| 28 | #define _KINGSLEYHEAP_H_ |
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| 29 | |
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| 30 | #include "segheap.h" |
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| 31 | |
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| 32 | /** |
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| 33 | * @file kingsleyheap.h |
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| 34 | * @brief Classes to implement a Kingsley (power-of-two, segregated fits) allocator. |
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| 35 | */ |
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| 36 | |
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| 37 | /** |
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| 38 | * @namespace Kingsley |
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| 39 | * @brief Functions to implement KingsleyHeap. |
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| 40 | */ |
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| 41 | |
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| 42 | |
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| 43 | |
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| 44 | namespace Kingsley { |
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| 45 | |
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| 46 | size_t class2Size (const int i); |
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| 47 | |
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| 48 | #if defined(__sparc) && defined(__GNUC__) |
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| 49 | inline int popc (int v) { |
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| 50 | int r; |
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| 51 | asm volatile ("popc %1, %0" |
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| 52 | : "=r" (r) |
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| 53 | : "r" (v)); |
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| 54 | return r; |
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| 55 | } |
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| 56 | #endif |
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| 57 | |
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| 58 | /** |
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| 59 | * A speed optimization: |
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| 60 | * we use this array to quickly return the size class of objects |
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| 61 | * from 8 to 128 bytes. |
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| 62 | */ |
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| 63 | const int cl[16] = { 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4 }; |
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| 64 | |
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| 65 | inline int size2Class (const size_t sz) { |
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| 66 | #if defined(__sparc) && defined(__GNUC__) |
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| 67 | // Adapted from _Hacker's Delight_, by Henry Warren (p.80) |
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| 68 | size_t x = sz; |
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| 69 | x = x | (x >> 1); |
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| 70 | x = x | (x >> 2); |
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| 71 | x = x | (x >> 4); |
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| 72 | x = x | (x >> 8); |
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| 73 | x = x | (x >> 16); |
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| 74 | return popc(x) - 3; |
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| 75 | #else |
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| 76 | if (sz < 128 ) { |
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| 77 | assert (class2Size(cl[sz >> 3]) >= sz); |
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| 78 | return cl[(sz - 1) >> 3]; |
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| 79 | } else { |
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| 80 | // |
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| 81 | // We know that the object is more than 128 bytes long, |
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| 82 | // so we can avoid iterating 5 times. |
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| 83 | // |
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| 84 | int c = 5; |
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| 85 | size_t sz1 = ((sz - 1) >> 5); |
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| 86 | while (sz1 > 7) { |
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| 87 | sz1 >>= 1; |
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| 88 | c++; |
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| 89 | } |
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| 90 | assert (class2Size(c) >= sz); |
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| 91 | return c; |
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| 92 | } |
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| 93 | #endif |
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| 94 | |
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| 95 | } |
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| 96 | |
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| 97 | inline size_t class2Size (const int i) { |
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| 98 | return (size_t) (1 << (i+3)); |
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| 99 | } |
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| 100 | |
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| 101 | enum { NUMBINS = 29 }; |
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| 102 | |
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| 103 | }; |
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| 104 | |
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| 105 | /** |
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| 106 | * @class KingsleyHeap |
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| 107 | * @brief The Kingsley-style allocator. |
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| 108 | * @param PerClassHeap The heap to use for each size class. |
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| 109 | * @param BigHeap The heap for "large" objects. |
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| 110 | * @see Kingsley |
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| 111 | */ |
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| 112 | |
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| 113 | namespace HL { |
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| 114 | |
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| 115 | template <class PerClassHeap, class BigHeap> |
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| 116 | class KingsleyHeap : |
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| 117 | public StrictSegHeap<Kingsley::NUMBINS, |
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| 118 | Kingsley::size2Class, |
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| 119 | Kingsley::class2Size, |
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| 120 | PerClassHeap, |
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| 121 | BigHeap> {}; |
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| 122 | |
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| 123 | }; |
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| 124 | |
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| 125 | #endif |
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