root / util / hbitmap.c @ 626187d8
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1 | e7c033c3 | Paolo Bonzini | /*
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2 | e7c033c3 | Paolo Bonzini | * Hierarchical Bitmap Data Type
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3 | e7c033c3 | Paolo Bonzini | *
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4 | e7c033c3 | Paolo Bonzini | * Copyright Red Hat, Inc., 2012
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5 | e7c033c3 | Paolo Bonzini | *
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6 | e7c033c3 | Paolo Bonzini | * Author: Paolo Bonzini <pbonzini@redhat.com>
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7 | e7c033c3 | Paolo Bonzini | *
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8 | e7c033c3 | Paolo Bonzini | * This work is licensed under the terms of the GNU GPL, version 2 or
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9 | e7c033c3 | Paolo Bonzini | * later. See the COPYING file in the top-level directory.
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10 | e7c033c3 | Paolo Bonzini | */
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11 | e7c033c3 | Paolo Bonzini | |
12 | e7c033c3 | Paolo Bonzini | #include <string.h> |
13 | e7c033c3 | Paolo Bonzini | #include <glib.h> |
14 | e7c033c3 | Paolo Bonzini | #include <assert.h> |
15 | e7c033c3 | Paolo Bonzini | #include "qemu/osdep.h" |
16 | e7c033c3 | Paolo Bonzini | #include "qemu/hbitmap.h" |
17 | e7c033c3 | Paolo Bonzini | #include "qemu/host-utils.h" |
18 | e7c033c3 | Paolo Bonzini | #include "trace.h" |
19 | e7c033c3 | Paolo Bonzini | |
20 | e7c033c3 | Paolo Bonzini | /* HBitmaps provides an array of bits. The bits are stored as usual in an
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21 | e7c033c3 | Paolo Bonzini | * array of unsigned longs, but HBitmap is also optimized to provide fast
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22 | e7c033c3 | Paolo Bonzini | * iteration over set bits; going from one bit to the next is O(logB n)
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23 | e7c033c3 | Paolo Bonzini | * worst case, with B = sizeof(long) * CHAR_BIT: the result is low enough
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24 | e7c033c3 | Paolo Bonzini | * that the number of levels is in fact fixed.
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25 | e7c033c3 | Paolo Bonzini | *
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26 | e7c033c3 | Paolo Bonzini | * In order to do this, it stacks multiple bitmaps with progressively coarser
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27 | e7c033c3 | Paolo Bonzini | * granularity; in all levels except the last, bit N is set iff the N-th
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28 | e7c033c3 | Paolo Bonzini | * unsigned long is nonzero in the immediately next level. When iteration
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29 | e7c033c3 | Paolo Bonzini | * completes on the last level it can examine the 2nd-last level to quickly
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30 | e7c033c3 | Paolo Bonzini | * skip entire words, and even do so recursively to skip blocks of 64 words or
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31 | e7c033c3 | Paolo Bonzini | * powers thereof (32 on 32-bit machines).
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32 | e7c033c3 | Paolo Bonzini | *
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33 | e7c033c3 | Paolo Bonzini | * Given an index in the bitmap, it can be split in group of bits like
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34 | e7c033c3 | Paolo Bonzini | * this (for the 64-bit case):
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35 | e7c033c3 | Paolo Bonzini | *
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36 | e7c033c3 | Paolo Bonzini | * bits 0-57 => word in the last bitmap | bits 58-63 => bit in the word
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37 | e7c033c3 | Paolo Bonzini | * bits 0-51 => word in the 2nd-last bitmap | bits 52-57 => bit in the word
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38 | e7c033c3 | Paolo Bonzini | * bits 0-45 => word in the 3rd-last bitmap | bits 46-51 => bit in the word
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39 | e7c033c3 | Paolo Bonzini | *
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40 | e7c033c3 | Paolo Bonzini | * So it is easy to move up simply by shifting the index right by
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41 | e7c033c3 | Paolo Bonzini | * log2(BITS_PER_LONG) bits. To move down, you shift the index left
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42 | e7c033c3 | Paolo Bonzini | * similarly, and add the word index within the group. Iteration uses
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43 | e7c033c3 | Paolo Bonzini | * ffs (find first set bit) to find the next word to examine; this
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44 | e7c033c3 | Paolo Bonzini | * operation can be done in constant time in most current architectures.
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45 | e7c033c3 | Paolo Bonzini | *
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46 | e7c033c3 | Paolo Bonzini | * Setting or clearing a range of m bits on all levels, the work to perform
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47 | e7c033c3 | Paolo Bonzini | * is O(m + m/W + m/W^2 + ...), which is O(m) like on a regular bitmap.
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48 | e7c033c3 | Paolo Bonzini | *
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49 | e7c033c3 | Paolo Bonzini | * When iterating on a bitmap, each bit (on any level) is only visited
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50 | e7c033c3 | Paolo Bonzini | * once. Hence, The total cost of visiting a bitmap with m bits in it is
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51 | e7c033c3 | Paolo Bonzini | * the number of bits that are set in all bitmaps. Unless the bitmap is
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52 | e7c033c3 | Paolo Bonzini | * extremely sparse, this is also O(m + m/W + m/W^2 + ...), so the amortized
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53 | e7c033c3 | Paolo Bonzini | * cost of advancing from one bit to the next is usually constant (worst case
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54 | e7c033c3 | Paolo Bonzini | * O(logB n) as in the non-amortized complexity).
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55 | e7c033c3 | Paolo Bonzini | */
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56 | e7c033c3 | Paolo Bonzini | |
57 | e7c033c3 | Paolo Bonzini | struct HBitmap {
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58 | e7c033c3 | Paolo Bonzini | /* Number of total bits in the bottom level. */
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59 | e7c033c3 | Paolo Bonzini | uint64_t size; |
60 | e7c033c3 | Paolo Bonzini | |
61 | e7c033c3 | Paolo Bonzini | /* Number of set bits in the bottom level. */
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62 | e7c033c3 | Paolo Bonzini | uint64_t count; |
63 | e7c033c3 | Paolo Bonzini | |
64 | e7c033c3 | Paolo Bonzini | /* A scaling factor. Given a granularity of G, each bit in the bitmap will
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65 | e7c033c3 | Paolo Bonzini | * will actually represent a group of 2^G elements. Each operation on a
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66 | e7c033c3 | Paolo Bonzini | * range of bits first rounds the bits to determine which group they land
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67 | e7c033c3 | Paolo Bonzini | * in, and then affect the entire page; iteration will only visit the first
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68 | e7c033c3 | Paolo Bonzini | * bit of each group. Here is an example of operations in a size-16,
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69 | e7c033c3 | Paolo Bonzini | * granularity-1 HBitmap:
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70 | e7c033c3 | Paolo Bonzini | *
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71 | e7c033c3 | Paolo Bonzini | * initial state 00000000
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72 | e7c033c3 | Paolo Bonzini | * set(start=0, count=9) 11111000 (iter: 0, 2, 4, 6, 8)
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73 | e7c033c3 | Paolo Bonzini | * reset(start=1, count=3) 00111000 (iter: 4, 6, 8)
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74 | e7c033c3 | Paolo Bonzini | * set(start=9, count=2) 00111100 (iter: 4, 6, 8, 10)
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75 | e7c033c3 | Paolo Bonzini | * reset(start=5, count=5) 00000000
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76 | e7c033c3 | Paolo Bonzini | *
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77 | e7c033c3 | Paolo Bonzini | * From an implementation point of view, when setting or resetting bits,
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78 | e7c033c3 | Paolo Bonzini | * the bitmap will scale bit numbers right by this amount of bits. When
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79 | e7c033c3 | Paolo Bonzini | * iterating, the bitmap will scale bit numbers left by this amount of
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80 | e7c033c3 | Paolo Bonzini | * bits.
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81 | e7c033c3 | Paolo Bonzini | */
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82 | e7c033c3 | Paolo Bonzini | int granularity;
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83 | e7c033c3 | Paolo Bonzini | |
84 | e7c033c3 | Paolo Bonzini | /* A number of progressively less coarse bitmaps (i.e. level 0 is the
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85 | e7c033c3 | Paolo Bonzini | * coarsest). Each bit in level N represents a word in level N+1 that
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86 | e7c033c3 | Paolo Bonzini | * has a set bit, except the last level where each bit represents the
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87 | e7c033c3 | Paolo Bonzini | * actual bitmap.
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88 | e7c033c3 | Paolo Bonzini | *
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89 | e7c033c3 | Paolo Bonzini | * Note that all bitmaps have the same number of levels. Even a 1-bit
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90 | e7c033c3 | Paolo Bonzini | * bitmap will still allocate HBITMAP_LEVELS arrays.
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91 | e7c033c3 | Paolo Bonzini | */
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92 | e7c033c3 | Paolo Bonzini | unsigned long *levels[HBITMAP_LEVELS]; |
93 | e7c033c3 | Paolo Bonzini | }; |
94 | e7c033c3 | Paolo Bonzini | |
95 | e7c033c3 | Paolo Bonzini | static inline int popcountl(unsigned long l) |
96 | e7c033c3 | Paolo Bonzini | { |
97 | e7c033c3 | Paolo Bonzini | return BITS_PER_LONG == 32 ? ctpop32(l) : ctpop64(l); |
98 | e7c033c3 | Paolo Bonzini | } |
99 | e7c033c3 | Paolo Bonzini | |
100 | e7c033c3 | Paolo Bonzini | /* Advance hbi to the next nonzero word and return it. hbi->pos
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101 | e7c033c3 | Paolo Bonzini | * is updated. Returns zero if we reach the end of the bitmap.
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102 | e7c033c3 | Paolo Bonzini | */
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103 | e7c033c3 | Paolo Bonzini | unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi) |
104 | e7c033c3 | Paolo Bonzini | { |
105 | e7c033c3 | Paolo Bonzini | size_t pos = hbi->pos; |
106 | e7c033c3 | Paolo Bonzini | const HBitmap *hb = hbi->hb;
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107 | e7c033c3 | Paolo Bonzini | unsigned i = HBITMAP_LEVELS - 1; |
108 | e7c033c3 | Paolo Bonzini | |
109 | e7c033c3 | Paolo Bonzini | unsigned long cur; |
110 | e7c033c3 | Paolo Bonzini | do {
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111 | e7c033c3 | Paolo Bonzini | cur = hbi->cur[--i]; |
112 | e7c033c3 | Paolo Bonzini | pos >>= BITS_PER_LEVEL; |
113 | e7c033c3 | Paolo Bonzini | } while (cur == 0); |
114 | e7c033c3 | Paolo Bonzini | |
115 | e7c033c3 | Paolo Bonzini | /* Check for end of iteration. We always use fewer than BITS_PER_LONG
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116 | e7c033c3 | Paolo Bonzini | * bits in the level 0 bitmap; thus we can repurpose the most significant
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117 | e7c033c3 | Paolo Bonzini | * bit as a sentinel. The sentinel is set in hbitmap_alloc and ensures
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118 | e7c033c3 | Paolo Bonzini | * that the above loop ends even without an explicit check on i.
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119 | e7c033c3 | Paolo Bonzini | */
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120 | e7c033c3 | Paolo Bonzini | |
121 | e7c033c3 | Paolo Bonzini | if (i == 0 && cur == (1UL << (BITS_PER_LONG - 1))) { |
122 | e7c033c3 | Paolo Bonzini | return 0; |
123 | e7c033c3 | Paolo Bonzini | } |
124 | e7c033c3 | Paolo Bonzini | for (; i < HBITMAP_LEVELS - 1; i++) { |
125 | e7c033c3 | Paolo Bonzini | /* Shift back pos to the left, matching the right shifts above.
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126 | e7c033c3 | Paolo Bonzini | * The index of this word's least significant set bit provides
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127 | e7c033c3 | Paolo Bonzini | * the low-order bits.
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128 | e7c033c3 | Paolo Bonzini | */
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129 | 18331e7c | Richard Henderson | assert(cur); |
130 | 18331e7c | Richard Henderson | pos = (pos << BITS_PER_LEVEL) + ctzl(cur); |
131 | e7c033c3 | Paolo Bonzini | hbi->cur[i] = cur & (cur - 1);
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132 | e7c033c3 | Paolo Bonzini | |
133 | e7c033c3 | Paolo Bonzini | /* Set up next level for iteration. */
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134 | e7c033c3 | Paolo Bonzini | cur = hb->levels[i + 1][pos];
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135 | e7c033c3 | Paolo Bonzini | } |
136 | e7c033c3 | Paolo Bonzini | |
137 | e7c033c3 | Paolo Bonzini | hbi->pos = pos; |
138 | e7c033c3 | Paolo Bonzini | trace_hbitmap_iter_skip_words(hbi->hb, hbi, pos, cur); |
139 | e7c033c3 | Paolo Bonzini | |
140 | e7c033c3 | Paolo Bonzini | assert(cur); |
141 | e7c033c3 | Paolo Bonzini | return cur;
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142 | e7c033c3 | Paolo Bonzini | } |
143 | e7c033c3 | Paolo Bonzini | |
144 | e7c033c3 | Paolo Bonzini | void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first) |
145 | e7c033c3 | Paolo Bonzini | { |
146 | e7c033c3 | Paolo Bonzini | unsigned i, bit;
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147 | e7c033c3 | Paolo Bonzini | uint64_t pos; |
148 | e7c033c3 | Paolo Bonzini | |
149 | e7c033c3 | Paolo Bonzini | hbi->hb = hb; |
150 | e7c033c3 | Paolo Bonzini | pos = first >> hb->granularity; |
151 | 1b095244 | Paolo Bonzini | assert(pos < hb->size); |
152 | e7c033c3 | Paolo Bonzini | hbi->pos = pos >> BITS_PER_LEVEL; |
153 | e7c033c3 | Paolo Bonzini | hbi->granularity = hb->granularity; |
154 | e7c033c3 | Paolo Bonzini | |
155 | e7c033c3 | Paolo Bonzini | for (i = HBITMAP_LEVELS; i-- > 0; ) { |
156 | e7c033c3 | Paolo Bonzini | bit = pos & (BITS_PER_LONG - 1);
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157 | e7c033c3 | Paolo Bonzini | pos >>= BITS_PER_LEVEL; |
158 | e7c033c3 | Paolo Bonzini | |
159 | e7c033c3 | Paolo Bonzini | /* Drop bits representing items before first. */
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160 | e7c033c3 | Paolo Bonzini | hbi->cur[i] = hb->levels[i][pos] & ~((1UL << bit) - 1); |
161 | e7c033c3 | Paolo Bonzini | |
162 | e7c033c3 | Paolo Bonzini | /* We have already added level i+1, so the lowest set bit has
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163 | e7c033c3 | Paolo Bonzini | * been processed. Clear it.
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164 | e7c033c3 | Paolo Bonzini | */
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165 | e7c033c3 | Paolo Bonzini | if (i != HBITMAP_LEVELS - 1) { |
166 | e7c033c3 | Paolo Bonzini | hbi->cur[i] &= ~(1UL << bit);
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167 | e7c033c3 | Paolo Bonzini | } |
168 | e7c033c3 | Paolo Bonzini | } |
169 | e7c033c3 | Paolo Bonzini | } |
170 | e7c033c3 | Paolo Bonzini | |
171 | e7c033c3 | Paolo Bonzini | bool hbitmap_empty(const HBitmap *hb) |
172 | e7c033c3 | Paolo Bonzini | { |
173 | e7c033c3 | Paolo Bonzini | return hb->count == 0; |
174 | e7c033c3 | Paolo Bonzini | } |
175 | e7c033c3 | Paolo Bonzini | |
176 | e7c033c3 | Paolo Bonzini | int hbitmap_granularity(const HBitmap *hb) |
177 | e7c033c3 | Paolo Bonzini | { |
178 | e7c033c3 | Paolo Bonzini | return hb->granularity;
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179 | e7c033c3 | Paolo Bonzini | } |
180 | e7c033c3 | Paolo Bonzini | |
181 | e7c033c3 | Paolo Bonzini | uint64_t hbitmap_count(const HBitmap *hb)
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182 | e7c033c3 | Paolo Bonzini | { |
183 | e7c033c3 | Paolo Bonzini | return hb->count << hb->granularity;
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184 | e7c033c3 | Paolo Bonzini | } |
185 | e7c033c3 | Paolo Bonzini | |
186 | e7c033c3 | Paolo Bonzini | /* Count the number of set bits between start and end, not accounting for
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187 | e7c033c3 | Paolo Bonzini | * the granularity. Also an example of how to use hbitmap_iter_next_word.
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188 | e7c033c3 | Paolo Bonzini | */
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189 | e7c033c3 | Paolo Bonzini | static uint64_t hb_count_between(HBitmap *hb, uint64_t start, uint64_t last)
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190 | e7c033c3 | Paolo Bonzini | { |
191 | e7c033c3 | Paolo Bonzini | HBitmapIter hbi; |
192 | e7c033c3 | Paolo Bonzini | uint64_t count = 0;
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193 | e7c033c3 | Paolo Bonzini | uint64_t end = last + 1;
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194 | e7c033c3 | Paolo Bonzini | unsigned long cur; |
195 | e7c033c3 | Paolo Bonzini | size_t pos; |
196 | e7c033c3 | Paolo Bonzini | |
197 | e7c033c3 | Paolo Bonzini | hbitmap_iter_init(&hbi, hb, start << hb->granularity); |
198 | e7c033c3 | Paolo Bonzini | for (;;) {
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199 | e7c033c3 | Paolo Bonzini | pos = hbitmap_iter_next_word(&hbi, &cur); |
200 | e7c033c3 | Paolo Bonzini | if (pos >= (end >> BITS_PER_LEVEL)) {
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201 | e7c033c3 | Paolo Bonzini | break;
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202 | e7c033c3 | Paolo Bonzini | } |
203 | e7c033c3 | Paolo Bonzini | count += popcountl(cur); |
204 | e7c033c3 | Paolo Bonzini | } |
205 | e7c033c3 | Paolo Bonzini | |
206 | e7c033c3 | Paolo Bonzini | if (pos == (end >> BITS_PER_LEVEL)) {
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207 | e7c033c3 | Paolo Bonzini | /* Drop bits representing the END-th and subsequent items. */
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208 | e7c033c3 | Paolo Bonzini | int bit = end & (BITS_PER_LONG - 1); |
209 | e7c033c3 | Paolo Bonzini | cur &= (1UL << bit) - 1; |
210 | e7c033c3 | Paolo Bonzini | count += popcountl(cur); |
211 | e7c033c3 | Paolo Bonzini | } |
212 | e7c033c3 | Paolo Bonzini | |
213 | e7c033c3 | Paolo Bonzini | return count;
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214 | e7c033c3 | Paolo Bonzini | } |
215 | e7c033c3 | Paolo Bonzini | |
216 | e7c033c3 | Paolo Bonzini | /* Setting starts at the last layer and propagates up if an element
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217 | e7c033c3 | Paolo Bonzini | * changes from zero to non-zero.
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218 | e7c033c3 | Paolo Bonzini | */
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219 | e7c033c3 | Paolo Bonzini | static inline bool hb_set_elem(unsigned long *elem, uint64_t start, uint64_t last) |
220 | e7c033c3 | Paolo Bonzini | { |
221 | e7c033c3 | Paolo Bonzini | unsigned long mask; |
222 | e7c033c3 | Paolo Bonzini | bool changed;
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223 | e7c033c3 | Paolo Bonzini | |
224 | e7c033c3 | Paolo Bonzini | assert((last >> BITS_PER_LEVEL) == (start >> BITS_PER_LEVEL)); |
225 | e7c033c3 | Paolo Bonzini | assert(start <= last); |
226 | e7c033c3 | Paolo Bonzini | |
227 | e7c033c3 | Paolo Bonzini | mask = 2UL << (last & (BITS_PER_LONG - 1)); |
228 | e7c033c3 | Paolo Bonzini | mask -= 1UL << (start & (BITS_PER_LONG - 1)); |
229 | e7c033c3 | Paolo Bonzini | changed = (*elem == 0);
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230 | e7c033c3 | Paolo Bonzini | *elem |= mask; |
231 | e7c033c3 | Paolo Bonzini | return changed;
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232 | e7c033c3 | Paolo Bonzini | } |
233 | e7c033c3 | Paolo Bonzini | |
234 | e7c033c3 | Paolo Bonzini | /* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... */
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235 | e7c033c3 | Paolo Bonzini | static void hb_set_between(HBitmap *hb, int level, uint64_t start, uint64_t last) |
236 | e7c033c3 | Paolo Bonzini | { |
237 | e7c033c3 | Paolo Bonzini | size_t pos = start >> BITS_PER_LEVEL; |
238 | e7c033c3 | Paolo Bonzini | size_t lastpos = last >> BITS_PER_LEVEL; |
239 | e7c033c3 | Paolo Bonzini | bool changed = false; |
240 | e7c033c3 | Paolo Bonzini | size_t i; |
241 | e7c033c3 | Paolo Bonzini | |
242 | e7c033c3 | Paolo Bonzini | i = pos; |
243 | e7c033c3 | Paolo Bonzini | if (i < lastpos) {
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244 | e7c033c3 | Paolo Bonzini | uint64_t next = (start | (BITS_PER_LONG - 1)) + 1; |
245 | e7c033c3 | Paolo Bonzini | changed |= hb_set_elem(&hb->levels[level][i], start, next - 1);
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246 | e7c033c3 | Paolo Bonzini | for (;;) {
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247 | e7c033c3 | Paolo Bonzini | start = next; |
248 | e7c033c3 | Paolo Bonzini | next += BITS_PER_LONG; |
249 | e7c033c3 | Paolo Bonzini | if (++i == lastpos) {
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250 | e7c033c3 | Paolo Bonzini | break;
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251 | e7c033c3 | Paolo Bonzini | } |
252 | e7c033c3 | Paolo Bonzini | changed |= (hb->levels[level][i] == 0);
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253 | e7c033c3 | Paolo Bonzini | hb->levels[level][i] = ~0UL;
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254 | e7c033c3 | Paolo Bonzini | } |
255 | e7c033c3 | Paolo Bonzini | } |
256 | e7c033c3 | Paolo Bonzini | changed |= hb_set_elem(&hb->levels[level][i], start, last); |
257 | e7c033c3 | Paolo Bonzini | |
258 | e7c033c3 | Paolo Bonzini | /* If there was any change in this layer, we may have to update
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259 | e7c033c3 | Paolo Bonzini | * the one above.
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260 | e7c033c3 | Paolo Bonzini | */
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261 | e7c033c3 | Paolo Bonzini | if (level > 0 && changed) { |
262 | e7c033c3 | Paolo Bonzini | hb_set_between(hb, level - 1, pos, lastpos);
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263 | e7c033c3 | Paolo Bonzini | } |
264 | e7c033c3 | Paolo Bonzini | } |
265 | e7c033c3 | Paolo Bonzini | |
266 | e7c033c3 | Paolo Bonzini | void hbitmap_set(HBitmap *hb, uint64_t start, uint64_t count)
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267 | e7c033c3 | Paolo Bonzini | { |
268 | e7c033c3 | Paolo Bonzini | /* Compute range in the last layer. */
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269 | e7c033c3 | Paolo Bonzini | uint64_t last = start + count - 1;
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270 | e7c033c3 | Paolo Bonzini | |
271 | e7c033c3 | Paolo Bonzini | trace_hbitmap_set(hb, start, count, |
272 | e7c033c3 | Paolo Bonzini | start >> hb->granularity, last >> hb->granularity); |
273 | e7c033c3 | Paolo Bonzini | |
274 | e7c033c3 | Paolo Bonzini | start >>= hb->granularity; |
275 | e7c033c3 | Paolo Bonzini | last >>= hb->granularity; |
276 | e7c033c3 | Paolo Bonzini | count = last - start + 1;
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277 | e7c033c3 | Paolo Bonzini | |
278 | e7c033c3 | Paolo Bonzini | hb->count += count - hb_count_between(hb, start, last); |
279 | e7c033c3 | Paolo Bonzini | hb_set_between(hb, HBITMAP_LEVELS - 1, start, last);
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280 | e7c033c3 | Paolo Bonzini | } |
281 | e7c033c3 | Paolo Bonzini | |
282 | e7c033c3 | Paolo Bonzini | /* Resetting works the other way round: propagate up if the new
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283 | e7c033c3 | Paolo Bonzini | * value is zero.
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284 | e7c033c3 | Paolo Bonzini | */
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285 | e7c033c3 | Paolo Bonzini | static inline bool hb_reset_elem(unsigned long *elem, uint64_t start, uint64_t last) |
286 | e7c033c3 | Paolo Bonzini | { |
287 | e7c033c3 | Paolo Bonzini | unsigned long mask; |
288 | e7c033c3 | Paolo Bonzini | bool blanked;
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289 | e7c033c3 | Paolo Bonzini | |
290 | e7c033c3 | Paolo Bonzini | assert((last >> BITS_PER_LEVEL) == (start >> BITS_PER_LEVEL)); |
291 | e7c033c3 | Paolo Bonzini | assert(start <= last); |
292 | e7c033c3 | Paolo Bonzini | |
293 | e7c033c3 | Paolo Bonzini | mask = 2UL << (last & (BITS_PER_LONG - 1)); |
294 | e7c033c3 | Paolo Bonzini | mask -= 1UL << (start & (BITS_PER_LONG - 1)); |
295 | e7c033c3 | Paolo Bonzini | blanked = *elem != 0 && ((*elem & ~mask) == 0); |
296 | e7c033c3 | Paolo Bonzini | *elem &= ~mask; |
297 | e7c033c3 | Paolo Bonzini | return blanked;
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298 | e7c033c3 | Paolo Bonzini | } |
299 | e7c033c3 | Paolo Bonzini | |
300 | e7c033c3 | Paolo Bonzini | /* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... */
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301 | e7c033c3 | Paolo Bonzini | static void hb_reset_between(HBitmap *hb, int level, uint64_t start, uint64_t last) |
302 | e7c033c3 | Paolo Bonzini | { |
303 | e7c033c3 | Paolo Bonzini | size_t pos = start >> BITS_PER_LEVEL; |
304 | e7c033c3 | Paolo Bonzini | size_t lastpos = last >> BITS_PER_LEVEL; |
305 | e7c033c3 | Paolo Bonzini | bool changed = false; |
306 | e7c033c3 | Paolo Bonzini | size_t i; |
307 | e7c033c3 | Paolo Bonzini | |
308 | e7c033c3 | Paolo Bonzini | i = pos; |
309 | e7c033c3 | Paolo Bonzini | if (i < lastpos) {
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310 | e7c033c3 | Paolo Bonzini | uint64_t next = (start | (BITS_PER_LONG - 1)) + 1; |
311 | e7c033c3 | Paolo Bonzini | |
312 | e7c033c3 | Paolo Bonzini | /* Here we need a more complex test than when setting bits. Even if
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313 | e7c033c3 | Paolo Bonzini | * something was changed, we must not blank bits in the upper level
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314 | e7c033c3 | Paolo Bonzini | * unless the lower-level word became entirely zero. So, remove pos
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315 | e7c033c3 | Paolo Bonzini | * from the upper-level range if bits remain set.
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316 | e7c033c3 | Paolo Bonzini | */
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317 | e7c033c3 | Paolo Bonzini | if (hb_reset_elem(&hb->levels[level][i], start, next - 1)) { |
318 | e7c033c3 | Paolo Bonzini | changed = true;
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319 | e7c033c3 | Paolo Bonzini | } else {
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320 | e7c033c3 | Paolo Bonzini | pos++; |
321 | e7c033c3 | Paolo Bonzini | } |
322 | e7c033c3 | Paolo Bonzini | |
323 | e7c033c3 | Paolo Bonzini | for (;;) {
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324 | e7c033c3 | Paolo Bonzini | start = next; |
325 | e7c033c3 | Paolo Bonzini | next += BITS_PER_LONG; |
326 | e7c033c3 | Paolo Bonzini | if (++i == lastpos) {
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327 | e7c033c3 | Paolo Bonzini | break;
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328 | e7c033c3 | Paolo Bonzini | } |
329 | e7c033c3 | Paolo Bonzini | changed |= (hb->levels[level][i] != 0);
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330 | e7c033c3 | Paolo Bonzini | hb->levels[level][i] = 0UL;
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331 | e7c033c3 | Paolo Bonzini | } |
332 | e7c033c3 | Paolo Bonzini | } |
333 | e7c033c3 | Paolo Bonzini | |
334 | e7c033c3 | Paolo Bonzini | /* Same as above, this time for lastpos. */
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335 | e7c033c3 | Paolo Bonzini | if (hb_reset_elem(&hb->levels[level][i], start, last)) {
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336 | e7c033c3 | Paolo Bonzini | changed = true;
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337 | e7c033c3 | Paolo Bonzini | } else {
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338 | e7c033c3 | Paolo Bonzini | lastpos--; |
339 | e7c033c3 | Paolo Bonzini | } |
340 | e7c033c3 | Paolo Bonzini | |
341 | e7c033c3 | Paolo Bonzini | if (level > 0 && changed) { |
342 | e7c033c3 | Paolo Bonzini | hb_reset_between(hb, level - 1, pos, lastpos);
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343 | e7c033c3 | Paolo Bonzini | } |
344 | e7c033c3 | Paolo Bonzini | } |
345 | e7c033c3 | Paolo Bonzini | |
346 | e7c033c3 | Paolo Bonzini | void hbitmap_reset(HBitmap *hb, uint64_t start, uint64_t count)
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347 | e7c033c3 | Paolo Bonzini | { |
348 | e7c033c3 | Paolo Bonzini | /* Compute range in the last layer. */
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349 | e7c033c3 | Paolo Bonzini | uint64_t last = start + count - 1;
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350 | e7c033c3 | Paolo Bonzini | |
351 | e7c033c3 | Paolo Bonzini | trace_hbitmap_reset(hb, start, count, |
352 | e7c033c3 | Paolo Bonzini | start >> hb->granularity, last >> hb->granularity); |
353 | e7c033c3 | Paolo Bonzini | |
354 | e7c033c3 | Paolo Bonzini | start >>= hb->granularity; |
355 | e7c033c3 | Paolo Bonzini | last >>= hb->granularity; |
356 | e7c033c3 | Paolo Bonzini | |
357 | e7c033c3 | Paolo Bonzini | hb->count -= hb_count_between(hb, start, last); |
358 | e7c033c3 | Paolo Bonzini | hb_reset_between(hb, HBITMAP_LEVELS - 1, start, last);
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359 | e7c033c3 | Paolo Bonzini | } |
360 | e7c033c3 | Paolo Bonzini | |
361 | e7c033c3 | Paolo Bonzini | bool hbitmap_get(const HBitmap *hb, uint64_t item) |
362 | e7c033c3 | Paolo Bonzini | { |
363 | e7c033c3 | Paolo Bonzini | /* Compute position and bit in the last layer. */
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364 | e7c033c3 | Paolo Bonzini | uint64_t pos = item >> hb->granularity; |
365 | e7c033c3 | Paolo Bonzini | unsigned long bit = 1UL << (pos & (BITS_PER_LONG - 1)); |
366 | e7c033c3 | Paolo Bonzini | |
367 | e7c033c3 | Paolo Bonzini | return (hb->levels[HBITMAP_LEVELS - 1][pos >> BITS_PER_LEVEL] & bit) != 0; |
368 | e7c033c3 | Paolo Bonzini | } |
369 | e7c033c3 | Paolo Bonzini | |
370 | e7c033c3 | Paolo Bonzini | void hbitmap_free(HBitmap *hb)
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371 | e7c033c3 | Paolo Bonzini | { |
372 | e7c033c3 | Paolo Bonzini | unsigned i;
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373 | e7c033c3 | Paolo Bonzini | for (i = HBITMAP_LEVELS; i-- > 0; ) { |
374 | e7c033c3 | Paolo Bonzini | g_free(hb->levels[i]); |
375 | e7c033c3 | Paolo Bonzini | } |
376 | e7c033c3 | Paolo Bonzini | g_free(hb); |
377 | e7c033c3 | Paolo Bonzini | } |
378 | e7c033c3 | Paolo Bonzini | |
379 | e7c033c3 | Paolo Bonzini | HBitmap *hbitmap_alloc(uint64_t size, int granularity)
|
380 | e7c033c3 | Paolo Bonzini | { |
381 | e7c033c3 | Paolo Bonzini | HBitmap *hb = g_malloc0(sizeof (struct HBitmap)); |
382 | e7c033c3 | Paolo Bonzini | unsigned i;
|
383 | e7c033c3 | Paolo Bonzini | |
384 | e7c033c3 | Paolo Bonzini | assert(granularity >= 0 && granularity < 64); |
385 | e7c033c3 | Paolo Bonzini | size = (size + (1ULL << granularity) - 1) >> granularity; |
386 | e7c033c3 | Paolo Bonzini | assert(size <= ((uint64_t)1 << HBITMAP_LOG_MAX_SIZE));
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387 | e7c033c3 | Paolo Bonzini | |
388 | e7c033c3 | Paolo Bonzini | hb->size = size; |
389 | e7c033c3 | Paolo Bonzini | hb->granularity = granularity; |
390 | e7c033c3 | Paolo Bonzini | for (i = HBITMAP_LEVELS; i-- > 0; ) { |
391 | e7c033c3 | Paolo Bonzini | size = MAX((size + BITS_PER_LONG - 1) >> BITS_PER_LEVEL, 1); |
392 | e7c033c3 | Paolo Bonzini | hb->levels[i] = g_malloc0(size * sizeof(unsigned long)); |
393 | e7c033c3 | Paolo Bonzini | } |
394 | e7c033c3 | Paolo Bonzini | |
395 | e7c033c3 | Paolo Bonzini | /* We necessarily have free bits in level 0 due to the definition
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396 | e7c033c3 | Paolo Bonzini | * of HBITMAP_LEVELS, so use one for a sentinel. This speeds up
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397 | e7c033c3 | Paolo Bonzini | * hbitmap_iter_skip_words.
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398 | e7c033c3 | Paolo Bonzini | */
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399 | e7c033c3 | Paolo Bonzini | assert(size == 1);
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400 | e7c033c3 | Paolo Bonzini | hb->levels[0][0] |= 1UL << (BITS_PER_LONG - 1); |
401 | e7c033c3 | Paolo Bonzini | return hb;
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402 | e7c033c3 | Paolo Bonzini | } |