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258
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1
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2 /*
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3 * Copyright (C) Igor Sysoev
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4 */
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5
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6 #include <ngx_config.h>
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7 #include <ngx_core.h>
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8
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9 /*
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10
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11 12
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12 2048 2 11
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13 1024 4 10
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14 512 8 9
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15 256 16 8
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16
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17 128 32 4 32 7
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18
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19 64 64 8 63 6 1
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20 32 128 16 127 5 1
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21 16 256 32 254 4 2
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22 8 512 64 504 3 8
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23
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24 */
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25
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26
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27 #define NGX_SLAB_PAGE_MASK 3
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28 #define NGX_SLAB_PAGE 0
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29 #define NGX_SLAB_BIG 1
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30 #define NGX_SLAB_EXACT 2
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31 #define NGX_SLAB_SMALL 3
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32
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33 #if (NGX_PTR_SIZE == 4)
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34
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35 #define NGX_SLAB_PAGE_FREE 0
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36 #define NGX_SLAB_PAGE_BUSY 0xffffffff
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37 #define NGX_SLAB_PAGE_START 0x80000000
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38
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39 #define NGX_SLAB_SHIFT_MASK 0x0000000f
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40 #define NGX_SLAB_MAP_MASK 0xffff0000
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41 #define NGX_SLAB_MAP_SHIFT 16
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42
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43 #define NGX_SLAB_BUSY 0xffffffff
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44
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45 #else /* (NGX_PTR_SIZE == 8) */
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46
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47 #define NGX_SLAB_PAGE_FREE 0
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48 #define NGX_SLAB_PAGE_BUSY 0xffffffffffffffff
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49 #define NGX_SLAB_PAGE_START 0x8000000000000000
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50
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51 #define NGX_SLAB_SHIFT_MASK 0x000000000000000f
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52 #define NGX_SLAB_MAP_MASK 0xffffffff00000000
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53 #define NGX_SLAB_MAP_SHIFT 32
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54
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55 #define NGX_SLAB_BUSY 0xffffffffffffffff
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56
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57 #endif
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58
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59
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60 #if (NGX_DEBUG_MALLOC)
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61 #define ngx_slab_junk(p, size) ngx_memset(p, 0xD0, size)
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62 #else
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63 #define ngx_slab_junk(p, size)
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64 #endif
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65
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66 static ngx_slab_page_t *ngx_slab_alloc_pages(ngx_slab_pool_t *pool,
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67 ngx_uint_t pages);
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68 static void ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page,
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69 ngx_uint_t pages);
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70
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71
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72 static ngx_uint_t ngx_slab_max_size;
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73 static ngx_uint_t ngx_slab_exact_size;
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74 static ngx_uint_t ngx_slab_exact_shift;
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75
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76
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77 void
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78 ngx_slab_init(ngx_slab_pool_t *pool)
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79 {
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80 u_char *p;
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81 size_t size;
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82 ngx_int_t m;
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83 ngx_uint_t i, n, pages;
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84 ngx_slab_page_t *slots;
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85
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86 /* STUB */
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87 if (ngx_slab_max_size == 0) {
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88 ngx_slab_max_size = ngx_pagesize / 2;
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89 ngx_slab_exact_size = ngx_pagesize / (8 * sizeof(uintptr_t));
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90 for (n = ngx_slab_exact_size; n >>= 1; ngx_slab_exact_shift++) {
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91 /* void */
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92 }
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93 }
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94 /**/
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95
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96 pool->min_size = 1 << pool->min_shift;
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97
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98 p = (u_char *) pool + sizeof(ngx_slab_pool_t);
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99 size = pool->end - p;
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100
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101 ngx_slab_junk(p, size);
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102
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103 slots = (ngx_slab_page_t *) p;
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104 n = ngx_pagesize_shift - pool->min_shift;
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105
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106 for (i = 0; i < n; i++) {
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107 slots[i].slab = 0;
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108 slots[i].next = &slots[i];
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109 slots[i].prev = 0;
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110 }
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111
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112 p += n * sizeof(ngx_slab_page_t);
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113
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330
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114 pages = (ngx_uint_t) (size / (ngx_pagesize + sizeof(ngx_slab_page_t)));
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258
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115
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116 ngx_memzero(p, pages * sizeof(ngx_slab_page_t));
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117
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118 pool->pages = (ngx_slab_page_t *) p;
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119
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120 pool->free.prev = 0;
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121 pool->free.next = (ngx_slab_page_t *) p;
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122
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123 pool->pages->slab = pages;
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124 pool->pages->next = &pool->free;
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125 pool->pages->prev = (uintptr_t) &pool->free;
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126
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127 pool->start = (u_char *)
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274
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128 ngx_align_ptr((uintptr_t) p + pages * sizeof(ngx_slab_page_t),
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258
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129 ngx_pagesize);
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130
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131 m = pages - (pool->end - pool->start) / ngx_pagesize;
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132 if (m > 0) {
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133 pages -= m;
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134 pool->pages->slab = pages;
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135 }
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136
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137 #if 0
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138 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "slab: %p, %p, %ui, %d",
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139 pool, pool->start, pages,
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140 (pool->end - pool->start) / ngx_pagesize - pages);
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141 #endif
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142 }
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143
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144
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145 void *
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146 ngx_slab_alloc(ngx_slab_pool_t *pool, size_t size)
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147 {
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272
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148 void *p;
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149
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150 ngx_shmtx_lock(&pool->mutex);
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151
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152 p = ngx_slab_alloc_locked(pool, size);
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153
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154 ngx_shmtx_unlock(&pool->mutex);
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155
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156 return p;
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157 }
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158
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159
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160 void *
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161 ngx_slab_alloc_locked(ngx_slab_pool_t *pool, size_t size)
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162 {
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258
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163 size_t s;
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260
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164 uintptr_t p, n, m, mask, *bitmap;
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165 ngx_uint_t i, slot, shift, map;
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258
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166 ngx_slab_page_t *page, *prev, *slots;
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167
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272
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168 if (size >= ngx_slab_max_size) {
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258
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169
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272
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170 ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0,
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171 "slab alloc: %uz", size);
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172
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258
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173 page = ngx_slab_alloc_pages(pool, (size + ngx_pagesize - 1)
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174 >> ngx_pagesize_shift);
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175 if (page) {
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176 p = (page - pool->pages) << ngx_pagesize_shift;
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177 p += (uintptr_t) pool->start;
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178
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179 } else {
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180 p = 0;
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181 }
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182
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183 goto done;
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184 }
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185
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186 if (size > pool->min_size) {
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187 shift = 1;
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188 for (s = size - 1; s >>= 1; shift++) { /* void */ }
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189 slot = shift - pool->min_shift;
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190
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191 } else {
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192 size = pool->min_size;
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193 shift = pool->min_shift;
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194 slot = 0;
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195 }
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196
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197 ngx_log_debug2(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0,
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198 "slab alloc: %uz slot: %ui", size, slot);
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199
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200 slots = (ngx_slab_page_t *) ((u_char *) pool + sizeof(ngx_slab_pool_t));
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201 page = slots[slot].next;
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202
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203 if (page->next != page) {
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204
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272
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205 if (shift < ngx_slab_exact_shift) {
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258
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206
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207 do {
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208 p = (page - pool->pages) << ngx_pagesize_shift;
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209 bitmap = (uintptr_t *) (pool->start + p);
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210
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211 map = (1 << (ngx_pagesize_shift - shift))
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212 / (sizeof(uintptr_t) * 8);
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213
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214 for (n = 0; n < map; n++) {
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215
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216 if (bitmap[n] != NGX_SLAB_BUSY) {
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217
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218 for (m = 1, i = 0; m; m <<= 1, i++) {
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219 if ((bitmap[n] & m)) {
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220 continue;
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221 }
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222
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223 bitmap[n] |= m;
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272
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224
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225 i = ((n * sizeof(uintptr_t) * 8) << shift)
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226 + (i << shift);
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258
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227
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228 if (bitmap[n] == NGX_SLAB_BUSY) {
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229 for (n = n + 1; n < map; n++) {
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230 if (bitmap[n] != NGX_SLAB_BUSY) {
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231 p = (uintptr_t) bitmap + i;
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232
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233 goto done;
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234 }
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235 }
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236
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237 prev = (ngx_slab_page_t *)
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238 (page->prev & ~NGX_SLAB_PAGE_MASK);
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239 prev->next = page->next;
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240 page->next->prev = page->prev;
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241
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242 page->next = NULL;
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243 page->prev = NGX_SLAB_SMALL;
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244 }
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245
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246 p = (uintptr_t) bitmap + i;
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247
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248 goto done;
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249 }
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250 }
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251 }
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252
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253 page = page->next;
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254
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255 } while (page);
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256
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272
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257 } else if (shift == ngx_slab_exact_shift) {
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258
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258
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259 do {
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260 if (page->slab != NGX_SLAB_BUSY) {
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261
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262 for (m = 1, i = 0; m; m <<= 1, i++) {
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263 if ((page->slab & m)) {
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264 continue;
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265 }
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266
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267 page->slab |= m;
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268
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269 if (page->slab == NGX_SLAB_BUSY) {
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270 prev = (ngx_slab_page_t *)
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271 (page->prev & ~NGX_SLAB_PAGE_MASK);
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272 prev->next = page->next;
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273 page->next->prev = page->prev;
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274
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275 page->next = NULL;
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276 page->prev = NGX_SLAB_EXACT;
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277 }
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278
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279 p = (page - pool->pages) << ngx_pagesize_shift;
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280 p += i << shift;
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281 p += (uintptr_t) pool->start;
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282
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283 goto done;
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284 }
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285 }
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286
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287 page = page->next;
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288
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289 } while (page);
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290
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272
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291 } else { /* shift > ngx_slab_exact_shift */
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258
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292
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293 n = ngx_pagesize_shift - (page->slab & NGX_SLAB_SHIFT_MASK);
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294 n = 1 << n;
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274
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295 n = ((uintptr_t) 1 << n) - 1;
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258
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296 mask = n << NGX_SLAB_MAP_SHIFT;
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297
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298 do {
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299 if ((page->slab & NGX_SLAB_MAP_MASK) != mask) {
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300
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260
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301 for (m = (uintptr_t) 1 << NGX_SLAB_MAP_SHIFT, i = 0;
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258
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302 m & mask;
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303 m <<= 1, i++)
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304 {
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305 if ((page->slab & m)) {
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306 continue;
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307 }
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308
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309 page->slab |= m;
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310
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311 if ((page->slab & NGX_SLAB_MAP_MASK) == mask) {
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312 prev = (ngx_slab_page_t *)
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313 (page->prev & ~NGX_SLAB_PAGE_MASK);
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314 prev->next = page->next;
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315 page->next->prev = page->prev;
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316
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317 page->next = NULL;
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318 page->prev = NGX_SLAB_BIG;
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319 }
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320
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321 p = (page - pool->pages) << ngx_pagesize_shift;
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322 p += i << shift;
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323 p += (uintptr_t) pool->start;
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324
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325 goto done;
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326 }
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327 }
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328
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329 page = page->next;
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330
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331 } while (page);
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332 }
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333 }
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334
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335 page = ngx_slab_alloc_pages(pool, 1);
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336
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337 if (page) {
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272
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338 if (shift < ngx_slab_exact_shift) {
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258
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339 p = (page - pool->pages) << ngx_pagesize_shift;
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340 bitmap = (uintptr_t *) (pool->start + p);
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341
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342 s = 1 << shift;
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343 n = (1 << (ngx_pagesize_shift - shift)) / 8 / s;
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344
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345 if (n == 0) {
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346 n = 1;
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347 }
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348
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349 bitmap[0] = (2 << n) - 1;
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350
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351 map = (1 << (ngx_pagesize_shift - shift)) / (sizeof(uintptr_t) * 8);
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352
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353 for (i = 1; i < map; i++) {
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354 bitmap[i] = 0;
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355 }
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356
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357 page->slab = shift;
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358 page->next = &slots[slot];
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359 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL;
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360
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361 slots[slot].next = page;
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362
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363 p = ((page - pool->pages) << ngx_pagesize_shift) + s * n;
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364 p += (uintptr_t) pool->start;
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365
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366 goto done;
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367
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272
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368 } else if (shift == ngx_slab_exact_shift) {
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258
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369
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370 page->slab = 1;
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371 page->next = &slots[slot];
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372 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT;
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373
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374 slots[slot].next = page;
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375
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376 p = (page - pool->pages) << ngx_pagesize_shift;
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377 p += (uintptr_t) pool->start;
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378
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379 goto done;
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380
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272
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381 } else { /* shift > ngx_slab_exact_shift */
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258
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382
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260
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383 page->slab = ((uintptr_t) 1 << NGX_SLAB_MAP_SHIFT) | shift;
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258
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384 page->next = &slots[slot];
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385 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG;
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386
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387 slots[slot].next = page;
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388
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389 p = (page - pool->pages) << ngx_pagesize_shift;
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390 p += (uintptr_t) pool->start;
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391
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392 goto done;
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393 }
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394 }
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395
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396 p = 0;
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397
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398 done:
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399
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400 ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %p", p);
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401
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402 return (void *) p;
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403 }
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404
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405
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406 void
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407 ngx_slab_free(ngx_slab_pool_t *pool, void *p)
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408 {
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272
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409 ngx_shmtx_lock(&pool->mutex);
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410
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411 ngx_slab_free_locked(pool, p);
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412
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413 ngx_shmtx_unlock(&pool->mutex);
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414 }
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415
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416
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417 void
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418 ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p)
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419 {
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258
|
420 size_t size;
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274
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421 uintptr_t slab, m, *bitmap;
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422 ngx_uint_t n, type, slot, shift, map;
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258
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423 ngx_slab_page_t *slots, *page;
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424
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425 ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab free: %p", p);
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426
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427 if ((u_char *) p < pool->start || (u_char *) p > pool->end) {
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428 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
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429 "ngx_slab_free(): outside of pool");
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430 goto fail;
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431 }
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432
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433 n = ((u_char *) p - pool->start) >> ngx_pagesize_shift;
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434 page = &pool->pages[n];
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435 slab = page->slab;
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436 type = page->prev & NGX_SLAB_PAGE_MASK;
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437
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438 switch (type) {
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439
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440 case NGX_SLAB_SMALL:
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441
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442 shift = slab & NGX_SLAB_SHIFT_MASK;
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443 size = 1 << shift;
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444
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445 if ((uintptr_t) p & (size - 1)) {
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446 goto wrong_chunk;
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447 }
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448
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449 n = ((uintptr_t) p & (ngx_pagesize - 1)) >> shift;
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274
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450 m = (uintptr_t) 1 << (n & (sizeof(uintptr_t) * 8 - 1));
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258
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451 n /= (sizeof(uintptr_t) * 8);
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452 bitmap = (uintptr_t *) ((uintptr_t) p & ~(ngx_pagesize - 1));
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453
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454 if (bitmap[n] & m) {
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455
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456 if (page->next == NULL) {
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457 slots = (ngx_slab_page_t *)
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458 ((u_char *) pool + sizeof(ngx_slab_pool_t));
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459 slot = shift - pool->min_shift;
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460
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461 page->next = slots[slot].next;
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462 slots[slot].next = page;
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463
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464 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL;
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465 page->next->prev = (uintptr_t) page | NGX_SLAB_SMALL;
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466 }
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467
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468 bitmap[n] &= ~m;
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469
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470 n = (1 << (ngx_pagesize_shift - shift)) / 8 / (1 << shift);
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471
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472 if (n == 0) {
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473 n = 1;
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474 }
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475
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274
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476 if (bitmap[0] & ~(((uintptr_t) 1 << n) - 1)) {
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258
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477 goto done;
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478 }
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479
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480 map = (1 << (ngx_pagesize_shift - shift)) / (sizeof(uintptr_t) * 8);
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481
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482 for (n = 1; n < map; n++) {
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483 if (bitmap[n]) {
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484 goto done;
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485 }
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486 }
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487
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488 ngx_slab_free_pages(pool, page, 1);
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489
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490 goto done;
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491 }
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492
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493 goto chunk_already_free;
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494
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495 case NGX_SLAB_EXACT:
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496
|
|
274
|
497 m = (uintptr_t) 1 <<
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|
|
498 (((uintptr_t) p & (ngx_pagesize - 1)) >> ngx_slab_exact_shift);
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|
258
|
499 size = ngx_slab_exact_size;
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|
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500
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|
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501 if ((uintptr_t) p & (size - 1)) {
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502 goto wrong_chunk;
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503 }
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504
|
|
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505 if (slab & m) {
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506 if (slab == NGX_SLAB_BUSY) {
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507 slots = (ngx_slab_page_t *)
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|
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508 ((u_char *) pool + sizeof(ngx_slab_pool_t));
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|
|
509 slot = ngx_slab_exact_shift - pool->min_shift;
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|
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510
|
|
|
511 page->next = slots[slot].next;
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|
|
512 slots[slot].next = page;
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|
|
513
|
|
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514 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT;
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|
|
515 page->next->prev = (uintptr_t) page | NGX_SLAB_EXACT;
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|
|
516 }
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|
|
517
|
|
|
518 page->slab &= ~m;
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|
|
519
|
|
|
520 if (page->slab) {
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|
|
521 goto done;
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|
|
522 }
|
|
|
523
|
|
|
524 ngx_slab_free_pages(pool, page, 1);
|
|
|
525
|
|
|
526 goto done;
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|
|
527 }
|
|
|
528
|
|
|
529 goto chunk_already_free;
|
|
|
530
|
|
|
531 case NGX_SLAB_BIG:
|
|
|
532
|
|
|
533 shift = slab & NGX_SLAB_SHIFT_MASK;
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|
|
534 size = 1 << shift;
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|
|
535
|
|
|
536 if ((uintptr_t) p & (size - 1)) {
|
|
|
537 goto wrong_chunk;
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|
|
538 }
|
|
|
539
|
|
274
|
540 m = (uintptr_t) 1 << ((((uintptr_t) p & (ngx_pagesize - 1)) >> shift)
|
|
|
541 + NGX_SLAB_MAP_SHIFT);
|
|
258
|
542
|
|
|
543 if (slab & m) {
|
|
|
544
|
|
|
545 if (page->next == NULL) {
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|
|
546 slots = (ngx_slab_page_t *)
|
|
|
547 ((u_char *) pool + sizeof(ngx_slab_pool_t));
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|
|
548 slot = shift - pool->min_shift;
|
|
|
549
|
|
|
550 page->next = slots[slot].next;
|
|
|
551 slots[slot].next = page;
|
|
|
552
|
|
|
553 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG;
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|
|
554 page->next->prev = (uintptr_t) page | NGX_SLAB_BIG;
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|
|
555 }
|
|
|
556
|
|
|
557 page->slab &= ~m;
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|
|
558
|
|
|
559 if (page->slab & NGX_SLAB_MAP_MASK) {
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|
|
560 goto done;
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|
|
561 }
|
|
|
562
|
|
|
563 ngx_slab_free_pages(pool, page, 1);
|
|
|
564
|
|
|
565 goto done;
|
|
|
566 }
|
|
|
567
|
|
|
568 goto chunk_already_free;
|
|
|
569
|
|
|
570 case NGX_SLAB_PAGE:
|
|
|
571
|
|
|
572 if ((uintptr_t) p & (ngx_pagesize - 1)) {
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|
|
573 goto wrong_chunk;
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|
|
574 }
|
|
|
575
|
|
|
576 if (slab == NGX_SLAB_PAGE_FREE) {
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|
|
577 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
|
|
|
578 "ngx_slab_free(): page is already free");
|
|
|
579 goto fail;
|
|
|
580 }
|
|
|
581
|
|
|
582 if (slab == NGX_SLAB_PAGE_BUSY) {
|
|
|
583 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
|
|
|
584 "ngx_slab_free(): pointer to wrong page");
|
|
|
585 goto fail;
|
|
|
586 }
|
|
|
587
|
|
|
588 n = ((u_char *) p - pool->start) >> ngx_pagesize_shift;
|
|
|
589 size = slab & ~NGX_SLAB_PAGE_START;
|
|
|
590
|
|
|
591 ngx_slab_free_pages(pool, &pool->pages[n], size);
|
|
|
592
|
|
|
593 size <<= ngx_pagesize_shift;
|
|
|
594
|
|
|
595 goto done;
|
|
|
596 }
|
|
|
597
|
|
|
598 /* not reached */
|
|
|
599
|
|
|
600 return;
|
|
|
601
|
|
|
602 done:
|
|
|
603
|
|
|
604 ngx_slab_junk(p, size);
|
|
|
605
|
|
|
606 return;
|
|
|
607
|
|
|
608 wrong_chunk:
|
|
|
609
|
|
|
610 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
|
|
|
611 "ngx_slab_free(): pointer to wrong chunk");
|
|
|
612
|
|
|
613 goto fail;
|
|
|
614
|
|
|
615 chunk_already_free:
|
|
|
616
|
|
|
617 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
|
|
|
618 "ngx_slab_free(): chunk is already free");
|
|
|
619
|
|
|
620 fail:
|
|
|
621
|
|
|
622 return;
|
|
|
623 }
|
|
|
624
|
|
|
625
|
|
|
626 static ngx_slab_page_t *
|
|
|
627 ngx_slab_alloc_pages(ngx_slab_pool_t *pool, ngx_uint_t pages)
|
|
|
628 {
|
|
|
629 ngx_slab_page_t *page, *p;
|
|
|
630
|
|
|
631 for (page = pool->free.next; page != &pool->free; page = page->next) {
|
|
|
632
|
|
|
633 if (page->slab >= pages) {
|
|
|
634
|
|
|
635 if (page->slab > pages) {
|
|
|
636 page[pages].slab = page->slab - pages;
|
|
|
637 page[pages].next = page->next;
|
|
|
638 page[pages].prev = page->prev;
|
|
|
639
|
|
|
640 p = (ngx_slab_page_t *) page->prev;
|
|
|
641 p->next = &page[pages];
|
|
|
642 page->next->prev = (uintptr_t) &page[pages];
|
|
|
643
|
|
|
644 } else {
|
|
|
645 p = (ngx_slab_page_t *) page->prev;
|
|
|
646 p->next = page->next;
|
|
|
647 page->next->prev = page->prev;
|
|
|
648 }
|
|
|
649
|
|
|
650 page->slab = pages | NGX_SLAB_PAGE_START;
|
|
|
651
|
|
|
652 #if (NGX_DEBUG)
|
|
|
653 page->next = NULL;
|
|
|
654 page->prev = NGX_SLAB_PAGE;
|
|
|
655 #endif
|
|
|
656
|
|
|
657 if (--pages == 0) {
|
|
|
658 return page;
|
|
|
659 }
|
|
|
660
|
|
|
661 for (p = page + 1; pages; pages--) {
|
|
|
662 p->slab = NGX_SLAB_PAGE_BUSY;
|
|
|
663 #if (NGX_DEBUG)
|
|
|
664 p->next = NULL;
|
|
|
665 p->prev = NGX_SLAB_PAGE;
|
|
|
666 #endif
|
|
|
667 p++;
|
|
|
668 }
|
|
|
669
|
|
|
670 return page;
|
|
|
671 }
|
|
|
672 }
|
|
|
673
|
|
|
674 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, NGX_ENOMEM,
|
|
|
675 "ngx_slab_alloc(): failed");
|
|
272
|
676
|
|
258
|
677 return NULL;
|
|
|
678 }
|
|
|
679
|
|
|
680
|
|
|
681 static void
|
|
|
682 ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page,
|
|
|
683 ngx_uint_t pages)
|
|
|
684 {
|
|
|
685 ngx_slab_page_t *prev;
|
|
|
686
|
|
|
687 page->slab = pages--;
|
|
|
688
|
|
|
689 if (pages) {
|
|
|
690 ngx_memzero(&page[1], pages * sizeof(ngx_slab_page_t));
|
|
|
691 }
|
|
|
692
|
|
272
|
693 if (page->next) {
|
|
|
694 prev = (ngx_slab_page_t *) (page->prev & ~NGX_SLAB_PAGE_MASK);
|
|
|
695 prev->next = page->next;
|
|
|
696 page->next->prev = page->prev;
|
|
|
697 }
|
|
258
|
698
|
|
272
|
699 page->prev = (uintptr_t) &pool->free;
|
|
258
|
700 page->next = pool->free.next;
|
|
272
|
701
|
|
|
702 page->next->prev = (uintptr_t) page;
|
|
|
703
|
|
258
|
704 pool->free.next = page;
|
|
|
705 }
|
