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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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660
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4 * Copyright (C) Nginx, Inc.
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258
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5 */
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6
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7 #include <ngx_config.h>
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8 #include <ngx_core.h>
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9
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10
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11 #define NGX_SLAB_PAGE_MASK 3
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12 #define NGX_SLAB_PAGE 0
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13 #define NGX_SLAB_BIG 1
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14 #define NGX_SLAB_EXACT 2
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15 #define NGX_SLAB_SMALL 3
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16
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17 #if (NGX_PTR_SIZE == 4)
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18
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19 #define NGX_SLAB_PAGE_FREE 0
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20 #define NGX_SLAB_PAGE_BUSY 0xffffffff
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21 #define NGX_SLAB_PAGE_START 0x80000000
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22
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23 #define NGX_SLAB_SHIFT_MASK 0x0000000f
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24 #define NGX_SLAB_MAP_MASK 0xffff0000
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25 #define NGX_SLAB_MAP_SHIFT 16
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26
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27 #define NGX_SLAB_BUSY 0xffffffff
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28
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29 #else /* (NGX_PTR_SIZE == 8) */
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30
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31 #define NGX_SLAB_PAGE_FREE 0
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32 #define NGX_SLAB_PAGE_BUSY 0xffffffffffffffff
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33 #define NGX_SLAB_PAGE_START 0x8000000000000000
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34
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35 #define NGX_SLAB_SHIFT_MASK 0x000000000000000f
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36 #define NGX_SLAB_MAP_MASK 0xffffffff00000000
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37 #define NGX_SLAB_MAP_SHIFT 32
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38
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39 #define NGX_SLAB_BUSY 0xffffffffffffffff
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40
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41 #endif
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42
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43
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44 #if (NGX_DEBUG_MALLOC)
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358
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45
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646
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46 #define ngx_slab_junk(p, size) ngx_memset(p, 0xA5, size)
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358
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47
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682
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48 #elif (NGX_HAVE_DEBUG_MALLOC)
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358
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49
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50 #define ngx_slab_junk(p, size) \
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646
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51 if (ngx_debug_malloc) ngx_memset(p, 0xA5, size)
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358
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52
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53 #else
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54
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258
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55 #define ngx_slab_junk(p, size)
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358
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56
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57 #endif
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58
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258
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59 static ngx_slab_page_t *ngx_slab_alloc_pages(ngx_slab_pool_t *pool,
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60 ngx_uint_t pages);
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61 static void ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page,
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62 ngx_uint_t pages);
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468
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63 static void ngx_slab_error(ngx_slab_pool_t *pool, ngx_uint_t level,
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64 char *text);
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258
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65
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66
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67 static ngx_uint_t ngx_slab_max_size;
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68 static ngx_uint_t ngx_slab_exact_size;
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69 static ngx_uint_t ngx_slab_exact_shift;
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70
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71
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72 void
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73 ngx_slab_init(ngx_slab_pool_t *pool)
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74 {
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75 u_char *p;
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76 size_t size;
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77 ngx_int_t m;
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78 ngx_uint_t i, n, pages;
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79 ngx_slab_page_t *slots;
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80
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81 /* STUB */
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82 if (ngx_slab_max_size == 0) {
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83 ngx_slab_max_size = ngx_pagesize / 2;
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84 ngx_slab_exact_size = ngx_pagesize / (8 * sizeof(uintptr_t));
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85 for (n = ngx_slab_exact_size; n >>= 1; ngx_slab_exact_shift++) {
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86 /* void */
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87 }
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88 }
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89 /**/
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90
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91 pool->min_size = 1 << pool->min_shift;
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92
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93 p = (u_char *) pool + sizeof(ngx_slab_pool_t);
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94 size = pool->end - p;
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95
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96 ngx_slab_junk(p, size);
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97
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98 slots = (ngx_slab_page_t *) p;
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99 n = ngx_pagesize_shift - pool->min_shift;
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100
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101 for (i = 0; i < n; i++) {
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102 slots[i].slab = 0;
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103 slots[i].next = &slots[i];
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104 slots[i].prev = 0;
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105 }
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106
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107 p += n * sizeof(ngx_slab_page_t);
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108
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348
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109 pages = (ngx_uint_t) (size / (ngx_pagesize + sizeof(ngx_slab_page_t)));
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258
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110
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111 ngx_memzero(p, pages * sizeof(ngx_slab_page_t));
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112
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113 pool->pages = (ngx_slab_page_t *) p;
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114
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115 pool->free.prev = 0;
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116 pool->free.next = (ngx_slab_page_t *) p;
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117
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118 pool->pages->slab = pages;
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119 pool->pages->next = &pool->free;
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120 pool->pages->prev = (uintptr_t) &pool->free;
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121
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122 pool->start = (u_char *)
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274
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123 ngx_align_ptr((uintptr_t) p + pages * sizeof(ngx_slab_page_t),
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258
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124 ngx_pagesize);
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125
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126 m = pages - (pool->end - pool->start) / ngx_pagesize;
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127 if (m > 0) {
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128 pages -= m;
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129 pool->pages->slab = pages;
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130 }
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131
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468
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132 pool->log_ctx = &pool->zero;
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133 pool->zero = '\0';
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258
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134 }
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135
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136
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137 void *
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138 ngx_slab_alloc(ngx_slab_pool_t *pool, size_t size)
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139 {
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272
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140 void *p;
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141
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142 ngx_shmtx_lock(&pool->mutex);
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143
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144 p = ngx_slab_alloc_locked(pool, size);
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145
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146 ngx_shmtx_unlock(&pool->mutex);
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147
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148 return p;
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149 }
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150
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151
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152 void *
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153 ngx_slab_alloc_locked(ngx_slab_pool_t *pool, size_t size)
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154 {
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258
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155 size_t s;
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260
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156 uintptr_t p, n, m, mask, *bitmap;
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157 ngx_uint_t i, slot, shift, map;
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258
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158 ngx_slab_page_t *page, *prev, *slots;
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159
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272
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160 if (size >= ngx_slab_max_size) {
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258
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161
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272
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162 ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0,
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163 "slab alloc: %uz", size);
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164
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258
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165 page = ngx_slab_alloc_pages(pool, (size + ngx_pagesize - 1)
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166 >> ngx_pagesize_shift);
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167 if (page) {
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168 p = (page - pool->pages) << ngx_pagesize_shift;
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169 p += (uintptr_t) pool->start;
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170
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171 } else {
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172 p = 0;
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173 }
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174
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175 goto done;
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176 }
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177
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178 if (size > pool->min_size) {
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179 shift = 1;
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180 for (s = size - 1; s >>= 1; shift++) { /* void */ }
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181 slot = shift - pool->min_shift;
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182
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183 } else {
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184 size = pool->min_size;
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185 shift = pool->min_shift;
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186 slot = 0;
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187 }
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188
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189 ngx_log_debug2(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0,
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190 "slab alloc: %uz slot: %ui", size, slot);
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191
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192 slots = (ngx_slab_page_t *) ((u_char *) pool + sizeof(ngx_slab_pool_t));
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193 page = slots[slot].next;
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194
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195 if (page->next != page) {
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196
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272
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197 if (shift < ngx_slab_exact_shift) {
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258
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198
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199 do {
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200 p = (page - pool->pages) << ngx_pagesize_shift;
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201 bitmap = (uintptr_t *) (pool->start + p);
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202
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203 map = (1 << (ngx_pagesize_shift - shift))
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204 / (sizeof(uintptr_t) * 8);
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205
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206 for (n = 0; n < map; n++) {
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207
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208 if (bitmap[n] != NGX_SLAB_BUSY) {
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209
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210 for (m = 1, i = 0; m; m <<= 1, i++) {
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211 if ((bitmap[n] & m)) {
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212 continue;
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213 }
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214
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215 bitmap[n] |= m;
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272
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216
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217 i = ((n * sizeof(uintptr_t) * 8) << shift)
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218 + (i << shift);
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258
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219
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220 if (bitmap[n] == NGX_SLAB_BUSY) {
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221 for (n = n + 1; n < map; n++) {
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222 if (bitmap[n] != NGX_SLAB_BUSY) {
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223 p = (uintptr_t) bitmap + i;
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224
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225 goto done;
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226 }
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227 }
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228
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229 prev = (ngx_slab_page_t *)
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230 (page->prev & ~NGX_SLAB_PAGE_MASK);
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231 prev->next = page->next;
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232 page->next->prev = page->prev;
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233
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234 page->next = NULL;
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235 page->prev = NGX_SLAB_SMALL;
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236 }
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237
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238 p = (uintptr_t) bitmap + i;
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239
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240 goto done;
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241 }
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242 }
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243 }
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244
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245 page = page->next;
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246
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247 } while (page);
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248
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272
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249 } else if (shift == ngx_slab_exact_shift) {
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258
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250
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251 do {
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252 if (page->slab != NGX_SLAB_BUSY) {
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253
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254 for (m = 1, i = 0; m; m <<= 1, i++) {
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255 if ((page->slab & m)) {
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256 continue;
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257 }
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258
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259 page->slab |= m;
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260
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261 if (page->slab == NGX_SLAB_BUSY) {
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262 prev = (ngx_slab_page_t *)
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263 (page->prev & ~NGX_SLAB_PAGE_MASK);
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264 prev->next = page->next;
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265 page->next->prev = page->prev;
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266
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267 page->next = NULL;
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268 page->prev = NGX_SLAB_EXACT;
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269 }
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270
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271 p = (page - pool->pages) << ngx_pagesize_shift;
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272 p += i << shift;
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273 p += (uintptr_t) pool->start;
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274
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275 goto done;
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276 }
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277 }
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278
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279 page = page->next;
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280
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281 } while (page);
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282
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272
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283 } else { /* shift > ngx_slab_exact_shift */
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258
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284
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285 n = ngx_pagesize_shift - (page->slab & NGX_SLAB_SHIFT_MASK);
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286 n = 1 << n;
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274
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287 n = ((uintptr_t) 1 << n) - 1;
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258
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288 mask = n << NGX_SLAB_MAP_SHIFT;
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289
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290 do {
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291 if ((page->slab & NGX_SLAB_MAP_MASK) != mask) {
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292
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260
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293 for (m = (uintptr_t) 1 << NGX_SLAB_MAP_SHIFT, i = 0;
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258
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294 m & mask;
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295 m <<= 1, i++)
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296 {
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297 if ((page->slab & m)) {
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298 continue;
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299 }
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300
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301 page->slab |= m;
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302
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303 if ((page->slab & NGX_SLAB_MAP_MASK) == mask) {
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304 prev = (ngx_slab_page_t *)
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305 (page->prev & ~NGX_SLAB_PAGE_MASK);
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306 prev->next = page->next;
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307 page->next->prev = page->prev;
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308
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309 page->next = NULL;
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310 page->prev = NGX_SLAB_BIG;
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311 }
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312
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313 p = (page - pool->pages) << ngx_pagesize_shift;
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314 p += i << shift;
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315 p += (uintptr_t) pool->start;
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316
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317 goto done;
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318 }
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319 }
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320
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321 page = page->next;
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322
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323 } while (page);
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324 }
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325 }
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326
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327 page = ngx_slab_alloc_pages(pool, 1);
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328
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329 if (page) {
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272
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330 if (shift < ngx_slab_exact_shift) {
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258
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331 p = (page - pool->pages) << ngx_pagesize_shift;
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332 bitmap = (uintptr_t *) (pool->start + p);
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333
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334 s = 1 << shift;
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335 n = (1 << (ngx_pagesize_shift - shift)) / 8 / s;
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336
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337 if (n == 0) {
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338 n = 1;
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339 }
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340
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341 bitmap[0] = (2 << n) - 1;
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342
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343 map = (1 << (ngx_pagesize_shift - shift)) / (sizeof(uintptr_t) * 8);
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344
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345 for (i = 1; i < map; i++) {
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346 bitmap[i] = 0;
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347 }
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348
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349 page->slab = shift;
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350 page->next = &slots[slot];
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351 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL;
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352
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353 slots[slot].next = page;
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354
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355 p = ((page - pool->pages) << ngx_pagesize_shift) + s * n;
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356 p += (uintptr_t) pool->start;
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357
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358 goto done;
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359
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272
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360 } else if (shift == ngx_slab_exact_shift) {
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258
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361
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362 page->slab = 1;
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363 page->next = &slots[slot];
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364 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT;
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365
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366 slots[slot].next = page;
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367
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368 p = (page - pool->pages) << ngx_pagesize_shift;
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369 p += (uintptr_t) pool->start;
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370
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371 goto done;
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372
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272
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373 } else { /* shift > ngx_slab_exact_shift */
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258
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374
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260
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375 page->slab = ((uintptr_t) 1 << NGX_SLAB_MAP_SHIFT) | shift;
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258
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376 page->next = &slots[slot];
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377 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG;
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378
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379 slots[slot].next = page;
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380
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381 p = (page - pool->pages) << ngx_pagesize_shift;
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382 p += (uintptr_t) pool->start;
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383
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384 goto done;
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385 }
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386 }
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387
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388 p = 0;
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389
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390 done:
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391
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392 ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %p", p);
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393
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394 return (void *) p;
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395 }
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396
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397
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398 void
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399 ngx_slab_free(ngx_slab_pool_t *pool, void *p)
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400 {
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272
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401 ngx_shmtx_lock(&pool->mutex);
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402
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403 ngx_slab_free_locked(pool, p);
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404
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405 ngx_shmtx_unlock(&pool->mutex);
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406 }
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407
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408
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409 void
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410 ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p)
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411 {
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258
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412 size_t size;
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274
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413 uintptr_t slab, m, *bitmap;
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414 ngx_uint_t n, type, slot, shift, map;
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258
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415 ngx_slab_page_t *slots, *page;
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416
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417 ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab free: %p", p);
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418
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419 if ((u_char *) p < pool->start || (u_char *) p > pool->end) {
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468
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420 ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): outside of pool");
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258
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421 goto fail;
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422 }
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423
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424 n = ((u_char *) p - pool->start) >> ngx_pagesize_shift;
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425 page = &pool->pages[n];
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426 slab = page->slab;
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427 type = page->prev & NGX_SLAB_PAGE_MASK;
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428
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429 switch (type) {
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430
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431 case NGX_SLAB_SMALL:
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432
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433 shift = slab & NGX_SLAB_SHIFT_MASK;
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434 size = 1 << shift;
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435
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436 if ((uintptr_t) p & (size - 1)) {
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437 goto wrong_chunk;
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438 }
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439
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440 n = ((uintptr_t) p & (ngx_pagesize - 1)) >> shift;
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274
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441 m = (uintptr_t) 1 << (n & (sizeof(uintptr_t) * 8 - 1));
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258
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442 n /= (sizeof(uintptr_t) * 8);
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443 bitmap = (uintptr_t *) ((uintptr_t) p & ~(ngx_pagesize - 1));
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444
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445 if (bitmap[n] & m) {
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446
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447 if (page->next == NULL) {
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448 slots = (ngx_slab_page_t *)
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449 ((u_char *) pool + sizeof(ngx_slab_pool_t));
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450 slot = shift - pool->min_shift;
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451
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452 page->next = slots[slot].next;
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453 slots[slot].next = page;
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454
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455 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL;
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456 page->next->prev = (uintptr_t) page | NGX_SLAB_SMALL;
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457 }
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458
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459 bitmap[n] &= ~m;
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460
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461 n = (1 << (ngx_pagesize_shift - shift)) / 8 / (1 << shift);
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462
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463 if (n == 0) {
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464 n = 1;
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465 }
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466
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274
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467 if (bitmap[0] & ~(((uintptr_t) 1 << n) - 1)) {
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258
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468 goto done;
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469 }
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470
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471 map = (1 << (ngx_pagesize_shift - shift)) / (sizeof(uintptr_t) * 8);
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472
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473 for (n = 1; n < map; n++) {
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474 if (bitmap[n]) {
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475 goto done;
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476 }
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477 }
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478
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479 ngx_slab_free_pages(pool, page, 1);
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480
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481 goto done;
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482 }
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483
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484 goto chunk_already_free;
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485
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486 case NGX_SLAB_EXACT:
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487
|
|
274
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488 m = (uintptr_t) 1 <<
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|
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489 (((uintptr_t) p & (ngx_pagesize - 1)) >> ngx_slab_exact_shift);
|
|
258
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490 size = ngx_slab_exact_size;
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|
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491
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|
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492 if ((uintptr_t) p & (size - 1)) {
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493 goto wrong_chunk;
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494 }
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495
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|
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496 if (slab & m) {
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497 if (slab == NGX_SLAB_BUSY) {
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498 slots = (ngx_slab_page_t *)
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499 ((u_char *) pool + sizeof(ngx_slab_pool_t));
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500 slot = ngx_slab_exact_shift - pool->min_shift;
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501
|
|
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502 page->next = slots[slot].next;
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|
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503 slots[slot].next = page;
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|
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504
|
|
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505 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT;
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|
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506 page->next->prev = (uintptr_t) page | NGX_SLAB_EXACT;
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|
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507 }
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|
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508
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|
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509 page->slab &= ~m;
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|
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510
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|
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511 if (page->slab) {
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512 goto done;
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513 }
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|
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514
|
|
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515 ngx_slab_free_pages(pool, page, 1);
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|
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516
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517 goto done;
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|
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518 }
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|
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519
|
|
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520 goto chunk_already_free;
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|
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521
|
|
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522 case NGX_SLAB_BIG:
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|
|
523
|
|
|
524 shift = slab & NGX_SLAB_SHIFT_MASK;
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|
|
525 size = 1 << shift;
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|
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526
|
|
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527 if ((uintptr_t) p & (size - 1)) {
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|
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528 goto wrong_chunk;
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|
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529 }
|
|
|
530
|
|
274
|
531 m = (uintptr_t) 1 << ((((uintptr_t) p & (ngx_pagesize - 1)) >> shift)
|
|
|
532 + NGX_SLAB_MAP_SHIFT);
|
|
258
|
533
|
|
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534 if (slab & m) {
|
|
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535
|
|
|
536 if (page->next == NULL) {
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|
|
537 slots = (ngx_slab_page_t *)
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|
|
538 ((u_char *) pool + sizeof(ngx_slab_pool_t));
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|
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539 slot = shift - pool->min_shift;
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|
|
540
|
|
|
541 page->next = slots[slot].next;
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|
|
542 slots[slot].next = page;
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|
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543
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|
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544 page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG;
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|
|
545 page->next->prev = (uintptr_t) page | NGX_SLAB_BIG;
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|
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546 }
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|
|
547
|
|
|
548 page->slab &= ~m;
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|
|
549
|
|
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550 if (page->slab & NGX_SLAB_MAP_MASK) {
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551 goto done;
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|
|
552 }
|
|
|
553
|
|
|
554 ngx_slab_free_pages(pool, page, 1);
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|
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555
|
|
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556 goto done;
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|
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557 }
|
|
|
558
|
|
|
559 goto chunk_already_free;
|
|
|
560
|
|
|
561 case NGX_SLAB_PAGE:
|
|
|
562
|
|
|
563 if ((uintptr_t) p & (ngx_pagesize - 1)) {
|
|
|
564 goto wrong_chunk;
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|
|
565 }
|
|
|
566
|
|
|
567 if (slab == NGX_SLAB_PAGE_FREE) {
|
|
468
|
568 ngx_slab_error(pool, NGX_LOG_ALERT,
|
|
|
569 "ngx_slab_free(): page is already free");
|
|
258
|
570 goto fail;
|
|
|
571 }
|
|
|
572
|
|
|
573 if (slab == NGX_SLAB_PAGE_BUSY) {
|
|
468
|
574 ngx_slab_error(pool, NGX_LOG_ALERT,
|
|
|
575 "ngx_slab_free(): pointer to wrong page");
|
|
258
|
576 goto fail;
|
|
|
577 }
|
|
|
578
|
|
|
579 n = ((u_char *) p - pool->start) >> ngx_pagesize_shift;
|
|
|
580 size = slab & ~NGX_SLAB_PAGE_START;
|
|
|
581
|
|
|
582 ngx_slab_free_pages(pool, &pool->pages[n], size);
|
|
|
583
|
|
480
|
584 ngx_slab_junk(p, size << ngx_pagesize_shift);
|
|
258
|
585
|
|
480
|
586 return;
|
|
258
|
587 }
|
|
|
588
|
|
|
589 /* not reached */
|
|
|
590
|
|
|
591 return;
|
|
|
592
|
|
|
593 done:
|
|
|
594
|
|
|
595 ngx_slab_junk(p, size);
|
|
|
596
|
|
|
597 return;
|
|
|
598
|
|
|
599 wrong_chunk:
|
|
|
600
|
|
468
|
601 ngx_slab_error(pool, NGX_LOG_ALERT,
|
|
|
602 "ngx_slab_free(): pointer to wrong chunk");
|
|
258
|
603
|
|
|
604 goto fail;
|
|
|
605
|
|
|
606 chunk_already_free:
|
|
|
607
|
|
468
|
608 ngx_slab_error(pool, NGX_LOG_ALERT,
|
|
|
609 "ngx_slab_free(): chunk is already free");
|
|
258
|
610
|
|
|
611 fail:
|
|
|
612
|
|
|
613 return;
|
|
|
614 }
|
|
|
615
|
|
|
616
|
|
|
617 static ngx_slab_page_t *
|
|
|
618 ngx_slab_alloc_pages(ngx_slab_pool_t *pool, ngx_uint_t pages)
|
|
|
619 {
|
|
|
620 ngx_slab_page_t *page, *p;
|
|
|
621
|
|
|
622 for (page = pool->free.next; page != &pool->free; page = page->next) {
|
|
|
623
|
|
|
624 if (page->slab >= pages) {
|
|
|
625
|
|
|
626 if (page->slab > pages) {
|
|
|
627 page[pages].slab = page->slab - pages;
|
|
|
628 page[pages].next = page->next;
|
|
|
629 page[pages].prev = page->prev;
|
|
|
630
|
|
|
631 p = (ngx_slab_page_t *) page->prev;
|
|
|
632 p->next = &page[pages];
|
|
|
633 page->next->prev = (uintptr_t) &page[pages];
|
|
|
634
|
|
|
635 } else {
|
|
|
636 p = (ngx_slab_page_t *) page->prev;
|
|
|
637 p->next = page->next;
|
|
|
638 page->next->prev = page->prev;
|
|
|
639 }
|
|
|
640
|
|
|
641 page->slab = pages | NGX_SLAB_PAGE_START;
|
|
|
642 page->next = NULL;
|
|
|
643 page->prev = NGX_SLAB_PAGE;
|
|
|
644
|
|
|
645 if (--pages == 0) {
|
|
|
646 return page;
|
|
|
647 }
|
|
|
648
|
|
|
649 for (p = page + 1; pages; pages--) {
|
|
|
650 p->slab = NGX_SLAB_PAGE_BUSY;
|
|
|
651 p->next = NULL;
|
|
|
652 p->prev = NGX_SLAB_PAGE;
|
|
|
653 p++;
|
|
|
654 }
|
|
|
655
|
|
|
656 return page;
|
|
|
657 }
|
|
|
658 }
|
|
|
659
|
|
468
|
660 ngx_slab_error(pool, NGX_LOG_CRIT, "ngx_slab_alloc() failed: no memory");
|
|
272
|
661
|
|
258
|
662 return NULL;
|
|
|
663 }
|
|
|
664
|
|
|
665
|
|
|
666 static void
|
|
|
667 ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page,
|
|
|
668 ngx_uint_t pages)
|
|
|
669 {
|
|
|
670 ngx_slab_page_t *prev;
|
|
|
671
|
|
|
672 page->slab = pages--;
|
|
|
673
|
|
|
674 if (pages) {
|
|
|
675 ngx_memzero(&page[1], pages * sizeof(ngx_slab_page_t));
|
|
|
676 }
|
|
|
677
|
|
272
|
678 if (page->next) {
|
|
|
679 prev = (ngx_slab_page_t *) (page->prev & ~NGX_SLAB_PAGE_MASK);
|
|
|
680 prev->next = page->next;
|
|
|
681 page->next->prev = page->prev;
|
|
|
682 }
|
|
258
|
683
|
|
272
|
684 page->prev = (uintptr_t) &pool->free;
|
|
258
|
685 page->next = pool->free.next;
|
|
272
|
686
|
|
|
687 page->next->prev = (uintptr_t) page;
|
|
|
688
|
|
258
|
689 pool->free.next = page;
|
|
|
690 }
|
|
468
|
691
|
|
|
692
|
|
|
693 static void
|
|
|
694 ngx_slab_error(ngx_slab_pool_t *pool, ngx_uint_t level, char *text)
|
|
|
695 {
|
|
|
696 ngx_log_error(level, ngx_cycle->log, 0, "%s%s", text, pool->log_ctx);
|
|
|
697 }
|
