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1
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2 /*
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3 * Copyright (C) Igor Sysoev
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644
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4 * Copyright (C) Nginx, Inc.
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5 */
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6
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7
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8 #include <ngx_config.h>
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9 #include <ngx_core.h>
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10 #include <ngx_event.h>
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11
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12
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340
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13 static ngx_int_t ngx_event_busy_lock_look_cacheable(ngx_event_busy_lock_t *bl,
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112
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14 ngx_event_busy_lock_ctx_t *ctx);
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0
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15 static void ngx_event_busy_lock_handler(ngx_event_t *ev);
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16 static void ngx_event_busy_lock_posted_handler(ngx_event_t *ev);
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17
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18
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19 /*
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20 * NGX_OK: the busy lock is held
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21 * NGX_AGAIN: the all busy locks are held but we will wait the specified time
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22 * NGX_BUSY: ctx->timer == 0: there are many the busy locks
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23 * ctx->timer != 0: there are many the waiting locks
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24 */
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25
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112
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26 ngx_int_t
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27 ngx_event_busy_lock(ngx_event_busy_lock_t *bl, ngx_event_busy_lock_ctx_t *ctx)
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28 {
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29 ngx_int_t rc;
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30
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112
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31 ngx_mutex_lock(bl->mutex);
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32
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33 ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ctx->event->log, 0,
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34 "event busy lock: b:%d mb:%d",
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35 bl->busy, bl->max_busy);
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36
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37 if (bl->busy < bl->max_busy) {
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38 bl->busy++;
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39
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40 rc = NGX_OK;
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41
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42 } else if (ctx->timer && bl->waiting < bl->max_waiting) {
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43 bl->waiting++;
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44 ngx_add_timer(ctx->event, ctx->timer);
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58
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45 ctx->event->handler = ngx_event_busy_lock_handler;
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46
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47 if (bl->events) {
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48 bl->last->next = ctx;
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49
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50 } else {
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51 bl->events = ctx;
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52 }
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53
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54 bl->last = ctx;
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55
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56 rc = NGX_AGAIN;
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57
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58 } else {
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59 rc = NGX_BUSY;
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60 }
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61
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62 ngx_mutex_unlock(bl->mutex);
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63
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64 return rc;
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65 }
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66
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67
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112
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68 ngx_int_t
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340
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69 ngx_event_busy_lock_cacheable(ngx_event_busy_lock_t *bl,
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112
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70 ngx_event_busy_lock_ctx_t *ctx)
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71 {
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72 ngx_int_t rc;
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73
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112
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74 ngx_mutex_lock(bl->mutex);
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75
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340
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76 rc = ngx_event_busy_lock_look_cacheable(bl, ctx);
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77
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78 ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ctx->event->log, 0,
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79 "event busy lock: %d w:%d mw:%d",
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80 rc, bl->waiting, bl->max_waiting);
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81
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82 /*
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83 * NGX_OK: no the same request, there is free slot and we locked it
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84 * NGX_BUSY: no the same request and there is no free slot
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85 * NGX_AGAIN: the same request is processing
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86 */
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87
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88 if (rc == NGX_AGAIN) {
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89
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90 if (ctx->timer && bl->waiting < bl->max_waiting) {
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91 bl->waiting++;
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92 ngx_add_timer(ctx->event, ctx->timer);
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93 ctx->event->handler = ngx_event_busy_lock_handler;
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94
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95 if (bl->events == NULL) {
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96 bl->events = ctx;
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97 } else {
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98 bl->last->next = ctx;
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99 }
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100 bl->last = ctx;
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101
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102 } else {
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103 rc = NGX_BUSY;
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104 }
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105 }
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106
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107 ngx_mutex_unlock(bl->mutex);
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108
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109 return rc;
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110 }
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111
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112
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112
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113 void
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114 ngx_event_busy_unlock(ngx_event_busy_lock_t *bl,
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115 ngx_event_busy_lock_ctx_t *ctx)
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116 {
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117 ngx_event_t *ev;
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118 ngx_event_busy_lock_ctx_t *wakeup;
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119
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112
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120 ngx_mutex_lock(bl->mutex);
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121
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122 if (bl->events) {
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123 wakeup = bl->events;
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124 bl->events = bl->events->next;
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125
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126 } else {
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127 wakeup = NULL;
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128 bl->busy--;
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129 }
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130
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131 /*
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132 * MP: all ctx's and their queue must be in shared memory,
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133 * each ctx has pid to wake up
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134 */
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135
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136 if (wakeup == NULL) {
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137 ngx_mutex_unlock(bl->mutex);
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112
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138 return;
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139 }
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140
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141 if (ctx->md5) {
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142 for (wakeup = bl->events; wakeup; wakeup = wakeup->next) {
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143 if (wakeup->md5 == NULL || wakeup->slot != ctx->slot) {
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144 continue;
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145 }
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146
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147 wakeup->handler = ngx_event_busy_lock_posted_handler;
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148 wakeup->cache_updated = 1;
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149
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150 ev = wakeup->event;
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151
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112
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152 ngx_post_event(ev, &ngx_posted_events);
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153 }
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154
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155 ngx_mutex_unlock(bl->mutex);
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156
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157 } else {
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158 bl->waiting--;
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159
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160 ngx_mutex_unlock(bl->mutex);
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161
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162 wakeup->handler = ngx_event_busy_lock_posted_handler;
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163 wakeup->locked = 1;
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164
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165 ev = wakeup->event;
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166
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167 if (ev->timer_set) {
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168 ngx_del_timer(ev);
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169 }
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170
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171 ngx_post_event(ev, &ngx_posted_events);
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172 }
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173 }
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174
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175
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112
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176 void
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177 ngx_event_busy_lock_cancel(ngx_event_busy_lock_t *bl,
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178 ngx_event_busy_lock_ctx_t *ctx)
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179 {
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180 ngx_event_busy_lock_ctx_t *c, *p;
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181
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112
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182 ngx_mutex_lock(bl->mutex);
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183
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184 bl->waiting--;
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185
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186 if (ctx == bl->events) {
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187 bl->events = ctx->next;
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188
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189 } else {
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190 p = bl->events;
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191 for (c = bl->events->next; c; c = c->next) {
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192 if (c == ctx) {
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193 p->next = ctx->next;
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194 break;
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195 }
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196 p = c;
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197 }
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198 }
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199
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200 ngx_mutex_unlock(bl->mutex);
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201 }
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202
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203
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112
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204 static ngx_int_t
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340
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205 ngx_event_busy_lock_look_cacheable(ngx_event_busy_lock_t *bl,
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112
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206 ngx_event_busy_lock_ctx_t *ctx)
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207 {
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208 ngx_int_t free;
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209 ngx_uint_t i, bit, cacheable, mask;
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210
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211 bit = 0;
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212 cacheable = 0;
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213 free = -1;
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214
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215 #if (NGX_SUPPRESS_WARN)
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216 mask = 0;
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217 #endif
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218
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219 for (i = 0; i < bl->max_busy; i++) {
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220
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221 if ((bit & 7) == 0) {
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222 mask = bl->md5_mask[i / 8];
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223 }
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224
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225 if (mask & 1) {
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226 if (ngx_memcmp(&bl->md5[i * 16], ctx->md5, 16) == 0) {
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227 ctx->waiting = 1;
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228 ctx->slot = i;
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229 return NGX_AGAIN;
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230 }
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340
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231 cacheable++;
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232
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233 } else if (free == -1) {
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234 free = i;
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235 }
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236
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340
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237 if (cacheable == bl->cacheable) {
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238 if (free == -1 && cacheable < bl->max_busy) {
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239 free = i + 1;
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240 }
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241
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242 break;
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243 }
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244
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245 mask >>= 1;
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246 bit++;
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247 }
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248
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249 if (free == -1) {
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250 return NGX_BUSY;
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251 }
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252
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253 #if 0
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254 if (bl->busy == bl->max_busy) {
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255 return NGX_BUSY;
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256 }
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257 #endif
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258
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259 ngx_memcpy(&bl->md5[free * 16], ctx->md5, 16);
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260 bl->md5_mask[free / 8] |= 1 << (free & 7);
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261 ctx->slot = free;
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262
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340
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263 bl->cacheable++;
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264 bl->busy++;
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265
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266 return NGX_OK;
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267 }
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268
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269
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112
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270 static void
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271 ngx_event_busy_lock_handler(ngx_event_t *ev)
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272 {
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273 ev->handler = ngx_event_busy_lock_posted_handler;
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274
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275 ngx_post_event(ev, &ngx_posted_events);
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276 }
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277
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278
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112
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279 static void
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280 ngx_event_busy_lock_posted_handler(ngx_event_t *ev)
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281 {
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282 ngx_event_busy_lock_ctx_t *ctx;
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283
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284 ctx = ev->data;
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285 ctx->handler(ev);
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286 }
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