0
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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
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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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112
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11 void
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160
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12 ngx_spinlock(ngx_atomic_t *lock, ngx_atomic_int_t value, ngx_uint_t spin)
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0
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13 {
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14
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15 #if (NGX_HAVE_ATOMIC_OPS)
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16
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160
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17 ngx_uint_t i, n;
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0
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18
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19 for ( ;; ) {
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20
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160
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21 if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
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22 return;
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23 }
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24
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25 if (ngx_ncpu > 1) {
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26
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27 for (n = 1; n < spin; n <<= 1) {
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28
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160
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29 for (i = 0; i < n; i++) {
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30 ngx_cpu_pause();
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31 }
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32
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160
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33 if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
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34 return;
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35 }
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0
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36 }
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37 }
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160
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38
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39 ngx_sched_yield();
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40 }
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41
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42 #else
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43
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44 #if (NGX_THREADS)
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45
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46 #error ngx_spinlock() or ngx_atomic_cmp_set() are not defined !
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47
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48 #endif
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49
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50 #endif
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51
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52 }
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