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54 lines
820 B
C
54 lines
820 B
C
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/*
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* Copyright (C) Igor Sysoev
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* Copyright (C) Nginx, Inc.
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*/
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#include <ngx_config.h>
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#include <ngx_core.h>
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void
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ngx_spinlock(ngx_atomic_t *lock, ngx_atomic_int_t value, ngx_uint_t spin)
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{
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#if (NGX_HAVE_ATOMIC_OPS)
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ngx_uint_t i, n;
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for ( ;; ) {
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if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
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return;
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}
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if (ngx_ncpu > 1) {
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for (n = 1; n < spin; n <<= 1) {
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for (i = 0; i < n; i++) {
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ngx_cpu_pause();
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}
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if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
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return;
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}
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}
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}
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ngx_sched_yield();
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}
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#else
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#if (NGX_THREADS)
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#error ngx_spinlock() or ngx_atomic_cmp_set() are not defined !
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#endif
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#endif
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}
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