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