/* | |
* Copyright (C) Igor Sysoev | |
*/ | |
#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 | |
} |