nginx 0.5.35 *) Change: now the ngx_http_userid_module adds start time microseconds to the cookie field contains a pid value. *) Change: now the uname(2) is used on Linux instead of procfs. Thanks to Ilya Novikov. *) Feature: the "If-Range" request header line support. Thanks to Alexander V. Inyukhin. *) Bugfix: in HTTPS mode requests might fail with the "bad write retry" error; bug appeared in 0.5.13. *) Bugfix: the STARTTLS in SMTP mode did not work. Thanks to Oleg Motienko. *) Bugfix: large_client_header_buffers did not freed before going to keep-alive state. Thanks to Olexander Shtepa. *) Bugfix: the "limit_rate" directive did not allow to use full throughput, even if limit value was very high. *) Bugfix: the $status variable was equal to 0 if a proxied server returned response in HTTP/0.9 version. *) Bugfix: if the "?" character was in a "error_page" directive, then it was escaped in a proxied request; bug appeared in 0.5.32.

/*
 * 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

}