nginx 0.7.53 *) Change: now a log set by --error-log-path is created from the very start-up. *) Feature: now the start up errors and warnings are outputted to an error_log and stderr. *) Feature: the empty --prefix= configure parameter forces nginx to use a directory where it was run as prefix. *) Feature: the -p switch. *) Feature: the -s switch on Unix platforms. *) Feature: the -? and -h switches. Thanks to Jerome Loyet. *) Feature: now switches may be set in condensed form. *) Bugfix: nginx/Windows did not work if configuration file was given by the -c switch. *) Bugfix: temporary files might be not removed if the "proxy_store", "fastcgi_store", "proxy_cache", or "fastcgi_cache" were used. Thanks to Maxim Dounin. *) Bugfix: an incorrect value was passed to mail proxy authentication server in "Auth-Method" header line; the bug had appeared in 0.7.34. Thanks to Simon Lecaille. *) Bugfix: system error text descriptions were not logged on Linux; the bug had appeared in 0.7.45. *) Bugfix: the "fastcgi_cache_min_uses" directive did not work. Thanks to Andrew Vorobyoff.

/*
 * 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

}