Workaround for "configuration file test failed" under OpenVZ. If nginx was used under OpenVZ and a container with nginx was suspended and resumed, configuration tests started to fail because of EADDRINUSE returned from listen() instead of bind(): # nginx -t nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: [emerg] listen() to 0.0.0.0:80, backlog 511 failed (98: Address already in use) nginx: configuration file /etc/nginx/nginx.conf test failed With this change EADDRINUSE errors returned by listen() are handled similarly to errors returned by bind(), and configuration tests work fine in the same environment: # nginx -t nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: configuration file /etc/nginx/nginx.conf test is successful More details about OpenVZ suspend/resume bug: https://bugzilla.openvz.org/show_bug.cgi?id=2470

/*
 * 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

}