nginx 1.1.0 *) Feature: cache loader run time decrease. *) Feature: "loader_files", "loader_sleep", and "loader_threshold" options of the "proxy/fastcgi/scgi/uwsgi_cache_path" directives. *) Feature: loading time decrease of configuration with large number of HTTPS sites. *) Feature: now nginx supports ECDHE key exchange ciphers. Thanks to Adrian Kotelba. *) Feature: the "lingering_close" directive. Thanks to Maxim Dounin. *) Bugfix: in closing connection for pipelined requests. Thanks to Maxim Dounin. *) Bugfix: nginx did not disable gzipping if client sent "gzip;q=0" in "Accept-Encoding" request header line. *) Bugfix: in timeout in unbuffered proxied mode. Thanks to Maxim Dounin. *) Bugfix: memory leaks when a "proxy_pass" directive contains variables and proxies to an HTTPS backend. Thanks to Maxim Dounin. *) Bugfix: in parameter validaiton of a "proxy_pass" directive with variables. Thanks to Lanshun Zhou. *) Bugfix: SSL did not work on QNX. Thanks to Maxim Dounin. *) Bugfix: SSL modules could not be built by gcc 4.6 without --with-debug option.

/*
 * 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

}