nginx 1.3.10 *) Change: domain names specified in configuration file are now resolved to IPv6 addresses as well as IPv4 ones. *) Change: now if the "include" directive with mask is used on Unix systems, included files are sorted in alphabetical order. *) Change: the "add_header" directive adds headers to 201 responses. *) Feature: the "geo" directive now supports IPv6 addresses in CIDR notation. *) Feature: the "flush" and "gzip" parameters of the "access_log" directive. *) Feature: variables support in the "auth_basic" directive. *) Bugfix: nginx could not be built with the ngx_http_perl_module in some cases. *) Bugfix: a segmentation fault might occur in a worker process if the ngx_http_xslt_module was used. *) Bugfix: nginx could not be built on MacOSX in some cases. Thanks to Piotr Sikora. *) Bugfix: the "limit_rate" directive with high rates might result in truncated responses on 32-bit platforms. Thanks to Alexey Antropov. *) Bugfix: a segmentation fault might occur in a worker process if the "if" directive was used. Thanks to Piotr Sikora. *) Bugfix: a "100 Continue" response was issued with "413 Request Entity Too Large" responses. *) Bugfix: the "image_filter", "image_filter_jpeg_quality" and "image_filter_sharpen" directives might be inherited incorrectly. Thanks to Ian Babrou. *) Bugfix: "crypt_r() failed" errors might appear if the "auth_basic" directive was used on Linux. *) Bugfix: in backup servers handling. Thanks to Thomas Chen. *) Bugfix: proxied HEAD requests might return incorrect response if the "gzip" directive was used.

/*
 * 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

}