nginx 1.1.12 *) Change: a "proxy_pass" directive without URI part now uses changed URI after redirection with the "error_page" directive; Thanks to Lanshun Zhou. *) Feature: the "proxy/fastcgi/scgi/uwsgi_cache_lock", "proxy/fastcgi/scgi/uwsgi_cache_lock_timeout" directives. *) Feature: the "pcre_jit" directive. *) Feature: the "if" SSI command supports captures in regular expressions. *) Bugfix: the "if" SSI command did not work inside the "block" command. *) Bugfix: the "limit_conn_log_level" and "limit_req_log_level" directives might not work. *) Bugfix: the "limit_rate" directive did not allow to use full throughput, even if limit value was very high. *) Bugfix: the "sendfile_max_chunk" directive did not work, if the "limit_rate" directive was used. *) Bugfix: a "proxy_pass" directive without URI part always used original request URI if variables were used. *) Bugfix: a "proxy_pass" directive without URI part might use original request after redirection with the "try_files" directive; Thanks to Lanshun Zhou. *) Bugfix: in the ngx_http_scgi_module. *) Bugfix: in the ngx_http_mp4_module. *) Bugfix: nginx could not be built on Solaris; the bug had appeared in 1.1.9.

/*
 * 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

}