nginx 0.3.3 *) Change: the "bl" and "af" parameters of the "listen" directive was renamed to the "backlog" and "accept_filter". *) Feature: the "rcvbuf" and "sndbuf" parameters of the "listen" directive. *) Change: the "$msec" log parameter does not require now the additional the gettimeofday() system call. *) Feature: the -t switch now tests the "listen" directives. *) Bugfix: if the invalid address was specified in the "listen" directive, then after the -HUP signal nginx left an open socket in the CLOSED state. *) Bugfix: the mime type may be incorrectly set to default value for index file with variable in the name; bug appeared in 0.3.0. *) Feature: the "timer_resolution" directive. *) Feature: the millisecond "$upstream_response_time" log parameter. *) Bugfix: a temporary file with client request body now is removed just after the response header was transferred to a client. *) Bugfix: OpenSSL 0.9.6 compatibility. *) Bugfix: the SSL certificate and key file paths could not be relative. *) Bugfix: the "ssl_prefer_server_ciphers" directive did not work in the ngx_imap_ssl_module. *) Bugfix: the "ssl_protocols" directive allowed to specify the single protocol only.

/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>


/*
 * TODO: the P4 optimized assembler version with the "pause" operation
 */

void
ngx_spinlock(ngx_atomic_t *lock, ngx_uint_t spin)
{

#if (NGX_HAVE_ATOMIC_OPS)

    ngx_uint_t  tries;

    tries = 0;

    for ( ;; ) {

        if (*lock) {
            if (ngx_ncpu > 1 && tries++ < spin) {
                continue;
            }

            ngx_sched_yield();

            tries = 0;

        } else {
            if (ngx_atomic_cmp_set(lock, 0, 1)) {
                return;
            }
        }
    }

#else

#if (NGX_THREADS)

#error ngx_spinlock() or ngx_atomic_cmp_set() are not defined !

#endif

#endif

}