nginx 0.5.33 *) Change: now by default the "echo" SSI command uses entity encoding. *) Feature: the "encoding" parameter in the "echo" SSI command. *) Change: mail proxy was split on three modules: pop3, imap and smtp. *) Feature: the --without-mail_pop3_module, --without-mail_imap_module, and --without-mail_smtp_module configuration parameters. *) Feature: the "smtp_greeting_delay" and "smtp_client_buffer" directives of the ngx_mail_smtp_module. *) Feature: the "server_name" and "valid_referers" directives support regular expressions. *) Feature: the "server_name", "map", and "valid_referers" directives support the "www.example.*" wildcards. *) Bugfix: sub_filter did not work with empty substitution. *) Bugfix: in sub_filter parsing. *) Bugfix: a worker process may got caught in an endless loop, if the memcached was used. *) Bugfix: nginx supported low case only "close" and "keep-alive" values in the "Connection" request header line; bug appeared in 0.5.32. *) Bugfix: nginx could not start on Solaris if the shared PCRE library located in non-standard place was used.

/*
 * 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

}