nginx-0.1.38-RELEASE import *) Feature: the "limit_rate" directive is supported in in proxy and FastCGI mode. *) Feature: the "X-Accel-Limit-Rate" response header line is supported in proxy and FastCGI mode. *) Feature: the "break" directive. *) Feature: the "log_not_found" directive. *) Bugfix: the response status code was not changed when request was redirected by the ""X-Accel-Redirect" header line. *) Bugfix: the variables set by the "set" directive could not be used in SSI. *) Bugfix: the segmentation fault may occurred if the SSI page has more than one remote subrequest. *) Bugfix: nginx treated the backend response as invalid if the status line in the header was transferred in two packets; the bug had appeared in 0.1.29. *) Feature: the "ssi_types" directive. *) Feature: the "autoindex_exact_size" directive. *) Bugfix: the ngx_http_autoindex_module did not support the long file names in UTF-8. *) Feature: the IMAP/POP3 proxy.

/*
 * 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

}