nginx 0.3.16 *) Feature: the ngx_http_map_module. *) Feature: the "types_hash_max_size" and "types_hash_bucket_size" directives. *) Feature: the "ssi_value_length" directive. *) Feature: the "worker_rlimit_core" directive. *) Workaround: the connection number in logs was always 1 if nginx was built by the icc 8.1 or 9.0 compilers with optimization for Pentium 4. *) Bugfix: the "config timefmt" SSI command set incorrect time format. *) Bugfix: nginx did not close connection to IMAP/POP3 backend for the SSL connections; bug appeared in 0.3.13. Thanks to Rob Mueller. *) Bugfix: segmentation fault may occurred in at SSL shutdown; bug appeared in 0.3.13.

/*
 * 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

}