nginx 1.1.1 *) Change: now cache loader processes either as many files as specified by "loader_files" parameter or works no more than time specified by "loader_threshold" parameter during each iteration. *) Change: now SIGWINCH signal works only in deamon mode. *) Feature: now shared zones and caches use POSIX semaphores on Solaris. Thanks to Den Ivanov. *) Feature: accept filters are now supported on NetBSD. *) Bugfix: nginx could not be build on Linux 3.0. *) Bugfix: nginx did not use gzipping in some cases; the bug had appeared in 1.1.0. *) Bugfix: request body might be incorrectly processed if client used pipelining. *) Bugfix: in the "request_body_in_single_buf" directive. *) Bugfix: in "proxy_set_body" and "proxy_pass_request_body" directives if SSL connection to backend was used. *) Bugfix: nginx hogged CPU if all servers in an upstream were marked as "down". *) Bugfix: a segmentation fault might occur during reconfiguration if ssl_session_cache was defined but not used in a previous configuration. *) Bugfix: a segmentation fault might occur in a worker process if many backup servers were used in an upstream. *) Bugfix: a segmentation fault might occur in a worker process if "fastcgi/scgi/uwsgi_param" directives were used with values starting with "HTTP_"; the bug had appeared in 0.8.40.

/*
 * 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

}