view src/core/ngx_spinlock.c @ 634:0d6525917227 NGINX_1_0_7

nginx 1.0.7 *) Change: now if total size of all ranges is greater than source response size, then nginx disables ranges and returns just the source response. *) Feature: the "max_ranges" directive. *) Feature: the module ngx_http_mp4_module. *) Feature: the "worker_aio_requests" directive. *) Bugfix: if nginx was built --with-file-aio it could not be run on Linux kernel which did not support AIO. *) Bugfix: in Linux AIO error processing. Thanks to Hagai Avrahami. *) Bugfix: in Linux AIO combined with open_file_cache. *) Bugfix: open_file_cache did not update file info on retest if file was not atomically changed. *) Bugfix: reduced memory consumption for long-lived requests. *) Bugfix: in the "proxy/fastcgi/scgi/uwsgi_ignore_client_abort" directives. *) Bugfix: nginx could not be built on MacOSX 10.7. *) Bugfix: in the "proxy/fastcgi/scgi/uwsgi_ignore_client_abort" directives. *) Bugfix: request body might be processed incorrectly 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 previous configuration. *) Bugfix: a segmentation fault might occur in a worker process if many backup servers were used in an upstream.
author Igor Sysoev <http://sysoev.ru>
date Fri, 30 Sep 2011 00:00:00 +0400
parents 73e8476f9142
children ad25218fd14b
line wrap: on
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/*
 * 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

}