view src/core/ngx_spinlock.c @ 473:8e8f3af115b5 release-0.1.11

nginx-0.1.11-RELEASE import *) Feature: the worker_priority directive. *) Change: both tcp_nopush and tcp_nodelay directives affect the transferred response. *) Bugfix: nginx did not call initgroups(). Thanks to Andrew Sitnikov and Andrei Nigmatulin. *) Change: now the ngx_http_autoindex_module shows the file size in the bytes. *) Bugfix: the ngx_http_autoindex_module returned the 500 error if the broken symlink was in a directory. *) Bugfix: the files bigger than 4G could not be transferred using sendfile. *) Bugfix: if the backend was resolved to several backends and there was an error while the response waiting then process may got caught in an endless loop. *) Bugfix: the worker process may exit with the "unknown cycle" message when the /dev/poll method was used. *) Bugfix: "close() channel failed" errors. *) Bugfix: the autodetection of the "nobody" and "nogroup" groups. *) Bugfix: the send_lowat directive did not work on Linux. *) Bugfix: the segmentation fault occurred if there was no events section in configuration. *) Bugfix: nginx could not be built on OpenBSD. *) Bugfix: the double slashes in "://" in the URI were converted to ":/".
author Igor Sysoev <igor@sysoev.ru>
date Thu, 02 Dec 2004 18:40:46 +0000
parents 42d11f017717
children 975f62e77f02
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_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

}