nginx/src/core/ngx_spinlock.c


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#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

}
nginx-0.0.7-2004-06-21-23:22:53 import 2004-06-22 03:22:53 +08:00
nginx-0.1.0-2004-09-28-12:34:51 import; set copyright and remove unused files 2004-09-28 16:34:51 +08:00			`/*`
nginx-0.1.0-2004-09-29-20:00:49 import; remove years from copyright 2004-09-30 00:00:49 +08:00			`* Copyright (C) Igor Sysoev`
Copyright updated. 2012-01-18 23:07:43 +08:00			`* Copyright (C) Nginx, Inc.`
nginx-0.1.0-2004-09-28-12:34:51 import; set copyright and remove unused files 2004-09-28 16:34:51 +08:00			`*/`


nginx-0.0.7-2004-06-30-19:30:41 import 2004-06-30 23:30:41 +08:00			`#include <ngx_config.h>`
			`#include <ngx_core.h>`
nginx-0.0.7-2004-06-21-23:22:53 import 2004-06-22 03:22:53 +08:00
nginx-0.0.7-2004-06-30-19:30:41 import 2004-06-30 23:30:41 +08:00
nginx-0.3.3-RELEASE import ) Change: the "bl" and "af" parameters of the "listen" directive was renamed to the "backlog" and "accept_filter". ) Feature: the "rcvbuf" and "sndbuf" parameters of the "listen" directive. ) Change: the "$msec" log parameter does not require now the additional the gettimeofday() system call. ) Feature: the -t switch now tests the "listen" directives. ) Bugfix: if the invalid address was specified in the "listen" directive, then after the -HUP signal nginx left an open socket in the CLOSED state. ) Bugfix: the mime type may be incorrectly set to default value for index file with variable in the name; the bug had appeared in 0.3.0. ) Feature: the "timer_resolution" directive. ) Feature: the millisecond "$upstream_response_time" log parameter. ) Bugfix: a temporary file with client request body now is removed just after the response header was transferred to a client. ) Bugfix: OpenSSL 0.9.6 compatibility. ) Bugfix: the SSL certificate and key file paths could not be relative. ) Bugfix: the "ssl_prefer_server_ciphers" directive did not work in the ngx_imap_ssl_module. *) Bugfix: the "ssl_protocols" directive allowed to specify the single protocol only. 2005-10-19 20:33:58 +08:00			`void`
nginx-0.3.27-RELEASE import ) Change: the "variables_hash_max_size" and "variables_hash_bucket_size" directives. ) Feature: the $body_bytes_sent variable can be used not only in the "log_format" directive. ) Feature: the $ssl_protocol and $ssl_cipher variables. ) Feature: the cache line size detection for widespread CPUs at start time. ) Feature: now the "accept_mutex" directive is supported using fcntl(2) on platforms different from i386, amd64, sparc64, and ppc. ) Feature: the "lock_file" directive and the --with-lock-path=PATH autoconfiguration directive. *) Bugfix: if the HTTPS protocol was used in the "proxy_pass" directive then the requests with the body was not transferred. 2006-02-08 23:33:12 +08:00			`ngx_spinlock(ngx_atomic_t *lock, ngx_atomic_int_t value, ngx_uint_t spin)`
nginx-0.0.7-2004-06-21-23:22:53 import 2004-06-22 03:22:53 +08:00			`{`
nginx-0.0.11-2004-09-22-20:18:21 import 2004-09-23 00:18:21 +08:00
			`#if (NGX_HAVE_ATOMIC_OPS)`

nginx-0.3.27-RELEASE import ) Change: the "variables_hash_max_size" and "variables_hash_bucket_size" directives. ) Feature: the $body_bytes_sent variable can be used not only in the "log_format" directive. ) Feature: the $ssl_protocol and $ssl_cipher variables. ) Feature: the cache line size detection for widespread CPUs at start time. ) Feature: now the "accept_mutex" directive is supported using fcntl(2) on platforms different from i386, amd64, sparc64, and ppc. ) Feature: the "lock_file" directive and the --with-lock-path=PATH autoconfiguration directive. *) Bugfix: if the HTTPS protocol was used in the "proxy_pass" directive then the requests with the body was not transferred. 2006-02-08 23:33:12 +08:00			`ngx_uint_t i, n;`
nginx-0.0.7-2004-06-21-23:22:53 import 2004-06-22 03:22:53 +08:00
			`for ( ;; ) {`

nginx-0.3.27-RELEASE import ) Change: the "variables_hash_max_size" and "variables_hash_bucket_size" directives. ) Feature: the $body_bytes_sent variable can be used not only in the "log_format" directive. ) Feature: the $ssl_protocol and $ssl_cipher variables. ) Feature: the cache line size detection for widespread CPUs at start time. ) Feature: now the "accept_mutex" directive is supported using fcntl(2) on platforms different from i386, amd64, sparc64, and ppc. ) Feature: the "lock_file" directive and the --with-lock-path=PATH autoconfiguration directive. *) Bugfix: if the HTTPS protocol was used in the "proxy_pass" directive then the requests with the body was not transferred. 2006-02-08 23:33:12 +08:00			`if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {`
			`return;`
			`}`
nginx-0.0.7-2004-06-21-23:22:53 import 2004-06-22 03:22:53 +08:00
nginx-0.3.27-RELEASE import ) Change: the "variables_hash_max_size" and "variables_hash_bucket_size" directives. ) Feature: the $body_bytes_sent variable can be used not only in the "log_format" directive. ) Feature: the $ssl_protocol and $ssl_cipher variables. ) Feature: the cache line size detection for widespread CPUs at start time. ) Feature: now the "accept_mutex" directive is supported using fcntl(2) on platforms different from i386, amd64, sparc64, and ppc. ) Feature: the "lock_file" directive and the --with-lock-path=PATH autoconfiguration directive. *) Bugfix: if the HTTPS protocol was used in the "proxy_pass" directive then the requests with the body was not transferred. 2006-02-08 23:33:12 +08:00			`if (ngx_ncpu > 1) {`
nginx-0.0.7-2004-06-30-19:30:41 import 2004-06-30 23:30:41 +08:00
nginx-0.3.27-RELEASE import ) Change: the "variables_hash_max_size" and "variables_hash_bucket_size" directives. ) Feature: the $body_bytes_sent variable can be used not only in the "log_format" directive. ) Feature: the $ssl_protocol and $ssl_cipher variables. ) Feature: the cache line size detection for widespread CPUs at start time. ) Feature: now the "accept_mutex" directive is supported using fcntl(2) on platforms different from i386, amd64, sparc64, and ppc. ) Feature: the "lock_file" directive and the --with-lock-path=PATH autoconfiguration directive. *) Bugfix: if the HTTPS protocol was used in the "proxy_pass" directive then the requests with the body was not transferred. 2006-02-08 23:33:12 +08:00			`for (n = 1; n < spin; n <<= 1) {`
nginx-0.0.7-2004-06-21-23:22:53 import 2004-06-22 03:22:53 +08:00
nginx-0.3.27-RELEASE import ) Change: the "variables_hash_max_size" and "variables_hash_bucket_size" directives. ) Feature: the $body_bytes_sent variable can be used not only in the "log_format" directive. ) Feature: the $ssl_protocol and $ssl_cipher variables. ) Feature: the cache line size detection for widespread CPUs at start time. ) Feature: now the "accept_mutex" directive is supported using fcntl(2) on platforms different from i386, amd64, sparc64, and ppc. ) Feature: the "lock_file" directive and the --with-lock-path=PATH autoconfiguration directive. *) Bugfix: if the HTTPS protocol was used in the "proxy_pass" directive then the requests with the body was not transferred. 2006-02-08 23:33:12 +08:00			`for (i = 0; i < n; i++) {`
			`ngx_cpu_pause();`
			`}`

			`if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {`
			`return;`
			`}`
nginx-0.0.7-2004-06-21-23:22:53 import 2004-06-22 03:22:53 +08:00			`}`
			`}`
nginx-0.3.27-RELEASE import ) Change: the "variables_hash_max_size" and "variables_hash_bucket_size" directives. ) Feature: the $body_bytes_sent variable can be used not only in the "log_format" directive. ) Feature: the $ssl_protocol and $ssl_cipher variables. ) Feature: the cache line size detection for widespread CPUs at start time. ) Feature: now the "accept_mutex" directive is supported using fcntl(2) on platforms different from i386, amd64, sparc64, and ppc. ) Feature: the "lock_file" directive and the --with-lock-path=PATH autoconfiguration directive. *) Bugfix: if the HTTPS protocol was used in the "proxy_pass" directive then the requests with the body was not transferred. 2006-02-08 23:33:12 +08:00
			`ngx_sched_yield();`
nginx-0.0.7-2004-06-21-23:22:53 import 2004-06-22 03:22:53 +08:00			`}`
nginx-0.0.11-2004-09-22-20:18:21 import 2004-09-23 00:18:21 +08:00
			`#else`

Core: guard against spinlock usage without atomic ops. The new thread pools code uses spinlocks. 2015-03-26 19:15:06 +08:00			`#if (NGX_THREADS)`
nginx-0.0.11-2004-09-22-20:18:21 import 2004-09-23 00:18:21 +08:00
			`#error ngx_spinlock() or ngx_atomic_cmp_set() are not defined !`

			`#endif`

			`#endif`

nginx-0.0.7-2004-06-21-23:22:53 import 2004-06-22 03:22:53 +08:00			`}`