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diff src/core/ngx_spinlock.c @ 160:73e8476f9142 NGINX_0_3_27

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nginx 0.3.27 *) 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.
author Igor Sysoev <http://sysoev.ru>
date Wed, 08 Feb 2006 00:00:00 +0300
parents 408f195b3482
children d0f7a625f27c
line wrap: on
line diff
--- a/src/core/ngx_spinlock.c
+++ b/src/core/ngx_spinlock.c
@@ -8,36 +8,35 @@
 #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)
+ngx_spinlock(ngx_atomic_t *lock, ngx_atomic_int_t value, ngx_uint_t spin)
 {
 
 #if (NGX_HAVE_ATOMIC_OPS)
 
-    ngx_uint_t  tries;
-
-    tries = 0;
+    ngx_uint_t  i, n;
 
     for ( ;; ) {
 
-        if (*lock) {
-            if (ngx_ncpu > 1 && tries++ < spin) {
-                continue;
-            }
+        if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
+            return;
+        }
+
+        if (ngx_ncpu > 1) {
+
+            for (n = 1; n < spin; n <<= 1) {
 
-            ngx_sched_yield();
-
-            tries = 0;
+                for (i = 0; i < n; i++) {
+                    ngx_cpu_pause();
+                }
 
-        } else {
-            if (ngx_atomic_cmp_set(lock, 0, 1)) {
-                return;
+                if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
+                    return;
+                }
             }
         }
+
+        ngx_sched_yield();
     }
 
 #else