new file mode 100644
--- /dev/null
+++ b/src/core/ngx_spinlock.c
@@ -0,0 +1,48 @@
+
+/*
+ * 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
+
+}