--- a/auto/lib/conf
+++ b/auto/lib/conf
@@ -70,6 +70,11 @@ fi
 if [ $HTTP_GEOIP = YES ]; then
     . auto/lib/geoip/conf
 fi
+
 if [ $NGX_GOOGLE_PERFTOOLS = YES ]; then
     . auto/lib/google-perftools/conf
 fi
+
+if [ $NGX_LIBATOMIC != NO ]; then
+    . auto/lib/libatomic/conf
+fi

new file mode 100644
--- /dev/null
+++ b/auto/lib/libatomic/conf
@@ -0,0 +1,38 @@
+
+# Copyright (C) Igor Sysoev
+
+
+if [ $NGX_LIBATOMIC != YES ]; then
+
+    have=NGX_HAVE_LIBATOMIC . auto/have
+    CORE_INCS="$CORE_INCS $NGX_LIBATOMIC/src"
+    LINK_DEPS="$LINK_DEPS $NGX_LIBATOMIC/src/libatomic_ops.a"
+    CORE_LIBS="$CORE_LIBS $NGX_LIBATOMIC/src/libatomic_ops.a"
+
+else
+
+    ngx_feature="atomic_ops library"
+    ngx_feature_name=NGX_HAVE_LIBATOMIC
+    ngx_feature_run=no
+    ngx_feature_incs="#include <atomic_ops.h>"
+    ngx_feature_path=
+    ngx_feature_libs="-latomic_ops"
+    ngx_feature_test="AO_t *n;
+                      AO_compare_and_swap(n, 0, 1);
+                      AO_fetch_and_add(n, 1);
+                      AO_nop();"
+
+    . auto/feature
+
+    if [ $ngx_found = yes ]; then
+        CORE_LIBS="$CORE_LIBS $ngx_feature_libs"
+    else
+
+cat << END
+
+$0: error: libatomic_ops library was not found.
+
+END
+        exit 1
+    fi
+fi

new file mode 100644
--- /dev/null
+++ b/auto/lib/libatomic/make
@@ -0,0 +1,13 @@
+
+# Copyright (C) Igor Sysoev
+
+
+    cat << END                                            >> $NGX_MAKEFILE
+
+$NGX_LIBATOMIC/src/libatomic_ops.a:	$NGX_LIBATOMIC/Makefile
+	cd $NGX_LIBATOMIC && make
+
+$NGX_LIBATOMIC/Makefile:	$NGX_MAKEFILE
+	cd $NGX_LIBATOMIC && ./configure
+
+END

--- a/auto/lib/make
+++ b/auto/lib/make
@@ -22,6 +22,10 @@ if [ $ZLIB != NONE -a $ZLIB != NO -a $ZL
     . auto/lib/zlib/make
 fi
 
+if [ $NGX_LIBATOMIC != NO -a $NGX_LIBATOMIC != YES ]; then
+    . auto/lib/libatomic/make
+fi
+
 if [ $USE_PERL = YES ]; then
     . auto/lib/perl/make
 fi

--- a/auto/options
+++ b/auto/options
@@ -132,6 +132,8 @@ USE_LIBGD=NO
 NGX_GOOGLE_PERFTOOLS=NO
 NGX_CPP_TEST=NO
 
+NGX_LIBATOMIC=NO
+
 NGX_CPU_CACHE_LINE=
 
 opt=
@@ -266,6 +268,9 @@ do
         --with-zlib-opt=*)               ZLIB_OPT="$value"          ;;
         --with-zlib-asm=*)               ZLIB_ASM="$value"          ;;
 
+        --with-libatomic)                NGX_LIBATOMIC=YES          ;;
+        --with-libatomic=*)              NGX_LIBATOMIC="$value"     ;;
+
         --test-build-devpoll)            NGX_TEST_BUILD_DEVPOLL=YES ;;
         --test-build-eventport)          NGX_TEST_BUILD_EVENTPORT=YES ;;
         --test-build-epoll)              NGX_TEST_BUILD_EPOLL=YES   ;;
@@ -400,6 +405,9 @@ cat << END
                                      for specified CPU, the valid values:
                                      pentium, pentiumpro
 
+  --with-libatomic                   force libatomic_ops library usage
+  --with-libatomic=DIR               set path to libatomic_ops library sources
+
   --with-openssl=DIR                 set path to OpenSSL library sources
   --with-openssl-opt=OPTIONS         set additional options for OpenSSL building
 

--- a/src/os/unix/ngx_atomic.h
+++ b/src/os/unix/ngx_atomic.h
@@ -12,7 +12,31 @@
 #include <ngx_core.h>
 
 
-#if (NGX_DARWIN_ATOMIC)
+#if (NGX_HAVE_LIBATOMIC)
+
+#include <atomic_ops.h>
+
+#define NGX_HAVE_ATOMIC_OPS  1
+
+typedef long                        ngx_atomic_int_t;
+typedef AO_t                        ngx_atomic_uint_t;
+typedef volatile ngx_atomic_uint_t  ngx_atomic_t;
+
+#if (NGX_PTR_SIZE == 8)
+#define NGX_ATOMIC_T_LEN            (sizeof("-9223372036854775808") - 1)
+#else
+#define NGX_ATOMIC_T_LEN            (sizeof("-2147483648") - 1)
+#endif
+
+#define ngx_atomic_cmp_set(lock, old, new)                                    \
+    AO_compare_and_swap(lock, old, new)
+#define ngx_atomic_fetch_add(value, add)                                      \
+    AO_fetch_and_add(value, add)
+#define ngx_memory_barrier()        AO_nop()
+#define ngx_cpu_pause()
+
+
+#elif (NGX_DARWIN_ATOMIC)
 
 /*
  * use Darwin 8 atomic(3) and barrier(3) operations