diff --git a/src/core/ngx_conf_file.c b/src/core/ngx_conf_file.c
index f6ecd4a..e02b8c4 100644
--- a/src/core/ngx_conf_file.c
+++ b/src/core/ngx_conf_file.c
@@ -645,21 +645,23 @@
 {
     char  *p = conf;
 
-    ngx_flag_t   flag;
-    ngx_str_t   *value;
+    ngx_str_t        *value;
+    ngx_flag_t       *fp;
+    ngx_conf_post_t  *post;
 
+    fp = (ngx_flag_t *) (p + cmd->offset);
 
-    if (*(ngx_flag_t *) (p + cmd->offset) != NGX_CONF_UNSET) {
+    if (*fp != NGX_CONF_UNSET) {
         return "is duplicate";
     }
 
     value = cf->args->elts;
 
     if (ngx_strcasecmp(value[1].data, "on") == 0) {
-        flag = 1;
+        *fp = 1;
 
     } else if (ngx_strcasecmp(value[1].data, "off") == 0) {
-        flag = 0;
+        *fp = 0;
 
     } else {
         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
@@ -669,7 +671,10 @@
         return NGX_CONF_ERROR;
     }
 
-    *(ngx_flag_t *) (p + cmd->offset) = flag;
+    if (cmd->post) {
+        post = cmd->post;
+        return post->post_handler(cf, post, fp);
+    }
 
     return NGX_CONF_OK;
 }
diff --git a/src/core/ngx_spinlock.c b/src/core/ngx_spinlock.c
index c3c65d3..4de23c1 100644
--- a/src/core/ngx_spinlock.c
+++ b/src/core/ngx_spinlock.c
@@ -5,6 +5,9 @@
 
 void ngx_spinlock(ngx_atomic_t *lock, ngx_uint_t spin)
 {
+
+#if (NGX_HAVE_ATOMIC_OPS)
+
     ngx_uint_t  tries;
 
     tries = 0;
@@ -26,4 +29,15 @@
             }
         }
     }
+
+#else
+
+#if (NGX_THREADS)
+
+#error ngx_spinlock() or ngx_atomic_cmp_set() are not defined !
+
+#endif
+
+#endif
+
 }
diff --git a/src/event/ngx_event.c b/src/event/ngx_event.c
index cb350f6..a2e275b 100644
--- a/src/event/ngx_event.c
+++ b/src/event/ngx_event.c
@@ -45,6 +45,7 @@
 
 static void *ngx_event_create_conf(ngx_cycle_t *cycle);
 static char *ngx_event_init_conf(ngx_cycle_t *cycle, void *conf);
+static char *ngx_accept_mutex_check(ngx_conf_t *cf, void *post, void *data);
 
 
 static ngx_uint_t                 ngx_event_max_module;
@@ -113,6 +114,9 @@
 
 static ngx_str_t  event_core_name = ngx_string("event_core");
 
+static ngx_conf_post_t  ngx_accept_mutex_post = { ngx_accept_mutex_check } ;
+
+
 static ngx_command_t  ngx_event_core_commands[] = {
 
     { ngx_string("connections"),
@@ -141,7 +145,7 @@
       ngx_conf_set_flag_slot,
       0,
       offsetof(ngx_event_conf_t, accept_mutex),
-      NULL },
+      &ngx_accept_mutex_post },
 
     { ngx_string("accept_mutex_delay"),
       NGX_EVENT_CONF|NGX_CONF_TAKE1,
@@ -777,3 +781,20 @@
 
     return NGX_CONF_OK;
 }
+
+
+static char *ngx_accept_mutex_check(ngx_conf_t *cf, void *post, void *data)
+{
+#if !(NGX_HAVE_ATOMIC_OPS)
+
+    ngx_flag_t *fp = data;
+
+    *fp = 0;
+
+    ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+                       "\"accept_mutex\" is not supported, ignored");
+
+#endif
+
+    return NGX_CONF_OK;
+}
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 06f1565..325a8fe 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -96,6 +96,13 @@
       offsetof(ngx_http_core_srv_conf_t, client_header_buffer_size),
       NULL },
 
+    { ngx_string("client_large_buffers"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE2,
+      ngx_conf_set_bufs_slot,
+      NGX_HTTP_SRV_CONF_OFFSET,
+      offsetof(ngx_http_core_srv_conf_t, client_large_buffers),
+      NULL },
+
     { ngx_string("large_client_header"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
       ngx_conf_set_flag_slot,
@@ -1247,6 +1254,15 @@
                   ngx_pcalloc(cf->pool, sizeof(ngx_http_core_srv_conf_t)),
                   NGX_CONF_ERROR);
 
+    /*
+
+    set by ngx_pcalloc():
+
+    conf->client_large_buffers.num = 0;
+
+    */
+
+
     ngx_init_array(cscf->locations, cf->pool,
                    5, sizeof(void *), NGX_CONF_ERROR);
     ngx_init_array(cscf->listen, cf->pool, 5, sizeof(ngx_http_listen_t),
@@ -1326,6 +1342,8 @@
                               prev->client_header_timeout, 60000);
     ngx_conf_merge_size_value(conf->client_header_buffer_size,
                               prev->client_header_buffer_size, 1024);
+    ngx_conf_merge_bufs_value(conf->client_large_buffers,
+                              prev->client_large_buffers, 4, ngx_pagesize);
     ngx_conf_merge_value(conf->large_client_header,
                          prev->large_client_header, 1);
     ngx_conf_merge_unsigned_value(conf->restrict_host_names,
@@ -1543,7 +1561,7 @@
         return NGX_CONF_OK;
     }
 
-    ls->port = port;
+    ls->port = (in_port_t) port;
 
     ls->addr = inet_addr((const char *) addr);
     if (ls->addr == INADDR_NONE) {
diff --git a/src/http/ngx_http_core_module.h b/src/http/ngx_http_core_module.h
index 8385f48..0122b8b 100644
--- a/src/http/ngx_http_core_module.h
+++ b/src/http/ngx_http_core_module.h
@@ -66,6 +66,8 @@
     size_t                request_pool_size;
     size_t                client_header_buffer_size;
 
+    ngx_bufs_t            client_large_buffers;
+
     ngx_msec_t            post_accept_timeout;
     ngx_msec_t            client_header_timeout;
 
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index bb1cc7d..49ca93a 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -12,6 +12,8 @@
 static void ngx_http_process_request_line(ngx_event_t *rev);
 static void ngx_http_process_request_headers(ngx_event_t *rev);
 static ssize_t ngx_http_read_request_header(ngx_http_request_t *r);
+static ngx_int_t ngx_http_alloc_header_buf(ngx_http_request_t *r,
+                                           ngx_uint_t request_line);
 static ngx_int_t ngx_http_process_request_header(ngx_http_request_t *r);
 
 static void ngx_http_set_write_handler(ngx_http_request_t *r);
@@ -935,6 +937,25 @@
 
         if (r->header_in->last == r->header_in->end) {
 
+#if 1
+            /* ngx_http_alloc_large_header_buffer() */
+
+            rc = ngx_http_alloc_header_buf(r, 0);
+
+            if (rc == NGX_ERROR) {
+                ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
+                ngx_http_close_connection(c);
+                return;
+            }
+
+            if (rc == NGX_DECLINED) {
+                ngx_http_client_error(r, NGX_HTTP_PARSE_TOO_LONG_HEADER,
+                                      NGX_HTTP_BAD_REQUEST);
+                return;
+            }
+#endif
+
+#if 0
             /*
              * if the large client headers are enabled then
              * we need to compact r->header_in buf
@@ -964,6 +985,7 @@
                                       NGX_HTTP_BAD_REQUEST);
                 return;
             }
+#endif
         }
     }
 }
@@ -1023,6 +1045,92 @@
 }
 
 
+#if 1
+
+static ngx_int_t ngx_http_alloc_header_buf(ngx_http_request_t *r,
+                                           ngx_uint_t request_line)
+{
+    u_char                    *old, *new;
+    ngx_int_t                  offset;
+    ngx_buf_t                 *b;
+    ngx_http_connection_t     *hc;
+    ngx_http_core_srv_conf_t  *cscf;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "http alloc large header buffer");
+
+    old = request_line ? r->request_start : r->header_name_start;
+
+    cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
+
+    if ((size_t) (r->header_in->pos - old) >= cscf->client_large_buffers.size) {
+        return NGX_DECLINED;
+    }
+
+    hc = r->http_connection;
+
+    if (hc->nfree) {
+        b = hc->free[--hc->nfree];
+
+    } else if (hc->nbusy < cscf->client_large_buffers.num) {
+
+        if (hc->busy == NULL) {
+            hc->busy = ngx_palloc(r->connection->pool,
+                         cscf->client_large_buffers.num * sizeof(ngx_buf_t *));
+            if (hc->busy == NULL) {
+                return NGX_ERROR;
+            }
+        }
+
+        b = ngx_create_temp_buf(r->connection->pool,
+                                cscf->client_large_buffers.size);
+        if (b == NULL) {
+            return NGX_ERROR;
+        }
+
+    } else {
+        return NGX_DECLINED;
+    }
+
+    hc->busy[hc->nbusy++] = b;
+
+    new = b->start;
+
+    ngx_memcpy(new, old, r->header_in->last - old);
+
+    b->pos = new + (r->header_in->pos - old);
+    b->last = new + (r->header_in->last - old);
+
+    if (request_line) {
+        r->request_start = new;
+        r->request_end = new + (r->request_end - old);
+
+        r->uri_start = new + (r->uri_start - old);
+        r->uri_end = new + (r->uri_end - old);
+
+        if (r->uri_ext) {
+            r->uri_ext = new + (r->uri_ext - old);
+        }
+
+        if (r->args_start) {
+            r->args_start = new + (r->args_start - old);
+        }
+
+    } else {
+        r->header_name_start = new;
+        r->header_name_end = new + (r->header_name_end - old);
+        r->header_start = new + (r->header_start - old);
+        r->header_end = new + (r->header_end - old);
+    }
+
+    r->header_in = b;
+
+    return NGX_OK;
+}
+
+#endif
+
+
 static ngx_int_t ngx_http_process_request_header(ngx_http_request_t *r)
 {
     u_char                    *ua, *user_agent;
diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
index 8ecdfd1..c719be8 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -221,10 +221,10 @@
     ngx_http_request_t   *request;
 
     ngx_buf_t           **busy;
-    ngx_uint_t            nbusy;
+    ngx_int_t             nbusy;
 
     ngx_buf_t           **free;
-    ngx_uint_t            nfree;
+    ngx_int_t             nfree;
 
     ngx_uint_t            pipeline;      /* unsigned  pipeline:1; */
 } ngx_http_connection_t;
diff --git a/src/os/unix/ngx_atomic.h b/src/os/unix/ngx_atomic.h
index 7f74038..c5197e5 100644
--- a/src/os/unix/ngx_atomic.h
+++ b/src/os/unix/ngx_atomic.h
@@ -8,6 +8,8 @@
 
 #if ( __i386__ || __amd64__ )
 
+#define NGX_HAVE_ATOMIC_OPS  1
+
 typedef volatile uint32_t  ngx_atomic_t;
 
 #if (NGX_SMP)
@@ -33,6 +35,8 @@
 }
 
 
+#if 0
+
 static ngx_inline uint32_t ngx_atomic_dec(ngx_atomic_t *value)
 {
     uint32_t  old;
@@ -48,6 +52,8 @@
     return old;
 }
 
+#endif
+
 
 static ngx_inline uint32_t ngx_atomic_cmp_set(ngx_atomic_t *lock,
                                               ngx_atomic_t old,
@@ -70,6 +76,8 @@
 
 #elif ( __sparc__ )
 
+#define NGX_HAVE_ATOMIC_OPS  1
+
 typedef volatile uint32_t  ngx_atomic_t;
 
 
@@ -99,11 +107,6 @@
 }
 
 
-/* STUB */
-#define ngx_atomic_dec(x)   (*(x))--;
-/**/
-
-
 static ngx_inline uint32_t ngx_atomic_cmp_set(ngx_atomic_t *lock,
                                               ngx_atomic_t old,
                                               ngx_atomic_t set)
@@ -121,13 +124,18 @@
 
 #else
 
+#define NGX_HAVE_ATOMIC_OPS  0
+
 typedef volatile uint32_t  ngx_atomic_t;
 
-/* STUB */
-#define ngx_atomic_inc(x)   ++(*(x));
-#define ngx_atomic_dec(x)   --(*(x));
-#define ngx_atomic_cmp_set(lock, old, set)   1
-/**/
+#define ngx_atomic_inc(x)  ++(*(x));
+
+static ngx_inline uint32_t ngx_atomic_cmp_set(ngx_atomic_t *lock,
+                                              ngx_atomic_t old,
+                                              ngx_atomic_t set)
+{
+     return 1;
+}
 
 #endif
 
diff --git a/src/os/win32/ngx_atomic.h b/src/os/win32/ngx_atomic.h
index fcc3ff1..9d75fab 100644
--- a/src/os/win32/ngx_atomic.h
+++ b/src/os/win32/ngx_atomic.h
@@ -6,17 +6,23 @@
 #include <ngx_core.h>
 
 
+#define NGX_HAVE_ATOMIC_OPS   1
+
+
 #define ngx_atomic_inc(p)       InterlockedIncrement((long *) p)
-#define ngx_atomic_dec(p)       InterlockedDecrement((long *) p)
 
 
 #if defined( __WATCOMC__ ) || defined( __BORLANDC__ )
 
+/* the new SDK headers */
+
 #define ngx_atomic_cmp_set(lock, old, set)                                    \
      (InterlockedCompareExchange((long *) lock, set, old) == old)
 
 #else
 
+/* the old MS VC6.0SP2 SDK headers */
+
 #define ngx_atomic_cmp_set(lock, old, set)                                    \
      (InterlockedCompareExchange((void **) lock, (void *) set, (void *) old)  \
       == (void *) old)