SPDY: push pending data while closing a stream as with keepalive.

This helps to avoid delays in sending the last chunk of data because
of bad interaction between Nagle's algorithm on nginx side and
delayed ACK on the client side.

Delays could also be caused by TCP_CORK/TCP_NOPUSH if SPDY was
working without SSL and sendfile() was used.

diff --git a/src/http/ngx_http_spdy.c b/src/http/ngx_http_spdy.c
index 9bd624c82bcb925cf322ff0cfa1113967c3fe67c..bd6d73d82db9cbd25231870346c6928abc3eed54 100644 (file)
--- a/src/http/ngx_http_spdy.c
+++ b/src/http/ngx_http_spdy.c
@@ -3156,8 +3156,10 @@ ngx_http_spdy_close_stream_handler(ngx_event_t *ev)
 void
 ngx_http_spdy_close_stream(ngx_http_spdy_stream_t *stream, ngx_int_t rc)
 {
+    int                           tcp_nodelay;
     ngx_event_t                  *ev;
-    ngx_connection_t             *fc;
+    ngx_connection_t             *c, *fc;
+    ngx_http_core_loc_conf_t     *clcf;
     ngx_http_spdy_stream_t      **index, *s;
     ngx_http_spdy_srv_conf_t     *sscf;
     ngx_http_spdy_connection_t   *sc;
@@ -3183,6 +3185,54 @@ ngx_http_spdy_close_stream(ngx_http_spdy_stream_t *stream, ngx_int_t rc)
         {
             sc->connection->error = 1;
         }
+
+    } else {
+        c = sc->connection;
+
+        if (c->tcp_nopush == NGX_TCP_NOPUSH_SET) {
+            if (ngx_tcp_push(c->fd) == -1) {
+                ngx_connection_error(c, ngx_socket_errno,
+                                     ngx_tcp_push_n " failed");
+                c->error = 1;
+                tcp_nodelay = 0;
+
+            } else {
+                c->tcp_nopush = NGX_TCP_NOPUSH_UNSET;
+                tcp_nodelay = ngx_tcp_nodelay_and_tcp_nopush ? 1 : 0;
+            }
+
+        } else {
+            tcp_nodelay = 1;
+        }
+
+        clcf = ngx_http_get_module_loc_conf(stream->request,
+                                            ngx_http_core_module);
+
+        if (tcp_nodelay
+            && clcf->tcp_nodelay
+            && c->tcp_nodelay == NGX_TCP_NODELAY_UNSET)
+        {
+            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "tcp_nodelay");
+
+            if (setsockopt(c->fd, IPPROTO_TCP, TCP_NODELAY,
+                           (const void *) &tcp_nodelay, sizeof(int))
+                == -1)
+            {
+#if (NGX_SOLARIS)
+                /* Solaris returns EINVAL if a socket has been shut down */
+                c->log_error = NGX_ERROR_IGNORE_EINVAL;
+#endif
+
+                ngx_connection_error(c, ngx_socket_errno,
+                                     "setsockopt(TCP_NODELAY) failed");
+
+                c->log_error = NGX_ERROR_INFO;
+                c->error = 1;
+
+            } else {
+                c->tcp_nodelay = NGX_TCP_NODELAY_SET;
+            }
+        }
     }
 
     if (sc->stream == stream) {