From decaffa805938a76977c3290ade67968bcef558e Mon Sep 17 00:00:00 2001
From: Valentin Bartenev <vbart@nginx.com>
Date: Fri, 21 Nov 2014 22:51:49 +0300
Subject: [PATCH] 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.
---
 src/http/ngx_http_spdy.c | 52 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 51 insertions(+), 1 deletion(-)

diff --git a/src/http/ngx_http_spdy.c b/src/http/ngx_http_spdy.c
index 9cac691e0..6eac9326a 100644
--- a/src/http/ngx_http_spdy.c
+++ b/src/http/ngx_http_spdy.c
@@ -3317,8 +3317,10 @@ 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;
@@ -3344,6 +3346,54 @@ 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) {