diff --git a/src/shrpx_client_handler.cc b/src/shrpx_client_handler.cc
index 7e7a750d..c4290e2b 100644
--- a/src/shrpx_client_handler.cc
+++ b/src/shrpx_client_handler.cc
@@ -834,7 +834,7 @@ void ClientHandler::write_accesslog(Downstream *downstream) {
           std::chrono::high_resolution_clock::now(), // request_end_time
 
           req.http_major, req.http_minor, resp.http_status,
-          downstream->get_response_sent_bodylen(), port_.c_str(),
+          downstream->response_sent_body_length, port_.c_str(),
           get_config()->port, get_config()->pid,
       });
 }
diff --git a/src/shrpx_downstream.cc b/src/shrpx_downstream.cc
index c4f8dec6..986526c6 100644
--- a/src/shrpx_downstream.cc
+++ b/src/shrpx_downstream.cc
@@ -113,11 +113,11 @@ void downstream_wtimeoutcb(struct ev_loop *loop, ev_timer *w, int revents) {
 // upstream could be nullptr for unittests
 Downstream::Downstream(Upstream *upstream, MemchunkPool *mcpool,
                        int32_t stream_id, int32_t priority)
-    : dlnext(nullptr), dlprev(nullptr),
+    : dlnext(nullptr), dlprev(nullptr), response_sent_body_length(0),
       request_start_time_(std::chrono::high_resolution_clock::now()),
-      request_buf_(mcpool), response_buf_(mcpool), response_sent_bodylen_(0),
-      upstream_(upstream), blocked_link_(nullptr), num_retry_(0),
-      stream_id_(stream_id), priority_(priority), downstream_stream_id_(-1),
+      request_buf_(mcpool), response_buf_(mcpool), upstream_(upstream),
+      blocked_link_(nullptr), num_retry_(0), stream_id_(stream_id),
+      priority_(priority), downstream_stream_id_(-1),
       response_rst_stream_error_code_(NGHTTP2_NO_ERROR),
       request_state_(INITIAL), response_state_(INITIAL),
       dispatch_state_(DISPATCH_NONE), upgraded_(false), chunked_request_(false),
@@ -627,14 +627,6 @@ bool Downstream::response_buf_full() {
   }
 }
 
-void Downstream::add_response_sent_bodylen(size_t amount) {
-  response_sent_bodylen_ += amount;
-}
-
-int64_t Downstream::get_response_sent_bodylen() const {
-  return response_sent_bodylen_;
-}
-
 bool Downstream::validate_request_recv_body_length() const {
   if (req_.fs.content_length == -1) {
     return true;
diff --git a/src/shrpx_downstream.h b/src/shrpx_downstream.h
index c267096a..785071cb 100644
--- a/src/shrpx_downstream.h
+++ b/src/shrpx_downstream.h
@@ -297,8 +297,6 @@ public:
   int get_response_state() const;
   DefaultMemchunks *get_response_buf();
   bool response_buf_full();
-  void add_response_sent_bodylen(size_t amount);
-  int64_t get_response_sent_bodylen() const;
   // Validates that received response body length and content-length
   // matches.
   bool validate_response_recv_body_length() const;
@@ -381,6 +379,9 @@ public:
 
   Downstream *dlnext, *dlprev;
 
+  // the length of response body sent to upstream client
+  int64_t response_sent_body_length;
+
 private:
   Request req_;
   Response resp_;
@@ -401,9 +402,6 @@ private:
   ev_timer downstream_rtimer_;
   ev_timer downstream_wtimer_;
 
-  // the length of response body sent to upstream client
-  int64_t response_sent_bodylen_;
-
   Upstream *upstream_;
   std::unique_ptr<DownstreamConnection> dconn_;
 
diff --git a/src/shrpx_http2_upstream.cc b/src/shrpx_http2_upstream.cc
index ac719484..f02a3868 100644
--- a/src/shrpx_http2_upstream.cc
+++ b/src/shrpx_http2_upstream.cc
@@ -728,9 +728,7 @@ int send_data_callback(nghttp2_session *session, nghttp2_frame *frame,
 
   // We have to add length here, so that we can log this amount of
   // data transferred.
-  if (length > 0) {
-    downstream->add_response_sent_bodylen(length);
-  }
+  downstream->response_sent_body_length += length;
 
   return (nwrite < length || npadwrite < padlen) ? NGHTTP2_ERR_PAUSE : 0;
 }
diff --git a/src/shrpx_https_upstream.cc b/src/shrpx_https_upstream.cc
index b2e11e67..b364608f 100644
--- a/src/shrpx_https_upstream.cc
+++ b/src/shrpx_https_upstream.cc
@@ -799,7 +799,7 @@ int HttpsUpstream::send_reply(Downstream *downstream, const uint8_t *body,
 
   output->append(body, bodylen);
 
-  downstream->add_response_sent_bodylen(bodylen);
+  downstream->response_sent_body_length += bodylen;
   downstream->set_response_state(Downstream::MSG_COMPLETE);
 
   return 0;
@@ -842,7 +842,7 @@ void HttpsUpstream::error_reply(unsigned int status_code) {
                  "charset=UTF-8\r\nConnection: close\r\n\r\n");
   output->append(html.c_str(), html.size());
 
-  downstream->add_response_sent_bodylen(html.size());
+  downstream->response_sent_body_length += html.size();
   downstream->set_response_state(Downstream::MSG_COMPLETE);
 }
 
@@ -1048,7 +1048,7 @@ int HttpsUpstream::on_downstream_body(Downstream *downstream,
   }
   output->append(data, len);
 
-  downstream->add_response_sent_bodylen(len);
+  downstream->response_sent_body_length += len;
 
   if (downstream->get_chunked_response()) {
     output->append("\r\n");
diff --git a/src/shrpx_spdy_upstream.cc b/src/shrpx_spdy_upstream.cc
index e29dca1c..629d5d12 100644
--- a/src/shrpx_spdy_upstream.cc
+++ b/src/shrpx_spdy_upstream.cc
@@ -804,7 +804,7 @@ ssize_t spdy_data_read_callback(spdylay_session *session, int32_t stream_id,
   }
 
   if (nread > 0) {
-    downstream->add_response_sent_bodylen(nread);
+    downstream->response_sent_body_length += nread;
   }
 
   return nread;