diff --git a/src/shrpx_http2_upstream.cc b/src/shrpx_http2_upstream.cc
index b49920af..649fae00 100644
--- a/src/shrpx_http2_upstream.cc
+++ b/src/shrpx_http2_upstream.cc
@@ -1168,9 +1168,6 @@ void Http2Upstream::remove_downstream(Downstream *downstream) {
   if (next_downstream) {
     initiate_downstream(std::move(next_downstream));
   }
-
-  mcpool_.shrink((downstream_queue_.get_active_downstreams().size() + 1) *
-                 65536);
 }
 
 Downstream *Http2Upstream::find_downstream(int32_t stream_id) {
diff --git a/src/shrpx_spdy_upstream.cc b/src/shrpx_spdy_upstream.cc
index 5844d587..d7c5c04a 100644
--- a/src/shrpx_spdy_upstream.cc
+++ b/src/shrpx_spdy_upstream.cc
@@ -811,9 +811,6 @@ void SpdyUpstream::remove_downstream(Downstream *downstream) {
   if (next_downstream) {
     initiate_downstream(std::move(next_downstream));
   }
-
-  mcpool_.shrink((downstream_queue_.get_active_downstreams().size() + 1) *
-                 65536);
 }
 
 Downstream *SpdyUpstream::find_downstream(int32_t stream_id) {