diff --git a/actix-http/src/h1/client.rs b/actix-http/src/h1/client.rs
index 6a50c027..f93bc496 100644
--- a/actix-http/src/h1/client.rs
+++ b/actix-http/src/h1/client.rs
@@ -10,7 +10,7 @@ use http::header::{
 use http::{Method, Version};
 
 use super::decoder::{PayloadDecoder, PayloadItem, PayloadType};
-use super::{decoder, encoder};
+use super::{decoder, encoder, reserve_readbuf};
 use super::{Message, MessageType};
 use crate::body::BodySize;
 use crate::config::ServiceConfig;
@@ -150,6 +150,7 @@ impl Decoder for ClientCodec {
             } else {
                 self.inner.payload = None;
             }
+            reserve_readbuf(src);
             Ok(Some(req))
         } else {
             Ok(None)
@@ -168,7 +169,10 @@ impl Decoder for ClientPayloadCodec {
         );
 
         Ok(match self.inner.payload.as_mut().unwrap().decode(src)? {
-            Some(PayloadItem::Chunk(chunk)) => Some(Some(chunk)),
+            Some(PayloadItem::Chunk(chunk)) => {
+                reserve_readbuf(src);
+                Some(Some(chunk))
+            }
             Some(PayloadItem::Eof) => {
                 self.inner.payload.take();
                 Some(None)
diff --git a/actix-http/src/h1/codec.rs b/actix-http/src/h1/codec.rs
index e4895f2d..6e891e7c 100644
--- a/actix-http/src/h1/codec.rs
+++ b/actix-http/src/h1/codec.rs
@@ -9,7 +9,7 @@ use http::header::{HeaderValue, CONNECTION, CONTENT_LENGTH, DATE, TRANSFER_ENCOD
 use http::{Method, StatusCode, Version};
 
 use super::decoder::{PayloadDecoder, PayloadItem, PayloadType};
-use super::{decoder, encoder};
+use super::{decoder, encoder, reserve_readbuf};
 use super::{Message, MessageType};
 use crate::body::BodySize;
 use crate::config::ServiceConfig;
@@ -19,9 +19,6 @@ use crate::message::{ConnectionType, Head, ResponseHead};
 use crate::request::Request;
 use crate::response::Response;
 
-const LW: usize = 2 * 1024;
-const HW: usize = 32 * 1024;
-
 bitflags! {
     struct Flags: u8 {
         const HEAD              = 0b0000_0001;
@@ -108,14 +105,12 @@ impl Decoder for Codec {
     type Error = ParseError;
 
     fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
-        let cap = src.capacity();
-        if cap < LW {
-            src.reserve(HW - cap);
-        }
-
         if self.payload.is_some() {
             Ok(match self.payload.as_mut().unwrap().decode(src)? {
-                Some(PayloadItem::Chunk(chunk)) => Some(Message::Chunk(Some(chunk))),
+                Some(PayloadItem::Chunk(chunk)) => {
+                    reserve_readbuf(src);
+                    Some(Message::Chunk(Some(chunk)))
+                }
                 Some(PayloadItem::Eof) => {
                     self.payload.take();
                     Some(Message::Chunk(None))
@@ -140,6 +135,7 @@ impl Decoder for Codec {
                     self.flags.insert(Flags::STREAM);
                 }
             }
+            reserve_readbuf(src);
             Ok(Some(Message::Item(req)))
         } else {
             Ok(None)
diff --git a/actix-http/src/h1/mod.rs b/actix-http/src/h1/mod.rs
index e3d63c52..472d7347 100644
--- a/actix-http/src/h1/mod.rs
+++ b/actix-http/src/h1/mod.rs
@@ -1,5 +1,5 @@
 //! HTTP/1 implementation
-use bytes::Bytes;
+use bytes::{Bytes, BytesMut};
 
 mod client;
 mod codec;
@@ -38,6 +38,16 @@ pub enum MessageType {
     Stream,
 }
 
+const LW: usize = 2 * 1024;
+const HW: usize = 32 * 1024;
+
+pub(crate) fn reserve_readbuf(src: &mut BytesMut) {
+    let cap = src.capacity();
+    if cap < LW {
+        src.reserve(HW - cap);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;