From: Christopher Faulet <cfaulet@haproxy.com>
Date: Mon, 9 Mar 2026 17:10:17 +0000 (+0100)
Subject: MEDIUM: stream: Try to use a small buffer for HTTP request on queuing
X-Git-Tag: v3.4-dev8~128
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5acdda4eedd0a5adfee2268bdf09b92e92458b80;p=thirdparty%2Fhaproxy.git

MEDIUM: stream: Try to use a small buffer for HTTP request on queuing

When a HTX stream is queued, if the request is small enough, it is moved
into a small buffer. This should save memory on instances intensively using
queues.

Applet and connection receive function were update to block receive when a
small buffer is in use.
---

diff --git a/src/stconn.c b/src/stconn.c
index 8d5dfeade..1aa136aff 100644
--- a/src/stconn.c
+++ b/src/stconn.c
@@ -1190,7 +1190,7 @@ int sc_conn_recv(struct stconn *sc)
 		 * SE_FL_RCV_MORE on the SC if more space is needed.
 		 */
 		max = channel_recv_max(ic);
-		if ((ic->flags & CF_WROTE_DATA) && b_is_large(sc_ib(sc)))
+		if (b_is_small(sc_ib(sc)) || ((ic->flags & CF_WROTE_DATA) && b_is_large(sc_ib(sc))))
 			max = 0;
 		ret = CALL_MUX_WITH_RET(conn->mux, rcv_buf(sc, &ic->buf, max, cur_flags));
 
@@ -1861,7 +1861,7 @@ int sc_applet_recv(struct stconn *sc)
 	 * SE_FL_RCV_MORE on the SC if more space is needed.
 	 */
 	max = channel_recv_max(ic);
-	if ((ic->flags & CF_WROTE_DATA) && b_is_large(sc_ib(sc)))
+	if (b_is_small(sc_ib(sc)) || ((ic->flags & CF_WROTE_DATA) && b_is_large(sc_ib(sc))))
 		max = 0;
 	ret = appctx_rcv_buf(sc, &ic->buf, max, flags);
 	if (sc_ep_test(sc, SE_FL_WANT_ROOM)) {
diff --git a/src/stream.c b/src/stream.c
index cb26fb68c..28989bd2f 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -2511,6 +2511,18 @@ struct task *process_stream(struct task *t, void *context, unsigned int state)
 			srv = objt_server(s->target);
 			if (scb->state == SC_ST_ASS && srv && srv->rdr_len && (s->flags & SF_REDIRECTABLE))
 				http_perform_server_redirect(s, scb);
+
+			if (unlikely(scb->state == SC_ST_QUE && IS_HTX_STRM(s))) {
+				struct buffer sbuf = BUF_NULL;
+
+				if (!htx_move_to_small_buffer(&sbuf, &req->buf))
+					break;
+				b_free(&req->buf);
+				offer_buffers(s, 1);
+				req->buf = sbuf;
+				DBG_TRACE_DEVEL("request moved to a small buffer", STRM_EV_STRM_PROC, s);
+			}
+
 		} while (scb->state == SC_ST_ASS);
 	}