From 06890aaa91aaf5d4ba34e9553e657177e4150927 Mon Sep 17 00:00:00 2001
From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Mon, 4 Apr 2022 16:15:06 +0200
Subject: [PATCH] MINOR: mux-quic: adjust timeout to accelerate closing

Improve timeout handling on the MUX. When releasing a stream, first
check if the connection can be considered as dead and should be freed
immediatly. This allows to liberate resources faster when possible.

If the connection is still active, ensure there is no attached
conn-stream before scheduling the timeout. To do this, add a nb_cs field
in the qcc structure.
---
 include/haproxy/mux_quic-t.h |  1 +
 include/haproxy/mux_quic.h   |  2 ++
 src/mux_quic.c               | 39 +++++++++++++++++++++++-------------
 3 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/include/haproxy/mux_quic-t.h b/include/haproxy/mux_quic-t.h
index 61ff95a3b..edc693026 100644
--- a/include/haproxy/mux_quic-t.h
+++ b/include/haproxy/mux_quic-t.h
@@ -27,6 +27,7 @@ enum qcs_type {
 
 struct qcc {
 	struct connection *conn;
+	uint64_t nb_cs; /* number of attached conn-streams */
 	uint32_t flags; /* QC_CF_* */
 
 	struct {
diff --git a/include/haproxy/mux_quic.h b/include/haproxy/mux_quic.h
index 715f7e9f5..c01d1560e 100644
--- a/include/haproxy/mux_quic.h
+++ b/include/haproxy/mux_quic.h
@@ -115,6 +115,8 @@ static inline struct conn_stream *qc_attach_cs(struct qcs *qcs, struct buffer *b
 	cs->ctx = qcs;
 	stream_new(qcs->qcc->conn->owner, cs, buf);
 
+	++qcs->qcc->nb_cs;
+
 	return cs;
 }
 
diff --git a/src/mux_quic.c b/src/mux_quic.c
index 8e91d7b4d..ad1a69367 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -471,14 +471,7 @@ static inline int qcc_is_dead(const struct qcc *qcc)
 /* Return true if the mux timeout should be armed. */
 static inline int qcc_may_expire(struct qcc *qcc)
 {
-
-	/* Consider that the timeout must be set if no bidirectional streams
-	 * are opened.
-	 */
-	if (!qcc->strms[QCS_CLT_BIDI].nb_streams)
-		return 1;
-
-	return 0;
+	return !qcc->nb_cs;
 }
 
 /* release function. This one should be called to free all resources allocated
@@ -502,6 +495,11 @@ static void qc_release(struct qcc *qcc)
 		if (qcc->app_ops && qcc->app_ops->release)
 			qcc->app_ops->release(qcc->ctx);
 
+		if (qcc->task) {
+			task_destroy(qcc->task);
+			qcc->task = NULL;
+		}
+
 		if (qcc->wait_event.tasklet)
 			tasklet_free(qcc->wait_event.tasklet);
 
@@ -894,9 +892,14 @@ static struct task *qc_io_cb(struct task *t, void *ctx, unsigned int status)
 	qc_send(qcc);
 
 	if (qc_release_detached_streams(qcc)) {
-		/* Schedule the mux timeout if no bidirectional streams left. */
-		if (qcc_may_expire(qcc)) {
-			qcc->task->expire = tick_add(now_ms, qcc->timeout);
+		if (qcc_is_dead(qcc)) {
+			qc_release(qcc);
+		}
+		else {
+			if (qcc_may_expire(qcc))
+				qcc->task->expire = tick_add(now_ms, qcc->timeout);
+			else
+				qcc->task->expire = TICK_ETERNITY;
 			task_queue(qcc->task);
 		}
 	}
@@ -955,6 +958,7 @@ static int qc_init(struct connection *conn, struct proxy *prx,
 
 	qcc->conn = conn;
 	conn->ctx = qcc;
+	qcc->nb_cs = 0;
 	qcc->flags = 0;
 
 	qcc->app_ops = NULL;
@@ -1052,6 +1056,8 @@ static void qc_detach(struct conn_stream *cs)
 	 * managment between xprt and mux is reorganized.
 	 */
 
+	--qcc->nb_cs;
+
 	if (b_data(&qcs->tx.buf) || qcs->tx.offset > qcs->tx.sent_offset) {
 		TRACE_DEVEL("leaving with remaining data, detaching qcs", QMUX_EV_STRM_END, qcc->conn, qcs);
 		qcs->flags |= QC_SF_DETACH;
@@ -1060,9 +1066,14 @@ static void qc_detach(struct conn_stream *cs)
 
 	qcs_destroy(qcs);
 
-	/* Schedule the mux timeout if no bidirectional streams left. */
-	if (qcc_may_expire(qcc)) {
-		qcc->task->expire = tick_add(now_ms, qcc->timeout);
+	if (qcc_is_dead(qcc)) {
+		qc_release(qcc);
+	}
+	else {
+		if (qcc_may_expire(qcc))
+			qcc->task->expire = tick_add(now_ms, qcc->timeout);
+		else
+			qcc->task->expire = TICK_ETERNITY;
 		task_queue(qcc->task);
 	}