From: Willy Tarreau <w@1wt.eu>
Date: Tue, 7 May 2024 15:52:11 +0000 (+0200)
Subject: MEDIUM: channel: allocate without queuing when retrying
X-Git-Tag: v3.0-dev11~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5b8d27617f4065f0a20476d6835588ff0fecd408;p=thirdparty%2Fhaproxy.git

MEDIUM: channel: allocate without queuing when retrying

Now when trying to allocate a channel buffer, we can check if we've been
notified of availability via the producer stream connector callback, in
which case we should not consult the queue, or if we're doing a first
allocation and check the queue.
---

diff --git a/include/haproxy/channel.h b/include/haproxy/channel.h
index 6e0c35bc75..22949e1453 100644
--- a/include/haproxy/channel.h
+++ b/include/haproxy/channel.h
@@ -915,7 +915,14 @@ static inline int ci_space_for_replace(const struct channel *chn)
  */
 static inline int channel_alloc_buffer(struct channel *chn, struct buffer_wait *wait)
 {
-	if (b_alloc(&chn->buf, DB_CHANNEL) != NULL)
+	int force_noqueue;
+
+	/* If the producer has been notified of recent availability, we must
+	 * not check the queue again.
+	 */
+	force_noqueue = !!(chn_prod(chn)->flags & SC_FL_HAVE_BUFF);
+
+	if (b_alloc(&chn->buf, DB_CHANNEL | (force_noqueue ? DB_F_NOQUEUE : 0)) != NULL)
 		return 1;
 
 	b_requeue(DB_CHANNEL, wait);