From: Marko Kreen <markokr@gmail.com>
Date: Fri, 4 Dec 2015 10:14:03 +0000 (+0200)
Subject: sbuf: improved sbuf_loopcnt logic
X-Git-Tag: pgbouncer_1_7~4
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=09e7ab43136fcf2f7ad84f03cb2053506f64efbf;p=pgbouncer

sbuf: improved sbuf_loopcnt logic

Simple early exit won't work for TLS as all data
may be in libssl buffers and no network wakeup is coming.

Use special-case event_add() with timeout for postponing.

It might be even improve non-tls case as there could
be specific buffers lengths when even that does
postponing while nothing is coming from network.
---

diff --git a/src/sbuf.c b/src/sbuf.c
index b651717..5c89ffe 100644
--- a/src/sbuf.c
+++ b/src/sbuf.c
@@ -409,6 +409,42 @@ static bool sbuf_wait_for_data(SBuf *sbuf)
 	return true;
 }
 
+static void sbuf_recv_forced_cb(int sock, short flags, void *arg)
+{
+	SBuf *sbuf = arg;
+
+	sbuf->wait_type = W_NONE;
+
+	if (sbuf_wait_for_data(sbuf)) {
+		sbuf_recv_cb(sock, flags, arg);
+	} else {
+		sbuf_call_proto(sbuf, SBUF_EV_RECV_FAILED);
+	}
+}
+
+static bool sbuf_wait_for_data_forced(SBuf *sbuf)
+{
+	int err;
+	struct timeval tv_min;
+
+	tv_min.tv_sec = 0;
+	tv_min.tv_usec = 1;
+
+	if (sbuf->wait_type != W_NONE) {
+		event_del(&sbuf->ev);
+		sbuf->wait_type = W_NONE;
+	}
+
+	event_set(&sbuf->ev, sbuf->sock, EV_READ, sbuf_recv_forced_cb, sbuf);
+	err = event_add(&sbuf->ev, &tv_min);
+	if (err < 0) {
+		log_warning("sbuf_wait_for_data: event_add failed: %s", strerror(errno));
+		return false;
+	}
+	sbuf->wait_type = W_ONCE;
+	return true;
+}
+
 /* libevent EV_WRITE: called when dest socket is writable again */
 static void sbuf_send_cb(int sock, short flags, void *arg)
 {
@@ -686,6 +722,8 @@ try_more:
 		 * after resync to process all data. (result is ignored)
 		 */
 		ok = sbuf_process_pending(sbuf);
+
+		sbuf_wait_for_data_forced(sbuf);
 		return;
 	}
 	loopcnt++;