From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Tue, 11 Jun 2019 22:34:32 +0000 (-0400)
Subject: Fix: Don't print ring-buffer's records count when it is not used
X-Git-Tag: v2.12.0-pre~39
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=97df3a7fbf6c344169344bada5f0b484c239729e;p=lttng-modules.git

Fix: Don't print ring-buffer's records count when it is not used

The teardown of a ring buffer causes a number of diagnostic messages
to be printed using printk. One of those contains the "records
count", which is only updated when lttng-modules is built with
LTTNG_RING_BUFFER_COUNT_EVENTS defined.

Move the "records count" printing to a different function and stub it
out when LTTNG_RING_BUFFER_COUNT_EVENTS is not defined
(default configuration).

This eliminates messages of the following form from the dmesg output
when an LTTng session is torn down.

[...] ring buffer relay-discard, cpu 0: 0 records written, 0 records overrun

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/lib/ringbuffer/ring_buffer_frontend.c b/lib/ringbuffer/ring_buffer_frontend.c
index f367dffc..0d2d6936 100644
--- a/lib/ringbuffer/ring_buffer_frontend.c
+++ b/lib/ringbuffer/ring_buffer_frontend.c
@@ -1498,12 +1498,13 @@ void lib_ring_buffer_print_buffer_errors(struct lib_ring_buffer *buf,
 						       cpu);
 }
 
+#ifdef LTTNG_RING_BUFFER_COUNT_EVENTS
 static
-void lib_ring_buffer_print_errors(struct channel *chan,
-				  struct lib_ring_buffer *buf, int cpu)
+void lib_ring_buffer_print_records_count(struct channel *chan,
+					 struct lib_ring_buffer *buf,
+					 int cpu)
 {
 	const struct lib_ring_buffer_config *config = &chan->backend.config;
-	void *priv = chan->backend.priv;
 
 	if (!strcmp(chan->backend.name, "relay-metadata")) {
 		printk(KERN_DEBUG "ring buffer %s: %lu records written, "
@@ -1517,7 +1518,26 @@ void lib_ring_buffer_print_errors(struct channel *chan,
 			chan->backend.name, cpu,
 			v_read(config, &buf->records_count),
 			v_read(config, &buf->records_overrun));
+	}
+}
+#else
+static
+void lib_ring_buffer_print_records_count(struct channel *chan,
+					 struct lib_ring_buffer *buf,
+					 int cpu)
+{
+}
+#endif
+
+static
+void lib_ring_buffer_print_errors(struct channel *chan,
+				  struct lib_ring_buffer *buf, int cpu)
+{
+	const struct lib_ring_buffer_config *config = &chan->backend.config;
+	void *priv = chan->backend.priv;
 
+	lib_ring_buffer_print_records_count(chan, buf, cpu);
+	if (strcmp(chan->backend.name, "relay-metadata")) {
 		if (v_read(config, &buf->records_lost_full)
 		    || v_read(config, &buf->records_lost_wrap)
 		    || v_read(config, &buf->records_lost_big))