ext4: Add debugging markers that can be used by systemtap
This debugging markers are designed to debug problems such as the
random filesystem latency problems reported by Arjan.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index af4651b..42895d36 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -20,6 +20,7 @@
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/jbd2.h>
+#include <linux/marker.h>
#include <linux/errno.h>
#include <linux/slab.h>
@@ -328,6 +329,8 @@
* journal straight away.
*/
result = jbd2_cleanup_journal_tail(journal);
+ trace_mark(jbd2_checkpoint, "dev %s need_checkpoint %d",
+ journal->j_devname, result);
jbd_debug(1, "cleanup_journal_tail returned %d\n", result);
if (result <= 0)
return result;