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/commit.c b/fs/jbd2/commit.c
index b091e53..e91f051 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -16,6 +16,7 @@
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/jbd2.h>
+#include <linux/marker.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/mm.h>
@@ -368,6 +369,8 @@
commit_transaction = journal->j_running_transaction;
J_ASSERT(commit_transaction->t_state == T_RUNNING);
+ trace_mark(jbd2_start_commit, "dev %s transaction %d",
+ journal->j_devname, commit_transaction->t_tid);
jbd_debug(1, "JBD: starting commit of transaction %d\n",
commit_transaction->t_tid);
@@ -985,6 +988,9 @@
}
spin_unlock(&journal->j_list_lock);
+ trace_mark(jbd2_end_commit, "dev %s transaction %d head %d",
+ journal->j_devname, commit_transaction->t_tid,
+ journal->j_tail_sequence);
jbd_debug(1, "JBD: commit %d complete, head %d\n",
journal->j_commit_sequence, journal->j_tail_sequence);