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authorTheodore Ts'o <tytso@mit.edu>2013-02-08 21:59:22 -0500
committerTheodore Ts'o <tytso@mit.edu>2013-02-08 21:59:22 -0500
commit9924a92a8c217576bd2a2b1bbbb854462f1a00ae (patch)
tree5c4eaee350e38cd2854fd6029da9f2a822ee184e /fs/ext4/file.c
parent722887ddc8982ff40e40b650fbca9ae1e56259bc (diff)
ext4: pass context information to jbd2__journal_start()
So we can better understand what bits of ext4 are responsible for long-running jbd2 handles, use jbd2__journal_start() so we can pass context information for logging purposes. The recommended way for finding the longer-running handles is: T=/sys/kernel/debug/tracing EVENT=$T/events/jbd2/jbd2_handle_stats echo "interval > 5" > $EVENT/filter echo 1 > $EVENT/enable ./run-my-fs-benchmark cat $T/trace > /tmp/problem-handles This will list handles that were active for longer than 20ms. Having longer-running handles is bad, because a commit started at the wrong time could stall for those 20+ milliseconds, which could delay an fsync() or an O_SYNC operation. Here is an example line from the trace file describing a handle which lived on for 311 jiffies, or over 1.2 seconds: postmark-2917 [000] .... 196.435786: jbd2_handle_stats: dev 254,32 tid 570 type 2 line_no 2541 interval 311 sync 0 requested_blocks 1 dirtied_blocks 0 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/file.c')
-rw-r--r--fs/ext4/file.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 405565a62277..2cf8ab810687 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -240,7 +240,7 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
handle_t *handle;
int err;
- handle = ext4_journal_start_sb(sb, 1);
+ handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
if (IS_ERR(handle))
return PTR_ERR(handle);
err = ext4_journal_get_write_access(handle, sbi->s_sbh);