[PATCHv3 09/10] ext4: Add commit tid info in ext4_fc_commit_start/stop trace events

Ritesh Harjani
2022-03-12T05:41:05Z

This adds commit_tid info in ext4_fc_commit_start/stop which is helpful
in debugging fast_commit issues.

For e.g. issues where due to jbd2 journal full commit, FC miss to commit
updates to a file.

Also improves TP_prink format string i.e. all ext4 and jbd2 trace events
starts with "dev MAjOR,MINOR". Let's follow the same convention while we
are still at it.

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
---
fs/ext4/fast_commit.c | 4 ++--
include/trace/events/ext4.h | 21 +++++++++++++--------
2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 88ed99e670c5..3d72565ec6e8 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1187,7 +1187,7 @@ static void ext4_fc_update_stats(struct super_block *sb, int status,
} else {
stats->fc_skipped_commits++;
}
- trace_ext4_fc_commit_stop(sb, nblks, status);
+ trace_ext4_fc_commit_stop(sb, nblks, status, commit_tid);
}

/*
@@ -1208,7 +1208,7 @@ int ext4_fc_commit(journal_t *journal, tid_t commit_tid)
if (!test_opt2(sb, JOURNAL_FAST_COMMIT))
return jbd2_complete_transaction(journal, commit_tid);

- trace_ext4_fc_commit_start(sb);
+ trace_ext4_fc_commit_start(sb, commit_tid);

start_time = ktime_get();

diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 6bd90df07b5c..aad97376e032 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -2686,26 +2686,29 @@ TRACE_EVENT(ext4_fc_replay,
);

TRACE_EVENT(ext4_fc_commit_start,
- TP_PROTO(struct super_block *sb),
+ TP_PROTO(struct super_block *sb, tid_t commit_tid),

- TP_ARGS(sb),
+ TP_ARGS(sb, commit_tid),

TP_STRUCT__entry(
__field(dev_t, dev)
+ __field(tid_t, tid)
),

TP_fast_assign(
__entry->dev = sb->s_dev;
+ __entry->tid = commit_tid;
),

- TP_printk("fast_commit started on dev %d,%d",
- MAJOR(__entry->dev), MINOR(__entry->dev))
+ TP_printk("dev %d,%d tid %u", MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->tid)
);

TRACE_EVENT(ext4_fc_commit_stop,
- TP_PROTO(struct super_block *sb, int nblks, int reason),
+ TP_PROTO(struct super_block *sb, int nblks, int reason,
+ tid_t commit_tid),

- TP_ARGS(sb, nblks, reason),
+ TP_ARGS(sb, nblks, reason, commit_tid),

TP_STRUCT__entry(
__field(dev_t, dev)
@@ -2714,6 +2717,7 @@ TRACE_EVENT(ext4_fc_commit_stop,
__field(int, num_fc)
__field(int, num_fc_ineligible)
__field(int, nblks_agg)
+ __field(tid_t, tid)
),

TP_fast_assign(
@@ -2724,12 +2728,13 @@ TRACE_EVENT(ext4_fc_commit_stop,
__entry->num_fc_ineligible =
EXT4_SB(sb)->s_fc_stats.fc_ineligible_commits;
__entry->nblks_agg = EXT4_SB(sb)->s_fc_stats.fc_numblks;
+ __entry->tid = commit_tid;
),

- TP_printk("fc on [%d,%d] nblks %d, reason %d, fc = %d, ineligible = %d, agg_nblks %d",
+ TP_printk("dev %d,%d nblks %d, reason %d, fc = %d, ineligible = %d, agg_nblks %d, tid %u",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->nblks, __entry->reason, __entry->num_fc,
- __entry->num_fc_ineligible, __entry->nblks_agg)
+ __entry->num_fc_ineligible, __entry->nblks_agg, __entry->tid)
);

#define FC_REASON_NAME_STAT(reason) \
--
2.31.1