Re: [RFC 6/9] ext4: Add commit tid info in ext4_fc_commit_start/stop trace events

[harshad shirwadkar <harshadshirwadkar@gmail.com>]

Looks good.

Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>

- Harshad

On Wed, 23 Feb 2022 at 01:44, Jan Kara <jack@suse.cz> wrote:
>
> On Wed 23-02-22 02:04:14, Ritesh Harjani wrote:
> > 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>
>
> Looks good. Feel free to add:
>
> Reviewed-by: Jan Kara <jack@suse.cz>
>
>                                                                 Honza
>
> > ---
> >  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 ee32aac0cbbf..8803ba087b07 100644
> > --- a/fs/ext4/fast_commit.c
> > +++ b/fs/ext4/fast_commit.c
> > @@ -1150,7 +1150,7 @@ 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);
> >  }
> >
> >  /*
> > @@ -1171,7 +1171,7 @@ 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 cd09dccea502..6e66cb7ce624 100644
> > --- a/include/trace/events/ext4.h
> > +++ b/include/trace/events/ext4.h
> > @@ -2685,26 +2685,29 @@ 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)
> > @@ -2713,6 +2716,7 @@ 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(
> > @@ -2723,12 +2727,13 @@ 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
> >
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR