Hi,
On Thu, 25 Sep 2014 22:20:32 +0900, Mitake Hitoshi wrote:
> This patch adds a tracepoint for transaction events of nilfs. With the
> tracepoint, these events can be tracked: begin, abort, commit,
> trylock, lock, and unlock. Basically, these events have corresponding
> functions e.g. begin event corresponds nilfs_transaction_begin(). The
> unlock event is an exception. It corresponds to the iteration in
> nilfs_transaction_lock().
>
> Only one tracepoint is introcued: nilfs2_transaction_transition. The
> above events are distinguished with newly introduced enum. With this
> tracepoint, we can analyse a critical section of segment constructoin.
>
> Sample output by tpoint of perf-tools:
> cp-4457 [000] ...1 63.266220: nilfs2_transaction_transition: sb = ffff8802112b8800, ti = ffff8800bf5ccc58, count = 1, flags = 9 state = BEGIN
> cp-4457 [000] ...1 63.266221: nilfs2_transaction_transition: sb = ffff8802112b8800, ti = ffff8800bf5ccc58, count = 0, flags = 9 state = COMMIT
> cp-4457 [000] ...1 63.266221: nilfs2_transaction_transition: sb = ffff8802112b8800, ti = ffff8800bf5ccc58, count = 0, flags = 9 state = COMMIT
> segctord-4371 [001] ...1 68.261196: nilfs2_transaction_transition: sb = ffff8802112b8800, ti = ffff8800b889bdf8, count = 0, flags = 10 state = TRYLOCK
> segctord-4371 [001] ...1 68.261280: nilfs2_transaction_transition: sb = ffff8802112b8800, ti = ffff8800b889bdf8, count = 0, flags = 10 state = LOCK
> segctord-4371 [001] ...1 68.261877: nilfs2_transaction_transition: sb = ffff8802112b8800, ti = ffff8800b889bdf8, count = 1, flags = 10 state = BEGIN
> segctord-4371 [001] ...1 68.262116: nilfs2_transaction_transition: sb = ffff8802112b8800, ti = ffff8800b889bdf8, count = 0, flags = 18 state = COMMIT
> segctord-4371 [001] ...1 68.265032: nilfs2_transaction_transition: sb = ffff8802112b8800, ti = ffff8800b889bdf8, count = 0, flags = 18 state = UNLOCK
> segctord-4371 [001] ...1 132.376847: nilfs2_transaction_transition: sb = ffff8802112b8800, ti = ffff8800b889bdf8, count = 0, flags = 10 state = TRYLOCK
>
> Signed-off-by: Hitoshi Mitake <mitake.hitoshi@xxxxxxxxxxxxx>
> ---
> fs/nilfs2/segment.c | 33 ++++++++++++++++++++++++++-
> include/trace/events/nilfs2.h | 53 +++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 85 insertions(+), 1 deletion(-)
>
> v2: fix a style problem
>
> diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
> index 0fcf8e7..1dd9330 100644
> --- a/fs/nilfs2/segment.c
> +++ b/fs/nilfs2/segment.c
> @@ -213,11 +213,18 @@ int nilfs_transaction_begin(struct super_block *sb,
> {
> struct the_nilfs *nilfs;
> int ret = nilfs_prepare_segment_lock(ti);
> + struct nilfs_transaction_info *trace_ti;
>
> if (unlikely(ret < 0))
> return ret;
> - if (ret > 0)
> + if (ret > 0) {
> + trace_ti = current->journal_info;
> +
> + trace_nilfs2_transaction_transition(sb, trace_ti,
> + trace_ti->ti_count, trace_ti->ti_flags,
> + TRACE_NILFS2_TRANSACTION_BEGIN);
> return 0;
> + }
>
> sb_start_intwrite(sb);
>
> @@ -228,6 +235,11 @@ int nilfs_transaction_begin(struct super_block *sb,
> ret = -ENOSPC;
> goto failed;
> }
> +
> + trace_ti = current->journal_info;
> + trace_nilfs2_transaction_transition(sb, trace_ti, trace_ti->ti_count,
> + trace_ti->ti_flags,
> + TRACE_NILFS2_TRANSACTION_BEGIN);
> return 0;
>
> failed:
> @@ -260,6 +272,8 @@ int nilfs_transaction_commit(struct super_block *sb)
> ti->ti_flags |= NILFS_TI_COMMIT;
> if (ti->ti_count > 0) {
> ti->ti_count--;
> + trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
> + ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
> return 0;
> }
> if (nilfs->ns_writer) {
> @@ -271,6 +285,9 @@ int nilfs_transaction_commit(struct super_block *sb)
> nilfs_segctor_do_flush(sci, 0);
> }
> up_read(&nilfs->ns_segctor_sem);
> + trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
> + ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
> +
> current->journal_info = ti->ti_save;
>
> if (ti->ti_flags & NILFS_TI_SYNC)
> @@ -289,10 +306,15 @@ void nilfs_transaction_abort(struct super_block *sb)
> BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
> if (ti->ti_count > 0) {
> ti->ti_count--;
> + trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
> + ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
> return;
> }
> up_read(&nilfs->ns_segctor_sem);
>
> + trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
> + ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
> +
> current->journal_info = ti->ti_save;
> if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
> kmem_cache_free(nilfs_transaction_cachep, ti);
> @@ -339,6 +361,9 @@ static void nilfs_transaction_lock(struct super_block *sb,
> current->journal_info = ti;
>
> for (;;) {
> + trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
> + ti->ti_flags, TRACE_NILFS2_TRANSACTION_TRYLOCK);
> +
> down_write(&nilfs->ns_segctor_sem);
> if (!test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags))
> break;
> @@ -350,6 +375,9 @@ static void nilfs_transaction_lock(struct super_block *sb,
> }
> if (gcflag)
> ti->ti_flags |= NILFS_TI_GC;
> +
> + trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
> + ti->ti_flags, TRACE_NILFS2_TRANSACTION_LOCK);
> }
>
> static void nilfs_transaction_unlock(struct super_block *sb)
> @@ -364,6 +392,9 @@ static void nilfs_transaction_unlock(struct super_block *sb)
> current->journal_info = ti->ti_save;
> if (!list_empty(&ti->ti_garbage))
> nilfs_dispose_list(nilfs, &ti->ti_garbage, 0);
> +
> + trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
> + ti->ti_flags, TRACE_NILFS2_TRANSACTION_UNLOCK);
> }
>
> static void *nilfs_segctor_map_segsum_entry(struct nilfs_sc_info *sci,
> diff --git a/include/trace/events/nilfs2.h b/include/trace/events/nilfs2.h
> index 285d5f3..1c71093 100644
> --- a/include/trace/events/nilfs2.h
> +++ b/include/trace/events/nilfs2.h
> @@ -42,6 +42,59 @@ TRACE_EVENT(nilfs2_collection_stage_transition,
> show_collection_stage(__entry->stage))
> );
>
> +#ifndef TRACE_HEADER_MULTI_READ
> +enum nilfs2_transaction_transition_state {
> + TRACE_NILFS2_TRANSACTION_BEGIN,
> + TRACE_NILFS2_TRANSACTION_COMMIT,
> + TRACE_NILFS2_TRANSACTION_ABORT,
> + TRACE_NILFS2_TRANSACTION_TRYLOCK,
> + TRACE_NILFS2_TRANSACTION_LOCK,
> + TRACE_NILFS2_TRANSACTION_UNLOCK,
> +};
> +#endif
> +
> +#define show_transaction_state(type) \
> + __print_symbolic(type, \
> + { TRACE_NILFS2_TRANSACTION_BEGIN, "BEGIN" }, \
> + { TRACE_NILFS2_TRANSACTION_COMMIT, "COMMIT" }, \
> + { TRACE_NILFS2_TRANSACTION_ABORT, "ABORT" }, \
> + { TRACE_NILFS2_TRANSACTION_TRYLOCK, "TRYLOCK" }, \
> + { TRACE_NILFS2_TRANSACTION_LOCK, "LOCK" }, \
> + { TRACE_NILFS2_TRANSACTION_UNLOCK, "UNLOCK" })
> +
> +TRACE_EVENT(nilfs2_transaction_transition,
> + TP_PROTO(struct super_block *sb,
> + struct nilfs_transaction_info *ti,
> + int count,
> + unsigned int flags,
> + enum nilfs2_transaction_transition_state state),
> +
> + TP_ARGS(sb, ti, count, flags, state),
> +
> + TP_STRUCT__entry(
> + __field(void *, sb)
> + __field(void *, ti)
> + __field(int, count)
> + __field(unsigned int, flags)
> + __field(int, state)
> + ),
> +
> + TP_fast_assign(
> + __entry->sb = sb;
> + __entry->ti = ti;
> + __entry->count = count;
> + __entry->flags = flags;
> + __entry->state = state;
> + ),
> +
> + TP_printk("sb = %p, ti = %p, count = %d, flags = %x state = %s",
The use of commas in this format looks inconsistent. It looks like
most tracepoint messages skip commas and extra space chars around
equal symbols as follows:
TP_printk("sb=%p ti=%p count=%d flags=%x state=%s",
Seem that it's preferable to follow such practice.
Regards,
Ryusuke Konishi
> + __entry->sb,
> + __entry->ti,
> + __entry->count,
> + __entry->flags,
> + show_transaction_state(__entry->state))
> +);
> +
> #endif /* _TRACE_NILFS2_H */
>
> /* This part must be outside protection */
> --
> 1.9.1
>
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