Re: [PATCH] blktrace: add missing probe argument to block_bio_complete

Mathieu Desnoyers
2011-01-07T17:41:14Z

* Jens Axboe (axboe@kernel.dk) wrote:
> On 2011-01-07 15:13, Jeff Moyer wrote:
> > Mathieu Desnoyers <mathieu.desnoyers@efficios.com> writes:
> >
> >> blktrace.c block bio complete callback needs to gain a new argument to reflect
> >> the newly added "error" tracepoint argument. This is needed to match the new
> >> block_bio_complete TRACE_EVENT as of
> >> commit de983a7bfcb7c020901ca6e2314cf55a4207ab5a.
> >>
> >> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> >> CC: Jeff Moyer <jmoyer@redhat.com>
> >> CC: Steven Rostedt <rostedt@goodmis.org>
> >> CC: Frederic Weisbecker <fweisbec@gmail.com>
> >> CC: Ingo Molnar <mingo@elte.hu>
> >> CC: Thomas Gleixner <tglx@linutronix.de>
> >> CC: Jens Axboe <axboe@kernel.dk>
> >> CC: Li Zefan <lizf@cn.fujitsu.com>
> >> ---
> >> kernel/trace/blktrace.c | 3 ++-
> >> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> Index: linux-2.6-lttng/kernel/trace/blktrace.c
> >> ===================================================================
> >> --- linux-2.6-lttng.orig/kernel/trace/blktrace.c
> >> +++ linux-2.6-lttng/kernel/trace/blktrace.c
> >> @@ -785,7 +785,8 @@ static void blk_add_trace_bio_bounce(voi
> >> }
> >>
> >> static void blk_add_trace_bio_complete(void *ignore,
> >> - struct request_queue *q, struct bio *bio)
> >> + struct request_queue *q, struct bio *bio,
> >> + int error)
> >> {
> >> blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
> >> }
> >
> > OK, I clearly didn't look closely enough last time. There's no sense
> > passing this information down if it isn't used (as you said initially).
> > blk_add_trace_bio sets the error based on whether or not the
> > BIO_UPTODATE bit is set. So, I think we should instead revert the patch
> > I sent you (Mathieu), and then completely get rid of the error field in
> > the TP macros.
> >
> > Does that make sense to everyone else?
>
> We usually use BIO_UPTODATE if we have no other information available.
> So if we have, then we should use it.

Good point. I tested your patch below applied after "trace event block fix
unassigned field", and it builds fine. Please feel free to add my

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Are you planning to apply it on top of "blktrace: add missing probe argument to
block_bio_complete" ? (which I see you have merged in block for-next)

Thanks,

Mathieu

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.