Hi, Jens, Jens Axboe <axboe@xxxxxxxxx> writes: > I like the change, hate the naming. I'd prefer one of two things: > > - Add bio_endio_complete() instead. That name sucks too, the > important part is flipping the __name() to have a trace > version instead. ITYM a notrace version. By default, we want tracing for bio_endio. The only callers that need the inverse of that are in the request-based path, and there are only 2 of them. > - Mark the bio as trace completed, and keep the naming. Since > it's only off the completion path, that can be just marking > the bi_flags non-atomically. One issue with this is in generic_make_request_checks, where we can call bio_endio without having called trace_block_bio_queue (so you could get a C event with no corresponding Q). To address that, we could make the flag indicate that trace_block_bio_queue was performed, and clear it in bio_complete, like so: if (test_and_clear_bit(BIO_QUEUE_TRACED, &bio->bi_flags)) trace_block_bio_complete(...); That would solve the problem of duplicate completions, but requires setting the flag in the submission path and clearing it in the completion path. I think the former can be done with just a bio_set_flag (i.e. non-atomic), right? Of course, where to stick that bio_set_flag call is another bike-shedding discussion waiting to happen (i.e. does it go in the tracepoint itself?). Alternatively, we could set the trace_completed flag in the paths where we end I/O without having done the trace_block_bio_queue, but that seems way uglier to me. Can you think of any other options? If we're choosing from the above, my preference is for adding the bio_endio_notrace(), since it's so much simpler. Cheers, Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
