On Tue, Nov 07, 2023 at 06:01:40PM +0800, Ming Lei wrote:
> In case of big chunk sequential IO, bio's size is often not aligned with
> this queue's max request size because of multipage bvec, then small sized
> bio can be made by bio split, so try to align bio with max io size if
> it isn't the last one.
I have a hard time parsing this long sentence.
> + /*
> + * If we still have data and bio is full, this bio size may not be
> + * aligned with max io size, small bio can be caused by split, try
> + * to avoid this situation by aligning bio with max io size.
> + *
> + * Big chunk of sequential IO workload can benefit from this way.
> + */
> + if (!ret && iov_iter_count(iter) && bio->bi_bdev &&
> + bio_op(bio) != REQ_OP_ZONE_APPEND) {
> + unsigned trim = bio_align_with_io_size(bio);
Besides the fact that bi_bdev should always be set, this really does
thing backwards. Instead of rewding things which is really
expensive don't add it in the first place.
