On Tue, 2023-11-07 at 18:01 +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. > > Ed Tsai reported this way improves 64MB read/write by > 15%~25% in > Antutu V10 Storage Test. > > Reported-by: Ed Tsai <ed.tsai@xxxxxxxxxxxx> > Closes: > https://lore.kernel.org/linux-block/20231025092255.27930-1-ed.tsai@xxxxxxxxxxxx/ > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> > --- > block/bio.c | 57 > +++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 57 insertions(+) > > diff --git a/block/bio.c b/block/bio.c > index 816d412c06e9..749b6283dab9 100644 > --- a/block/bio.c > +++ b/block/bio.c > @@ -1294,6 +1294,47 @@ static int __bio_iov_iter_get_pages(struct bio > *bio, struct iov_iter *iter) > return ret; > } > > +/* should only be called before submission */ > +static void bio_shrink(struct bio *bio, unsigned bytes) > +{ > + unsigned int size = bio->bi_iter.bi_size; > + int idx; > + > + if (bytes >= size) > + return; > + > + WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)); > + > + idx = bio->bi_vcnt - 1; > + bio->bi_iter.bi_size -= bytes; > + while (bytes > 0) { > + struct bio_vec *bv = &bio->bi_io_vec[idx]; > + unsigned int len = min_t(unsigned, bv->bv_len, bytes); > + > + bytes -= len; > + bv->bv_len -= len; > + if (!bv->bv_len) { > + bio_release_page(bio, bv->bv_page); > + idx--; > + } > + } > + WARN_ON_ONCE(idx < 0); > + bio->bi_vcnt = idx + 1; > +} > + > +static unsigned bio_align_with_io_size(struct bio *bio) > +{ > + struct request_queue *q = bdev_get_queue(bio->bi_bdev); > + unsigned int size = bio->bi_iter.bi_size; > + unsigned int trim = size & ((queue_max_sectors(q) << 9) - 1); > + > + if (trim && trim != size) { > + bio_shrink(bio, trim); > + return trim; > + } > + return 0; > +} > + > /** > * bio_iov_iter_get_pages - add user or kernel pages to a bio > * @bio: bio to add pages to > @@ -1333,6 +1374,22 @@ int bio_iov_iter_get_pages(struct bio *bio, > struct iov_iter *iter) > ret = __bio_iov_iter_get_pages(bio, iter); > } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); > > + > + /* > + * 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); > + > + if (trim) > + iov_iter_revert(iter, trim); > + } > + > return bio->bi_vcnt ? 0 : ret; > } > EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages); > -- > 2.41.0 Thanks. This looks good to me. Acked-by: Ed Tsai <ed.tsai@xxxxxxxxxxxx> -- Best Regards, Ed Tsai
