biovecs has become immutable since v3.13, so it isn't necessary
to allocate biovecs for the new cloned bios, then we can save
one extra biovecs allocation/copy, and the allocation is often
not fixed-length and a bit more expensive.
For example, if the 'max_sectors_kb' of null blk's queue is set
as 16(32 sectors) via sysfs just for making more splits, this patch
can increase throught about ~70% in the sequential read test over
null_blk(direct io, bs: 1M).
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Ming Lin <ming.l@ssi.samsung.com>
Cc: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
This fixes a performance regression introduced by commit
54efd50bfd,
and allows us to take full advantage of the fact that we have immutable
bio_vecs. Hand applied, as it rejected violently with commit
5014c311baa2.
Signed-off-by: Jens Axboe <axboe@fb.com>
struct bio *bio,
struct bio_set *bs)
{
struct bio *bio,
struct bio_set *bs)
{
struct bio_vec bv, bvprv, *bvprvp = NULL;
struct bvec_iter iter;
unsigned seg_size = 0, nsegs = 0, sectors = 0;
bio_for_each_segment(bv, bio, iter) {
struct bio_vec bv, bvprv, *bvprvp = NULL;
struct bvec_iter iter;
unsigned seg_size = 0, nsegs = 0, sectors = 0;
bio_for_each_segment(bv, bio, iter) {
- sectors += bv.bv_len >> 9;
-
- if (sectors > queue_max_sectors(q))
+ if (sectors + (bv.bv_len >> 9) > queue_max_sectors(q))
seg_size += bv.bv_len;
bvprv = bv;
bvprvp = &bv;
seg_size += bv.bv_len;
bvprv = bv;
bvprvp = &bv;
+ sectors += bv.bv_len >> 9;
bvprv = bv;
bvprvp = &bv;
seg_size = bv.bv_len;
bvprv = bv;
bvprvp = &bv;
seg_size = bv.bv_len;
+ sectors += bv.bv_len >> 9;
- split = bio_clone_bioset(bio, GFP_NOIO, bs);
-
- split->bi_iter.bi_size -= iter.bi_size;
- bio->bi_iter = iter;
-
- if (bio_integrity(bio)) {
- bio_integrity_advance(bio, split->bi_iter.bi_size);
- bio_integrity_trim(split, 0, bio_sectors(split));
- }
-
- return split;
+ return bio_split(bio, sectors, GFP_NOIO, bs);
}
void blk_queue_split(struct request_queue *q, struct bio **bio,
}
void blk_queue_split(struct request_queue *q, struct bio **bio,