Commit da521626 authored by Jens Axboe's avatar Jens Axboe
Browse files

bio: optimize initialization of a bio 



The memset() used is measurably slower in targeted benchmarks, wasting
about 1% of the total runtime, or 50% of the (later) hot path cached
bio alloc. Get rid of it and fill in the bio manually.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent fd08e530

block/bio.c

+30 −2
Original line number Diff line number Diff line
@@ -246,12 +246,40 @@ static void bio_free(struct bio *bio) 
void bio_init(struct bio *bio, struct bio_vec *table,

	      unsigned short max_vecs)

{

	memset(bio, 0, sizeof(*bio));

	bio->bi_next = NULL;

	bio->bi_bdev = NULL;

	bio->bi_opf = 0;

	bio->bi_flags = 0;

	bio->bi_ioprio = 0;

	bio->bi_write_hint = 0;

	bio->bi_status = 0;

	bio->bi_iter.bi_sector = 0;

	bio->bi_iter.bi_size = 0;

	bio->bi_iter.bi_idx = 0;

	bio->bi_iter.bi_bvec_done = 0;

	bio->bi_end_io = NULL;

	bio->bi_private = NULL;

#ifdef CONFIG_BLK_CGROUP

	bio->bi_blkg = NULL;

	bio->bi_issue.value = 0;

#ifdef CONFIG_BLK_CGROUP_IOCOST

	bio->bi_iocost_cost = 0;

#endif

#endif

#ifdef CONFIG_BLK_INLINE_ENCRYPTION

	bio->bi_crypt_context = NULL;

#endif

#ifdef CONFIG_BLK_DEV_INTEGRITY

	bio->bi_integrity = NULL;

#endif

	bio->bi_vcnt = 0;



	atomic_set(&bio->__bi_remaining, 1);

	atomic_set(&bio->__bi_cnt, 1);



	bio->bi_io_vec = table;

	bio->bi_max_vecs = max_vecs;

	bio->bi_io_vec = table;

	bio->bi_pool = NULL;

}

EXPORT_SYMBOL(bio_init);