Re: [PATCH 07/15] blkcg: consolidate bio_issue_init and blkg association

Josef Bacik
2018-08-31T15:42:26Z

On Thu, Aug 30, 2018 at 09:53:48PM -0400, Dennis Zhou wrote:
> From: "Dennis Zhou (Facebook)" <dennisszhou@gmail.com>
>
> This removes the now duplicate association logic in blk-throttle and
> blk-iolatency. bio_issue_init is moved into blkcg_bio_issue_check and
> into the bio clone variants to allow for the future addition of a
> latency moving average for IOs.
>
> Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
> ---
> block/bio.c | 2 ++
> block/blk-iolatency.c | 24 +-----------------------
> block/blk-throttle.c | 13 +------------
> block/bounce.c | 2 ++
> include/linux/blk-cgroup.h | 2 ++
> 5 files changed, 8 insertions(+), 35 deletions(-)
>
> diff --git a/block/bio.c b/block/bio.c
> index e937f9681188..ab41f5b7eb1f 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -610,6 +610,8 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
> bio->bi_io_vec = bio_src->bi_io_vec;
>
> bio_clone_blkcg_association(bio, bio_src);
> +
> + bio_issue_init(&bio->bi_issue, bio_sectors(bio));
> }
> EXPORT_SYMBOL(__bio_clone_fast);
>
> diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
> index 22b2ff0440cc..9d7052bad6f7 100644
> --- a/block/blk-iolatency.c
> +++ b/block/blk-iolatency.c
> @@ -395,34 +395,12 @@ static void blkcg_iolatency_throttle(struct rq_qos *rqos, struct bio *bio,
> spinlock_t *lock)
> {
> struct blk_iolatency *blkiolat = BLKIOLATENCY(rqos);
> - struct blkcg *blkcg;
> - struct blkcg_gq *blkg;
> - struct request_queue *q = rqos->q;
> + struct blkcg_gq *blkg = bio->bi_blkg;
> bool issue_as_root = bio_issue_as_root_blkg(bio);
>
> if (!blk_iolatency_enabled(blkiolat))
> return;
>
> - rcu_read_lock();
> - bio_associate_blkcg(bio, NULL);
> - blkcg = bio_blkcg(bio);
> - blkg = blkg_lookup(blkcg, q);
> - if (unlikely(!blkg)) {
> - if (!lock)
> - spin_lock_irq(q->queue_lock);
> - blkg = __blkg_lookup_create(blkcg, q);
> - if (IS_ERR(blkg))
> - blkg = NULL;
> - if (!lock)
> - spin_unlock_irq(q->queue_lock);
> - }
> - if (!blkg)
> - goto out;
> -
> - bio_issue_init(&bio->bi_issue, bio_sectors(bio));
> - bio_associate_blkg(bio, blkg);
> -out:
> - rcu_read_unlock();

Move this removal to the previous patch, so you keep this patch soley about the
bio_issue_init. Thanks,

Josef