From a7b39b4e961c4e2b3ed837803a7441a65c90ce33 Mon Sep 17 00:00:00 2001 From: "Dennis Zhou (Facebook)" Date: Tue, 11 Sep 2018 14:41:29 -0400 Subject: blkcg: always associate a bio with a blkg Previously, blkg's were only assigned as needed by blk-iolatency and blk-throttle. bio->css was also always being associated while blkg was being looked up and then thrown away in blkcg_bio_issue_check. This patch begins the cleanup of bio->css and bio->bi_blkg by always associating a blkg in blkcg_bio_issue_check. This tries to create the blkg, but if it is not possible, falls back to using the root_blkg of the request_queue. Therefore, a bio will always be associated with a blkg. The duplicate association logic is removed from blk-throttle and blk-iolatency. Signed-off-by: Dennis Zhou Acked-by: Tejun Heo Signed-off-by: Jens Axboe --- include/linux/bio.h | 3 +++ include/linux/blk-cgroup.h | 16 ++-------------- 2 files changed, 5 insertions(+), 14 deletions(-) (limited to 'include') diff --git a/include/linux/bio.h b/include/linux/bio.h index 14b4fa266357..829cd0bb407d 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -542,11 +542,14 @@ static inline int bio_associate_blkcg_from_page(struct bio *bio, #ifdef CONFIG_BLK_CGROUP int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css); int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg); +int bio_associate_create_blkg(struct request_queue *q, struct bio *bio); void bio_disassociate_task(struct bio *bio); void bio_clone_blkcg_association(struct bio *dst, struct bio *src); #else /* CONFIG_BLK_CGROUP */ static inline int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) { return 0; } +static inline int bio_associate_create_blkg(struct request_queue *q, + struct bio *bio) { return 0; } static inline void bio_disassociate_task(struct bio *bio) { } static inline void bio_clone_blkcg_association(struct bio *dst, struct bio *src) { } diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 1fbff1bbb651..6e33ad1d92b4 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -900,29 +900,17 @@ static inline bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg static inline bool blkcg_bio_issue_check(struct request_queue *q, struct bio *bio) { - struct blkcg *blkcg; struct blkcg_gq *blkg; bool throtl = false; rcu_read_lock(); - /* associate blkcg if bio hasn't attached one */ - bio_associate_blkcg(bio, NULL); - blkcg = bio_blkcg(bio); - - blkg = blkg_lookup(blkcg, q); - if (unlikely(!blkg)) { - spin_lock_irq(q->queue_lock); - blkg = __blkg_lookup_create(blkcg, q); - if (IS_ERR(blkg)) - blkg = NULL; - spin_unlock_irq(q->queue_lock); - } + bio_associate_create_blkg(q, bio); + blkg = bio->bi_blkg; throtl = blk_throtl_bio(q, blkg, bio); if (!throtl) { - blkg = blkg ?: q->root_blkg; /* * If the bio is flagged with BIO_QUEUE_ENTERED it means this * is a split bio and we would have already accounted for the -- cgit v1.2.3