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block: always attach cgroup info into bio

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blkcg_bio_issue_check() already gets blkcg for a BIO.
bio_associate_blkcg() uses a percpu refcounter, so it's a very cheap
operation. There is no point we don't attach the cgroup info into bio at
blkcg_bio_issue_check. This also makes blktrace outputs correct cgroup
info.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Shaohua Li 2017-07-12 11:49:54 -07:00 • committed by Jens Axboe
parent ca1136c99b
commit 007cc56b7e
2 changed files with 4 additions and 6 deletions
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7
block/blk-throttle.c
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@ -2104,14 +2104,9 @@ static inline void throtl_update_latency_buckets(struct throtl_data *td)
static void blk_throtl_assoc_bio(struct throtl_grp *tg, struct bio *bio) static void blk_throtl_assoc_bio(struct throtl_grp *tg, struct bio *bio)
{ {
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
int ret; if (bio->bi_css)
ret = bio_associate_current(bio);
if (ret == 0 || ret == -EBUSY)
bio->bi_cg_private = tg; bio->bi_cg_private = tg;
blk_stat_set_issue(&bio->bi_issue_stat, bio_sectors(bio)); blk_stat_set_issue(&bio->bi_issue_stat, bio_sectors(bio));
#else
bio_associate_current(bio);
#endif #endif
} }

3
include/linux/blk-cgroup.h
View file

@ -691,6 +691,9 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q,
rcu_read_lock(); rcu_read_lock();
blkcg = bio_blkcg(bio); blkcg = bio_blkcg(bio);
/* associate blkcg if bio hasn't attached one */
bio_associate_blkcg(bio, &blkcg->css);
blkg = blkg_lookup(blkcg, q); blkg = blkg_lookup(blkcg, q);
if (unlikely(!blkg)) { if (unlikely(!blkg)) {
spin_lock_irq(q->queue_lock); spin_lock_irq(q->queue_lock);