block: always attach cgroup info into bio (007cc56b) · Commits · 戴 / test

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>

block/blk-throttle.c

+1 −6

Original line number	Diff line number	Diff line
		@@ -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)
		{
		#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
		int ret;

		ret = bio_associate_current(bio);
		if (ret == 0 \|\| ret == -EBUSY)
		if (bio->bi_css)
		bio->bi_cg_private = tg;
		blk_stat_set_issue(&bio->bi_issue_stat, bio_sectors(bio));
		#else
		bio_associate_current(bio);
		#endif
		}

include/linux/blk-cgroup.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -691,6 +691,9 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q,
		rcu_read_lock();
		blkcg = bio_blkcg(bio);

		/* associate blkcg if bio hasn't attached one */
		bio_associate_blkcg(bio, &blkcg->css);

		blkg = blkg_lookup(blkcg, q);
		if (unlikely(!blkg)) {
		spin_lock_irq(q->queue_lock);

Admin message