[PATCH V4 09/12] block: always attach cgroup info into bio
From: Shaohua Li <shli@kernel.org>
Date: 2017-06-28 16:30:37
Also in:
lkml
Subsystem:
block layer, control group - block io controller (blkio), the rest · Maintainers:
Jens Axboe, Tejun Heo, Josef Bacik, Linus Torvalds
From: Shaohua Li <redacted> 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 <redacted> --- block/blk-throttle.c | 7 +------ include/linux/blk-cgroup.h | 3 +++ 2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index a7285bf..a6ebd2b 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c@@ -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 }
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 7104bea..9d92153 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h@@ -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);
--
2.9.3