diff options
| author | Dennis Zhou <dennis@kernel.org> | 2018-12-05 12:10:38 -0500 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-12-07 22:26:38 -0700 |
| commit | 7fcf2b033b84e261dca283bc2911aaea4b07b525 (patch) | |
| tree | 87573c8336fd2fb9063dc554262d5b293877aa84 /include/linux/blk-cgroup.h | |
| parent | 6f70fb66182b02e50deea65e9a3a86b7bf659a39 (diff) | |
| download | lwn-7fcf2b033b84e261dca283bc2911aaea4b07b525.tar.gz lwn-7fcf2b033b84e261dca283bc2911aaea4b07b525.zip | |
blkcg: change blkg reference counting to use percpu_ref
Every bio is now associated with a blkg putting blkg_get, blkg_try_get,
and blkg_put on the hot path. Switch over the refcnt in blkg to use
percpu_ref.
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/blk-cgroup.h')
| -rw-r--r-- | include/linux/blk-cgroup.h | 15 |
1 files changed, 5 insertions, 10 deletions
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 284819a4d122..d19ef15a673d 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -124,7 +124,7 @@ struct blkcg_gq { struct blkcg_gq *parent; /* reference count */ - atomic_t refcnt; + struct percpu_ref refcnt; /* is this blkg online? protected by both blkcg and q locks */ bool online; @@ -487,8 +487,7 @@ static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen) */ static inline void blkg_get(struct blkcg_gq *blkg) { - WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0); - atomic_inc(&blkg->refcnt); + percpu_ref_get(&blkg->refcnt); } /** @@ -500,7 +499,7 @@ static inline void blkg_get(struct blkcg_gq *blkg) */ static inline struct blkcg_gq *blkg_try_get(struct blkcg_gq *blkg) { - if (atomic_inc_not_zero(&blkg->refcnt)) + if (percpu_ref_tryget(&blkg->refcnt)) return blkg; return NULL; } @@ -514,23 +513,19 @@ static inline struct blkcg_gq *blkg_try_get(struct blkcg_gq *blkg) */ static inline struct blkcg_gq *blkg_try_get_closest(struct blkcg_gq *blkg) { - while (!atomic_inc_not_zero(&blkg->refcnt)) + while (!percpu_ref_tryget(&blkg->refcnt)) blkg = blkg->parent; return blkg; } -void __blkg_release_rcu(struct rcu_head *rcu); - /** * blkg_put - put a blkg reference * @blkg: blkg to put */ static inline void blkg_put(struct blkcg_gq *blkg) { - WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0); - if (atomic_dec_and_test(&blkg->refcnt)) - call_rcu(&blkg->rcu_head, __blkg_release_rcu); + percpu_ref_put(&blkg->refcnt); } /** |