diff options
| author |   Dennis Zhou (Facebook) <dennisszhou@gmail.com> | 2018-09-11 14:41:36 -0400 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2018-09-21 20:29:18 -0600 |
| commit | b3b9f24f5fcc099c41f7dc1d02350635830888e5 (patch) | |
| tree | f5d5e1a689c0e7ae5d99625a75fd5235c2f21fe8 /include/linux/blk-cgroup.h | |
| parent | blkcg: cleanup and make blk_get_rl use blkg_lookup_create (diff) | |
| download | linux-dev-b3b9f24f5fcc099c41f7dc1d02350635830888e5.tar.xz linux-dev-b3b9f24f5fcc099c41f7dc1d02350635830888e5.zip | |
blkcg: change blkg reference counting to use percpu_ref
Now that every bio is associated with a blkg, this puts the use of
blkg_get, blkg_try_get, and blkg_put on the hot path. This switches over
the refcnt in blkg to use percpu_ref.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
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 d2f7f1b00fcf..7ff5d8ba8c7a 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -126,7 +126,7 @@ struct blkcg_gq { struct request_list rl; /* reference count */ - atomic_t refcnt; + struct percpu_ref refcnt; /* is this blkg online? protected by both blkcg and q locks */ bool online; @@ -490,8 +490,7 @@ 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); } /** @@ -503,7 +502,7 @@ 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; } @@ -517,23 +516,19 @@ 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); } /** |