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authorDennis Zhou <dennis@kernel.org>2018-12-05 20:10:38 +0300
committerJens Axboe <axboe@kernel.dk>2018-12-08 08:26:38 +0300
commit7fcf2b033b84e261dca283bc2911aaea4b07b525 (patch)
tree87573c8336fd2fb9063dc554262d5b293877aa84 /include/linux/blk-cgroup.h
parent6f70fb66182b02e50deea65e9a3a86b7bf659a39 (diff)
downloadlinux-7fcf2b033b84e261dca283bc2911aaea4b07b525.tar.xz
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.h15
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);
}
/**