diff options
| author | Tejun Heo <tj@kernel.org> | 2014-09-24 21:31:49 +0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2014-09-24 21:31:49 +0400 |
| commit | f47ad45784611297b699f3dffb6c7222b76afe64 (patch) | |
| tree | 9497c0a4bad4c6b97cfd08bf22a8b2313606ce6a /include/linux/percpu-refcount.h | |
| parent | 490c79a65708873228cf114cf00e32c204e4e907 (diff) | |
| download | linux-f47ad45784611297b699f3dffb6c7222b76afe64.tar.xz | |
percpu_ref: decouple switching to percpu mode and reinit
percpu_ref has treated the dropping of the base reference and
switching to atomic mode as an integral operation; however, there's
nothing inherent tying the two together.
The use cases for percpu_ref have been expanding continuously. While
the current init/kill/reinit/exit model can cover a lot, the coupling
of kill/reinit with atomic/percpu mode switching is turning out to be
too restrictive for use cases where many percpu_refs are created and
destroyed back-to-back with only some of them reaching extended
operation. The coupling also makes implementing always-atomic debug
mode difficult.
This patch separates out percpu mode switching into
percpu_ref_switch_to_percpu() and reimplements percpu_ref_reinit() on
top of it.
* DEAD still requires ATOMIC. A dead ref can't be switched to percpu
mode w/o going through reinit.
v2: __percpu_ref_switch_to_percpu() was missing static. Fixed.
Reported by Fengguang aka kbuild test robot.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: kbuild test robot <fengguang.wu@intel.com>
Diffstat (limited to 'include/linux/percpu-refcount.h')
| -rw-r--r-- | include/linux/percpu-refcount.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index d1252e1335e8..cd7e20f0fe47 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -80,9 +80,10 @@ int __must_check percpu_ref_init(struct percpu_ref *ref, void percpu_ref_exit(struct percpu_ref *ref); void percpu_ref_switch_to_atomic(struct percpu_ref *ref, percpu_ref_func_t *confirm_switch); -void percpu_ref_reinit(struct percpu_ref *ref); +void percpu_ref_switch_to_percpu(struct percpu_ref *ref); void percpu_ref_kill_and_confirm(struct percpu_ref *ref, percpu_ref_func_t *confirm_kill); +void percpu_ref_reinit(struct percpu_ref *ref); /** * percpu_ref_kill - drop the initial ref |