blkcg: delete redundant get/put operations for queue

When calling blkcg_schedule_throttle(), for the same queue,
redundant get/put operations can be removed.

Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 3465d6e..02ce205 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1757,12 +1757,15 @@ void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay)
        if (unlikely(current->flags & PF_KTHREAD))
                return;
 
-       if (!blk_get_queue(q))
-               return;
+       if (current->throttle_queue != q) {
+               if (!blk_get_queue(q))
+                       return;
+
+               if (current->throttle_queue)
+                       blk_put_queue(current->throttle_queue);
+               current->throttle_queue = q;
+       }
 
-       if (current->throttle_queue)
-               blk_put_queue(current->throttle_queue);
-       current->throttle_queue = q;
        if (use_memdelay)
                current->use_memdelay = use_memdelay;
        set_notify_resume(current);