Commit 0549e87c authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

block: move 'q_usage_counter' into front of 'request_queue' 



The field of 'q_usage_counter' is always fetched in fast path of every
block driver, and move it into front of 'request_queue', so it can be
fetched into 1st cacheline of 'request_queue' instance.

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Tested-by: default avatarVeronika Kabatova <vkabatov@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 2b0d3d3e

include/linux/blkdev.h

+2 −1
Original line number Diff line number Diff line
@@ -397,6 +397,8 @@ struct request_queue { 
	struct request		*last_merge;

	struct elevator_queue	*elevator;



	struct percpu_ref	q_usage_counter;



	struct blk_queue_stats	*stats;

	struct rq_qos		*rq_qos;
@@ -569,7 +571,6 @@ struct request_queue { 
	 * percpu_ref_kill() and percpu_ref_reinit().

	 */

	struct mutex		mq_freeze_lock;

	struct percpu_ref	q_usage_counter;



	struct blk_mq_tag_set	*tag_set;

	struct list_head	tag_set_list;