Commit 0549e87c authored Oct 01, 2020 by Ming Lei Committed by Jens Axboe Oct 06, 2020

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: Ming Lei <ming.lei@redhat.com>
Tested-by: Veronika Kabatova <vkabatov@redhat.com>
Reviewed-by: Christoph 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: Jens 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;

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