In [0] Kashyap reports high CPU usage for blk_mq_queue_tag_busy_iter() and callees for shared tags. Indeed blk_mq_queue_tag_busy_iter() would be less optimum for moving to shared tags, but it was not optimum previously. This series optimises by having only a single iter (per regular and resv tags) for the shared tags, instead of an iter per HW queue. [0] https://lore.kernel.org/linux-block/e4e92abbe9d52bcba6b8cc6c91c442cc@xxxxxxxxxxxxxx/ Differences to v1: - Add tested-by and reviewed-by tags - Reformat 3/3 a bit to keep <= 80 char lines - I kept the RB tags, so please check and let me know if not ok with the changes John Garry (3): blk-mq: Drop busy_iter_fn blk_mq_hw_ctx argument blk-mq: Delete busy_iter_fn blk-mq: Optimise blk_mq_queue_tag_busy_iter() for shared tags block/blk-mq-tag.c | 65 ++++++++++++++++++++++++++++-------------- block/blk-mq-tag.h | 2 +- block/blk-mq.c | 17 ++++++----- include/linux/blk-mq.h | 2 -- 4 files changed, 53 insertions(+), 33 deletions(-) -- 2.26.2
