Re: [PATCH 10/14] blk-mq: initial support for multiple queue maps
From: Bart Van Assche <bvanassche@acm.org>
Date: 2018-10-29 19:40:39
Also in:
linux-scsi, lkml
On Mon, 2018-10-29 at 10:37 -0600, Jens Axboe wrote:
quoted hunk ↗ jump to hunk
-static int cpu_to_queue_index(unsigned int nr_queues, const int cpu) +static int cpu_to_queue_index(struct blk_mq_queue_map *qmap, + unsigned int nr_queues, const int cpu) { - return cpu % nr_queues; + return qmap->queue_offset + (cpu % nr_queues); } [ ... ]--- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h@@ -78,10 +78,11 @@ struct blk_mq_hw_ctx { struct blk_mq_queue_map { unsigned int *mq_map; unsigned int nr_queues; + unsigned int queue_offset; };
I think it's unfortunate that the blk-mq core uses the .queue_offset member but that mapping functions in block drivers are responsible for setting that member. Since the block driver mapping functions have to set blk_mq_queue_map.nr_queues, how about adding a loop in blk_mq_update_queue_map() that derives .queue_offset from .nr_queues from previous array entries? Thanks, Bart.