Commit fe35ec58 authored Jun 17, 2020 by Weiping Zhang Committed by Jens Axboe Jun 17, 2020

block: update hctx map when use multiple maps



There is an issue when tune the number for read and write queues,
if the total queue count was not changed. The hctx->type cannot
be updated, since __blk_mq_update_nr_hw_queues will return directly
if the total queue count has not been changed.

Reproduce:

dmesg | grep "default/read/poll"
[    2.607459] nvme nvme0: 48/0/0 default/read/poll queues
cat /sys/kernel/debug/block/nvme0n1/hctx*/type | sort | uniq -c
     48 default

tune the write queues to 24:
echo 24 > /sys/module/nvme/parameters/write_queues
echo 1 > /sys/block/nvme0n1/device/reset_controller

dmesg | grep "default/read/poll"
[  433.547235] nvme nvme0: 24/24/0 default/read/poll queues

cat /sys/kernel/debug/block/nvme0n1/hctx*/type | sort | uniq -c
     48 default

The driver's hardware queue mapping is not same as block layer.

Signed-off-by: Weiping Zhang <zhangweiping@didiglobal.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent c3dbe541

block/blk-mq.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -3479,7 +3479,9 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,

		if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
		nr_hw_queues = nr_cpu_ids;
		if (nr_hw_queues < 1 \|\| nr_hw_queues == set->nr_hw_queues)
		if (nr_hw_queues < 1)
		return;
		if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
		return;

		list_for_each_entry(q, &set->tag_list, tag_set_list)

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