On Wed, Jun 17, 2020 at 02:18:37PM +0800, Weiping Zhang wrote: > 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@xxxxxxxxxxxxxx> > --- > block/blk-mq.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 4f57d27bfa73..a9aa6d1e44cf 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -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) > -- > 2.18.2 > Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> -- Ming
