[PATCH 0/3] Add BLK_MQ_F_NO_SCHED flag to admin tag set

[Sagi Grimberg]

>>> Since commit b86dd81
>>> "block: get rid of blk-mq default scheduler choice Kconfig entries",
>>> when setting nr_hw_queues to 1 the admin tag set uses mq-deadline 
>>> scheduler.
>>> This flag is useful for admin queues that aren't used for normal IO.
>>> We already use this flag at nvme-pci.
>>
>> How is the fact that we set a single hw queue has anything to do with
>> the admin tagset?
> 
> Setting nr_hw_queues attribute of admin tag set to 1 influence the value
> of nr_hw_queues attribute of the admin queue.
> At /block/elevator.c
> elevator_init() selects the scheduler according to the value of 
> nr_hw_queues
> attribute of the admin queue.

Oh, I confused your meaning with setting nr_hw_queues to 1 in the IO
tagset makes a difference for the admin tagset.