Re: [PATCH v2 1/1] scsi: ufs: core: Make UFS_MCQ_NUM_DEV_CMD_QUEUES a module parameter

[Bart Van Assche <bvanassche@acm.org>]

On 5/29/23 19:35, Po-Wen Kao wrote:
> A dedicated queue for dev commands is not mandatory, hence let
> UFS_MCQ_NUM_DEV_CMD_QUEUES become module parameter `dev_cmd_queues`
> to allow sharing first hw queue for dev commands.
> 
> When `dev_cmd_queues` is set to 0, the hwq 0 will be shared for I/O
> requests and dev commands. In the same hwq, commands are processed based
> on submission order hence might take longer to dispatch dev command
> under heavy traffic. For the host with dedicated hwq for dev commands
> can benefit in such scenario.

The UFS core has already too many kernel module parameters. I don't 
think that we need more kernel module parameters. Instead of adding a 
new kernel module parameter, I propose to never reserve a hardware queue 
for device commands. Reserving a hardware queue for device commands 
seems wasteful to me.

Thanks,

Bart.