Re: [PATCH v9 03/17] block/mq-deadline: Only use zone locking if necessary

Damien Le Moal
2023-08-17T11:03:39Z

On 8/17/23 04:53, Bart Van Assche wrote:
> Measurements have shown that limiting the queue depth to one per zone for
> zoned writes has a significant negative performance impact on zoned UFS
> devices. Hence this patch that disables zone locking by the mq-deadline
> scheduler if the storage controller preserves the command order. This
> patch is based on the following assumptions:
> - It happens infrequently that zoned write requests are reordered by the
> block layer.
> - The I/O priority of all write requests is the same per zone.
> - Either no I/O scheduler is used or an I/O scheduler is used that
> serializes write requests per zone.
>
> Cc: Damien Le Moal <dlemoal@kernel.org>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Ming Lei <ming.lei@redhat.com>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>

Looks OK to me.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

--
Damien Le Moal
Western Digital Research