Re: [PATCH RFC] virtio-blk: support per-device queue depth

On 2021/1/18 下午2:06, Joseph Qi wrote:

Hi Jason,

On 1/18/21 1:25 PM, Jason Wang wrote:

quoted

On 2021/1/18 上午11:58, Joseph Qi wrote:

quoted

module parameter 'virtblk_queue_depth' was firstly introduced for
testing/benchmarking purposes described in commit fc4324b4597c
("virtio-blk: base queue-depth on virtqueue ringsize or module param").
Since we have different virtio-blk devices which have different
capabilities, it requires that we support per-device queue depth instead
of per-module. So defaultly use vq free elements if module parameter
'virtblk_queue_depth' is not set.

I wonder if it's better to use sysfs instead (or whether it has already had something like this in the blocker layer).

Thanks for quick response.
Do you mean adjust /sys/block/vdX/queue/nr_requests?
But current logic in virtblk_probe() is, virtblk_queue_depth is
used as a saved value for first probed vdev, not purely module
parameter.

Right, I see. So I think the patch is fine.

Thanks

Thanks,
Joseph