Re: [PATCH v3 6/6] dmaengine: idxd: add ABI documentation for shared wq

From: Dave Hansen
Date: Mon Jul 06 2020 - 14:57:37 EST


On 7/6/20 11:22 AM, Dave Jiang wrote:
> +What: /sys/bus/dsa/devices/dsa<m>/pasid_enabled
> +Date: Jul 5, 2020
> +KernelVersion: 5.9.0
> +Contact: dmaengine@xxxxxxxxxxxxxxx
> +Description: To indicate if PASID (process address space identifier) is
> + enabled or not for this device.
> +
> What: /sys/bus/dsa/devices/dsa<m>/state
> Date: Oct 25, 2019
> KernelVersion: 5.6.0
> @@ -116,6 +123,13 @@ Description: The maximum number of bandwidth tokens that may be in use at
> one time by operations that access low bandwidth memory in the
> device.
>
> +What: /sys/bus/dsa/devices/wq<m>.<n>/block_on_fault
> +Date: Jul 5, 2020
> +KernelVersion: 5.9.0
> +Contact: dmaengine@xxxxxxxxxxxxxxx
> +Description: To indicate block on fault is allowed or not for the work queue
> + to support on demand paging.

I'd also really appreciate some more "why" in addition to the "what" in
the documentation. Why would a program or end user care that PASIDs are
enabled or that on-demand paging is supported?