[PATCH 2/2] drm/xe/uapi: Restore uapi for access counting

[Lucas De Marchi]

On Wed, Oct 02, 2024 at 03:03:46PM GMT, Matthew Brost wrote:
>On Tue, Oct 01, 2024 at 04:02:55PM -0500, Lucas De Marchi wrote:
>> On Tue, Oct 01, 2024 at 07:24:32PM GMT, apoorva.singh at intel.com wrote:
>> > From: Brian Welty <brian.welty at intel.com>
>> >
>> > In order to enable access counters, this must be enabled in LRC for
>> > the exec_queue. Add basic uAPI to set configuration of access counter
>> > trigger threshold and granularity.
>> >
>> > When access counters are enabled and threshold is hit, the access
>> > counter handler in xe_gt_pagefault.c will migrate the buffer to that
>> > to that GT's local VRAM.
>> >
>> > Signed-off-by: Brian Welty <brian.welty at intel.com>
>> > Signed-off-by: Apoorva Singh <apoorva.singh at intel.com>
>>
>>
>> What do you mean by **Restore**? I'd expect a minimum amount of
>> documentation explaining what this is and how a real
>> userspace can be used it for implementing X, Y and Z.  Link to userspace
>> is also missing, and is required for uapi.
>>
>
>I was going to say do we have user space for this yet? I also suspect
>getting this implementation right is going to part of the SVM work. I
>personally rather leave this disabled until we get the SVM
>implementation for this all worked out so we can freely change this if
>required.

Agreed. If we want to merge parts that are required and we are still not
ready with the entire feature, then it'd be ok... provided it's properly
explained and documented. But touching the UAPI is not. This should come
only after we have everything in place and a userspace consumer is
ready.

Lucas De Marchi

>
>I can't imagine any user space is really demanding this to be enabled
>yet.
>
>Matt
>
>> Lucas De Marchi