Sparsely populated TTM bos

[Christian König]

Hi Thomas,

Am 19.11.21 um 15:28 schrieb Thomas Hellström:
> Hi, Christian,
>
> We have an upcoming use-case in i915 where one solution would be 
> sparsely populated TTM bos.
>
> We had that at one point where ttm_tt pages were allocated on demand, 
> but this time we'd rather be looking at multiple struct ttm_resources 
> per bo and those resources could be from different managers.
>
> There might theoretically be other ways we can handle this use-case 
> but I wanted to check with you whether this is something AMD is 
> already looking into and if not, your general opinion.

oh, yes I've looked into this as well a very long time ago.

At that point the basic blocker was that we couldn't have different 
cache setting for the same VMA, but I think that's fixed by now.

Another thing is that you essentially need to move the LRU handling into 
the resource like I already planned to do anyway.

Regards,
Christian.

>
> Thanks,
> Thomas
>
>