[pull] amdgpu/kfd, radeon, ttm drm-next-5.5

[Daniel Vetter]

On Thu, Oct 10, 2019 at 4:37 PM Koenig, Christian
<Christian.Koenig at amd.com> wrote:
> Am 10.10.19 um 16:34 schrieb Alex Deucher:
> > AOn Thu, Oct 10, 2019 at 5:54 AM Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> >> On Thu, Oct 10, 2019 at 6:17 AM Alex Deucher <alexdeucher at gmail.com> wrote:
> >>> [SNIP]
> >>> Christian König (22):
> >>>        drm/amdgpu: use moving fence instead of exclusive for VM updates
> >>>        drm/amdgpu: reserve at least 4MB of VRAM for page tables v2
> >>>        drm/amdgpu: remove amdgpu_cs_try_evict
> >> Patch no handy for a direct reply, so asking here (but this is totally
> >> unrelated to the pull):
> >>
> >> Do you have other stuff than scanout and pagetables that need to be in
> >> vram? I was kinda assume this is needed for big vram-only objects to
> >> fit, making space by throwing stuff out that could also be put into
> >> system memory. But sounds like it was only for making pagetables fit.
> > Yes, basically making page tables fit.  If you push a bunch of stuff
> > to system ram, your page table requirements go up too.  See the
> > discussion here:
> > https://www.spinics.net/lists/amd-gfx/msg38640.html

Yeah read that, that's why I asked whether pagetables was the only big thing.

> Yeah, typical chicken and egg problem.
>
> When you evict things to system memory because you don't have enough
> VRAM you need more VRAM for page tables so you need to evict even more
> things to system memory....
>
> Additional to that we have a few other cases where we really need VRAM
> for correct operation (firmware, old MM engines etc...), but nothing
> major like page tables.

Yeah makes sense. Afaiui we'll have a few more big things in vram
only, so I think we'll steal this idea for i915.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch