On Thu, Oct 10, 2019 at 4:37 PM Koenig, Christian Christian.Koenig@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@ffwll.ch wrote:
On Thu, Oct 10, 2019 at 6:17 AM Alex Deucher alexdeucher@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