[PATCH 7/9] drm/amdgpu: Throttle visible VRAM moves separately

[Michel Dänzer]

On 24/06/17 02:39 AM, John Brooks wrote:
> The BO move throttling code is designed to allow VRAM to fill quickly if it
> is relatively empty. However, this does not take into account situations
> where the visible VRAM is smaller than total VRAM, and total VRAM may not
> be close to full but the visible VRAM segment is under pressure. In such
> situations, visible VRAM would experience unrestricted swapping and
> performance would drop.
> 
> Add a separate counter specifically for moves involving visible VRAM, and
> check it before moving BOs there.
> 
> Fixes: 95844d20ae02 (drm/amdgpu: throttle buffer migrations at CS using a fixed MBps limit (v2))
> Signed-off-by: John Brooks <john at fastquake.com>

Something like this patch is definitely needed, good catch.

However, as is one issue is that it incurs CPU overhead even when all of
VRAM is CPU visible. Can that be avoided somehow?


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer