Re: [PATCH 0/5] Add reclaim to the dmem cgroup controller

Thomas Hellström
2026-03-27T08:33:48Z

On Fri, 2026-03-27 at 09:15 +0100, Thomas Hellström wrote:
> When writing a "max" limit lower than the current usage, the
> existing code silently failed. This series aims to improve
> on that by returning -EBUSY on failure and also attempt
> to synchronously reclaim device memory to push the usage
> under the new max limit to avoid the error.
>
> Patch 1 implements error propagation.
> Patch 2 implements and documents a reclaim callback interface
>       for the dmem controller.
> Patch 3 implements a TTM reclaim callback.
> Patch 4-5 hooks up the reclaim callback to the dmem cgroups-
>       aware drivers xe and amdgpu.
>
> Thomas Hellström (5):
>   cgroup/dmem: Return error when setting max below current usage
>   cgroup/dmem: Add reclaim callback for lowering max below current
> usage
>   drm/ttm: Hook up a cgroup-aware reclaim callback for the dmem
>     controller
>   drm/xe: Wire up dmem cgroup reclaim for VRAM manager
>   drm/amdgpu: Wire up dmem cgroup reclaim for VRAM manager
>
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c      |   2 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c |  10 +-
>  drivers/gpu/drm/ttm/ttm_bo.c                 |  95 ++++++++++++++++-
>  drivers/gpu/drm/ttm/ttm_bo_util.c            |   3 +-
>  drivers/gpu/drm/ttm/ttm_resource.c           |  36 +++++++
>  drivers/gpu/drm/xe/xe_ttm_vram_mgr.c         |  19 ++--
>  include/drm/ttm/ttm_bo.h                     |  10 ++
>  include/drm/ttm/ttm_resource.h               |   4 +
>  include/linux/cgroup_dmem.h                  |  11 ++
>  kernel/cgroup/dmem.c                         | 102 ++++++++++++++++-
> --
>  10 files changed, 265 insertions(+), 27 deletions(-)

For reference, Series introducing igt test is here:
https://patchwork.freedesktop.org/series/163935/

/Thomas