On Thu, 2026-06-11 at 19:33 +0200, Thomas Hellström wrote:
> Register the VRAM manager with the dmem cgroup reclaim infrastructure
> so that lowering dmem.max below current VRAM usage triggers TTM
> eviction rather than failing with -EBUSY.
>
> Guard place->flags in amdgpu_ttm_bo_eviction_valuable() against NULL,
> as the TTM reclaim path passes a NULL place in cgroup drain mode.
>
> v3:
> - Rebased on fix for uninitialized list and buddy allocator on the
> drmm_cgroup_register_region() error path.
>
> v5:
> - Rebased on the introduction of struct dmem_cgroup_init.
> - Clear the reclaim callback in amdgpu_vram_mgr_fini() to prevent
> use-after-free if cgroup reclaim is triggered after driver unbind
> while userspace holds an open DRM file descriptor. (Sashiko-bot)
> - Switch from drmm_cgroup_register_region() to the raw
> dmem_cgroup_register_region() and store the region in
> amdgpu_vram_mgr.cg_region. Call dmem_cgroup_unregister_region()
> in amdgpu_vram_mgr_fini() after ttm_resource_manager_evict_all()
> to drain in-flight reclaim callbacks, and clear man->cg afterwards.
> This is required because amdgpu's vram manager fini is called
> explicitly during driver unbind, which may precede the DRM device
> release and thus precede any drmm-based cleanup. (Sashiko-bot)
>
> v6:
> - Fix mgr->cg_region never being assigned, so
> dmem_cgroup_unregister_region() in fini silently no-ops on NULL
> and leaks the region. (Sashiko-bot)
> - Reorder fini to call set_used(false) and evict_all() before
> dmem_cgroup_unregister_region(), so ttm_resource_free() can
> uncharge via man->cg during eviction; clear man->cg after
> unregister. (Sashiko-bot)
>
> Assisted-by: GitHub_Copilot:claude-sonnet-4.6
> Signed-off-by: Thomas Hellström <[email protected]>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +-
> drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 31 ++++++++++++++++--
> --
> drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h | 2 ++
> 3 files changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 2740de94e93c..8cbcd33f51a5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -1488,7 +1488,7 @@ static bool
> amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
> dma_resv_for_each_fence(&resv_cursor, bo->base.resv,
> DMA_RESV_USAGE_BOOKKEEP, f) {
> if (amdkfd_fence_check_mm(f, current->mm) &&
> - !(place->flags & TTM_PL_FLAG_CONTIGUOUS))
> + !(place && (place->flags &
> TTM_PL_FLAG_CONTIGUOUS)))
> return false;
> }
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> index 08f05c3aed1d..2250bab0970d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -906,6 +906,10 @@ static const struct ttm_resource_manager_func
> amdgpu_vram_mgr_func = {
> .debug = amdgpu_vram_mgr_debug
> };
>
> +static const struct dmem_cgroup_ops amdgpu_vram_mgr_dmem_ops = {
> + .reclaim = ttm_resource_manager_dmem_reclaim,
> +};
Probably might want to block reclaim after device unbind, just like xe.
I'll look at that for v7.
> +
> /**
> * amdgpu_vram_mgr_init - init VRAM manager and DRM MM
> *
> @@ -917,6 +921,7 @@ int amdgpu_vram_mgr_init(struct amdgpu_device
> *adev)
> {
> struct amdgpu_vram_mgr *mgr = &adev->mman.vram_mgr;
> struct ttm_resource_manager *man = &mgr->manager;
> + struct dmem_cgroup_region *cg;
> int err;
>
> ttm_resource_manager_init(man, &adev->mman.bdev,
> @@ -933,12 +938,16 @@ int amdgpu_vram_mgr_init(struct amdgpu_device
> *adev)
> if (err)
> return err;
>
> - man->cg = drmm_cgroup_register_region(adev_to_drm(adev),
> "vram",
> - &(struct
> dmem_cgroup_init){
> - .size = adev-
> >gmc.real_vram_size,
> - });
> - if (IS_ERR(man->cg))
> - return PTR_ERR(man->cg);
> + cg = dmem_cgroup_register_region(&(struct dmem_cgroup_init){
> + .size = adev-
> >gmc.real_vram_size,
> + .ops =
> &amdgpu_vram_mgr_dmem_ops,
> + .reclaim_priv = man,
> + }, "vram");
> + if (IS_ERR(cg))
> + return PTR_ERR(cg);
> +
> + mgr->cg_region = cg;
> + ttm_resource_manager_set_dmem_region(man, cg);
>
> ttm_set_driver_manager(&adev->mman.bdev, TTM_PL_VRAM, &mgr-
> >manager);
> ttm_resource_manager_set_used(man, true);
> @@ -966,6 +975,16 @@ void amdgpu_vram_mgr_fini(struct amdgpu_device
> *adev)
> if (ret)
> return;
>
> + /*
> + * Drain any in-flight dmem cgroup reclaim callbacks and
> remove the
> + * region from the global list. This must happen after
> evict_all()
> + * so that ttm_resource_free() can still uncharge via man-
> >cg while
> + * BOs are being evicted.
> + */
> + dmem_cgroup_unregister_region(mgr->cg_region);
> + mgr->cg_region = NULL;
> + man->cg = NULL;
> +
> mutex_lock(&mgr->lock);
> list_for_each_entry_safe(rsv, temp, &mgr-
> >reservations_pending, blocks)
> kfree(rsv);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
> index 429a21a2e9b2..07103cddb335 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
> @@ -36,6 +36,8 @@ struct amdgpu_vram_mgr {
> atomic64_t vis_usage;
> u64 default_page_size;
> struct list_head allocated_vres_list;
> + /** @cg_region: dmem cgroup region for VRAM; unregistered in
> fini. */
> + struct dmem_cgroup_region *cg_region;
> };
>
> struct amdgpu_vres_task {
