If we keep the BO in the GTT domain, it means it will not be updated if we validate it again later in kfd_mem_dmamap_dmabuf. This means we'll use stale DMA addresses when we update the page tables after evictions.

I think we'll need to find a different way to avoid triggering the eviction fence on the original BO when changing the placement of the DMABuf import here. If you need help brainstorming here, please share a backtrace from the eviction generated with the debug_evictions module param.

Regards,
  Felix


Am 2023-04-03 um 13:59 schrieb Eric Huang:
dmabuf is allocated/mapped as GTT domain, when dma-unmapping dmabuf
changing placement to CPU will trigger memory eviction after calling
ttm_bo_validate, and the eviction will cause performance drop.
Keeping the correct domain will solve the issue.

Signed-off-by: Eric Huang <jinhuieric.hu...@amd.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index a3b09edfd1bf..17b708acb447 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -642,7 +642,7 @@ kfd_mem_dmaunmap_dmabuf(struct kfd_mem_attachment 
*attachment)
        struct ttm_operation_ctx ctx = {.interruptible = true};
        struct amdgpu_bo *bo = attachment->bo_va->base.bo;
- amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_CPU);
+       amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);
        ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
  }

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