From: Alex Deucher Date: Wed, 30 Oct 2019 17:53:27 +0000 (-0400) Subject: drm/amdgpu/gpuvm: add some additional comments in amdgpu_vm_update_ptes X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=8863baefaf02415fcb9894b03793711157fa1c82;p=uclinux-h8%2Flinux.git drm/amdgpu/gpuvm: add some additional comments in amdgpu_vm_update_ptes To better clarify what is happening in this function. Reviewed-by: Christian König Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index e775f271f1ed..598c24505c73 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -1418,6 +1418,9 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params, uint64_t incr, entry_end, pe_start; struct amdgpu_bo *pt; + /* make sure that the page tables covering the address range are + * actually allocated + */ r = amdgpu_vm_alloc_pts(params->adev, params->vm, &cursor, params->direct); if (r) @@ -1491,7 +1494,12 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params, } while (frag_start < entry_end); if (amdgpu_vm_pt_descendant(adev, &cursor)) { - /* Free all child entries */ + /* Free all child entries. + * Update the tables with the flags and addresses and free up subsequent + * tables in the case of huge pages or freed up areas. + * This is the maximum you can free, because all other page tables are not + * completely covered by the range and so potentially still in use. + */ while (cursor.pfn < frag_start) { amdgpu_vm_free_pts(adev, params->vm, &cursor); amdgpu_vm_pt_next(adev, &cursor);