[PATCH v2] drm/amdgpu: skip clearing empty freed VM list on GEM close

amdgpu_vm_clear_freed() allocates an amdgpu_sync object and walks the VM
reservation fences via amdgpu_sync_resv() before checking whether vm->freed
has anything to clear. Return early when the list is empty to skip this
overhead on a hot path (every GEM close and command submission).

Signed-off-by: Bob Zhou <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 157d4168907ce..eb6a70fe79ceb 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1553,6 +1553,8 @@ int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
 	struct amdgpu_sync sync;
 	int r;
 
+	if (list_empty(&vm->freed))
+		return 0;
 
 	/*
 	 * Implicitly sync to command submissions in the same VM before
-- 
2.34.1