Am 26.03.2018 um 03:31 schrieb Felix Kühling:
Am 2018-03-24 um 04:34 AM schrieb Christian König:
Am 23.03.2018 um 20:53 schrieb Felix Kuehling:
On 2018-03-23 03:35 PM, Christian König wrote:
Am 23.03.2018 um 20:30 schrieb Felix Kuehling:
On large-BAR systems the VM page tables for compute are accessed by
the CPU. Always allow CPU access to the page directory so that it can
be used later by the CPU when a VM is converted to a compute VM.
NAK, that means we initial place the PD in the visible are for GFX
which is not desired (not much of an issue for Vega/Raven, but bad for
older generations).
I'm not setting AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED. Doesn't that mean
the buffer can be placed in invisible VRAM initially?
The difference is the preference. When AMDGPU_GEM_CREATE_NO_CPU_ACCESS
is set we try to place it initially in invisible VRAM.
Where is that done? I'm looking at amdgpu_ttm_placement_from_domain. It
only looks at AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED.
Of course! I have to apologize, my memory fooled me and I mixed up the
handling of two flags.
Didn't had the chance on the weekend to actually double check the code,
but you're absolutely right.
[SNIP]
If you want to avoid the move of the page directory on large BAR
systems when switching a VM from GFX to compute we can also initially
create the BO in the system domain.
Thinking about that a bit more that is probably a good idea anyway
because it avoids using VRAM by just opening the device.
Sure, I'd do that as a separate change because it actually changes the
initial placement, whereas my patch did not (as far as I can tell).
Yeah, indeed. Creating the BO in the system domain would also simplify
the eviction double check dance.
Anyway this patch is Reviewed-by: Christian König
<christian.koe...@amd.com> and sorry for the noise.
Regards,
Christian.
Regards,
Felix
Regards,
Christian.
Regards,
Felix
Regards,
Christian.
Signed-off-by: Felix Kuehling <felix.kuehl...@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 90ff79e..bc3557b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2406,8 +2406,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev,
struct amdgpu_vm *vm,
if (vm->use_cpu_for_update)
flags |= AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
else
- flags |= (AMDGPU_GEM_CREATE_NO_CPU_ACCESS |
- AMDGPU_GEM_CREATE_SHADOW);
+ flags |= AMDGPU_GEM_CREATE_SHADOW;
size = amdgpu_vm_bo_size(adev, adev->vm_manager.root_level);
r = amdgpu_bo_create(adev, size, align, true,
AMDGPU_GEM_DOMAIN_VRAM,
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