[PATCH] drm/amdgpu: only use kernel zone if need_dma32 is not required

[Christian König]

Am 12.06.19 um 17:13 schrieb Yang, Philip:
> TTM create two zones, kernel zone and dma32 zone for system memory. If
> system memory address allocated is below 4GB, this account to dma32 zone
> and will exhaust dma32 zone and trigger unnesssary TTM eviction.
>
> Patch "drm/ttm: Account for kernel allocations in kernel zone only" only
> handle the allocation for acc_size, the system memory page allocation is
> through ttm_mem_global_alloc_page which still account to dma32 zone if
> page is below 4GB.

NAK, as the name says the mem_glob is global for all devices in the system.

So this will break if you mix DMA32 and non DMA32 in the same system 
which is exactly the configuration my laptop here has :(

Christian.

>
> Change-Id: I289b85d891b8f64a1422c42b1eab398098ab7ef7
> Signed-off-by: Philip Yang <Philip.Yang at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 2778ff63d97d..79bb9dfe617b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -1686,6 +1686,10 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
>   	}
>   	adev->mman.initialized = true;
>   
> +	/* Only kernel zone (no dma32 zone) if device does not require dma32 */
> +	if (!adev->need_dma32)
> +		adev->mman.bdev.glob->mem_glob->num_zones = 1;
> +
>   	/* We opt to avoid OOM on system pages allocations */
>   	adev->mman.bdev.no_retry = true;
>