Re: [PATCH 1/3] drm/amdgpu: remove acc_size from reserve/unreserve mem

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 28.06.22 um 02:23 schrieb Alex Sierra:
> TTM used to track the "acc_size" of all BOs internally. We needed to
> keep track of it in our memory reservation to avoid TTM running out
> of memory in its own accounting. However, that "acc_size" accounting
> has since been removed from TTM. Therefore we don't really need to
> track it any more.
>
> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
> Reviewed-by: Philip Yang <philip.yang@amd.com>
> Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>

Acked-by: Christian König <christian.koenig@amd.com>

> ---
>   .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 60 ++++++-------------
>   1 file changed, 17 insertions(+), 43 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> index 5ba9070d8722..9142f6cc3f4d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> @@ -114,21 +114,12 @@ void amdgpu_amdkfd_reserve_system_mem(uint64_t size)
>    * compromise that should work in most cases without reserving too
>    * much memory for page tables unnecessarily (factor 16K, >> 14).
>    */
> -#define ESTIMATE_PT_SIZE(mem_size) max(((mem_size) >> 14), AMDGPU_VM_RESERVED_VRAM)
> -
> -static size_t amdgpu_amdkfd_acc_size(uint64_t size)
> -{
> -	size >>= PAGE_SHIFT;
> -	size *= sizeof(dma_addr_t) + sizeof(void *);
>   
> -	return __roundup_pow_of_two(sizeof(struct amdgpu_bo)) +
> -		__roundup_pow_of_two(sizeof(struct ttm_tt)) +
> -		PAGE_ALIGN(size);
> -}
> +#define ESTIMATE_PT_SIZE(mem_size) max(((mem_size) >> 14), AMDGPU_VM_RESERVED_VRAM)
>   
>   /**
>    * amdgpu_amdkfd_reserve_mem_limit() - Decrease available memory by size
> - * of buffer including any reserved for control structures
> + * of buffer.
>    *
>    * @adev: Device to which allocated BO belongs to
>    * @size: Size of buffer, in bytes, encapsulated by B0. This should be
> @@ -142,19 +133,16 @@ static int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
>   {
>   	uint64_t reserved_for_pt =
>   		ESTIMATE_PT_SIZE(amdgpu_amdkfd_total_mem_size);
> -	size_t acc_size, system_mem_needed, ttm_mem_needed, vram_needed;
> +	size_t system_mem_needed, ttm_mem_needed, vram_needed;
>   	int ret = 0;
>   
> -	acc_size = amdgpu_amdkfd_acc_size(size);
> -
> +	system_mem_needed = 0;
> +	ttm_mem_needed = 0;
>   	vram_needed = 0;
>   	if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_GTT) {
> -		system_mem_needed = acc_size + size;
> -		ttm_mem_needed = acc_size + size;
> +		system_mem_needed = size;
> +		ttm_mem_needed = size;
>   	} else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_VRAM) {
> -		system_mem_needed = acc_size;
> -		ttm_mem_needed = acc_size;
> -
>   		/*
>   		 * Conservatively round up the allocation requirement to 2 MB
>   		 * to avoid fragmentation caused by 4K allocations in the tail
> @@ -162,14 +150,10 @@ static int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
>   		 */
>   		vram_needed = ALIGN(size, VRAM_ALLOCATION_ALIGN);
>   	} else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) {
> -		system_mem_needed = acc_size + size;
> -		ttm_mem_needed = acc_size;
> -	} else if (alloc_flag &
> -		   (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
> -		    KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)) {
> -		system_mem_needed = acc_size;
> -		ttm_mem_needed = acc_size;
> -	} else {
> +		system_mem_needed = size;
> +	} else if (!(alloc_flag &
> +				(KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
> +				 KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP))) {
>   		pr_err("%s: Invalid BO type %#x\n", __func__, alloc_flag);
>   		return -ENOMEM;
>   	}
> @@ -207,28 +191,18 @@ static int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
>   static void unreserve_mem_limit(struct amdgpu_device *adev,
>   		uint64_t size, u32 alloc_flag)
>   {
> -	size_t acc_size;
> -
> -	acc_size = amdgpu_amdkfd_acc_size(size);
> -
>   	spin_lock(&kfd_mem_limit.mem_limit_lock);
>   
>   	if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_GTT) {
> -		kfd_mem_limit.system_mem_used -= (acc_size + size);
> -		kfd_mem_limit.ttm_mem_used -= (acc_size + size);
> +		kfd_mem_limit.system_mem_used -= size;
> +		kfd_mem_limit.ttm_mem_used -= size;
>   	} else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_VRAM) {
> -		kfd_mem_limit.system_mem_used -= acc_size;
> -		kfd_mem_limit.ttm_mem_used -= acc_size;
>   		adev->kfd.vram_used -= ALIGN(size, VRAM_ALLOCATION_ALIGN);
>   	} else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) {
> -		kfd_mem_limit.system_mem_used -= (acc_size + size);
> -		kfd_mem_limit.ttm_mem_used -= acc_size;
> -	} else if (alloc_flag &
> -		   (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
> -		    KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)) {
> -		kfd_mem_limit.system_mem_used -= acc_size;
> -		kfd_mem_limit.ttm_mem_used -= acc_size;
> -	} else {
> +		kfd_mem_limit.system_mem_used -= size;
> +	} else if (!(alloc_flag &
> +				(KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
> +				 KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP))) {
>   		pr_err("%s: Invalid BO type %#x\n", __func__, alloc_flag);
>   		goto release;
>   	}