[PATCH] drm/amdgpu: take back kvmalloc_array for entries alloc because of kzalloc memory limit

[Das, Nirmoy]

On 6/2/2021 10:30 AM, Changfeng wrote:
> From: changzhu <Changfeng.Zhu at amd.com>
>
> From: Changfeng <Changfeng.Zhu at amd.com>
>
> It will cause error when alloc memory larger than 128KB in
> amdgpu_bo_create->kzalloc.


I wonder why I didn't see the error on my machine. Is there any config I 
might be missing ?


Thanks,

Nirmoy

> Call Trace:
>     alloc_pages_current+0x6a/0xe0
>     kmalloc_order+0x32/0xb0
>     kmalloc_order_trace+0x1e/0x80
>     __kmalloc+0x249/0x2d0
>     amdgpu_bo_create+0x102/0x500 [amdgpu]
>     ? xas_create+0x264/0x3e0
>     amdgpu_bo_create_vm+0x32/0x60 [amdgpu]
>     amdgpu_vm_pt_create+0xf5/0x260 [amdgpu]
>     amdgpu_vm_init+0x1fd/0x4d0 [amdgpu]
>
> Change-Id: I29e479db45ead37c39449e856599fd4f6a0e34ce
> Signed-off-by: Changfeng <Changfeng.Zhu at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 27 +++++++++++++++-----------
>   1 file changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 1923f035713a..714d613d020b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -894,6 +894,10 @@ static int amdgpu_vm_pt_create(struct amdgpu_device *adev,
>   		num_entries = 0;
>   
>   	bp.bo_ptr_size = struct_size((*vmbo), entries, num_entries);
> +	if (bp.bo_ptr_size > 32*AMDGPU_GPU_PAGE_SIZE) {
> +		DRM_INFO("Can't alloc memory larger than 128KB by using kzalloc in amdgpu_bo_create\n");
> +		bp.bo_ptr_size = sizeof(struct amdgpu_bo_vm);
> +	}
>   
>   	if (vm->use_cpu_for_update)
>   		bp.flags |= AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
> @@ -965,15 +969,19 @@ static int amdgpu_vm_alloc_pts(struct amdgpu_device *adev,
>   	struct amdgpu_bo_vm *pt;
>   	int r;
>   
> -	if (entry->base.bo) {
> -		if (cursor->level < AMDGPU_VM_PTB)
> -			entry->entries =
> -				to_amdgpu_bo_vm(entry->base.bo)->entries;
> -		else
> -			entry->entries = NULL;
> -		return 0;
> +	if (cursor->level < AMDGPU_VM_PTB && !entry->entries) {
> +		unsigned num_entries;
> +		num_entries = amdgpu_vm_num_entries(adev, cursor->level);
> +		entry->entries = kvmalloc_array(num_entries,
> +						sizeof(*entry->entries),
> +						GFP_KERNEL | __GFP_ZERO);
> +		if (!entry->entries)
> +			return -ENOMEM;
>   	}
>   
> +	if (entry->base.bo)
> +		return 0;
> +
>   	r = amdgpu_vm_pt_create(adev, vm, cursor->level, immediate, &pt);
>   	if (r)
>   		return r;
> @@ -984,10 +992,6 @@ static int amdgpu_vm_alloc_pts(struct amdgpu_device *adev,
>   	pt_bo = &pt->bo;
>   	pt_bo->parent = amdgpu_bo_ref(cursor->parent->base.bo);
>   	amdgpu_vm_bo_base_init(&entry->base, vm, pt_bo);
> -	if (cursor->level < AMDGPU_VM_PTB)
> -		entry->entries = pt->entries;
> -	else
> -		entry->entries = NULL;
>   
>   	r = amdgpu_vm_clear_bo(adev, vm, pt, immediate);
>   	if (r)
> @@ -1017,6 +1021,7 @@ static void amdgpu_vm_free_table(struct amdgpu_vm_pt *entry)
>   		amdgpu_bo_unref(&shadow);
>   		amdgpu_bo_unref(&entry->base.bo);
>   	}
> +	kvfree(entry->entries);
>   	entry->entries = NULL;
>   }
>