[PATCH] drm/amdkfd: use resource cursor in svm_migrate_copy_to_vram

[Christian König]

Am 21.05.21 um 21:28 schrieb philip yang:
>
> This simply the logic, several comments inline.
>
> Thanks,
>
> Philip
>
> On 2021-05-21 9:52 a.m., Christian König wrote:
>> Access to the mm_node is now forbidden. So instead of hand wiring that
>> use the cursor functionality.
>>
>> Signed-off-by: Christian König<christian.koenig at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 76 +++---------------------
>>   1 file changed, 9 insertions(+), 67 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> index fd8f544f0de2..cb28d1e660af 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> @@ -29,6 +29,7 @@
>>   #include "amdgpu_object.h"
>>   #include "amdgpu_vm.h"
>>   #include "amdgpu_mn.h"
>> +#include "amdgpu_res_cursor.h"
>>   #include "kfd_priv.h"
>>   #include "kfd_svm.h"
>>   #include "kfd_migrate.h"
>> @@ -205,34 +206,6 @@ svm_migrate_copy_done(struct amdgpu_device *adev, struct dma_fence *mfence)
>>   	return r;
>>   }
>>   
>> -static uint64_t
>> -svm_migrate_node_physical_addr(struct amdgpu_device *adev,
>> -			       struct drm_mm_node **mm_node, uint64_t *offset)
>> -{
>> -	struct drm_mm_node *node = *mm_node;
>> -	uint64_t pos = *offset;
>> -
>> -	if (node->start == AMDGPU_BO_INVALID_OFFSET) {
>> -		pr_debug("drm node is not validated\n");
>> -		return 0;
>> -	}
>> -
>> -	pr_debug("vram node start 0x%llx npages 0x%llx\n", node->start,
>> -		 node->size);
>> -
>> -	if (pos >= node->size) {
>> -		do  {
>> -			pos -= node->size;
>> -			node++;
>> -		} while (pos >= node->size);
>> -
>> -		*mm_node = node;
>> -		*offset = pos;
>> -	}
>> -
>> -	return (node->start + pos) << PAGE_SHIFT;
>> -}
>> -
>>   unsigned long
>>   svm_migrate_addr_to_pfn(struct amdgpu_device *adev, unsigned long addr)
>>   {
>> @@ -297,11 +270,9 @@ svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
>>   {
>>   	uint64_t npages = migrate->cpages;
>>   	struct device *dev = adev->dev;
>> -	struct drm_mm_node *node;
>> +	struct amdgpu_res_cursor cursor;
>>   	dma_addr_t *src;
>>   	uint64_t *dst;
>> -	uint64_t vram_addr;
>> -	uint64_t offset;
>>   	uint64_t i, j;
>>   	int r;
>>   
>> @@ -317,19 +288,12 @@ svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
>>   		goto out;
>>   	}
>>   
>> -	node = prange->ttm_res->mm_node;
>> -	offset = prange->offset;
>> -	vram_addr = svm_migrate_node_physical_addr(adev, &node, &offset);
>> -	if (!vram_addr) {
> The prange->ttm_res valid check is not needed because we already check 
> svm_range_vram_node_new return value
>> -		WARN_ONCE(1, "vram node address is 0\n");
>> -		r = -ENOMEM;
>> -		goto out;
>> -	}
>> -
>> +	amdgpu_res_first(prange->ttm_res, prange->offset, npages << PAGE_SHIFT,
>
> prange->offset<< PAGE_SHIFT
>
> amdgpu_res_first takes start and size in bytes, prange->offset use 
> page aligned offset
>

Ah, yes good point.

>
>> +			 &cursor);
>>   	for (i = j = 0; i < npages; i++) {
>>   		struct page *spage;
>>   
>> -		dst[i] = vram_addr + (j << PAGE_SHIFT);
>> +		dst[i] = cursor.start + (j << PAGE_SHIFT);
>>   		migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]);
>>   		svm_migrate_get_vram_page(prange, migrate->dst[i]);
>>   
>> @@ -354,18 +318,10 @@ svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
>>   						mfence);
>>   				if (r)
>>   					goto out_free_vram_pages;
>> -				offset += j;
>> -				vram_addr = (node->start + offset) << PAGE_SHIFT;
>> +				amdgpu_res_next(&cursor, j << PAGE_SHIFT);
>>   				j = 0;
>>   			} else {
>> -				offset++;
>> -				vram_addr += PAGE_SIZE;
>> -			}
>> -			if (offset >= node->size) {
>> -				node++;
>> -				pr_debug("next node size 0x%llx\n", node->size);
>> -				vram_addr = node->start << PAGE_SHIFT;
>> -				offset = 0;
>> +				amdgpu_res_next(&cursor, PAGE_SIZE);
>>   			}
>>   			continue;
>>   		}
>> @@ -373,22 +329,8 @@ svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
>>   		pr_debug("dma mapping src to 0x%llx, page_to_pfn 0x%lx\n",
>>   			 src[i] >> PAGE_SHIFT, page_to_pfn(spage));
>>   
>> -		if (j + offset >= node->size - 1 && i < npages - 1) {
>> -			r = svm_migrate_copy_memory_gart(adev, src + i - j,
>> -							 dst + i - j, j + 1,
>> -							 FROM_RAM_TO_VRAM,
>> -							 mfence);
>> -			if (r)
>> -				goto out_free_vram_pages;
>> -
>> -			node++;
>> -			pr_debug("next node size 0x%llx\n", node->size);
>> -			vram_addr = node->start << PAGE_SHIFT;
>> -			offset = 0;
>> -			j = 0;
>> -		} else {
>> -			j++;
>> -		}
>> +		amdgpu_res_next(&cursor, PAGE_SIZE);
>> +		j++;
> Here to handle cross mm_node case.
>
> if (j >= cursor->size - 1 && i < npages - 1) {
>
>     r = svm_migrate_copy_memory_gart(adev, src + i - j,
>
>                                 dst + i - j, j + 1,
>
> 			FROM_RAM_TO_VRAM,
> 			 mfence);
>      if (r)
> 	goto out_free_vram_pages;
>      
>      amdgpu_res_next(&cursor, (j + 1) * PAGE_SIZE);
>      j= 0;
> } else {
>     j++;
> }

Yeah, that was the point I couldn't understand. Why would we want that 
anyway?

Regards,
Christian.

>
>
>>   	}
>>   
>>   	r = svm_migrate_copy_memory_gart(adev, src + i - j, dst + i - j, j,