[PATCH v4] drm/amdkfd: Fix partial migrate issue

[Chen, Xiaogang]

On 1/10/2025 8:37 AM, Philip Yang wrote:
>
>
> On 2025-01-10 02:49, Emily Deng wrote:
>> For partial migrate from ram to vram, the migrate->cpages is not
>> equal to migrate->npages, should use migrate->npages to check all needed
>> migrate pages which could be copied or not.
>>
>> And only need to set those pages could be migrated to migrate->dst[i], or
>> the migrate_vma_pages will migrate the wrong pages based on the migrate->dst[i].
>>
>> v2:
>> Add mpages to break the loop earlier.
>>
>> v3:
>> Uses MIGRATE_PFN_MIGRATE to identify whether page could be migrated.
>
> The error handling need below change, with that fixed, this patch is
>
> Reviewed-by: Philip Yang<Philip.Yang at amd.com>
>
>> Signed-off-by: Emily Deng<Emily.Deng at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 17 ++++++++++-------
>>   1 file changed, 10 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> index 4b275937d05e..bfaccabeb3a0 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> @@ -278,10 +278,11 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange,
>>   			 struct migrate_vma *migrate, struct dma_fence **mfence,
>>   			 dma_addr_t *scratch, uint64_t ttm_res_offset)
>>   {
>> -	uint64_t npages = migrate->cpages;
>> +	uint64_t npages = migrate->npages;
>>   	struct amdgpu_device *adev = node->adev;
>>   	struct device *dev = adev->dev;
>>   	struct amdgpu_res_cursor cursor;
>> +	uint64_t mpages = 0;
>>   	dma_addr_t *src;
>>   	uint64_t *dst;
>>   	uint64_t i, j;
>> @@ -295,14 +296,16 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange,
>>   
>>   	amdgpu_res_first(prange->ttm_res, ttm_res_offset,
>>   			 npages << PAGE_SHIFT, &cursor);
>> -	for (i = j = 0; i < npages; i++) {
>> +	for (i = j = 0; (i < npages) && (mpages < migrate->cpages); i++) {
>>   		struct page *spage;
>>   
>> -		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]);
>> -		migrate->dst[i] = migrate_pfn(migrate->dst[i]);
>> -
>> +		if (migrate->src[i] & MIGRATE_PFN_MIGRATE) {
>> +			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]);
>> +			migrate->dst[i] = migrate_pfn(migrate->dst[i]);
>> +			mpages++;
>> +		}
>>   		spage = migrate_pfn_to_page(migrate->src[i]);
>>   		if (spage && !is_zone_device_page(spage)) {
>>   			src[i] = dma_map_page(dev, spage, 0, PAGE_SIZE,
>  out_free_vram_pages:
>         if (r) {
>                 pr_debug("failed %d to copy memory to vram\n", r);
> -               while (i--) {
> +
> +               for (i = 0; i < npages && mpages; i++) {
> +                       if (!dst[i])
> +                               continue;
>                         svm_migrate_put_vram_page(adev, dst[i]);
>                         migrate->dst[i] = 0;
> +                       mpages--;
>                 }
>         }

This error handing not need recover all vram pages as error happened at 
middle. Can use se do {....} while(i--);

Regards

Xiaogang