Re: [PATCH] drm/amdkfd: Use huge page size to check split svm range alignment

[Philip Yang <yangp@amd.com>]

On 2025-11-10 15:30, Xiaogang.Chen wrote:
> From: Xiaogang Chen <xiaogang.chen@amd.com>
>
> Fixes: 7ef6b2d4b7e5 (drm/amdkfd: remap unaligned svm ranges that have split)
>
> When split svm ranges that have been mapped using huge page should use huge
> page size(2MB) to check split range alignment, not prange->granularity that
> means migration granularity.
>
> Signed-off-by: Xiaogang Chen <xiaogang.chen@amd.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index 521c14c7a789..3af85c232659 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -1149,7 +1149,7 @@ svm_range_split_tail(struct svm_range *prange, uint64_t new_last,
>   
>   	if (!r) {
>   		list_add(&tail->list, insert_list);
> -		if (!IS_ALIGNED(new_last + 1, 1UL << prange->granularity))
> +		if (!IS_ALIGNED(new_last + 1, 512))
we should check the original prange size is larger than 512 pages
           if (!IS_ALIGNED(new_last + 1, 512) && tail->last - 
prange->start >= 512)
>   			list_add(&tail->update_list, remap_list);
>   	}
>   	return r;
> @@ -1164,7 +1164,7 @@ svm_range_split_head(struct svm_range *prange, uint64_t new_start,
>   
>   	if (!r) {
>   		list_add(&head->list, insert_list);
> -		if (!IS_ALIGNED(new_start, 1UL << prange->granularity))
> +		if (!IS_ALIGNED(new_start, 512))

if (!IS_ALIGNED(new_start, 512) && prange->last - head->start >= 512)

Regards,

Philip

>   			list_add(&head->update_list, remap_list);
>   	}
>   	return r;