Re: [PATCH v2 3/3] drm/amdkfd: Split giant svm range

[Felix Kuehling <felix.kuehling@xxxxxxx>]

Am 2022-07-25 um 13:19 schrieb Philip Yang:
> Giant svm range split to smaller ranges, align the range start address
> to max svm range pages to improve MMU TLB usage.
>
> Signed-off-by: Philip Yang <Philip.Yang@xxxxxxx>

Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>


> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 49 +++++++++++++++++++---------
>   1 file changed, 33 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index 098060147de6..6529a40fb508 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -1889,6 +1889,31 @@ void svm_range_set_max_pages(struct amdgpu_device *adev)
>   	WRITE_ONCE(max_svm_range_pages, max_pages);
>   }
>   
> +static int
> +svm_range_split_new(struct svm_range_list *svms, uint64_t start, uint64_t last,
> +		    uint64_t max_pages, struct list_head *insert_list,
> +		    struct list_head *update_list)
> +{
> +	struct svm_range *prange;
> +	uint64_t l;
> +
> +	pr_debug("max_svm_range_pages 0x%llx adding [0x%llx 0x%llx]\n",
> +		 max_pages, start, last);
> +
> +	while (last >= start) {
> +		l = min(last, ALIGN_DOWN(start + max_pages, max_pages) - 1);
> +
> +		prange = svm_range_new(svms, start, l);
> +		if (!prange)
> +			return -ENOMEM;
> +		list_add(&prange->list, insert_list);
> +		list_add(&prange->update_list, update_list);
> +
> +		start = l + 1;
> +	}
> +	return 0;
> +}
> +
>   /**
>    * svm_range_add - add svm range and handle overlap
>    * @p: the range add to this process svms
> @@ -1991,14 +2016,11 @@ svm_range_add(struct kfd_process *p, uint64_t start, uint64_t size,
>   
>   		/* insert a new node if needed */
>   		if (node->start > start) {
> -			prange = svm_range_new(svms, start, node->start - 1);
> -			if (!prange) {
> -				r = -ENOMEM;
> +			r = svm_range_split_new(svms, start, node->start - 1,
> +						READ_ONCE(max_svm_range_pages),
> +						insert_list, update_list);
> +			if (r)
>   				goto out;
> -			}
> -
> -			list_add(&prange->list, insert_list);
> -			list_add(&prange->update_list, update_list);
>   		}
>   
>   		node = next;
> @@ -2006,15 +2028,10 @@ svm_range_add(struct kfd_process *p, uint64_t start, uint64_t size,
>   	}
>   
>   	/* add a final range at the end if needed */
> -	if (start <= last) {
> -		prange = svm_range_new(svms, start, last);
> -		if (!prange) {
> -			r = -ENOMEM;
> -			goto out;
> -		}
> -		list_add(&prange->list, insert_list);
> -		list_add(&prange->update_list, update_list);
> -	}
> +	if (start <= last)
> +		r = svm_range_split_new(svms, start, last,
> +					READ_ONCE(max_svm_range_pages),
> +					insert_list, update_list);
>   
>   out:
>   	if (r)