Re: [PATCH v2 1/2] drm/xe/svm: Ensure data will be migrated to system if indicated by madvise.

["Ghimiray, Himal Prasad" <himal.prasad.ghimiray@intel.com>]

On 10-10-2025 16:11, Thomas Hellström wrote:
> If the location madvise() is set to
> DRM_XE_PREFERRED_LOC_DEFAULT_SYSTEM, the drm_pagemap in the
> SVM gpu fault handler will be set to NULL. However there is nothing
> that explicitly migrates the data to system if it is already present
> in device memory.
> 
> In that case, set the device memory owner to NULL to ensure
> data gets properly migrated to system on page-fault.
> 
> v2:
> - Remove redundant dpagemap assignment (Himal Prasad Ghimiray)

Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>


> 
> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Reviewed-by: Matthew Brost <matthew.brost@intel.com> #v1
> ---
>   drivers/gpu/drm/xe/xe_svm.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
> index 7e2db71ff34e..ef8c7aa485b5 100644
> --- a/drivers/gpu/drm/xe/xe_svm.c
> +++ b/drivers/gpu/drm/xe/xe_svm.c
> @@ -1034,6 +1034,9 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
>   	if (err)
>   		return err;
>   
> +	dpagemap = xe_vma_resolve_pagemap(vma, tile);
> +	if (!dpagemap && !ctx.devmem_only)
> +		ctx.device_private_page_owner = NULL;
>   	range = xe_svm_range_find_or_insert(vm, fault_addr, vma, &ctx);
>   
>   	if (IS_ERR(range))
> @@ -1054,7 +1057,6 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
>   
>   	range_debug(range, "PAGE FAULT");
>   
> -	dpagemap = xe_vma_resolve_pagemap(vma, tile);
>   	if (--migrate_try_count >= 0 &&
>   	    xe_svm_range_needs_migrate_to_vram(range, vma, !!dpagemap || ctx.devmem_only)) {
>   		ktime_t migrate_start = xe_svm_stats_ktime_get();