Re: [PATCH v2] drm/xe/madvise: Skip invalidation for purgeable state updates

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

On 26-05-2026 19:24, Arvind Yadav wrote:
> Purgeable state updates only change VMA/BO metadata. They do not zap
> PTEs when switching between DONTNEED and WILLNEED. PTEs are zapped
> later if the BO is actually purged.
> 
> xe_vm_invalidate_madvise_range() waits on the VM dma-resv before checking
> vma->skip_invalidation. Since purgeable madvise marks all affected VMAs to
> skip invalidation, this wait is unnecessary and can stall on unrelated
> in-flight work.
> 
> Skip the invalidate path entirely for purgeable state updates.
> 
> v2:
>    - Replace inline 'args->type != DRM_XE_VMA_ATTR_PURGEABLE_STATE'
>      check with a small helper madvise_range_needs_invalidation().
>      (Himal)
> 
> Suggested-by: Matthew Brost <matthew.brost@intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
> Signed-off-by: Arvind Yadav <arvind.yadav@intel.com>


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


> ---
>   drivers/gpu/drm/xe/xe_vm_madvise.c | 19 +++++++++++++++++--
>   1 file changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_vm_madvise.c b/drivers/gpu/drm/xe/xe_vm_madvise.c
> index c4fb29004195..9e343f9aa44d 100644
> --- a/drivers/gpu/drm/xe/xe_vm_madvise.c
> +++ b/drivers/gpu/drm/xe/xe_vm_madvise.c
> @@ -332,6 +332,20 @@ static int xe_vm_invalidate_madvise_range(struct xe_vm *vm, u64 start, u64 end)
>   	return err;
>   }
>   
> +/**
> + * madvise_range_needs_invalidation() - Check whether madvise needs invalidation
> + * @args: madvise ioctl arguments
> + *
> + * Purgeable state updates only touch VMA/BO metadata. PTEs stay valid and are
> + * zapped only if the BO is later purged.
> + *
> + * Return: true when the update needs PTE invalidation.
> + */
> +static bool madvise_range_needs_invalidation(const struct drm_xe_madvise *args)
> +{
> +	return args->type != DRM_XE_VMA_ATTR_PURGEABLE_STATE;
> +}
> +
>   static bool madvise_args_are_sane(struct xe_device *xe, const struct drm_xe_madvise *args)
>   {
>   	if (XE_IOCTL_DBG(xe, !args))
> @@ -708,8 +722,9 @@ int xe_vm_madvise_ioctl(struct drm_device *dev, void *data, struct drm_file *fil
>   	madvise_funcs[attr_type](xe, vm, madvise_range.vmas, madvise_range.num_vmas, args,
>   				 &details);
>   
> -	err = xe_vm_invalidate_madvise_range(vm, madvise_range.addr,
> -					     madvise_range.addr + args->range);
> +	if (madvise_range_needs_invalidation(args))
> +		err = xe_vm_invalidate_madvise_range(vm, madvise_range.addr,
> +						     madvise_range.addr + args->range);
>   
>   	if (madvise_range.has_svm_userptr_vmas)
>   		xe_svm_notifier_unlock(vm);