Re: [PATCH mm-unstable v2 01/10] mm/kvm: add mmu_notifier_ops->test_clear_young()

[Jason Gunthorpe]

On Fri, May 26, 2023 at 05:44:26PM -0600, Yu Zhao wrote:
> @@ -122,6 +124,10 @@ struct mmu_notifier_ops {
>  			  struct mm_struct *mm,
>  			  unsigned long address);
>  
> +	int (*test_clear_young)(struct mmu_notifier *mn, struct mm_struct *mm,
> +				unsigned long start, unsigned long end,
> +				bool clear, unsigned long *bitmap);
> +

Why leave clear_young behind? Just make a NULL bitmap mean
clear_young?

Jason