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

[Paolo Bonzini <pbonzini@xxxxxxxxxx>]

On 5/31/23 21:17, Jason Gunthorpe wrote:
> > +	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?

It goes away in patch 2, together with:

@@ -437,7 +412,7 @@ static inline int mmu_notifier_clear_young(struct mm_struct *mm,
 					   unsigned long end)
 {
 	if (mm_has_notifiers(mm))
-		return __mmu_notifier_clear_young(mm, start, end);
+		return __mmu_notifier_test_clear_young(mm, start, end, true, NULL);
 	return 0;
 }
 
@@ -445,7 +420,7 @@ static inline int mmu_notifier_test_young(struct mm_struct *mm,
 					  unsigned long address)
 {
 	if (mm_has_notifiers(mm))
-		return __mmu_notifier_test_young(mm, address);
+		return __mmu_notifier_test_clear_young(mm, address, address + 1, false, NULL);
 	return 0;
 }
 

Paolo