Re: [PATCH] mm/damon: Validate if the pmd entry is present before accessing

[Andrew Morton]

On Wed, 17 Aug 2022 14:21:12 +0800 Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> wrote:

> The pmd_huge() is used to validate if the pmd entry is mapped by a huge
> page, also including the case of non-present (migration or hwpoisoned)
> pmd entry on arm64 or x86 architectures. Thus we should validate if it
> is present before making the pmd entry old or getting young state,
> otherwise we can not get the correct corresponding page.
> 

What are the user-visible runtime effects of this change?