Re: [PATCH v1 06/14] mm, x86: support the access bit on non-leaf PMD entries

[Zi Yan]

On 13 Mar 2021, at 2:57, Yu Zhao wrote:

> Some architectures support the accessed bit on non-leaf PMD entries
> (parents) in addition to leaf PTE entries (children) where pages are
> mapped, e.g., x86_64 sets the accessed bit on a parent when using it
> as part of linear-address translation [1]. Page table walkers who are
> interested in the accessed bit on children can take advantage of this:
> they do not need to search the children when the accessed bit is not
> set on a parent, given that they have previously cleared the accessed
> bit on this parent in addition to its children.
>
> [1]: Intel 64 and IA-32 Architectures Software Developer's Manual
>      Volume 3 (October 2019), section 4.8

Just curious. Does this also apply to non-leaf PUD entries? Do you
mind sharing which sentence from the manual gives the information?

Thanks.

—
Best Regards,
Yan Zi

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