Re: [PATCH v2 00/16] Multigenerational LRU Framework

Rik van Riel
2021-04-14T15:59:24Z

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On Wed, 2021-04-14 at 08:51 -0700, Andi Kleen wrote:
> > 2) It will not scan PTE tables under non-leaf PMD entries that
> > do not
> > have the accessed bit set, when
> > CONFIG_HAVE_ARCH_PARENT_PMD_YOUNG=y.
>
> This assumes that workloads have reasonable locality. Could there
> be a worst case where only one or two pages in each PTE are used,
> so this PTE skipping trick doesn't work?

Databases with large shared memory segments shared between
many processes come to mind as a real-world example of a
worst case scenario.

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