Re: [RFC v2 PATCH 05/17] mm: Routines to determine max anon folio allocation order

Kirill A. Shutemov
2023-04-14T14:11:04Z

On Fri, Apr 14, 2023 at 02:02:51PM +0100, Ryan Roberts wrote:
> For variable-order anonymous folios, we want to tune the order that we
> prefer to allocate based on the vma. Add the routines to manage that
> heuristic.
>
> TODO: Currently we always use the global maximum. Add per-vma logic!
>
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
> ---
> include/linux/mm.h | 5 +++++
> mm/memory.c | 8 ++++++++
> 2 files changed, 13 insertions(+)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index cdb8c6031d0f..cc8d0b239116 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3674,4 +3674,9 @@ madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
> }
> #endif
>
> +/*
> + * TODO: Should this be set per-architecture?
> + */
> +#define ANON_FOLIO_ORDER_MAX 4
> +

I think it has to be derived from size in bytes, not directly specifies
page order. For 4K pages, order 4 is 64k and for 64k pages it is 1M.

--
Kiryl Shutsemau / Kirill A. Shutemov