Re: [PATCH 2/2] mm: Simplify PageDoubleMap with PF_SECOND policy

[Zi Yan <ziy@nvidia.com>]

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On 29 Jun 2020, at 11:19, Matthew Wilcox (Oracle) wrote:

> Introduce the new page policy of PF_SECOND which lets us use the
> normal pageflags generation machinery to create the various DoubleMap
> manipulation functions.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  include/linux/page-flags.h | 40 ++++++++++----------------------------
>  1 file changed, 10 insertions(+), 30 deletions(-)
>
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index b4e6051aa311..7182103583d2 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -232,6 +232,9 @@ static inline void page_init_poison(struct page *page, size_t size)
>   *
>   * PF_NO_COMPOUND:
>   *     the page flag is not relevant for compound pages.
> + *
> + * PF_SECOND:
> + *     the page flag is stored in the first tail page.

Just wonder if PF_FIRST_TAIL_PAGE is more informative, although it has more characters to type. :)


—
Best Regards,
Yan Zi

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