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From:   "Zi Yan" <zi.yan@sent.com>
To:     "Matthew Wilcox" <willy@infradead.org>
Cc:     linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 05/51] mm: Simplify PageDoubleMap with PF_SECOND policy
Date:   Thu, 11 Jun 2020 11:14:45 -0400
Message-ID: <A8271172-074D-43E2-928B-EE267544EA82@sent.com>
In-Reply-To: <20200610201345.13273-6-willy@infradead.org>
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 <20200610201345.13273-6-willy@infradead.org>
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On 10 Jun 2020, at 16:12, Matthew Wilcox wrote:

> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> 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 de6e0696f55c..979460df4768 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 *pa=
ge, 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.
>   */

Would PF_FIRST_TAIL or PF_SECOND_IN_COMPOUND be more informative?

=E2=80=94
Best Regards,
Yan Zi

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