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References: <20210223180820.ee39f1544f2630d0eecf3a57@linux-foundation.org> <20210224040439.351882-1-mike.kravetz@oracle.com>
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From:   Muchun Song <songmuchun@bytedance.com>
Date:   Wed, 24 Feb 2021 16:48:15 +0800
Message-ID: <CAMZfGtU-TUZjMccm1BBp15YB6DyUufRTf-z-AqqB9ovWVx=KqA@mail.gmail.com>
Subject: Re: [External] [PATCH] hugetlb: document the new location of page
 subpool pointer
To:     Mike Kravetz <mike.kravetz@oracle.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        Michal Hocko <mhocko@suse.com>,
        Oscar Salvador <osalvador@suse.de>,
        Andrew Morton <akpm@linux-foundation.org>
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On Wed, Feb 24, 2021 at 12:04 PM Mike Kravetz <mike.kravetz@oracle.com> wrote:
>
> Expand comments, no functional change.
>
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>

Reviewed-by: Muchun Song <songmuchun@bytedance.com>

Thanks

> ---
>  include/linux/hugetlb.h | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index cccd1aab69dd..c0467a7a1fe0 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -476,6 +476,9 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
>   * huegtlb page specific state flags.  These flags are located in page.private
>   * of the hugetlb head page.  Functions created via the below macros should be
>   * used to manipulate these flags.
> + * Note: The hugetlb page subpool pointer previously located at page.private
> + * was moved to page[1].private to make room for flags in the head page.  See
> + * hugetlb_page_subpool().
>   *
>   * HPG_restore_reserve - Set when a hugetlb page consumes a reservation at
>   *     allocation time.  Cleared when page is fully instantiated.  Free
> --
> 2.29.2
>