linux-kernel - Re: [RFC PATCH 03/16] mm: proc: add 1GB THP kpageflag.

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Date:   Wed, 9 Sep 2020 16:46:57 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Zi Yan <ziy@...dia.com>
Cc:     linux-mm@...ck.org, Roman Gushchin <guro@...com>,
        Rik van Riel <riel@...riel.com>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Matthew Wilcox <willy@...radead.org>,
        Shakeel Butt <shakeelb@...gle.com>,
        Yang Shi <yang.shi@...ux.alibaba.com>,
        David Nellans <dnellans@...dia.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 03/16] mm: proc: add 1GB THP kpageflag.

On Wed, Sep 02, 2020 at 02:06:15PM -0400, Zi Yan wrote:
> From: Zi Yan <ziy@...dia.com>
> 
> Bit 27 is used to identify 1GB THP.
> 
> Signed-off-by: Zi Yan <ziy@...dia.com>
> ---
>  fs/proc/page.c                         | 2 ++
>  include/uapi/linux/kernel-page-flags.h | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/fs/proc/page.c b/fs/proc/page.c
> index f3b39a7d2bf3..e4e2ad3612c9 100644
> --- a/fs/proc/page.c
> +++ b/fs/proc/page.c
> @@ -161,6 +161,8 @@ u64 stable_page_flags(struct page *page)
>  			u |= BIT_ULL(KPF_ZERO_PAGE);
>  			u |= BIT_ULL(KPF_THP);
>  		}
> +		if (compound_order(head) == HPAGE_PUD_ORDER)
> +			u |= 1 << KPF_PUD_THP;
>  	} else if (is_zero_pfn(page_to_pfn(page)))
>  		u |= BIT_ULL(KPF_ZERO_PAGE);
>  
> diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h
> index 6f2f2720f3ac..cdeb33ab655c 100644
> --- a/include/uapi/linux/kernel-page-flags.h
> +++ b/include/uapi/linux/kernel-page-flags.h
> @@ -36,5 +36,7 @@
>  #define KPF_ZERO_PAGE		24
>  #define KPF_IDLE		25
>  #define KPF_PGTABLE		26
> +#define KPF_PUD_THP		27
> +

Redundant newline.

>  #endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */
> -- 
> 2.28.0
> 
> 

-- 
 Kirill A. Shutemov