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Date:   Thu, 29 Dec 2022 17:03:21 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     yang.yang29@zte.com.cn
Cc:     akpm@linux-foundation.org, hannes@cmpxchg.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, iamjoonsoo.kim@lge.com
Subject: Re: [PATCH linux-next] swap_state: update shadow_nodes for anonymous
 page
Message-ID: <Y63IWTOE4sNKuseL@casper.infradead.org>
References: <202212292130035747813@zte.com.cn>
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On Thu, Dec 29, 2022 at 09:30:03PM +0800, yang.yang29@zte.com.cn wrote:
> From: Yang Yang <yang.yang29@zte.com.cn>
> 
> Shadow_nodes is for shadow nodes reclaiming of workingset handling,
> it is updated when page cache add or delete since long time ago
> workingset only supported page cache. But when workingset supports
> anonymous page detection[1], we missied updating shadow nodes for
> it.

Please include a description of the user-visible effect of this (I
think I can guess, but I'd like it spelled out)

> [1] commit aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU")
> 
> Signed-off-by: Yang Yang <yang.yang29@zte.com>

No Fixes: line?  It doesn't need to be backported?

> ---
>  include/linux/xarray.h | 3 ++-
>  mm/swap_state.c        | 4 ++++
>  2 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/xarray.h b/include/linux/xarray.h
> index 44dd6d6e01bc..cd2ccb09c596 100644
> --- a/include/linux/xarray.h
> +++ b/include/linux/xarray.h
> @@ -1643,7 +1643,8 @@ static inline void xas_set_order(struct xa_state *xas, unsigned long index,
>   * @update: Function to call when updating a node.
>   *
>   * The XArray can notify a caller after it has updated an xa_node.
> - * This is advanced functionality and is only needed by the page cache.
> + * This is advanced functionality and is only needed by the page cache
> + * and anonymous page.

... "and swap cache.", not anonymous page.