linux-kernel - Re: [PATCH v2 3/3] mm/damon/paddr: minor refactor of damon_pa_mark_accessed_or

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Date:   Fri,  3 Mar 2023 18:26:33 +0000
From:   SeongJae Park <sj@...nel.org>
To:     Kefeng Wang <wangkefeng.wang@...wei.com>
Cc:     SeongJae Park <sj@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, damon@...ts.linux.dev
Subject: Re: [PATCH v2 3/3] mm/damon/paddr: minor refactor of damon_pa_mark_accessed_or_deactivate()

On Fri, 3 Mar 2023 16:43:43 +0800 Kefeng Wang <wangkefeng.wang@...wei.com> wrote:

> Omit one line by unified folio_put(), and make code more clear.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
> ---
>  mm/damon/paddr.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
> index 2ef9db0189ca..6930ebf3667c 100644
> --- a/mm/damon/paddr.c
> +++ b/mm/damon/paddr.c
> @@ -266,17 +266,16 @@ static inline unsigned long damon_pa_mark_accessed_or_deactivate(
>  		if (!folio)
>  			continue;
>  
> -		if (damos_pa_filter_out(s, folio)) {
> -			folio_put(folio);
> -			continue;
> -		}
> +		if (damos_pa_filter_out(s, folio))
> +			goto put_folio;
>  
>  		if (mark_accessed)
>  			folio_mark_accessed(folio);
>  		else
>  			folio_deactivate(folio);
> -		folio_put(folio);
>  		applied += folio_nr_pages(folio);
> +put_folio:
> +		folio_put(folio);

I think this change is ok, but shouldn't the 'folio_put()' have called before
'folio_nr_pages()' anyway?  If so, could we make the change as a separate fix
first, and then make this change, so that it can be easily applied to relevant
stable kernels?


Thanks,
SJ

>  	}
>  	return applied * PAGE_SIZE;
>  }
> -- 
> 2.35.3
> 
>