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 18:37:22 +0000
From:   SeongJae Park <sj@...nel.org>
To:     SeongJae Park <sj@...nel.org>
Cc:     Kefeng Wang <wangkefeng.wang@...wei.com>,
        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 18:26:33 +0000 SeongJae Park <sj@...nel.org> wrote:

> 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

s/before/after/

> '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
> > 
> >