linux-kernel - Re: [PATCH RFC 3/6] mm: swap: make should_try_to_free

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Message-ID: <CAF8kJuPjXJVhh40k2utk80ho1y9j5OjvgGwxp1D_Qbt2AmL7KQ@mail.gmail.com>
Date: Fri, 26 Jan 2024 15:22:02 -0800
From: Chris Li <chrisl@...nel.org>
To: Barry Song <21cnbao@...il.com>
Cc: ryan.roberts@....com, akpm@...ux-foundation.org, david@...hat.com, 
	linux-mm@...ck.org, linux-kernel@...r.kernel.org, mhocko@...e.com, 
	shy828301@...il.com, wangkefeng.wang@...wei.com, willy@...radead.org, 
	xiang@...nel.org, ying.huang@...el.com, yuzhao@...gle.com, surenb@...gle.com, 
	steven.price@....com, Chuanhua Han <hanchuanhua@...o.com>, 
	Barry Song <v-songbaohua@...o.com>
Subject: Re: [PATCH RFC 3/6] mm: swap: make should_try_to_free_swap() support large-folio

Acked-by: Chris Li <chrisl@...nel.org>

Chris

On Thu, Jan 18, 2024 at 3:11 AM Barry Song <21cnbao@...il.com> wrote:
>
> From: Chuanhua Han <hanchuanhua@...o.com>
>
> should_try_to_free_swap() works with an assumption that swap-in is always done
> at normal page granularity, aka, folio_nr_pages = 1. To support large folio
> swap-in, this patch removes the assumption.
>
> Signed-off-by: Chuanhua Han <hanchuanhua@...o.com>
> Co-developed-by: Barry Song <v-songbaohua@...o.com>
> Signed-off-by: Barry Song <v-songbaohua@...o.com>
> ---
>  mm/memory.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 7e1f4849463a..f61a48929ba7 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3714,7 +3714,7 @@ static inline bool should_try_to_free_swap(struct folio *folio,
>          * reference only in case it's likely that we'll be the exlusive user.
>          */
>         return (fault_flags & FAULT_FLAG_WRITE) && !folio_test_ksm(folio) &&
> -               folio_ref_count(folio) == 2;
> +               folio_ref_count(folio) == (1 + folio_nr_pages(folio));
>  }
>
>  static vm_fault_t pte_marker_clear(struct vm_fault *vmf)
> --
> 2.34.1
>
>