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From:   Yang Shi <shy828301@gmail.com>
Date:   Tue, 25 Jan 2022 09:45:01 -0800
Message-ID: <CAHbLzkr_w+E7AWoiAwjmjZhGMAt=donXV6SUSep0fkp=ZtOnkg@mail.gmail.com>
Subject: Re: [PATCH v1] mm, hwpoison: remove obsolete comment
To:     Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc:     Linux MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Tony Luck <tony.luck@intel.com>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Jan 24, 2022 at 6:56 PM Naoya Horiguchi
<naoya.horiguchi@linux.dev> wrote:
>
> From: Naoya Horiguchi <naoya.horiguchi@nec.com>
>
> With the introduction of mf_mutex, most of memory error handling
> process is mutually exclusive, so the in-line comment about
> subtlety about double-checking PageHWPoison is no more correct.
> So remove it.
>
> Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
> Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>

Reviewed-by: Yang Shi <shy828301@gmail.com>

> ---
>  mm/memory-failure.c | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 4c9bd1d37301..a6a1e02759e7 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -2146,12 +2146,6 @@ static int __soft_offline_page(struct page *page)
>                 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
>         };
>
> -       /*
> -        * Check PageHWPoison again inside page lock because PageHWPoison
> -        * is set by memory_failure() outside page lock. Note that
> -        * memory_failure() also double-checks PageHWPoison inside page lock,
> -        * so there's no race between soft_offline_page() and memory_failure().
> -        */
>         lock_page(page);
>         if (!PageHuge(page))
>                 wait_on_page_writeback(page);
> --
> 2.25.1
>
>