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References: <20220130013042.1906881-1-willy@infradead.org>
In-Reply-To: <20220130013042.1906881-1-willy@infradead.org>
From:   Yang Shi <shy828301@gmail.com>
Date:   Tue, 1 Feb 2022 10:29:05 -0800
Message-ID: <CAHbLzkrMNo4f=ATeHV=yADjW1yCbmE6jCAC=puhG-=_5j0jymg@mail.gmail.com>
Subject: Re: [PATCH] mm/hwpoison: Check the subpage, not the head page
To:     "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Linux MM <linux-mm@kvack.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>
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On Sat, Jan 29, 2022 at 5:30 PM Matthew Wilcox (Oracle)
<willy@infradead.org> wrote:
>
> Hardware poison is tracked on a per-page basis, not on the head page.

Looks correct to me. Reviewed-by: Yang Shi <shy828301@gmail.com>

>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  mm/rmap.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 6a1e8c7f6213..09b08888120e 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1553,7 +1553,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
>                 /* Update high watermark before we lower rss */
>                 update_hiwater_rss(mm);
>
> -               if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
> +               if (PageHWPoison(subpage) && !(flags & TTU_IGNORE_HWPOISON)) {
>                         pteval = swp_entry_to_pte(make_hwpoison_entry(subpage));
>                         if (PageHuge(page)) {
>                                 hugetlb_count_sub(compound_nr(page), mm);
> @@ -1873,7 +1873,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
>                          * memory are supported.
>                          */
>                         subpage = page;
> -               } else if (PageHWPoison(page)) {
> +               } else if (PageHWPoison(subpage)) {
>                         pteval = swp_entry_to_pte(make_hwpoison_entry(subpage));
>                         if (PageHuge(page)) {
>                                 hugetlb_count_sub(compound_nr(page), mm);
> --
> 2.34.1
>
>