Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v1] mm, hwpoison: add is_free_buddy_page() in
 HWPoisonHandlable()
To:     Naoya Horiguchi <naoya.horiguchi@linux.dev>, linux-mm@kvack.org
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Tony Luck <tony.luck@intel.com>,
        Oscar Salvador <osalvador@suse.de>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Michal Hocko <mhocko@suse.com>, Yang Shi <shy828301@gmail.com>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        linux-kernel@vger.kernel.org
References: <20210909004131.163221-1-naoya.horiguchi@linux.dev>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
Message-ID: <0363dc08-64af-8e59-7e1e-930194710e51@redhat.com>
Date:   Fri, 10 Sep 2021 13:16:37 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.11.0
MIME-Version: 1.0
In-Reply-To: <20210909004131.163221-1-naoya.horiguchi@linux.dev>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 09.09.21 02:41, Naoya Horiguchi wrote:
> From: Naoya Horiguchi <naoya.horiguchi@nec.com>
> 
> commit fcc00621d88b ("mm/hwpoison: retry with shake_page() for
> unhandlable pages") changes the return value of __get_hwpoison_page() to
> retry for transiently unhandlable cases.  However, __get_hwpoison_page()
> currently fails to properly judge buddy pages as handlable, so hard/soft
> offline for buddy pages always fail as "unhandlable page".  This is
> totally regrettable.
> 
> So let's add is_free_buddy_page() in HWPoisonHandlable(), so that
> __get_hwpoison_page() returns different return values between buddy
> pages and unhandlable pages as intended.
> 
> Fixes: fcc00621d88b ("mm/hwpoison: retry with shake_page() for unhandlable pages")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
> ---
>   mm/memory-failure.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git v5.14-rc7-mmotm-2021-08-23-16-42/mm/memory-failure.c v5.14-rc7-mmotm-2021-08-23-16-42_patched/mm/memory-failure.c
> index 60df8fcd0444..3416c55be810 100644
> --- v5.14-rc7-mmotm-2021-08-23-16-42/mm/memory-failure.c
> +++ v5.14-rc7-mmotm-2021-08-23-16-42_patched/mm/memory-failure.c
> @@ -1126,7 +1126,7 @@ static int page_action(struct page_state *ps, struct page *p,
>    */
>   static inline bool HWPoisonHandlable(struct page *page)
>   {
> -	return PageLRU(page) || __PageMovable(page);
> +	return PageLRU(page) || __PageMovable(page) || is_free_buddy_page(page);
>   }
>   
>   static int __get_hwpoison_page(struct page *page)
> 

LGTM and I agree that code might desrve some cleanups.

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb