linux-kernel - Re: [PATCH 4/4] mm: memory-failure: add PageOffline() check

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Message-ID: <0161d32a-79d8-912c-0981-496a15f3eebf@huawei.com>
Date:   Thu, 20 Jul 2023 16:42:04 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     Naoya Horiguchi <naoya.horiguchi@...ux.dev>
CC:     <akpm@...ux-foundation.org>, <naoya.horiguchi@....com>,
        <shy828301@...il.com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/4] mm: memory-failure: add PageOffline() check

On 2023/7/20 9:09, Naoya Horiguchi wrote:
> On Sat, Jul 15, 2023 at 11:17:29AM +0800, Miaohe Lin wrote:
>> Memory failure is not interested in logically offlined page. Skip this
>> type of pages.
>>
>> Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
>> ---
>>  mm/memory-failure.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index 42e63b0ab5f7..ed79b69837de 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -1559,7 +1559,7 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
>>  	 * Here we are interested only in user-mapped pages, so skip any
>>  	 * other types of pages.
>>  	 */
>> -	if (PageReserved(p) || PageSlab(p) || PageTable(p))
>> +	if (PageReserved(p) || PageSlab(p) || PageTable(p) || PageOffline(p))
> 
> hwpoison_user_mappings() is called after some checks are done, so I'm not
> sure that it's the right place to check PageOffline().

hwpoison_user_mappings() is called after the "if (!PageLRU(p) && !PageWriteback(p))" check in memory_failure().
So the page can't also be PageReserved(p) or PageSlab(p) or PageTable(p) here? I think the check here just wants
to make things clear that only user-mapped pages are interested. Or am I miss something?

Thanks Naoya.