linux-kernel - Re: [PATCH 2/2] mm: memory-failure: kill __soft_offline

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Date:   Tue, 30 Aug 2022 17:26:12 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     HORIGUCHI NAOYA(堀口 直也) 
        <naoya.horiguchi@....com>
CC:     Miaohe Lin <linmiaohe@...wei.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] mm: memory-failure: kill __soft_offline_page()


On 2022/8/30 15:15, HORIGUCHI NAOYA(堀口 直也) wrote:
> On Fri, Aug 19, 2022 at 11:34:02AM +0800, Kefeng Wang wrote:
>> Squash the __soft_offline_page() into soft_offline_in_use_page() and
>> kill __soft_offline_page().
>>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
>> ---
>>   mm/memory-failure.c | 24 +++++++++---------------
>>   1 file changed, 9 insertions(+), 15 deletions(-)
>>
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index 1a7d6548ccb2..5b368124956d 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -2432,11 +2432,11 @@ static bool isolate_page(struct page *page, struct list_head *pagelist)
>>   }
>>   
>>   /*
>> - * __soft_offline_page handles hugetlb-pages and non-hugetlb pages.
>> + * soft_offline_in_use_page handles hugetlb-pages and non-hugetlb pages.
>>    * If the page is a non-dirty unmapped page-cache page, it simply invalidates.
>>    * If the page is mapped, it migrates the contents over.
>>    */
>> -static int __soft_offline_page(struct page *page)
>> +static int soft_offline_in_use_page(struct page *page)
>>   {
>>   	long ret = 0;
>>   	unsigned long pfn = page_to_pfn(page);
>> @@ -2449,6 +2449,13 @@ static int __soft_offline_page(struct page *page)
>>   		.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
>>   	};
>>   
>> +	if (!huge && PageTransHuge(hpage)) {
>> +		if (try_to_split_thp_page(page)) {
>> +			pr_info("soft offline: %#lx: thp split failed\n", pfn);
>> +			return -EBUSY;
>> +		}
> I've found that this change causes a regression. After the thp is
> successfully split here, hpage no longer points to a proper page.
> So hpage should be updated to point to the raw error page.
>
> +		hpage = page;
Sorry for the regression,  will update.
>
> Could you update the patch?
>
> Thanks,
> Naoya Horiguchi