linux-kernel - Re: [PATCH] mm/hugetlb: remove a meaningless if statement in gigantic page initialization

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Date:   Tue, 2 Feb 2021 18:19:21 +0800
From:   "Xu, Yanfei" <yanfei.xu@...driver.com>
To:     David Hildenbrand <david@...hat.com>, mike.kravetz@...cle.com,
        akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm/hugetlb: remove a meaningless if statement in gigantic
 page initialization



On 2/2/21 6:06 PM, David Hildenbrand wrote:
> [Please note: This e-mail is from an EXTERNAL e-mail address]
> 
> On 02.02.21 11:12, yanfei.xu@...driver.com wrote:
>> From: Yanfei Xu <yanfei.xu@...driver.com>
>>
>> Gigantic page is a compound page and its order is more than 1.
>> Thus it must be available for hpage_pincount. Let's remove this
>> meaningless if statement.
>>
>> Signed-off-by: Yanfei Xu <yanfei.xu@...driver.com>
>> ---
>>   mm/hugetlb.c | 4 +---
>>   1 file changed, 1 insertion(+), 3 deletions(-)
>>
>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>> index a3e4fa2c5e94..73d602f8c7e2 100644
>> --- a/mm/hugetlb.c
>> +++ b/mm/hugetlb.c
>> @@ -1501,9 +1501,7 @@ static void prep_compound_gigantic_page(struct 
>> page *page, unsigned int order)
>>               set_compound_head(p, page);
>>       }
>>       atomic_set(compound_mapcount_ptr(page), -1);
>> -
>> -     if (hpage_pincount_available(page))
>> -             atomic_set(compound_pincount_ptr(page), 0);
>> +     atomic_set(compound_pincount_ptr(page), 0);
>>   }
>>
>>   /*
>>
> 
> I can spot similar handling in destroy_compound_gigantic_page(). If this
> is correct (which I think it is), we should tackle both occurrences at 
> once.
> 
Agree. Will do it in v2.

Thanks,
Yanfei
> -- 
> Thanks,
> 
> David / dhildenb
>