linux-kernel - Re: [PATCH] mm/shmem.c: use helper transhuge_vma

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Message-ID: <7c363619-4159-8a21-d55a-535e21b5c8b4@arm.com>
Date:   Wed, 15 Jun 2022 10:32:30 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     Hugh Dickins <hughd@...gle.com>, Miaohe Lin <linmiaohe@...wei.com>
Cc:     akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm/shmem.c: use helper transhuge_vma_enabled()



On 6/11/22 08:44, Hugh Dickins wrote:
> On Sat, 11 Jun 2022, Miaohe Lin wrote:
> 
>> Use helper transhuge_vma_enabled() to check whether transhuge is enable
>> on vma. Minor readability improvement.
>>
>> Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
> 
> No thanks, that's a readability regression, forcing reader
> to go and look up what transhuge_vma_enabled() actually means.
> 
> What you call a helper, I call an obfuscator - as I implied in
> b9e2faaf6fa0 ("huge tmpfs: revert shmem's use of transhuge_vma_enabled()")

The same reasoning should also be applicable for other calls sites
for transhuge_vma_enabled(). Should not they be dropped as well ?

> 
> Hugh
> 
>> ---
>>  mm/shmem.c | 3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/mm/shmem.c b/mm/shmem.c
>> index 133c67057d41..59cc2e980c95 100644
>> --- a/mm/shmem.c
>> +++ b/mm/shmem.c
>> @@ -480,8 +480,7 @@ bool shmem_is_huge(struct vm_area_struct *vma,
>>  		return false;
>>  	if (shmem_huge == SHMEM_HUGE_DENY)
>>  		return false;
>> -	if (vma && ((vma->vm_flags & VM_NOHUGEPAGE) ||
>> -	    test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)))
>> +	if (vma && !transhuge_vma_enabled(vma, vma->vm_flags))
>>  		return false;
>>  	if (shmem_huge == SHMEM_HUGE_FORCE)
>>  		return true;
>> -- 
>> 2.23.0
>