linux-kernel - Re: [PATCH v2 1/5] mm/huge_memory.c: remove dedicated macro HPAGE_CACHE_INDEX

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Message-ID: <cb8c3df7-92e1-bce6-9268-12fc10797e23@huawei.com>
Date:   Fri, 30 Apr 2021 09:39:29 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     David Hildenbrand <david@...hat.com>, <akpm@...ux-foundation.org>
CC:     <ziy@...dia.com>, <william.kucharski@...cle.com>,
        <willy@...radead.org>, <yang.shi@...ux.alibaba.com>,
        <aneesh.kumar@...ux.ibm.com>, <rcampbell@...dia.com>,
        <songliubraving@...com>, <kirill.shutemov@...ux.intel.com>,
        <riel@...riel.com>, <hannes@...xchg.org>, <minchan@...nel.org>,
        <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>
Subject: Re: [PATCH v2 1/5] mm/huge_memory.c: remove dedicated macro
 HPAGE_CACHE_INDEX_MASK

On 2021/4/29 22:48, David Hildenbrand wrote:
> On 29.04.21 15:26, Miaohe Lin wrote:
>> Rewrite the pgoff checking logic to remove macro HPAGE_CACHE_INDEX_MASK
>> which is only used here to simplify the code.
>>
>> Reviewed-by: Yang Shi <shy828301@...il.com>
>> Reviewed-by: Anshuman Khandual <anshuman.khandual@....com>
>> Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
>> ---
>>   include/linux/huge_mm.h | 6 ++----
>>   1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
>> index 9626fda5efce..0a526f211fec 100644
>> --- a/include/linux/huge_mm.h
>> +++ b/include/linux/huge_mm.h
>> @@ -152,15 +152,13 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
>>     bool transparent_hugepage_enabled(struct vm_area_struct *vma);
>>   -#define HPAGE_CACHE_INDEX_MASK (HPAGE_PMD_NR - 1)
>> -
>>   static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
>>           unsigned long haddr)
>>   {
>>       /* Don't have to check pgoff for anonymous vma */
>>       if (!vma_is_anonymous(vma)) {
>> -        if (((vma->vm_start >> PAGE_SHIFT) & HPAGE_CACHE_INDEX_MASK) !=
>> -            (vma->vm_pgoff & HPAGE_CACHE_INDEX_MASK))
>> +        if (!IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
>> +                HPAGE_PMD_NR))
>>               return false;
> 
> I'd have used
> 
> if (!IS_ALIGNED(PHYS_PFN(vma->vm_start) - vma->vm_pgoff,
> 

It's because I want keep the code style consistent with hugepage_vma_check().
There is similiar code in hugepage_vma_check():

	return IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
			HPAGE_PMD_NR);

> Reviewed-by: David Hildenbrand <david@...hat.com>

Many thanks for review!

>