Re: [PATCH v7 5/9] arm64: hugetlb: Handle swap entries in huge_pte_offset() for contiguous hugepages

[Punit Agrawal <punit.agrawal@arm.com>]

Catalin Marinas <catalin.marinas@arm.com> writes:

> On Tue, Aug 22, 2017 at 11:42:45AM +0100, Punit Agrawal wrote:
>> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
>> index 594232598cac..b95e24dc3477 100644
>> --- a/arch/arm64/mm/hugetlbpage.c
>> +++ b/arch/arm64/mm/hugetlbpage.c
>> @@ -214,6 +214,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
>>  	pgd_t *pgd;
>>  	pud_t *pud;
>>  	pmd_t *pmd;
>> +	pte_t *pte;
>>  
>>  	pgd = pgd_offset(mm, addr);
>>  	pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd);
>> @@ -221,19 +222,29 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
>>  		return NULL;
>>  
>>  	pud = pud_offset(pgd, addr);
>> -	if (pud_none(*pud))
>> +	if (sz != PUD_SIZE && pud_none(*pud))
>>  		return NULL;
>> -	/* swap or huge page */
>> -	if (!pud_present(*pud) || pud_huge(*pud))
>> +	/* hugepage or swap? */
>> +	if (pud_huge(*pud) || !pud_present(*pud))
>>  		return (pte_t *)pud;
>>  	/* table; check the next level */
>>  
>> +	if (sz == CONT_PMD_SIZE)
>> +		addr &= CONT_PMD_MASK;
>> +
>>  	pmd = pmd_offset(pud, addr);
>> -	if (pmd_none(*pmd))
>> +	if (!(sz == PMD_SIZE || sz == CONT_PMD_SIZE) &&
>> +	    pmd_none(*pmd))
>>  		return NULL;
>> -	if (!pmd_present(*pmd) || pmd_huge(*pmd))
>> +	if (pmd_huge(*pmd) || !pmd_present(*pmd))
>>  		return (pte_t *)pmd;
>>  
>> +	if (sz == CONT_PTE_SIZE) {
>> +		pte = pte_offset_kernel(
>> +			pmd, (addr & CONT_PTE_MASK));
>> +		return pte;
>> +	}
>> +
>>  	return NULL;
>>  }
>
> I merged the patch almost as is (with the pte variable but
> pte_offset_kernel() arguments on the same line); the pte variable is a
> minor personal preference, so I'm not going to argue either way ;)).
>
> Anyway, I pulled the whole series for 4.14, though I'll run some tests
> over the next day or so.

Thanks for picking up the patches. Hopefully, there won't be a need for
another revert this time around. :)

>
> Thanks.

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