[PATCH v4 10/13] mm/debug_vm_pgtable/thp: Use page table depost/withdraw with THP

[Anshuman Khandual]

On 09/02/2020 05:12 PM, Aneesh Kumar K.V wrote:
> Architectures like ppc64 use deposited page table while updating the
> huge pte entries.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
> ---
>  mm/debug_vm_pgtable.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index 2bc1952e5f83..26023d990bd0 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -154,7 +154,7 @@ static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
>  static void __init pmd_advanced_tests(struct mm_struct *mm,
>  				      struct vm_area_struct *vma, pmd_t *pmdp,
>  				      unsigned long pfn, unsigned long vaddr,
> -				      pgprot_t prot)
> +				      pgprot_t prot, pgtable_t pgtable)
>  {
>  	pmd_t pmd;
>  
> @@ -165,6 +165,8 @@ static void __init pmd_advanced_tests(struct mm_struct *mm,
>  	/* Align the address wrt HPAGE_PMD_SIZE */
>  	vaddr = (vaddr & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE;
>  
> +	pgtable_trans_huge_deposit(mm, pmdp, pgtable);
> +
>  	pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
>  	set_pmd_at(mm, vaddr, pmdp, pmd);
>  	pmdp_set_wrprotect(mm, vaddr, pmdp);
> @@ -193,6 +195,8 @@ static void __init pmd_advanced_tests(struct mm_struct *mm,
>  	pmdp_test_and_clear_young(vma, vaddr, pmdp);
>  	pmd = READ_ONCE(*pmdp);
>  	WARN_ON(pmd_young(pmd));
> +
> +	pgtable = pgtable_trans_huge_withdraw(mm, pmdp);
>  }
>  
>  static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
> @@ -371,7 +375,7 @@ static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { }
>  static void __init pmd_advanced_tests(struct mm_struct *mm,
>  				      struct vm_area_struct *vma, pmd_t *pmdp,
>  				      unsigned long pfn, unsigned long vaddr,
> -				      pgprot_t prot)
> +				      pgprot_t prot, pgtable_t pgtable)
>  {
>  }
>  static void __init pud_advanced_tests(struct mm_struct *mm,
> @@ -1048,7 +1052,7 @@ static int __init debug_vm_pgtable(void)
>  
>  	ptl = pmd_lock(mm, pmdp);
>  	pmd_clear_tests(mm, pmdp);
> -	pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot);
> +	pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot, saved_ptep);
>  	pmd_huge_tests(pmdp, pmd_aligned, prot);
>  	pmd_populate_tests(mm, pmdp, saved_ptep);
>  	spin_unlock(ptl);
> 

Moving this down further in the series has not really helped the possible
git bisect problem on arm64. Nonetheless, the patch in itself, makes sense.

Reviewed-by: Anshuman Khandual <anshuman.khandual at arm.com>