[PATCH v3 05/13] mm/debug_vm_pgtable/savedwrite: Enable savedwrite test with CONFIG_NUMA_BALANCING

[Anshuman Khandual]

On 08/27/2020 01:34 PM, Aneesh Kumar K.V wrote:
> Saved write support was added to track the write bit of a pte after marking the
> pte protnone. This was done so that AUTONUMA can convert a write pte to protnone
> and still track the old write bit. When converting it back we set the pte write
> bit correctly thereby avoiding a write fault again. Hence enable the test only
> when CONFIG_NUMA_BALANCING is enabled and use protnone protflags.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
> ---
>  mm/debug_vm_pgtable.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index 28f9d0558c20..5c0680836fe9 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -119,10 +119,14 @@ static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot)
>  {
>  	pte_t pte = pfn_pte(pfn, prot);
>  
> +	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
> +		return;
> +
>  	pr_debug("Validating PTE saved write\n");
>  	WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte))));
>  	WARN_ON(pte_savedwrite(pte_clear_savedwrite(pte_mk_savedwrite(pte))));
>  }
> +
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
>  {
> @@ -235,6 +239,9 @@ static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
>  {
>  	pmd_t pmd = pfn_pmd(pfn, prot);
>  
> +	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
> +		return;
> +
>  	pr_debug("Validating PMD saved write\n");
>  	WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
>  	WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));
> @@ -1020,8 +1027,8 @@ static int __init debug_vm_pgtable(void)
>  	pmd_huge_tests(pmdp, pmd_aligned, prot);
>  	pud_huge_tests(pudp, pud_aligned, prot);
>  
> -	pte_savedwrite_tests(pte_aligned, prot);
> -	pmd_savedwrite_tests(pmd_aligned, prot);
> +	pte_savedwrite_tests(pte_aligned, protnone);
> +	pmd_savedwrite_tests(pmd_aligned, protnone);
>  
>  	pte_unmap_unlock(ptep, ptl);
>  
> 

There is a checkpatch.pl warning here.

WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#7: 
Saved write support was added to track the write bit of a pte after marking the

total: 0 errors, 1 warnings, 33 lines checked

Otherwise this looks good. With the checkpatch.pl warning fixed

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