[PATCH V8] mm/debug: Add tests validating architecture page table helpers

[Vineet Gupta]

On 11/6/19 8:44 PM, Anshuman Khandual wrote:
>
>>
>>>   */
>>> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>> +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE
>>>  #include <asm/hugepage.h>
>>>  #endif
>> This in wrong.  CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE is a just a glue toggle,
>> used only in Kconfig files (and not in any "C" code).  It enables generic Kconfig
>> code to allow visibility of CONFIG_TRANSPARENT_HUGEPAGE w/o every arch needing to
>> do a me too.
>>
>> I think you need to use CONFIG_TRANSPARENT_HUGEPAGE to guard appropriate tests. I
>> understand that it only
> We can probably replace CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE wrapper with
> CONFIG_TRANSPARENT_HUGEPAGE. But CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
> explicitly depends on CONFIG_TRANSPARENT_HUGEPAGE as a prerequisite. Could
> you please confirm if the following change on this test will work on ARC
> platform for both THP and !THP cases ? Thank you.
>
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index 621ac09..99ebc7c 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -67,7 +67,7 @@ static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot)
>  	WARN_ON(pte_write(pte_wrprotect(pte)));
>  }
>  
> -#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
>  {
>  	pmd_t pmd = pfn_pmd(pfn, prot);
> @@ -85,9 +85,6 @@ static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
>  	 */
>  	WARN_ON(!pmd_bad(pmd_mkhuge(pmd)));
>  }
> -#else
> -static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) { }
> -#endif
>  
>  #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
>  static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot)
> @@ -112,6 +109,10 @@ static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot)
>  #else
>  static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { }
>  #endif
> +#else
> +static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) { }
> +static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { }
> +#endif

Fails to build for THP case since

CONFIG_TRANSPARENT_HUGEPAGE=y
CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD=n

../mm/debug_vm_pgtable.c:112:20: error: redefinition of ‘pmd_basic_tests’