[PATCH v2 00/13] mm/debug_vm_pgtable fixes

[Anshuman Khandual]

On 08/19/2020 07:15 PM, Aneesh Kumar K.V wrote:
> "Aneesh Kumar K.V" <aneesh.kumar at linux.ibm.com> writes:
> 
>> This patch series includes fixes for debug_vm_pgtable test code so that
>> they follow page table updates rules correctly. The first two patches introduce
>> changes w.r.t ppc64. The patches are included in this series for completeness. We can
>> merge them via ppc64 tree if required.
>>
>> Hugetlb test is disabled on ppc64 because that needs larger change to satisfy
>> page table update rules.
>>
>> Changes from V1:
>> * Address review feedback
>> * drop test specific pfn_pte and pfn_pmd.
>> * Update ppc64 page table helper to add _PAGE_PTE 
>>
>> Aneesh Kumar K.V (13):
>>   powerpc/mm: Add DEBUG_VM WARN for pmd_clear
>>   powerpc/mm: Move setting pte specific flags to pfn_pte
>>   mm/debug_vm_pgtable/ppc64: Avoid setting top bits in radom value
>>   mm/debug_vm_pgtables/hugevmap: Use the arch helper to identify huge
>>     vmap support.
>>   mm/debug_vm_pgtable/savedwrite: Enable savedwrite test with
>>     CONFIG_NUMA_BALANCING
>>   mm/debug_vm_pgtable/THP: Mark the pte entry huge before using
>>     set_pmd/pud_at
>>   mm/debug_vm_pgtable/set_pte/pmd/pud: Don't use set_*_at to update an
>>     existing pte entry
>>   mm/debug_vm_pgtable/thp: Use page table depost/withdraw with THP
>>   mm/debug_vm_pgtable/locks: Move non page table modifying test together
>>   mm/debug_vm_pgtable/locks: Take correct page table lock
>>   mm/debug_vm_pgtable/pmd_clear: Don't use pmd/pud_clear on pte entries
>>   mm/debug_vm_pgtable/hugetlb: Disable hugetlb test on ppc64
>>   mm/debug_vm_pgtable: populate a pte entry before fetching it
>>
>>  arch/powerpc/include/asm/book3s/64/pgtable.h |  29 +++-
>>  arch/powerpc/include/asm/nohash/pgtable.h    |   5 -
>>  arch/powerpc/mm/book3s64/pgtable.c           |   2 +-
>>  arch/powerpc/mm/pgtable.c                    |   5 -
>>  include/linux/io.h                           |  12 ++
>>  mm/debug_vm_pgtable.c                        | 151 +++++++++++--------
>>  6 files changed, 127 insertions(+), 77 deletions(-)
>>
> 
> BTW I picked a wrong branch when sending this. Attaching the diff
> against what I want to send.  pfn_pmd() no more updates _PAGE_PTE
> because that is handled by pmd_mkhuge().
> 
> diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
> index 3b4da7c63e28..e18ae50a275c 100644
> --- a/arch/powerpc/mm/book3s64/pgtable.c
> +++ b/arch/powerpc/mm/book3s64/pgtable.c
> @@ -141,7 +141,7 @@ pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
>  	unsigned long pmdv;
>  
>  	pmdv = (pfn << PAGE_SHIFT) & PTE_RPN_MASK;
> -	return __pmd(pmdv | pgprot_val(pgprot) | _PAGE_PTE);
> +	return pmd_set_protbits(__pmd(pmdv), pgprot);
>  }
>  
>  pmd_t mk_pmd(struct page *page, pgprot_t pgprot)
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index 7d9f8e1d790f..cad61d22f33a 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -229,7 +229,7 @@ static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
>  
>  static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
>  {
> -	pmd_t pmd = pfn_pmd(pfn, prot);
> +	pmd_t pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
>  
>  	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
>  		return;
> 

Cover letter does not mention which branch or tag this series applies on.
Just assumed it to be 5.9-rc1. Should the above changes be captured as a
pre-requisite patch ?

Anyways, the series fails to be build on arm64.

A) Without CONFIG_TRANSPARENT_HUGEPAGE

mm/debug_vm_pgtable.c: In function ‘debug_vm_pgtable’:
mm/debug_vm_pgtable.c:1045:2: error: too many arguments to function ‘pmd_advanced_tests’
  pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot, saved_ptep);
  ^~~~~~~~~~~~~~~~~~
mm/debug_vm_pgtable.c:366:20: note: declared here
 static void __init pmd_advanced_tests(struct mm_struct *mm,
                    ^~~~~~~~~~~~~~~~~~

B) As mentioned previously, this should be solved by including <linux/io.h>

mm/debug_vm_pgtable.c: In function ‘pmd_huge_tests’:
mm/debug_vm_pgtable.c:215:7: error: implicit declaration of function ‘arch_ioremap_pmd_supported’; did you mean ‘arch_disable_smp_support’? [-Werror=implicit-function-declaration]
  if (!arch_ioremap_pmd_supported())
       ^~~~~~~~~~~~~~~~~~~~~~~~~~

Please make sure that the series builds on all enabled platforms i.e x86,
arm64, ppc32, ppc64, arc, s390 along with selectively enabling/disabling
all the features that make various #ifdefs in the test.

- Anshuman