Re: [PATCH v4 1/9] hugetlb: Pass vma into huge_pte_alloc()

[Mike Kravetz]

On 2/1/21 1:38 PM, Mike Kravetz wrote:
> On 1/28/21 3:42 PM, Axel Rasmussen wrote:
>> From: Peter Xu <peterx@xxxxxxxxxx>
>>
>> It is a preparation work to be able to behave differently in the per
>> architecture huge_pte_alloc() according to different VMA attributes.
>>
>> Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
>> [axelrasmussen@xxxxxxxxxx: fixed typo in arch/mips/mm/hugetlbpage.c]
>> Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
>> ---
>>  arch/arm64/mm/hugetlbpage.c   | 2 +-
>>  arch/ia64/mm/hugetlbpage.c    | 3 ++-
>>  arch/mips/mm/hugetlbpage.c    | 4 ++--
>>  arch/parisc/mm/hugetlbpage.c  | 2 +-
>>  arch/powerpc/mm/hugetlbpage.c | 3 ++-
>>  arch/s390/mm/hugetlbpage.c    | 2 +-
>>  arch/sh/mm/hugetlbpage.c      | 2 +-
>>  arch/sparc/mm/hugetlbpage.c   | 2 +-
>>  include/linux/hugetlb.h       | 2 +-
>>  mm/hugetlb.c                  | 6 +++---
>>  mm/userfaultfd.c              | 2 +-
>>  11 files changed, 16 insertions(+), 14 deletions(-)
> 
> Sorry for the delay in reviewing.
> 
> huge_pmd_share() will do a find_vma() to get the vma.  So, it would be
> 'possible' to not add an extra argument to huge_pmd_alloc() and simply
> do the uffd_disable_huge_pmd_share() check inside vma_shareable.  This
> would reduce the amount of modified code, but would not be as efficient.
> I prefer passing the vma argument as is done here.
> 
> Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>


Another thought.

We should pass the vma to huge_pmd_share to avoid the find_vma.

-- 
Mike Kravetz