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SubjectRe: [PATCH v3] hugetlb: simplify hugetlb handling in follow_page_mask
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On 19.09.22 04:13, Mike Kravetz wrote:
> During discussions of this series [1], it was suggested that hugetlb
> handling code in follow_page_mask could be simplified. At the beginning
> of follow_page_mask, there currently is a call to follow_huge_addr which
> 'may' handle hugetlb pages. ia64 is the only architecture which provides
> a follow_huge_addr routine that does not return error. Instead, at each
> level of the page table a check is made for a hugetlb entry. If a hugetlb
> entry is found, a call to a routine associated with that entry is made.
>
> Currently, there are two checks for hugetlb entries at each page table
> level. The first check is of the form:
> if (p?d_huge())
> page = follow_huge_p?d();
> the second check is of the form:
> if (is_hugepd())
> page = follow_huge_pd().
>
> We can replace these checks, as well as the special handling routines
> such as follow_huge_p?d() and follow_huge_pd() with a single routine to
> handle hugetlb vmas.
>
> A new routine hugetlb_follow_page_mask is called for hugetlb vmas at the
> beginning of follow_page_mask. hugetlb_follow_page_mask will use the
> existing routine huge_pte_offset to walk page tables looking for hugetlb
> entries. huge_pte_offset can be overwritten by architectures, and already
> handles special cases such as hugepd entries.
>
> [1] https://lore.kernel.org/linux-mm/cover.1661240170.git.baolin.wang@linux.alibaba.com/
>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
> ---

Reviewed-by: David Hildenbrand <david@redhat.com>

--
Thanks,

David / dhildenb

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