mm/hugetlb: make pud_huge() and follow_huge_pud() aware of non-present pud entry

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follow_pud_mask() does not support non-present pud entry now.  As long as
I tested on x86_64 server, follow_pud_mask() still simply returns
no_page_table() for non-present_pud_entry() due to pud_bad(), so no severe
user-visible effect should happen.  But generally we should call
follow_huge_pud() for non-present pud entry for 1GB hugetlb page.

Update pud_huge() and follow_huge_pud() to handle non-present pud entries.
The changes are similar to previous works for pud entries commit
e66f17ff71 ("mm/hugetlb: take page table lock in follow_huge_pmd()") and
commit cbef8478be ("mm/hugetlb: pmd_huge() returns true for non-present
hugepage").

Link: https://lkml.kernel.org/r/20220714042420.1847125-3-naoya.horiguchi@linux.dev
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

...

This commit is contained in:

Naoya Horiguchi 2022-07-14 13:24:14 +09:00 • committed by Andrew Morton

parent c0531714d6

commit 3a194f3f8a

2 changed files with 37 additions and 3 deletions

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8

arch/x86/mm/hugetlbpage.c

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32

mm/hugetlb.c

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