Re: [PATCH] mm/page_vma_mapped.c: Exactly compare hugetlbfs page's pfn in pfn_in_hpage()

["Li Xinhai" <lixinhai.lxh@gmail.com>]

On 2020-01-09 at 22:26 Li Xinhai wrote:
>check_pte is called for hugetlbfs page and comparing pfn in pfn_in_page,
>where pfn is compared in range [hpage_pfn, hpage_pfn+HPAGE_PMD_NR). Now
>change it to match exactly for hugetlbfs page to avoid hiding any
>potential problems.
>
>Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com>
>Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
>---
> mm/page_vma_mapped.c | 2 ++
> 1 file changed, 2 insertions(+)
>
>diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
>index eff4b45..434978b 100644
>--- a/mm/page_vma_mapped.c
>+++ b/mm/page_vma_mapped.c
>@@ -55,6 +55,8 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw)
> static inline bool pfn_in_hpage(struct page *hpage, unsigned long pfn)
> {
> unsigned long hpage_pfn = page_to_pfn(hpage);
>+	if (unlikely(PageHuge(hpage)))
>+	return pfn == hpage_pfn;
>
> /* THP can be referenced by any subpage */
> return pfn >= hpage_pfn && pfn - hpage_pfn < hpage_nr_pages(hpage);
>--
>1.8.3.1
> 

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