The patch titled
Subject: mm/page_vma_mapped.c: explicitly compare pfn for normal, hugetlbfs and THP page
has been added to the -mm tree. Its filename is
mm-page_vma_mappedc-explicitly-compare-pfn-for-normal-hugetlbfs-and-thp-page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_vma_mappedc-explicitly-compare-pfn-for-normal-hugetlbfs-and-thp-page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_vma_mappedc-explicitly-compare-pfn-for-normal-hugetlbfs-and-thp-page.patch
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------------------------------------------------------
From: Li Xinhai <lixinhai.lxh@xxxxxxxxx>
Subject: mm/page_vma_mapped.c: explicitly compare pfn for normal, hugetlbfs and THP page
When check_pte, pfn of normal, hugetlbfs and THP page need be compared.
The current implementation apply comparison as
- normal 4K page: page_pfn <= pfn < page_pfn + 1
- hugetlbfs page: page_pfn <= pfn < page_pfn + HPAGE_PMD_NR
- THP page: page_pfn <= pfn < page_pfn + HPAGE_PMD_NR
in pfn_in_hpage. For hugetlbfs page, it should be page_pfn == pfn
Now, change pfn_in_hpage to pfn_is_match to highlight that comparison is
not only for THP and explicitly compare for these cases.
Link: http://lkml.kernel.org/r/1578737885-8890-1-git-send-email-lixinhai.lxh@xxxxxxxxx
Signed-off-by: Li Xinhai <lixinhai.lxh@xxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_vma_mapped.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
--- a/mm/page_vma_mapped.c~mm-page_vma_mappedc-explicitly-compare-pfn-for-normal-hugetlbfs-and-thp-page
+++ a/mm/page_vma_mapped.c
@@ -52,12 +52,16 @@ static bool map_pte(struct page_vma_mapp
return true;
}
-static inline bool pfn_in_hpage(struct page *hpage, unsigned long pfn)
+static inline bool pfn_is_match(struct page *page, unsigned long pfn)
{
- unsigned long hpage_pfn = page_to_pfn(hpage);
+ unsigned long page_pfn = page_to_pfn(page);
+
+ /* normal page and hugetlbfs page */
+ if (!PageTransCompound(page) || PageHuge(page))
+ return page_pfn == pfn;
/* THP can be referenced by any subpage */
- return pfn >= hpage_pfn && pfn - hpage_pfn < hpage_nr_pages(hpage);
+ return pfn >= page_pfn && pfn - page_pfn < hpage_nr_pages(page);
}
/**
@@ -108,7 +112,7 @@ static bool check_pte(struct page_vma_ma
pfn = pte_pfn(*pvmw->pte);
}
- return pfn_in_hpage(pvmw->page, pfn);
+ return pfn_is_match(pvmw->page, pfn);
}
/**
_
Patches currently in -mm which might be from lixinhai.lxh@xxxxxxxxx are
mm-page_vma_mappedc-explicitly-compare-pfn-for-normal-hugetlbfs-and-thp-page.patch
