diff options
| author | Li Xinhai <lixinhai.lxh@gmail.com> | 2020-01-30 22:13:45 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-01-31 10:30:38 -0800 |
| commit | 5b8d6e37b519e455661cd847654c2e6ad20b4b1d (patch) | |
| tree | fcbc36d500bc0bb9c75849cc091472362731c67b /mm/page_vma_mapped.c | |
| parent | 92855270ff0827865109447b59e7e5df9c2bef68 (diff) | |
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.
No impact upon current behavior, just make the code clear. I think it
is important to make the code clear - comparing hugetlbfs page in range
page_pfn <= pfn < page_pfn + HPAGE_PMD_NR is confusing.
Link: http://lkml.kernel.org/r/1578737885-8890-1-git-send-email-lixinhai.lxh@gmail.com
Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_vma_mapped.c')
| -rw-r--r-- | mm/page_vma_mapped.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index eff4b4520c8d..719c35246cfa 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -52,12 +52,16 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw) 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_mapped_walk *pvmw) pfn = pte_pfn(*pvmw->pte); } - return pfn_in_hpage(pvmw->page, pfn); + return pfn_is_match(pvmw->page, pfn); } /** |