| Message ID | 1578671804-8297-1-git-send-email-lixinhai.lxh@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] mm/page_vma_mapped.c: Explicitly compare pfn for noraml, hugetlbfs and THP page | expand |
On Fri, Jan 10, 2020 at 03:56:44PM +0000, Li Xinhai wrote: > When check_pte, pfn of normal, hugetlbfs and THP page need be compared. > The current implementation apply comparison as > - normal 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. > > Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com> > Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Cc: Mike Kravetz <mike.kravetz@oracle.com> > Cc: Michal Hocko <mhocko@kernel.org> > --- > mm/page_vma_mapped.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c > index eff4b45..a286ff7 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 (!PageCompound(page) || PageHuge(page)) !PageTransCompound() instead of !PageCompound() would be better for cases when THP is disabled compile-time. Otherwise: Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index eff4b45..a286ff7 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 (!PageCompound(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); } /**
When check_pte, pfn of normal, hugetlbfs and THP page need be compared. The current implementation apply comparison as - normal 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. Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Michal Hocko <mhocko@kernel.org> --- mm/page_vma_mapped.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)