mm, page_vma_mapped: Introduce pfn_in_hpage()
The new helper would check if the pfn belongs to the page. For huge
pages it checks if the PFN is within range covered by the huge page.
The helper is used in check_pte(). The original code the helper replaces
had two call to page_to_pfn(). page_to_pfn() is relatively costly.
Although current GCC is able to optimize code to have one call, it's
better to do this explicitly.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 9560156..ae3c2a3 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -30,6 +30,14 @@
return true;
}
+static inline bool pfn_in_hpage(struct page *hpage, unsigned long pfn)
+{
+ unsigned long hpage_pfn = page_to_pfn(hpage);
+
+ /* THP can be referenced by any subpage */
+ return pfn >= hpage_pfn && pfn - hpage_pfn < hpage_nr_pages(hpage);
+}
+
/**
* check_pte - check if @pvmw->page is mapped at the @pvmw->pte
*
@@ -78,14 +86,7 @@
pfn = pte_pfn(*pvmw->pte);
}
- if (pfn < page_to_pfn(pvmw->page))
- return false;
-
- /* THP can be referenced by any subpage */
- if (pfn - page_to_pfn(pvmw->page) >= hpage_nr_pages(pvmw->page))
- return false;
-
- return true;
+ return pfn_in_hpage(pvmw->page, pfn);
}
/**