mm-prepare-page_referenced-and-page_idle-to-new-thp-refcounting-fix

x86_64 allnoconfig:

In file included from mm/rmap.c:47:
include/linux/mm.h: In function 'page_referenced':
include/linux/mm.h:448: error: call to '__compiletime_assert_448' declared with attribute error: BUILD_BUG failed
make[1]: *** [mm/rmap.o] Error 1
make: *** [mm/rmap.o] Error 2

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/mm.h

@@ -448,24 +448,14 @@ static inline int page_mapcount(struct page *page)
 	return ret;
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+int total_mapcount(struct page *page);
+#else
 static inline int total_mapcount(struct page *page)
 {
-	int i, ret;
-
-	VM_BUG_ON_PAGE(PageTail(page), page);
-
-	if (likely(!PageCompound(page)))
-		return atomic_read(&page->_mapcount) + 1;
-
-	ret = compound_mapcount(page);
-	if (PageHuge(page))
-		return ret;
-	for (i = 0; i < HPAGE_PMD_NR; i++)
-		ret += atomic_read(&page[i]._mapcount) + 1;
-	if (PageDoubleMap(page))
-		ret -= HPAGE_PMD_NR;
-	return ret;
+	return page_mapcount(page);
 }
+#endif
 
 static inline int page_count(struct page *page)
 {

mm/huge_memory.c

@@ -3216,6 +3216,25 @@ static void __split_huge_page(struct page *page, struct list_head *list)
 	}
 }
 
+int total_mapcount(struct page *page)
+{
+	int i, ret;
+
+	VM_BUG_ON_PAGE(PageTail(page), page);
+
+	if (likely(!PageCompound(page)))
+		return atomic_read(&page->_mapcount) + 1;
+
+	ret = compound_mapcount(page);
+	if (PageHuge(page))
+		return ret;
+	for (i = 0; i < HPAGE_PMD_NR; i++)
+		ret += atomic_read(&page[i]._mapcount) + 1;
+	if (PageDoubleMap(page))
+		ret -= HPAGE_PMD_NR;
+	return ret;
+}
+
 /*
  * This function splits huge page into normal pages. @page can point to any
  * subpage of huge page to split. Split doesn't change the position of @page.