From b3ebc513d9ef54ff6e6e92ac94c4d05b7b060ec1 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill@shutemov.name>
Date: Thu, 19 Nov 2015 10:48:26 +1100
Subject: [PATCH] 
 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 | 20 +++++---------------
 mm/huge_memory.c   | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 91c3f0887d58d0..53e9f4b4f5221b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -433,24 +433,14 @@ 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)
 {
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b071974686fd2d..b41793b12a2dd8 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3223,6 +3223,25 @@ 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.