From b20ce5e03b936be077463015661dcf52be274e5b Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Fri, 15 Jan 2016 16:54:37 -0800
Subject: mm: prepare page_referenced() and page_idle to new THP refcounting

Both page_referenced() and page_idle_clear_pte_refs_one() assume that
THP can only be mapped with PMD, so there's no reason to look on PTEs
for PageTransHuge() pages.  That's no true anymore: THP can be mapped
with PTEs too.

The patch removes PageTransHuge() test from the functions and opencode
page table check.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 include/linux/huge_mm.h |  5 -----
 include/linux/mm.h      | 23 ++++++++++++++---------
 2 files changed, 14 insertions(+), 14 deletions(-)

(limited to 'include/linux')

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 7aec5ee..72cd942 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -48,11 +48,6 @@ enum transparent_hugepage_flag {
 #endif
 };
 
-extern pmd_t *page_check_address_pmd(struct page *page,
-				     struct mm_struct *mm,
-				     unsigned long address,
-				     spinlock_t **ptl);
-
 #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
 #define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index aa8ae83..0ef5f21 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -433,20 +433,25 @@ static inline void page_mapcount_reset(struct page *page)
 	atomic_set(&(page)->_mapcount, -1);
 }
 
+int __page_mapcount(struct page *page);
+
 static inline int page_mapcount(struct page *page)
 {
-	int ret;
 	VM_BUG_ON_PAGE(PageSlab(page), page);
 
-	ret = atomic_read(&page->_mapcount) + 1;
-	if (PageCompound(page)) {
-		page = compound_head(page);
-		ret += atomic_read(compound_mapcount_ptr(page)) + 1;
-		if (PageDoubleMap(page))
-			ret--;
-	}
-	return ret;
+	if (unlikely(PageCompound(page)))
+		return __page_mapcount(page);
+	return atomic_read(&page->_mapcount) + 1;
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+int total_mapcount(struct page *page);
+#else
+static inline int total_mapcount(struct page *page)
+{
+	return page_mapcount(page);
 }
+#endif
 
 static inline int page_count(struct page *page)
 {
-- 
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