---
 include/linux/page-flags.h |   46 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 45 insertions(+), 1 deletion(-)

Index: linux-2.6/include/linux/page-flags.h
===================================================================
--- linux-2.6.orig/include/linux/page-flags.h	2008-02-17 21:11:40.000000000 -0800
+++ linux-2.6/include/linux/page-flags.h	2008-02-17 21:12:14.000000000 -0800
@@ -87,6 +87,20 @@ enum pageflags {
 	PG_reclaim,		/* To be reclaimed asap */
 	PG_buddy,		/* Page is free, on buddy lists */
 
+#ifdef CONFIG_EXTENDED_PAGE_FLAGS
+/*
+ * Page flags that are only available without sparsemem
+ * (sparsemem vmemmap is ok)
+ */
+
+	PG_mlock,		/* Page cannot be swapped out */
+	PG_pin,			/* Page cannot be moved in memory */
+	PG_tail,		/* Tail of a compound page */
+	PG_export,		/* Page is referenced directly from a driver */
+	PG_vcompound,		/* Compound page is virtually mapped */
+	PG_filebacked,		/* Page is backed by an actual disk (not RAM) */
+#endif
+
 #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
 	PG_uncached,		/* Page has been mapped as uncached */
 #endif
@@ -99,8 +113,14 @@ enum pageflags {
 #define FLAGS_IA64	0
 #endif
 
+#ifdef CONFIG_EXTENDED_BASE_FLAGS
+#define FLAGS_EXTENDED	6
+#else
+#define FLAGS_EXTENDED	0
+#endif
+
 #define FLAGS_NORMAL	18
-#define NR_PAGEFLAGS 	(FLAGS_NORMAL + FLAGS_IA64)
+#define NR_PAGEFLAGS 	(FLAGS_NORMAL + FLAGS_EXTENDED + FLAGS_IA64)
 
 struct page;	/* forward declaration */
 
@@ -253,6 +273,28 @@ static inline void set_page_writeback(st
 __PAGEFLAG(Compound, head)
 __PAGEFLAG(Head, head)
 
+#ifdef CONFIG_EXTENDED_PAGE_FLAGS
+
+__PAGEFLAG(Head, head)
+__PAGEFLAG(Tail, tail)
+__PAGEFLAG(Vcompound, vcompound)
+__PAGEFLAG(Mlock, mlock)
+__PAGEFLAG(Pin, pin)
+__PAGEFLAG(FileBacked, filebacked)
+__PAGEFLAG(Export, export)
+
+static inline int PageCompound(struct page *page)
+{
+	return (page->flags & ((1 << PG_tail) | (1 << PG_head))) != 0;
+}
+
+#else
+/*
+ * Fallback for sparsemem (not vmemmap) configurations that require
+ * the use of a lot of page flags. Could be removed if those
+ * sparsemem configuration are no longer used.
+ */
+
 /*
  * PG_reclaim is used in combination with PG_compound to mark the
  * head and tail of a compound page. This saved one page flag
@@ -285,4 +327,6 @@ static inline void __ClearPageTail(struc
  */
 __PAGEFLAG(Vcompound, dirty)
 
+#endif
+
 #endif	/* PAGE_FLAGS_H */