[PATCH 2/5] Breakout page_order() to internal.h to avoid special knowledge of the buddy allocator

[Mel Gorman]

The statistics patch later needs to know what order a free page is on the
free lists. Rather than having special knowledge of page_private() when
PageBuddy() is set, this patch places out page_order() in internal.h and
adds a VM_BUG_ON to catch using it on non-PageBuddy pages.

Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>
Acked-by: Andy Whitcroft <apw@xxxxxxxxxxxx>
---

 internal.h   |   10 ++++++++++
 page_alloc.c |   10 ----------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.22-rc2-mm1-001_fix_movefreepages/mm/internal.h linux-2.6.22-rc2-mm1-002_breakout_pageorder/mm/internal.h
--- linux-2.6.22-rc2-mm1-001_fix_movefreepages/mm/internal.h	2007-05-19 05:06:17.000000000 +0100
+++ linux-2.6.22-rc2-mm1-002_breakout_pageorder/mm/internal.h	2007-05-24 16:41:31.000000000 +0100
@@ -37,4 +37,14 @@ static inline void __put_page(struct pag
 extern void fastcall __init __free_pages_bootmem(struct page *page,
 						unsigned int order);
 
+/*
+ * function for dealing with page's order in buddy system.
+ * zone->lock is already acquired when we use these.
+ * So, we don't need atomic page->flags operations here.
+ */
+static inline unsigned long page_order(struct page *page)
+{
+	VM_BUG_ON(!PageBuddy(page));
+	return page_private(page);
+}
 #endif
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.22-rc2-mm1-001_fix_movefreepages/mm/page_alloc.c linux-2.6.22-rc2-mm1-002_breakout_pageorder/mm/page_alloc.c
--- linux-2.6.22-rc2-mm1-001_fix_movefreepages/mm/page_alloc.c	2007-05-24 16:37:27.000000000 +0100
+++ linux-2.6.22-rc2-mm1-002_breakout_pageorder/mm/page_alloc.c	2007-05-24 16:41:31.000000000 +0100
@@ -336,16 +336,6 @@ static inline void prep_zero_page(struct
 		clear_highpage(page + i);
 }
 
-/*
- * function for dealing with page's order in buddy system.
- * zone->lock is already acquired when we use these.
- * So, we don't need atomic page->flags operations here.
- */
-static inline unsigned long page_order(struct page *page)
-{
-	return page_private(page);
-}
-
 static inline void set_page_order(struct page *page, int order)
 {
 	set_page_private(page, order);
-
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