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DateSun, 06 Nov 2005 19:24:09 +1100
FromNick Piggin <>
Subject[patch 6/14] mm: microopt conditions
6/14

-- 
SUSE Labs, Novell Inc.

Micro optimise some conditionals where we don't need lazy evaluation.

Index: linux-2.6/mm/page_alloc.c
===================================================================
--- linux-2.6.orig/mm/page_alloc.c
+++ linux-2.6/mm/page_alloc.c
@@ -339,9 +339,9 @@ static inline void __free_pages_bulk (st
 
 static inline void free_pages_check(const char *function, struct page *page)
 {
-	if (	page_mapcount(page) ||
-		page->mapping != NULL ||
-		page_count(page) != 0 ||
+	if (unlikely(page_mapcount(page) |
+		(page->mapping != NULL)  |
+		(page_count(page) != 0)  |
 		(page->flags & (
 			1 << PG_lru	|
 			1 << PG_private |
@@ -351,7 +351,7 @@ static inline void free_pages_check(cons
 			1 << PG_slab	|
 			1 << PG_swapcache |
 			1 << PG_writeback |
-			1 << PG_reserved )))
+			1 << PG_reserved ))))
 		bad_page(function, page);
 	if (PageDirty(page))
 		__ClearPageDirty(page);
@@ -452,9 +452,9 @@ expand(struct zone *zone, struct page *p
  */
 static void prep_new_page(struct page *page, int order)
 {
-	if (	page_mapcount(page) ||
-		page->mapping != NULL ||
-		page_count(page) != 0 ||
+	if (unlikely(page_mapcount(page) |
+		(page->mapping != NULL)  |
+		(page_count(page) != 0)  |
 		(page->flags & (
 			1 << PG_lru	|
 			1 << PG_private	|
@@ -465,7 +465,7 @@ static void prep_new_page(struct page *p
 			1 << PG_slab    |
 			1 << PG_swapcache |
 			1 << PG_writeback |
-			1 << PG_reserved )))
+			1 << PG_reserved ))))
 		bad_page(__FUNCTION__, page);
 
 	page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
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