[PATCH] mm: slab less atomics

Atomic operation removal from slab
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/page-flags.h

@@ -250,10 +250,8 @@ extern void __mod_page_state_offset(unsigned long offset, unsigned long delta);
 #define __ClearPageActive(page)	__clear_bit(PG_active, &(page)->flags)
 
 #define PageSlab(page)		test_bit(PG_slab, &(page)->flags)
-#define SetPageSlab(page)	set_bit(PG_slab, &(page)->flags)
-#define ClearPageSlab(page)	clear_bit(PG_slab, &(page)->flags)
-#define TestClearPageSlab(page)	test_and_clear_bit(PG_slab, &(page)->flags)
-#define TestSetPageSlab(page)	test_and_set_bit(PG_slab, &(page)->flags)
+#define __SetPageSlab(page)	__set_bit(PG_slab, &(page)->flags)
+#define __ClearPageSlab(page)	__clear_bit(PG_slab, &(page)->flags)
 
 #ifdef CONFIG_HIGHMEM
 #define PageHighMem(page)	is_highmem(page_zone(page))

mm/slab.c

@@ -1402,7 +1402,7 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
 		atomic_add(i, &slab_reclaim_pages);
 	add_page_state(nr_slab, i);
 	while (i--) {
-		SetPageSlab(page);
+		__SetPageSlab(page);
 		page++;
 	}
 	return addr;
@@ -1418,8 +1418,8 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr)
 	const unsigned long nr_freed = i;
 
 	while (i--) {
-		if (!TestClearPageSlab(page))
-			BUG();
+		BUG_ON(!PageSlab(page));
+		__ClearPageSlab(page);
 		page++;
 	}
 	sub_page_state(nr_slab, nr_freed);