[PATCH] mm: less atomic ops

In the page release paths, we can be sure that nobody will mess with our
page->flags because the refcount has dropped to 0.  So no need for atomic
operations here.

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

3 files changed, 5 insertions, 3 deletions

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 8ac854f7f190..3b6723dfaff3 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -32,7 +32,7 @@ del_page_from_lru(struct zone *zone, struct page *page)
 {
         list_del(&page->lru);
         if (PageActive(page)) {
-                ClearPageActive(page);
+                __ClearPageActive(page);
                 zone->nr_active--;
         } else {
                 zone->nr_inactive--;
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 5d1e7bd85107..da71d63df465 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -242,10 +242,12 @@ extern void __mod_page_state_offset(unsigned long offset, unsigned long delta);
 #define PageLRU(page)           test_bit(PG_lru, &(page)->flags)
 #define SetPageLRU(page)        set_bit(PG_lru, &(page)->flags)
 #define ClearPageLRU(page)      clear_bit(PG_lru, &(page)->flags)
+#define __ClearPageLRU(page)    __clear_bit(PG_lru, &(page)->flags)
 
 #define PageActive(page)        test_bit(PG_active, &(page)->flags)
 #define SetPageActive(page)     set_bit(PG_active, &(page)->flags)
 #define ClearPageActive(page)   clear_bit(PG_active, &(page)->flags)
+#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)
diff --git a/mm/swap.c b/mm/swap.c
index cf88226cf96d..91b7e2026f69 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -215,7 +215,7 @@ void fastcall __page_cache_release(struct page *page)
 
                 spin_lock_irqsave(&zone->lru_lock, flags);
                 BUG_ON(!PageLRU(page));
-                ClearPageLRU(page);
+                __ClearPageLRU(page);
                 del_page_from_lru(zone, page);
                 spin_unlock_irqrestore(&zone->lru_lock, flags);
         }
@@ -266,7 +266,7 @@ void release_pages(struct page **pages, int nr, int cold)
                                 spin_lock_irq(&zone->lru_lock);
                         }
                         BUG_ON(!PageLRU(page));
-                        ClearPageLRU(page);
+                        __ClearPageLRU(page);
                         del_page_from_lru(zone, page);
                 }