[PATCH] mm: PageLRU can be non-atomic bit operation

Hisashi Hifumi
2007-04-23T10:55:24Z

Hi

PageLRU flag operation is protected by zone->lru_lock, so SetPageLRU/ClearPageLRU
can be replaced to __SetPageLRU/__ClearPageLRU non-atomic bit operation.

Thanks.

Signed-off-by :Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>

diff -Nrup linux-2.6.21-rc7.org/include/linux/page-flags.h
linux-2.6.21-rc7/include/linux/page-flags.h
--- linux-2.6.21-rc7.org/include/linux/page-flags.h 2007-04-17
16:36:05.000000000 +0900
+++ linux-2.6.21-rc7/include/linux/page-flags.h 2007-04-23
18:28:19.000000000 +0900
@@ -148,8 +148,7 @@ static inline void SetPageUptodate(struc
#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)

#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 __SetPageLRU(page) __set_bit(PG_lru, &(page)->flags)
#define __ClearPageLRU(page) __clear_bit(PG_lru, &(page)->flags)

#define PageActive(page) test_bit(PG_active, &(page)->flags)
diff -Nrup linux-2.6.21-rc7.org/mm/migrate.c linux-2.6.21-rc7/mm/migrate.c
--- linux-2.6.21-rc7.org/mm/migrate.c 2007-04-17 16:36:05.000000000 +0900
+++ linux-2.6.21-rc7/mm/migrate.c 2007-04-23 18:30:43.000000000 +0900
@@ -52,7 +52,7 @@ int isolate_lru_page(struct page *page,
if (PageLRU(page)) {
ret = 0;
get_page(page);
- ClearPageLRU(page);
+ __ClearPageLRU(page);
if (PageActive(page))
del_page_from_active_list(zone, page);
else
diff -Nrup linux-2.6.21-rc7.org/mm/swap.c linux-2.6.21-rc7/mm/swap.c
--- linux-2.6.21-rc7.org/mm/swap.c 2007-02-05 03:44:54.000000000 +0900
+++ linux-2.6.21-rc7/mm/swap.c 2007-04-23 18:29:51.000000000 +0900
@@ -364,7 +364,7 @@ void __pagevec_lru_add(struct pagevec *p
spin_lock_irq(&zone->lru_lock);
}
VM_BUG_ON(PageLRU(page));
- SetPageLRU(page);
+ __SetPageLRU(page);
add_page_to_inactive_list(zone, page);
}
if (zone)
@@ -391,7 +391,7 @@ void __pagevec_lru_add_active(struct pag
spin_lock_irq(&zone->lru_lock);
}
VM_BUG_ON(PageLRU(page));
- SetPageLRU(page);
+ __SetPageLRU(page);
VM_BUG_ON(PageActive(page));
SetPageActive(page);
add_page_to_active_list(zone, page);
diff -Nrup linux-2.6.21-rc7.org/mm/vmscan.c linux-2.6.21-rc7/mm/vmscan.c
--- linux-2.6.21-rc7.org/mm/vmscan.c 2007-04-17 16:36:05.000000000 +0900
+++ linux-2.6.21-rc7/mm/vmscan.c 2007-04-23 18:30:30.000000000 +0900
@@ -642,7 +642,7 @@ static unsigned long isolate_lru_pages(u
* sure the page is not being freed elsewhere -- the
* page release code relies on it.
*/
- ClearPageLRU(page);
+ __ClearPageLRU(page);
target = dst;
nr_taken++;
} /* else it is being freed elsewhere */
@@ -704,7 +704,7 @@ static unsigned long shrink_inactive_lis
while (!list_empty(&page_list)) {
page = lru_to_page(&page_list);
VM_BUG_ON(PageLRU(page));
- SetPageLRU(page);
+ __SetPageLRU(page);
list_del(&page->lru);
if (PageActive(page))
add_page_to_active_list(zone, page);
@@ -851,7 +851,7 @@ force_reclaim_mapped:
page = lru_to_page(&l_inactive);
prefetchw_prev_lru_page(page, &l_inactive, flags);
VM_BUG_ON(PageLRU(page));
- SetPageLRU(page);
+ __SetPageLRU(page);
VM_BUG_ON(!PageActive(page));
ClearPageActive(page);

@@ -881,7 +881,7 @@ force_reclaim_mapped:
page = lru_to_page(&l_active);
prefetchw_prev_lru_page(page, &l_active, flags);
VM_BUG_ON(PageLRU(page));
- SetPageLRU(page);
+ __SetPageLRU(page);
VM_BUG_ON(!PageActive(page));
list_move(&page->lru, &zone->active_list);
pgmoved++;