From: Nick Piggin PG_lru is protected by zone->lru_lock. It does not need TestSet/TestClear operations. Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton --- include/linux/page-flags.h | 5 ++--- mm/swap.c | 16 ++++++++-------- mm/vmscan.c | 20 +++++++++++--------- 3 files changed, 21 insertions(+), 20 deletions(-) diff -puN include/linux/page-flags.h~mm-pagelru-no-testset include/linux/page-flags.h --- devel/include/linux/page-flags.h~mm-pagelru-no-testset 2006-03-16 02:08:06.000000000 -0800 +++ devel-akpm/include/linux/page-flags.h 2006-03-16 02:08:06.000000000 -0800 @@ -239,10 +239,9 @@ extern void __mod_page_state_offset(unsi #define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags) #define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags) -#define SetPageLRU(page) set_bit(PG_lru, &(page)->flags) #define PageLRU(page) test_bit(PG_lru, &(page)->flags) -#define TestSetPageLRU(page) test_and_set_bit(PG_lru, &(page)->flags) -#define TestClearPageLRU(page) test_and_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) #define SetPageActive(page) set_bit(PG_active, &(page)->flags) diff -puN mm/swap.c~mm-pagelru-no-testset mm/swap.c --- devel/mm/swap.c~mm-pagelru-no-testset 2006-03-16 02:08:06.000000000 -0800 +++ devel-akpm/mm/swap.c 2006-03-16 02:08:06.000000000 -0800 @@ -214,8 +214,8 @@ void fastcall __page_cache_release(struc struct zone *zone = page_zone(page); spin_lock_irqsave(&zone->lru_lock, flags); - if (!TestClearPageLRU(page)) - BUG(); + BUG_ON(!PageLRU(page)); + ClearPageLRU(page); del_page_from_lru(zone, page); spin_unlock_irqrestore(&zone->lru_lock, flags); } @@ -265,8 +265,8 @@ void release_pages(struct page **pages, zone = pagezone; spin_lock_irq(&zone->lru_lock); } - if (!TestClearPageLRU(page)) - BUG(); + BUG_ON(!PageLRU(page)); + ClearPageLRU(page); del_page_from_lru(zone, page); } @@ -345,8 +345,8 @@ void __pagevec_lru_add(struct pagevec *p zone = pagezone; spin_lock_irq(&zone->lru_lock); } - if (TestSetPageLRU(page)) - BUG(); + BUG_ON(PageLRU(page)); + SetPageLRU(page); add_page_to_inactive_list(zone, page); } if (zone) @@ -372,8 +372,8 @@ void __pagevec_lru_add_active(struct pag zone = pagezone; spin_lock_irq(&zone->lru_lock); } - if (TestSetPageLRU(page)) - BUG(); + BUG_ON(PageLRU(page)); + SetPageLRU(page); if (TestSetPageActive(page)) BUG(); add_page_to_active_list(zone, page); diff -puN mm/vmscan.c~mm-pagelru-no-testset mm/vmscan.c --- devel/mm/vmscan.c~mm-pagelru-no-testset 2006-03-16 02:08:06.000000000 -0800 +++ devel-akpm/mm/vmscan.c 2006-03-16 02:08:06.000000000 -0800 @@ -1042,9 +1042,10 @@ int isolate_lru_page(struct page *page) if (PageLRU(page)) { struct zone *zone = page_zone(page); spin_lock_irq(&zone->lru_lock); - if (TestClearPageLRU(page)) { + if (PageLRU(page)) { ret = 1; get_page(page); + ClearPageLRU(page); if (PageActive(page)) del_page_from_active_list(zone, page); else @@ -1085,6 +1086,8 @@ static int isolate_lru_pages(int nr_to_s page = lru_to_page(src); prefetchw_prev_lru_page(page, src, flags); + BUG_ON(!PageLRU(page)); + list_del(&page->lru); if (unlikely(get_page_testone(page))) { /* @@ -1100,8 +1103,7 @@ static int isolate_lru_pages(int nr_to_s * the page is not being freed elsewhere -- the page release * code relies on it. */ - if (!TestClearPageLRU(page)) - BUG(); + ClearPageLRU(page); list_add(&page->lru, dst); nr_taken++; } @@ -1156,8 +1158,8 @@ static void shrink_cache(struct zone *zo */ while (!list_empty(&page_list)) { page = lru_to_page(&page_list); - if (TestSetPageLRU(page)) - BUG(); + BUG_ON(PageLRU(page)); + SetPageLRU(page); list_del(&page->lru); if (PageActive(page)) add_page_to_active_list(zone, page); @@ -1276,8 +1278,8 @@ refill_inactive_zone(struct zone *zone, while (!list_empty(&l_inactive)) { page = lru_to_page(&l_inactive); prefetchw_prev_lru_page(page, &l_inactive, flags); - if (TestSetPageLRU(page)) - BUG(); + BUG_ON(PageLRU(page)); + SetPageLRU(page); if (!TestClearPageActive(page)) BUG(); list_move(&page->lru, &zone->inactive_list); @@ -1305,8 +1307,8 @@ refill_inactive_zone(struct zone *zone, while (!list_empty(&l_active)) { page = lru_to_page(&l_active); prefetchw_prev_lru_page(page, &l_active, flags); - if (TestSetPageLRU(page)) - BUG(); + BUG_ON(PageLRU(page)); + SetPageLRU(page); BUG_ON(!PageActive(page)); list_move(&page->lru, &zone->active_list); pgmoved++; _