mm/swap.c: clear PageActive before adding pages onto unevictable list
As a result of commit 13f7f78981e4 ("mm: pagevec: defer deciding which
LRU to add a page to until pagevec drain time"), pages on unevictable
lists can have both of PageActive and PageUnevictable set. This is not
only confusing, but also corrupts page migration and
shrink_[in]active_list.
This patch fixes the problem by adding ClearPageActive before adding
pages into unevictable list. It also cleans up VM_BUG_ONs.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swap.c b/mm/swap.c
index 4a1d0d2..d3982c0 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -512,12 +512,7 @@
*/
void lru_cache_add(struct page *page)
{
- if (PageActive(page)) {
- VM_BUG_ON(PageUnevictable(page));
- } else if (PageUnevictable(page)) {
- VM_BUG_ON(PageActive(page));
- }
-
+ VM_BUG_ON(PageActive(page) && PageUnevictable(page));
VM_BUG_ON(PageLRU(page));
__lru_cache_add(page);
}
@@ -539,6 +534,7 @@
spin_lock_irq(&zone->lru_lock);
lruvec = mem_cgroup_page_lruvec(page, zone);
+ ClearPageActive(page);
SetPageUnevictable(page);
SetPageLRU(page);
add_page_to_lru_list(page, lruvec, LRU_UNEVICTABLE);
@@ -833,7 +829,6 @@
int active = PageActive(page);
enum lru_list lru = page_lru(page);
- VM_BUG_ON(PageUnevictable(page));
VM_BUG_ON(PageLRU(page));
SetPageLRU(page);