diff --git a/mm/vmscan.c b/mm/vmscan.c index 0ea71e887bb6e3fdf51d9b18ad56fe993423249d..64f9570cff568103c8031706322c0e78b8f93029 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -511,10 +511,11 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc) * PageDirty _after_ making sure that the page is freeable and * not in use by anybody. (pagecache + us == 2) */ - if (page_count(page) != 2 || PageDirty(page)) { - write_unlock_irq(&mapping->tree_lock); - goto keep_locked; - } + if (unlikely(page_count(page) != 2)) + goto cannot_free; + smp_rmb(); + if (unlikely(PageDirty(page))) + goto cannot_free; #ifdef CONFIG_SWAP if (PageSwapCache(page)) { @@ -538,6 +539,10 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc) __pagevec_release_nonlru(&freed_pvec); continue; +cannot_free: + write_unlock_irq(&mapping->tree_lock); + goto keep_locked; + activate_locked: SetPageActive(page); pgactivate++;