[PATCH 12/14] lru/vmscan: use pre lruvec lock in check_move_unevictable_pages

[Alex Shi <alex.shi@linux.alibaba.com>]

to replace per pgdat lru_lock.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/vmscan.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index defc2c4778eb..123447b9beda 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4249,24 +4249,24 @@ int page_evictable(struct page *page)
  */
 void check_move_unevictable_pages(struct pagevec *pvec)
 {
-	struct lruvec *lruvec;
-	struct pglist_data *pgdat = NULL;
+	struct lruvec *locked_lruvec = NULL;
 	int pgscanned = 0;
 	int pgrescued = 0;
 	int i;
 
 	for (i = 0; i < pvec->nr; i++) {
 		struct page *page = pvec->pages[i];
-		struct pglist_data *pagepgdat = page_pgdat(page);
+		struct pglist_data *pgdat = page_pgdat(page);
+		struct lruvec *lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		pgscanned++;
-		if (pagepgdat != pgdat) {
-			if (pgdat)
-				spin_unlock_irq(&pgdat->lruvec.lru_lock);
-			pgdat = pagepgdat;
-			spin_lock_irq(&pgdat->lruvec.lru_lock);
+		if (lruvec != locked_lruvec) {
+			if (locked_lruvec)
+				spin_unlock_irq(&locked_lruvec->lru_lock);
+			locked_lruvec = lruvec;
+			spin_lock_irq(&lruvec->lru_lock);
+			sync_lruvec_pgdat(lruvec, pgdat);
 		}
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		if (!PageLRU(page) || !PageUnevictable(page))
 			continue;
@@ -4282,10 +4282,10 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 		}
 	}
 
-	if (pgdat) {
+	if (locked_lruvec) {
 		__count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued);
 		__count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned);
-		spin_unlock_irq(&pgdat->lruvec.lru_lock);
+		spin_unlock_irq(&locked_lruvec->lru_lock);
 	}
 }
 EXPORT_SYMBOL_GPL(check_move_unevictable_pages);
-- 
1.8.3.1