[PATCH 03/14] lru/memcg: using per lruvec lock in un/lock_page_lru

[Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>]

Now we repeatly assign the lruvec->pgdat in memcg. Will remove the
assignment in lruvec getting function after very points are protected.

Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 mm/memcontrol.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e8a1b0d95ba8..19fd911e8098 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2550,12 +2550,12 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
 static void lock_page_lru(struct page *page, int *isolated)
 {
 	pg_data_t *pgdat = page_pgdat(page);
+	struct lruvec *lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
-	spin_lock_irq(&pgdat->lruvec.lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
+	sync_lruvec_pgdat(lruvec, pgdat);
 	if (PageLRU(page)) {
-		struct lruvec *lruvec;
 
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 		ClearPageLRU(page);
 		del_page_from_lru_list(page, lruvec, page_lru(page));
 		*isolated = 1;
@@ -2566,16 +2566,14 @@ static void lock_page_lru(struct page *page, int *isolated)
 static void unlock_page_lru(struct page *page, int isolated)
 {
 	pg_data_t *pgdat = page_pgdat(page);
+	struct lruvec *lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 	if (isolated) {
-		struct lruvec *lruvec;
-
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 		VM_BUG_ON_PAGE(PageLRU(page), page);
 		SetPageLRU(page);
 		add_page_to_lru_list(page, lruvec, page_lru(page));
 	}
-	spin_unlock_irq(&pgdat->lruvec.lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 }
 
 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
-- 
1.8.3.1