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

[Alex Shi]

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....@linux.alibaba.com>
Cc: Johannes Weiner <han...@cmpxchg.org>
Cc: Michal Hocko <mho...@kernel.org>
Cc: Vladimir Davydov <vdavydov....@gmail.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Tejun Heo <t...@kernel.org>
Cc: cgro...@vger.kernel.org
Cc: linux...@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 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