[PATCH v21 10/19] mm/lru: move lock into lru_note_cost

[Alex Shi]

We have to move lru_lock into lru_note_cost, since it cycle up on memcg
tree, for future per lruvec lru_lock replace. It's a bit ugly and may
cost a bit more locking, but benefit from multiple memcg locking could
cover the lost.

Signed-off-by: Alex Shi <alex....@linux.alibaba.com>
Acked-by: Hugh Dickins <hu...@google.com>
Acked-by: Johannes Weiner <han...@cmpxchg.org>
Cc: Johannes Weiner <han...@cmpxchg.org>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: linux...@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/swap.c       | 3 +++
 mm/vmscan.c     | 4 +---
 mm/workingset.c | 2 --
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index ce8c97146e0d..2681d9023998 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -268,7 +268,9 @@ void lru_note_cost(struct lruvec *lruvec, bool file, 
unsigned int nr_pages)
 {
        do {
                unsigned long lrusize;
+               struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 
+               spin_lock_irq(&pgdat->lru_lock);
                /* Record cost event */
                if (file)
                        lruvec->file_cost += nr_pages;
@@ -292,6 +294,7 @@ void lru_note_cost(struct lruvec *lruvec, bool file, 
unsigned int nr_pages)
                        lruvec->file_cost /= 2;
                        lruvec->anon_cost /= 2;
                }
+               spin_unlock_irq(&pgdat->lru_lock);
        } while ((lruvec = parent_lruvec(lruvec)));
 }
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b9935668d121..d771f812e983 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1973,19 +1973,17 @@ static int current_may_throttle(void)
                                &stat, false);
 
        spin_lock_irq(&pgdat->lru_lock);
-
        move_pages_to_lru(lruvec, &page_list);
 
        __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
-       lru_note_cost(lruvec, file, stat.nr_pageout);
        item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
        if (!cgroup_reclaim(sc))
                __count_vm_events(item, nr_reclaimed);
        __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed);
        __count_vm_events(PGSTEAL_ANON + file, nr_reclaimed);
-
        spin_unlock_irq(&pgdat->lru_lock);
 
+       lru_note_cost(lruvec, file, stat.nr_pageout);
        mem_cgroup_uncharge_list(&page_list);
        free_unref_page_list(&page_list);
 
diff --git a/mm/workingset.c b/mm/workingset.c
index 130348cbf40a..a915a812c363 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -381,9 +381,7 @@ void workingset_refault(struct page *page, void *shadow)
        if (workingset) {
                SetPageWorkingset(page);
                /* XXX: Move to lru_cache_add() when it supports new vs putback 
*/
-               spin_lock_irq(&page_pgdat(page)->lru_lock);
                lru_note_cost_page(page);
-               spin_unlock_irq(&page_pgdat(page)->lru_lock);
                inc_lruvec_state(lruvec, WORKINGSET_RESTORE_BASE + file);
        }
 out:
-- 
1.8.3.1