[PATCH v14 11/20] mm/lru: move lock into lru_note_cost

[Alex Shi]

This patch move lru_lock into lru_note_cost. It's a bit ugly and may
cost more locking, but it's necessary for later per pgdat lru_lock to
per memcg lru_lock change.

Signed-off-by: Alex Shi <alex....@linux.alibaba.com>
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   | 5 +++--
 mm/vmscan.c | 4 +---
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index b88ca630db70..c67699de4869 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -269,7 +269,9 @@ void lru_note_cost(struct lruvec *lruvec, bool file, 
unsigned int nr_pages)
 {
        do {
                unsigned long lrusize;
+               pglist_data *pgdat = lruvec_pgdat(lruvec);
 
+               spin_lock_irq(&pgdat->lru_lock);
                /* Record cost event */
                if (file)
                        lruvec->file_cost += nr_pages;
@@ -293,15 +295,14 @@ 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)));
 }
 
 void lru_note_cost_page(struct page *page)
 {
-       spin_lock_irq(&page_pgdat(page)->lru_lock);
        lru_note_cost(mem_cgroup_page_lruvec(page, page_pgdat(page)),
                      page_is_file_lru(page), hpage_nr_pages(page));
-       spin_unlock_irq(&page_pgdat(page)->lru_lock);
 }
 
 static void __activate_page(struct page *page, struct lruvec *lruvec)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index ddb29d813d77..c1c4259b4de5 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1976,19 +1976,17 @@ 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);
 
-- 
1.8.3.1