[PATCH 10/14] lru/swap: use per lruvec lock in release_pages

[Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>]

Replace pgdat lru_lock with lruvec lru_lock.

Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
Cc: Peng Fan <peng.fan@xxxxxxx>
Cc: Nikolay Borisov <nborisov@xxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 mm/swap.c | 40 +++++++++++++++++++++-------------------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 24a2b3456e10..798bffe7875d 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -724,8 +724,7 @@ void release_pages(struct page **pages, int nr)
 {
 	int i;
 	LIST_HEAD(pages_to_free);
-	struct pglist_data *locked_pgdat = NULL;
-	struct lruvec *lruvec;
+	struct lruvec *locked_lruvec = NULL;
 	unsigned long uninitialized_var(flags);
 	unsigned int uninitialized_var(lock_batch);
 
@@ -737,19 +736,19 @@ void release_pages(struct page **pages, int nr)
 		 * excessive with a continuous string of pages from the
 		 * same pgdat. The lock is held only if pgdat != NULL.
 		 */
-		if (locked_pgdat && ++lock_batch == SWAP_CLUSTER_MAX) {
-			spin_unlock_irqrestore(&locked_pgdat->lruvec.lru_lock, flags);
-			locked_pgdat = NULL;
+		if (locked_lruvec && ++lock_batch == SWAP_CLUSTER_MAX) {
+			spin_unlock_irqrestore(&locked_lruvec->lru_lock, flags);
+			locked_lruvec = NULL;
 		}
 
 		if (is_huge_zero_page(page))
 			continue;
 
 		if (is_zone_device_page(page)) {
-			if (locked_pgdat) {
-				spin_unlock_irqrestore(&locked_pgdat->lruvec.lru_lock,
+			if (locked_lruvec) {
+				spin_unlock_irqrestore(&locked_lruvec->lru_lock,
 						       flags);
-				locked_pgdat = NULL;
+				locked_lruvec = NULL;
 			}
 			/*
 			 * ZONE_DEVICE pages that return 'false' from
@@ -766,27 +765,30 @@ void release_pages(struct page **pages, int nr)
 			continue;
 
 		if (PageCompound(page)) {
-			if (locked_pgdat) {
-				spin_unlock_irqrestore(&locked_pgdat->lruvec.lru_lock, flags);
-				locked_pgdat = NULL;
+			if (locked_lruvec) {
+				spin_unlock_irqrestore(&locked_lruvec->lru_lock, flags);
+				locked_lruvec = NULL;
 			}
 			__put_compound_page(page);
 			continue;
 		}
 
 		if (PageLRU(page)) {
+			struct lruvec *lruvec;
 			struct pglist_data *pgdat = page_pgdat(page);
 
-			if (pgdat != locked_pgdat) {
-				if (locked_pgdat)
-					spin_unlock_irqrestore(&locked_pgdat->lruvec.lru_lock,
+			lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
+			if (lruvec != locked_lruvec) {
+				if (locked_lruvec)
+					spin_unlock_irqrestore(&locked_lruvec->lru_lock,
 									flags);
 				lock_batch = 0;
-				locked_pgdat = pgdat;
-				spin_lock_irqsave(&locked_pgdat->lruvec.lru_lock, flags);
+				locked_lruvec = lruvec;
+				spin_lock_irqsave(&locked_lruvec->lru_lock, flags);
+				sync_lruvec_pgdat(lruvec, pgdat);
 			}
 
-			lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
 			VM_BUG_ON_PAGE(!PageLRU(page), page);
 			__ClearPageLRU(page);
 			del_page_from_lru_list(page, lruvec, page_off_lru(page));
@@ -798,8 +800,8 @@ void release_pages(struct page **pages, int nr)
 
 		list_add(&page->lru, &pages_to_free);
 	}
-	if (locked_pgdat)
-		spin_unlock_irqrestore(&locked_pgdat->lruvec.lru_lock, flags);
+	if (locked_lruvec)
+		spin_unlock_irqrestore(&locked_lruvec->lru_lock, flags);
 
 	mem_cgroup_uncharge_list(&pages_to_free);
 	free_unref_page_list(&pages_to_free);
-- 
1.8.3.1