memcg: move memcg reclaimable page into tail of inactive list

The rotate_reclaimable_page function moves just written out pages, which
the VM wanted to reclaim, to the end of the inactive list.  That way the
VM will find those pages first next time it needs to free memory.

This patch applies the rule in memcg.  It can help to prevent unnecessary
working page eviction of memcg.

Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 28 insertions, 1 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6ef5c53..9e0f05e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -829,6 +829,32 @@ void mem_cgroup_del_lru(struct page *page)
 	mem_cgroup_del_lru_list(page, page_lru(page));
 }
 
+/*
+ * Writeback is about to end against a page which has been marked for immediate
+ * reclaim.  If it still appears to be reclaimable, move it to the tail of the
+ * inactive list.
+ */
+void mem_cgroup_rotate_reclaimable_page(struct page *page)
+{
+	struct mem_cgroup_per_zone *mz;
+	struct page_cgroup *pc;
+	enum lru_list lru = page_lru(page);
+
+	if (mem_cgroup_disabled())
+		return;
+
+	pc = lookup_page_cgroup(page);
+	/* unused or root page is not rotated. */
+	if (!PageCgroupUsed(pc))
+		return;
+	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
+	smp_rmb();
+	if (mem_cgroup_is_root(pc->mem_cgroup))
+		return;
+	mz = page_cgroup_zoneinfo(pc);
+	list_move_tail(&pc->lru, &mz->lists[lru]);
+}
+
 void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
 {
 	struct mem_cgroup_per_zone *mz;
diff --git a/mm/swap.c b/mm/swap.c
index 4aea806..1b9e4eb 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -200,8 +200,9 @@ static void pagevec_move_tail(struct pagevec *pvec)
 			spin_lock(&zone->lru_lock);
 		}
 		if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
-			int lru = page_lru_base_type(page);
+			enum lru_list lru = page_lru_base_type(page);
 			list_move_tail(&page->lru, &zone->lru[lru].list);
+			mem_cgroup_rotate_reclaimable_page(page);
 			pgmoved++;
 		}
 	}